Macular ganglion cell-inner plexiform layer: automated detection and thickness reproducibility with spectral domain-optical coherence tomography in glaucoma

A Combined Index of Steady-State Pattern Electroretinogram and Optical Coherence Tomography Improved the Detection of Early Glaucoma

INTRODUCTION

The aims of the study were to evaluate the structure-function relationship between steady-state pattern electroretinogram (ssPERG), optical coherence tomography (OCT), and visual field (VF) tests and to investigate indicators that enhance the detection of preperimetric and early-stage primary open-angle glaucoma (POAG).

METHODS

In this retrospective cohort study, patients with POAG and normal subjects who underwent ssPERG, OCT, and VF tests were included. We defined the ratio of the amplitudes from 0.8° checks to 16° checks as the pattern electroretinogram ratio (PERGratio). The thickness of the macular ganglion cell inner plexiform layer and the circumpapillary retinal nerve fiber layer (cpRNFL) were measured using spectral-domain OCT. We compared the areas under the receiver operating characteristic curves (AUCs) for ssPERG, OCT, and VF test parameters. A combined index using structural and functional measures was generated using logistic regression models to improve diagnostic accuracy.

RESULTS

Four parameters had AUCs higher than 0.8; PERGratio (AUC = 0.890), average cpRNFL thickness (AUC = 0.827), 7 o'clock cpRNFL thickness (AUC = 0.844), and inferior quadrant cpRNFL thickness (AUC = 0.830). The new index, which combines the PERGratio and 7 o'clock cpRNFL thickness, significantly improved diagnostic accuracy (AUC = 0.951), outperforming the best four parameters (all p ≤ 0.004). Furthermore, the combined index of PERGratio and 7 o'clock cpRNFL thickness showed significantly higher diagnostic accuracy compared to those combining the 7 o'clock cpRNFL thickness with VF mean deviation, pattern standard deviation, and VF index.

CONCLUSION

The combined index of ssPERG, indicative of retinal ganglion cell dysfunction, and the OCT test, indicative of focal structural damage, improved the detection of patients with POAG in its early stage.

Structural and Vascular Features of Macula Related to the Recurrence of Macular Edema in Central Retinal Vein Occlusion After Anti-VEGF Therapy

Purpose: To identify the structural and vascular features of the macula related to the recurrence of macular edema (ME) in central retinal vein occlusion (CRVO) after intravitreal anti-VEGF injections. Methods: This was a cross-sectional study including CRVO patients without ME and age-matched individuals. CRVO patients were divided into the ME-resolved group and the ME-recurrence group on the basis of whether ME recurred within 3 months. All subjects provided a detailed history and underwent a comprehensive ophthalmological examination. Measurements of the macula by swept-source optical coherence tomography angiography (SS-OCTA) were recorded. We also created the Δparameter, which represents the difference in OCTA parameters between CRVO-affected eyes and their fellow eyes. Results: The study included 13 ME-resolved CRVO patients, 20 ME-recurrence CRVO patients, and 24 age-matched controls. Compared with the ME-recurrence group, the ME-resolved group had a longer CRVO duration, more previous intravitreal anti-VEGF injections, and a higher proportion of previous retinal photocoagulation (all p < 0.05). Additionally, retinal thickness (RT) and choroidal thickness (CT) were thinner in the ME-resolved group than in the ME-recurrence and control groups (all p < 0.01). The ME-resolved group also had significantly lower vessel density (VD) in both superficial and deep vascular complexes (SVC/DVC) and larger foveal avascular zone area (FAZa) in SVC and DVC than the ME-recurrence group and the control group (all p < 0.01). The results were the same with the Δparameters. Multivariate logistic regression revealed that ΔVD and ΔFAZa in SVC and DVC were independently associated with ME recurrence after adjusting for the effects of CRVO duration, previous anti-VEGF injections, and retinal photocoagulation (all p < 0.05). Conclusion: With prolonged CRVO duration, more anti-VEGF injections, and more retinal photocoagulation procedures, retinal, choroidal, and vascular atrophy in the macula occurs in CRVO eyes, making ME less likely to recur. Macular vascular atrophy is vital for the resolution of ME and might be a manifestation of capillary remodeling.

Quantifying the spatial patterns of retinal ganglion cell loss and progression in optic neuropathy by applying a deep learning variational autoencoder approach to optical coherence tomography

Introduction

Glaucoma, optic neuritis (ON), and non-arteritic anterior ischemic optic neuropathy (NAION) produce distinct patterns of retinal ganglion cell (RGC) damage. We propose a booster Variational Autoencoder (bVAE) to capture spatial variations in RGC loss and generate latent space (LS) montage maps that visualize different degrees and spatial patterns of optic nerve bundle injury. Furthermore, the bVAE model is capable of tracking the spatial pattern of RGC thinning over time and classifying the underlying cause.

Methods

The bVAE model consists of an encoder, a display decoder, and a booster decoder. The encoder decomposes input ganglion cell layer (GCL) thickness maps into two display latent variables (dLVs) and eight booster latent variables (bLVs). The dLVs capture primary spatial patterns of RGC thinning, while the display decoder reconstructs the GCL map and creates the LS montage map. The bLVs add finer spatial details, improving reconstruction accuracy. XGBoost was used to analyze the dLVs and bLVs, estimating normal/abnormal GCL thinning and classifying diseases (glaucoma, ON, and NAION). A total of 10,701 OCT macular scans from 822 subjects were included in this study.

Results

Incorporating bLVs improved reconstruction accuracy, with the image-based root-mean-square error (RMSE) between input and reconstructed GCL thickness maps decreasing from 5.55 ± 2.29 µm (two dLVs only) to 4.02 ± 1.61 µm (two dLVs and eight bLVs). However, the image-based structural similarity index (SSIM) remained similar (0.91 ± 0.04), indicating that just two dLVs effectively capture the main GCL spatial patterns. For classification, the XGBoost model achieved an AUC of 0.98 for identifying abnormal spatial patterns of GCL thinning over time using the dLVs. Disease classification yielded AUCs of 0.95 for glaucoma, 0.84 for ON, and 0.93 for NAION, with bLVs further increasing the AUCs to 0.96 for glaucoma, 0.93 for ON, and 0.99 for NAION.

Conclusion

This study presents a novel approach to visualizing and quantifying GCL thinning patterns in optic neuropathies using the bVAE model. The combination of dLVs and bLVs enhances the model's ability to capture key spatial features and predict disease progression. Future work will focus on integrating additional image modalities to further refine the model's diagnostic capabilities.

Physiological change in ganglion cell inner plexiform layer and nerve fibre layer thickness over six years

BACKGROUND

To evaluate the 6-year physiological rates-of-change in ganglion cell inner plexiform layer (GCIPL) and retinal nerve fibre layer (RNFL) thickness measured with optical coherence tomography.

METHODS

We included 2202 out of 2661 subjects from the population-based Singapore Chinese Eye Study who returned for follow-up 6 years after baseline examination (follow-up rate 87.7%). OCT scans with signal strength (SS) <6, imaging errors, and ocular pathologies were excluded. A linear mixed model was used to measure the rates-of-change in GCIPL and RNFL thickness. Time and difference between baseline and follow-up scan SS were modelled as fixed effect. Baseline age, baseline measurement, gender, hypertensive medication, diabetes status, cardiovascular disease, smoking status, body mass index, spherical equivalent (SE), intraocular pressure and optic disc area were each analysed in an interaction term with time.

RESULTS

The adjusted mean rate-of-change in average GCIPL was -0.312 μm/year in males and -0.235 μm/year in females. Older age and thicker GCIPL thickness at baseline were associated with higher rates-of-change while females and more hyperopic SE were associated with lower rates-of-change. The adjusted mean rate-of-change in average RNFL was -0.374 μm, with higher rates-of-change in the vertical quadrants and no differences between genders. Older age and thicker RNFL thickness at baseline were associated with higher rates-of-change in average RNFL and RNFL thickness in the vertical quadrants, and vice versa for each unit increase in scan SS and SE.

CONCLUSION

Our population cohort provides data on physiological thinning of GCIPL and RNFL with age. Differentiating physiological changes in GCIPL and RNFL is important for more accurate clinical assessment.

Retinal thickness predicts the risk of cognitive decline over five years

BACKGROUND

Dementia poses a significant burden on healthcare systems. Early identification of individuals at risk for cognitive decline is crucial. The retina, an extension of the central nervous system, reflects neurodegenerative changes. Optical coherence tomography (OCT) is a non-invasive tool for assessing retinal health and has shown promise in predicting cognitive decline. However, prior studies produced mixed results.

METHODS

This study investigated a large cohort (n = 490) of Asian individuals attending memory clinics. Participants underwent comprehensive neuropsychological testing annually for five years. Retinal thickness was measured by OCT at baseline. We assessed the association between baseline retinal thickness and subsequent cognitive decline.

RESULTS

Participants with a significantly thinner macular ganglion cell-inner plexiform layer (GCIPL) at baseline (≤ 79 μm) had a 38% greater risk of cognitive decline compared to those who did not (≥ 88 μm; p = 0.037). In a multivariable model accounting for age, education, cerebrovascular disease status, hypertension, hyperlipidemia, diabetes and smoking, thinner GCIPL was associated with an increased risk of cognitive decline (hazard ratio = 1.14, 95% CI = 1.01-1.30, p = 0.035). Retinal nerve fiber layer (RNFL) thickness was not associated with cognitive decline.

CONCLUSIONS

This study suggests that OCT-derived macular GCIPL thickness may be a valuable biomarker for identifying individuals at risk of cognitive decline. Our findings highlight GCIPL as a potentially more sensitive marker compared to RNFL thickness for detecting early neurodegenerative changes.

TRIAL REGISTRATION NUMBER AND NAME OF THE TRIAL REGISTRY

National Healthcare Group Domain-Specific Review Board (NHG DSRB) reference numbers DSRB Ref: 2018/01368. Name of the trial: Harmonisation project.

Dyslipidemia and reduced retinal layer thicknesses in mild to moderate non-proliferative diabetic retinopathy

OBJECTIVE

To investigate the changes in ganglion cell layer-inner plexiform layer (GCL-IPL) thickness and its association with peripheral blood indices in non-proliferative diabetic retinopathy (NPDR).

METHODS

In this cross-sectional study, 132 participants were categorized into three groups: 30 healthy volunteers (control group), 50 diabetic patients with non-diabetic retinopathy (NDR group), and 52 patients with NPDR. Optical coherence tomography (OCT) was used to measure the retinal nerve fiber layer (RNFL) and GCL-IPL thicknesses in the macula. The associations between RNFL loss and systemic risk factors for DR, such as diabetes duration, triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and hemoglobin A1c (HbA1c) were evaluated.

RESULTS

The average, superior, and nasal thicknesses in the NDR and NPDR groups were significantly thinner compared to the control group (P=0.002, 0.020, 0.090, respectively). Similarly, GCL-IPL thicknesses in the 3 mm and 6 mm zones of the NDR and NPDR groups were thinner than those in the control group (P=0.040, 0.022, 0.037, respectively). Temporal thicknesses in the 3 mm range of the NDR and NPDR groups were also thinner than in the control group (P=0.010). Superior RNFL thickness was positively correlated with HbA1c (r=0.200, P=0.044), and negatively correlated with HDL (r=-0.198, P=0.047). The average inferior and nasal GCL-IPL thicknesses were negatively correlated with TC across the 3 mm zone (r=-0.211, P=0.033; r=-0.224, P=0.023; r=-0.227, P=0.022). Additionally, the average thickness of GCL-IPL in the 6-mm range were positively correlated with the duration of diabetes (r=0.196, P=0.048).

CONCLUSION

This study demonstrates that dyslipidemia in diabetic patients correlates with reductions in RNFL and GCL-IPL thicknesses, suggesting a role in the pathogenesis of diabetic retinopathy.

A parafoveal retinal cones analysis using adaptive-optics retinal camera in patients with primary open angle glaucoma

OBJECTIVES

To study the density, spacing, and regularity of retinal cone photoreceptors using an Adaptive Optics (AO) retinal camera (Rtx1TM, Imagine Eyes, Orsay, France) in patients with Primary Open Angle Glaucoma (POAG) and to compare the outcomes with those of healthy age-matched control subjects.

METHODS

The study included 43 eyes with POAG and 31 eyes of normal subjects. POAG patients were divided into three groups according to the severity of the visual field defect. The AO Rtx1TM was used to obtain images of the parafoveal cone mosaic to calculate cone values. Analysis was performed at two and four degrees of eccentricity from the fovea along the four meridians (nasal, temporal, superior, inferior).

RESULTS

In POAG eyes, the mean ± standard deviation (SD) cone density at 2° considering all meridians was significantly lower than in normal controls (23,058.6 ± 3532.0 cones/mm2, and 25,511.7 ± 3157.5 cones/mm2, respectively; p = 0.003). Cone spacing was 7.3 ± 0.5 µm in POAG and 7.0 ± 0.4 µm in normal controls (p = 0.005), and cone regularity was 90.5 ± 4.9% and 93.5 ± 1.9% in POAG and normal controls, respectively (p < 0.001). At 4° similar trends were observed. However, no significant differences were found among patients with different severity of POAG (p > 0.05).

CONCLUSIONS

Using AO Rtx1TM, significant differences in retinal photoreceptors mosaic pattern were found between POAG eyes and age-matched controls, indicating a reduction in photoreceptors in POAG. No significant differences in retinal photoreceptor values were found among the three POAG groups.

The thickness of the retinal nerve fiber layer, macula, and ganglion cell-inner plexiform layer in people with drug-resistant epilepsy

OBJECTIVE

Using Optical coherence tomography (OCT), we evaluated the association between peripapillary retinal nerve fiber, macular thickness, macular ganglion cell-inner plexiform layer, and drug resistance.

METHODS

In this cross-sectional study, we recruited people diagnosed with epilepsy and healthy controls. People with epilepsy were further stratified as drug-resistant or non-drug-resistant based on their response to anti-seizure medications. OCT measurements were conducted, and findings in right eye were analyzed.

RESULTS

Fifty-one drug-resistant participants, 37 non-drug-resistant, and 45 controls were enrolled. The average peripapillary retinal nerve fiber layer, ganglion cell-inner plexiform layer, and macular thickness were thinner in the epilepsy groups than in controls. The drug-resistant group had significantly lower average ganglion cell-inner plexiform layer thickness (p = 0.004) and a higher proportion of abnormal/borderline GC/IPL thickness (p = 5.40E-04) than the non-drug-resistant group. Nevertheless, no significant differences were seen between the average thickness of peripapillary retinal nerve fiber and macular thickness. The temporal sectors of these three parameters were also significantly thinner in the drug-resistant group than in the non-drug-resistant. In a multivariate regression model, drug resistance was an independent predictor of reduced ganglion cell-inner plexiform thickness (Odds ratios OR = 10.25, 95% CI 2.82 to 37.28). Increased seizure frequency (r = -0.23, p = 0.039) and a higher number of anti-seizure medications ever used (r = -0.27, p = 0.013) were negatively associated with ganglion cell-inner plexiform layer thickness.

SIGNIFICANCE

Individuals with drug-resistant epilepsy had a consistent reduction in average ganglion cell-inner plexiform layer thickness and the temporal sector of peripapillary retinal nerve fiber layer and macular thickness. This suggests that ganglion cell-inner plexiform layer thickness could potentially serve as an indicator of the burden of drug resistance, as it correlated with reduced thickness in individuals having more frequent seizures and greater exposure to ASMs.

PLAIN LANGUAGE SUMMARY

In our study, we used a special tool called OCT to measure how thick the retina is in people with epilepsy and in healthy control. We found that the retina was consistently thinner in all areas for those with epilepsy compared to healthy control. Particularly, a specific layer called the ganglion cell-inner plexiform layer was a lot thinner in the group that didn't respond to medications, and this thinning was related to how often seizures occurred and how much medications were taken. Also, certain parts of the retina were thinner in the drug-resistant group.

Understanding Patterns of Preserved Retinal Ganglion Cell Layer in Advanced Glaucoma as Seen With Optical Coherence Tomography

PRCIS

Using optical coherence tomography (OCT), eyes with advanced glaucoma were found to have a wide range of patterns of damage that were consistent with the natural history of progression based on a model of macular progression.

PURPOSE

To understand the patterns of preserved retinal ganglion cells in eyes with advanced glaucoma using OCT and a model of progression of the central macula.

METHODS

OCT GCL thickness was measured in 94 eyes with advanced glaucoma, defined as glaucomatous eyes with a 24-2 MD (mean deviation) worse than -12 dB. A commercial report supplied the GCL thickness in 6 sectors of the thick, donut-shaped GCL region around the fovea. For each eye, the 6 sectors were coded as green (within normal limits, WNL), yellow (≤5th, ≥1st percentile), or red (<1st percentile).

RESULTS

In all 94 eyes, one or more of the 6 sectors of the donut were abnormal (red or yellow), while all 6 sectors were red in 52 (55%) of the eyes. On the other hand, 33 eyes had one or more sectors WNL (green). While the pattern of donut damage varied widely across these 33 eyes, 61 of the 66 hemiretinas were consistent with a temporal-to-nasal progression of damage within each hemiretina as predicted by our model.

CONCLUSIONS

All eyes with advanced glaucoma had damage to the critically important central, donut-shaped GCL region. This region showed a wide range of patterns of damage, but these patterns were consistent with the natural history of progression based on a model of macular progression. These results have implications for the clinical identification of macular progression, as well as for inclusion criteria for clinical trials seeking to preserve central macular function.

Hybrid deep learning and optimal graph search method for optical coherence tomography layer segmentation in diseases affecting the optic nerve

Accurate segmentation of retinal layers in optical coherence tomography (OCT) images is critical for assessing diseases that affect the optic nerve, but existing automated algorithms often fail when pathology causes irregular layer topology, such as extreme thinning of the ganglion cell-inner plexiform layer (GCIPL). Deep LOGISMOS, a hybrid approach that combines the strengths of deep learning and 3D graph search to overcome their limitations, was developed to improve the accuracy, robustness and generalizability of retinal layer segmentation. The method was trained on 124 OCT volumes from both eyes of 31 non-arteritic anterior ischemic optic neuropathy (NAION) patients and tested on three cross-sectional datasets with available reference tracings: Test-NAION (40 volumes from both eyes of 20 NAION subjects), Test-G (29 volumes from 29 glaucoma subjects/eyes), and Test-JHU (35 volumes from 21 multiple sclerosis and 14 control subjects/eyes) and one longitudinal dataset without reference tracings: Test-G-L (155 volumes from 15 glaucoma patients/eyes). In the three test datasets with reference tracings (Test-NAION, Test-G, and Test-JHU), Deep LOGISMOS achieved very high Dice similarity coefficients (%) on GCIPL: 89.97±3.59, 90.63±2.56, and 94.06±1.76, respectively. In the same context, Deep LOGISMOS outperformed the Iowa reference algorithms by improving the Dice score by 17.5, 5.4, and 7.5, and also surpassed the deep learning framework nnU-Net with improvements of 4.4, 3.7, and 1.0. For the 15 severe glaucoma eyes with marked GCIPL thinning (Test-G-L), it demonstrated reliable regional GCIPL thickness measurement over five years. The proposed Deep LOGISMOS approach has potential to enhance precise quantification of retinal structures, aiding diagnosis and treatment management of optic nerve diseases.

Degradation of Photopic and Mesopic Contrast Sensitivity Function in High Myopes With Partial Posterior Vitreous Detachment

Purpose

The purpose of this study was to evaluate the effects of posterior vitreous detachment (PVD) on visual quality in patients with high myopia, as well as investigate the associated factors of photopic and mesopic contrast sensitivity function (CSF) in high myopia.

Methods

Visual quality was comprehensively assessed in patients with high myopia. Visual acuity, contrast sensitivity (CS) at four spatial frequencies (3, 6, 12, and 18 cycles per degree [c.p.d.]) under photopic and mesopic conditions, as well as the modulation transfer function cutoff value (MTFcutoff), the objective scatter index (OSI), the Strehl ratio (SR), and internal aberrations, were measured in this cross-sectional study.

Results

This study included 94 eyes from 47 subjects with bilateral high myopia, including 23 eyes with complete PVD (cPVD), 21 eyes with partial PVD (pPVD), and 50 eyes without PVD (nPVD). There was no significant difference in visual quality between the cPVD group and the nPVD group. Whereas in eyes with pPVD, there was a degradation of overall photopic CSF (versus nPVD, P = 0.048), photopic CS at 3 c.p.d. (versus cPVD, P = 0.009 and versus nPVD, P = 0.032), photopic CS at 18 c.p.d. (versus nPVD, P = 0.033), overall mesopic CSF (versus nPVD, P = 0.033), and secondary astigmatism (versus cPVD, P = 0.044). Under photopic conditions, the factors affecting CSF were pPVD and SR, whereas the factors affecting mesopic CSF were pPVD, OSI, and ganglion cell-inner plexiform layer thickness.

Conclusions

The pPVD impaired visual quality in patients with high myopia compared to nPVD or cPVD, and pPVD could be a factor explaining CSF at both photopic and mesopic illumination.

Translational Relevance

Clinicians need to closely monitor patients with high myopia with pPVD due to the potential decline in visual quality and the development of vitreoretinal disorders.

Aging-associated changes of optical coherence tomography-measured ganglion cell-related retinal layer thickness and visual sensitivity in normal Japanese

PURPOSE

To report aging-associated change rates in circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell-inner plexiform layer and complex thickness (MGCIPLT, MGCCT) in normal Japanese eyes and to compare the data in linear scaled visual field (VF) sensitivity of central 4 points of Humphrey Field Analyzer (HFA) 24-2 test (VF4TestPoints) to that in MGCIPLT in four 0.6-mm-diameter circles corresponding to the four central points of HFA 24-2 adjusted for retinal ganglion cell displacement (GCIPLT4TestPoints).

STUDY DESIGN

Prospective observational study METHODS: HFA 24-2 tests and spectral-domain optical coherence tomography (SD-OCT) measurements of cpRNFLT, MGCIPLT, MGCCT and GCIPLT4TestPoints were performed every 3 months for 3 years in 73 eyes of 37 healthy Japanese with mean age of 50.4 years. The time changes of SD-OCT-measured parameters and VF4TestPoints were analyzed using a linear mixed model.

RESULTS

The aging-associated change rates were -0.064 μm/year for MGCIPLT and and -0.095 for MGCCT (P=0.020 and 0.017), but could not be detected for cpRNFLT. They accelerated with aging at -0.009μm/year/year of age for MGCIPLT (P<0.001), at 0.011 for MGCCT (P<0.001) and at 0.013 for cpRNFLT(0.031). The aging-associated decline of -82.1 [1/Lambert]/year of VF4TestPoints corresponded to -0.095 μm/year of GCIPLT4TestPoints.

CONCLUSION

We report that aging-associated change rates of cpRNFLT, MGCIPLT and MGCCT in normal Japanese eyes were found to be significantly accelerated along with aging. Relationship between VF sensitivity decline rates and SD-OCT measured GCIPLT decline rates during physiological aging in the corresponding parafoveal retinal areas are also documented.

Correlation of peripapillary retinal nerve fiber layer and macular ganglion cell-inner plexiform layer in early to moderate glaucoma using the Cirrus ® widefield analysis (PanoMap ® )

PURPOSE

To evaluate and correlate the structural changes between peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer (GCL) + inner plexiform layer (IPL) in different stages of glaucoma using PanoMap ® optical coherence tomography (OCT).

DESIGN

Retrospective observational study.

METHODS

Glaucoma diagnostic test data were collected from early to moderate open-angle glaucoma patients. The average and minimum GCL + IPL thickness, sectoral GCL + IPL thickness, and the average and sectoral RNFL thickness were correlated with the different glaucoma stages.

RESULTS

This study included 157 eyes from 157 glaucoma patients. Patients were grouped into pre-perimetric, early, and moderate glaucoma. The mean average RNFL thickness, RNFL thickness per sector, average GCL + IPL thickness, and minimum GCL + IPL thickness were different between the three groups ( P < 0.001), except for the nasal sector ( P = 0.643). The mean GCL + IPL thickness in all six sectors showed differences between the groups ( P < 0.001), except the superonasal sector ( P < 0.002). The inferior GCL + IPL sector is the thinnest, followed by the inferotemporal sector. There was a strong correlation between the mean average RNFL and the average GCL + IPL thickness in the pre-perimetric group ( r = 0.4963, P < 0.001) and the moderate group ( r = 0.6534, P < 0.001). The early glaucoma group did not show significant correlation ( r = 0.2963, P = 0.0536).

CONCLUSION

Peripapillary RNFL and macular GCL + IPL thinning was evident in different stages of glaucoma, with more thinning observed with increasing glaucoma severity. The peripapillary RNFL and macular GCL + IPL average thickness values were highly correlated in the pre-perimetric and moderate stages of glaucoma.

Early inner plexiform layer thinning and retinal nerve fiber layer thickening in excitotoxic retinal injury using deep learning-assisted optical coherence tomography

Excitotoxicity from the impairment of glutamate uptake constitutes an important mechanism in neurodegenerative diseases such as Alzheimer's, multiple sclerosis, and Parkinson's disease. Within the eye, excitotoxicity is thought to play a critical role in retinal ganglion cell death in glaucoma, diabetic retinopathy, retinal ischemia, and optic nerve injury, yet how excitotoxic injury impacts different retinal layers is not well understood. Here, we investigated the longitudinal effects of N-methyl-D-aspartate (NMDA)-induced excitotoxic retinal injury in a rat model using deep learning-assisted retinal layer thickness estimation. Before and after unilateral intravitreal NMDA injection in nine adult Long Evans rats, spectral-domain optical coherence tomography (OCT) was used to acquire volumetric retinal images in both eyes over 4 weeks. Ten retinal layers were automatically segmented from the OCT data using our deep learning-based algorithm. Retinal degeneration was evaluated using layer-specific retinal thickness changes at each time point (before, and at 3, 7, and 28 days after NMDA injection). Within the inner retina, our OCT results showed that retinal thinning occurred first in the inner plexiform layer at 3 days after NMDA injection, followed by the inner nuclear layer at 7 days post-injury. In contrast, the retinal nerve fiber layer exhibited an initial thickening 3 days after NMDA injection, followed by normalization and thinning up to 4 weeks post-injury. Our results demonstrated the pathological cascades of NMDA-induced neurotoxicity across different layers of the retina. The early inner plexiform layer thinning suggests early dendritic shrinkage, whereas the initial retinal nerve fiber layer thickening before subsequent normalization and thinning indicates early inflammation before axonal loss and cell death. These findings implicate the inner plexiform layer as an early imaging biomarker of excitotoxic retinal degeneration, whereas caution is warranted when interpreting the ganglion cell complex combining retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer thicknesses in conventional OCT measures. Deep learning-assisted retinal layer segmentation and longitudinal OCT monitoring can help evaluate the different phases of retinal layer damage upon excitotoxicity.

Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes

Purpose

To evaluate and compare optical coherence tomography angiography (OCTA) retinal vasculature measurements in healthy, glaucoma suspect (GS), and glaucoma patients.

Methods

One hundred fourteen eyes with good quality OCTA pictures were included from 38 healthy, 38 GS, 38 and primary open-angle glaucoma (POAG) participants. The information on retinal vasculature was summarized as a vessel density map and as vessel density (%), which is the fraction of the flowing vessel area over the total area examined. The superior, inferior, nasal, and temporal quadrants, as well as whole vessel density (wVD) and peripapillary vessel density (ppVD) data taken from the retinal nerve fiber layer, were studied. Global indices of the visual field were correlated with vessel density measurement.

Results

Mean vessel density was significantly lower in POAG eyes compared with GSs and healthy eyes (wVD) 45.34% ± 6.64%, 50.06% ± 1.97% and 53.06% ± 2.12%, respectively (P < 0.001), and ppVD 47.42% ± 7.73%, 47.42% ± 7.73% and 56.074% ± 2.71%, respectively (P < 0.001). A linear relationship between vessel density (wVD and ppVD) and global indices of the visual field (mean deviation [MD] and pattern standard deviation [PSD]) shows a significant (P < 0.001) relation. R 2 is 0.35, 0.36, 0.36, and 0.33 for MD and wVD, PSD and wVD, PSD and ppVD, and MD and ppVD, respectively.

Conclusions

For distinguishing between healthy and glaucoma eyes, OCTA vessel density demonstrated near similar diagnostic accuracy to visual field tests. These findings imply that OCTA measurements reflect damage to tissues important in the pathogenesis of POAG.

Associations between Chronic Kidney Disease and Thinning of Neuroretinal Layers in Multiethnic Asian and White Populations

Purpose

To evaluate the relationships between chronic kidney disease (CKD) with retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness profiles of eyes in Asian and White populations.

Design

Cross-sectional analysis.

Participants

A total of 5066 Asian participants (1367 Malays, 1772 Indians, and 1927 Chinese) from the Singapore Epidemiology of Eye Diseases Study (SEED) were included, consisting of 9594 eyes for peripapillary RNFL analysis and 8661 eyes for GCIPL analysis. Additionally, 45 064 White participants (87 649 eyes) from the United Kingdom Biobank (UKBB) were included for both macular RNFL analysis and GCIPL analysis.

Methods

Nonglaucoma participants aged ≥ 40 years with complete data for estimated glomerular filtration rate (eGFR) were included from both SEED and UKBB. In SEED, peripapillary RNFL and GCIPL thickness were measured by Cirrus HD-OCT 4000. In UKBB, macular RNFL and GCIPL were measured by Topcon 3D-OCT 1000 Mark II. Chronic kidney disease was defined as eGFR < 60 ml/min/1.73 m2 in both data sets. To evaluate the associations between kidney function status with RNFL and GCIPL thickness profiles, multivariable linear regression with generalized estimating equation models were performed in SEED and UKBB data sets separately.

Main Outcome Measures

Average peripapillary and macular RNFL thickness and macular GCIPL thickness.

Results

In SEED, after adjusting for age, gender, ethnicity, systolic blood pressure, antihypertensive medication, diabetes, hyperlipidemia, body mass index, smoking status, and intraocular pressure, presence of CKD (β = -1.31; 95% confidence interval [CI], -2.37 to -0.26; P = 0.015) and reduced eGFR (per 10 ml/min/1.73 m2; β = -0.32; 95% CI, -0.50 to -0.13; P = 0.001) were associated with thinner average peripapillary RNFL. Presence of CKD (β = -1.63; 95% CI, -2.42 to -0.84) and reduced eGFR (per 10 ml/min/1.73 m2; β = -0.30; 95% CI, -0.44 to -0.16) were consistently associated with thinner GCIPL in SEED (all P < 0.001). In UKBB, after adjusting for the above-mentioned covariates (except ethnicity), reduced eGFR (per 10 ml/min/1.73 m2; β = -0.06; 95% CI, -0.10 to -0.01; P = 0.008) was associated with thinner macular RNFL and CKD (β = -0.62; 95% CI, -1.16 to -0.08; P = 0.024) was associated with thinner average GCIPL.

Conclusion

We consistently observed associations between CKD and thinning of RNFL and GCIPL across Asian and White populations' eyes. These findings further suggest that compromised kidney function is associated with RNFL and GCIPL thinning.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A Model of Progression to Help Identify Macular Damage Due to Glaucoma

The central macula contains a thick donut shaped region of the ganglion cell layer (GCL) that surrounds the fovea. This region, which is about 12 degrees (3.5 mm) in diameter, is essential for everyday functions such as driving, reading, and face recognition. Here, we describe a model of progression of glaucomatous damage to this GCL donut. This model is based upon assumptions supported by the literature, and it predicts the patterns of glaucomatous damage to the GCL donut, as seen with optical coherence tomography (OCT). After describing the assumptions and predictions of this model, we test the model against data from our laboratory, as well as from the literature. Finally, three uses of the model are illustrated. One, it provides an aid to help clinicians focus on the essential central macula and to alert them to look for other, non-glaucomatous causes, when the GCL damage does not fit the pattern predicted by the model. Second, the patterns of progression predicted by the model suggest alternative end points for clinical trials. Finally, the model provides a heuristic for future research concerning the anatomic basis of glaucomatous damage.

Evaluating the performance of OCT in assessing static and potential dynamic properties of the retinal ganglion cells and nerve fiber bundles in the living mouse eye

Glaucoma is a group of eye diseases characterized by the thinning of the retinal nerve fiber layer (RNFL), which is primarily caused by the progressive death of retinal ganglion cells (RGCs). Precise monitoring of these changes at a cellular resolution in living eyes is significant for glaucoma research. In this study, we aimed to assess the effectiveness of temporal speckle averaging optical coherence tomography (TSA-OCT) and dynamic OCT (dOCT) in examining the static and potential dynamic properties of RGCs and RNFL in living mouse eyes. We evaluated parameters such as RNFL thickness and possible dynamics, as well as compared the ganglion cell layer (GCL) soma density obtained from in vivo OCT, fluorescence scanning laser ophthalmoscopy (SLO), and ex vivo histology.

Predictive potential of optical coherence tomography parameters for the prognosis of decreased visual acuity after trabeculectomy in open-angle glaucoma patients with good vision

BACKGROUND

Trabeculectomy (trab) is the most effective surgical procedure for lowering IOP and preventing glaucoma progression. However, decline in best-corrected visual acuity (BCVA) is one of the most serious postoperative complications of trab. Here, we investigated methods to predict decreased BCVA after trab in glaucoma patients with good preoperative BCVA.

METHODS

This study included 35 eyes of 35 open-angle glaucoma (OAG) patients (male / female: 21 / 14, age: 64.0 ± 9.7 years old, preoperative intraocular pressure: 15.9 ± 5.4 mmHg, mean deviation: -18.1 ± 5.6 dB) with preoperative BCVA of 0.7 or better who underwent trab and were observed for more than 12 months. As a preoperative analysis, we measured temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and ganglion cell complex thickness in a central strip between the disc and fovea (csGCCT), an area that corresponds to the location of the papillomacular bundle (PMB) in swept-source optical coherence tomography (OCT). We defined BCVA decline as a loss of more than 3 lines of BCVA after 12 months. Measurement parameters were compared between the BCVA-decline group and the non-BCVA-decline group.

RESULTS

BCVA decline was detected in 11 cases (31.4%) 12 months after trab. There was a statistically significant difference in axial length (P = 0.049). A single logistic analysis showed that the BCVA-decline group had significantly lower cpRNFLT than the non-BCVA-decline group (27.7 ± 8.0 μm vs. 45.1 ± 5.3 μm, P < 0.001, cut-off value: 33.4 μm), as well as lower csGCCT (72.4 ± 7.7 μm vs. 87.5 ± 5.1 μm, P = 0.002, cut-off value: 82.3 μm). Multivariable logistic analysis showed that the BCVA-decline group had significantly lower temporal quadrant cpRNFLT (P < 0.001) and lower middle csGCCT (P < 0.001) compared to the non-BCVA-decline group.

CONCLUSIONS

Lower temporal quadrant cpRNFLT and middle csGCCT, OCT scan areas that correspond to the location of the PMB, might be biomarkers that predict BCVA decline after trab in OAG patients with good vision.

Discrimination of glaucomatous from non-glaucomatous optic neuropathy with swept-source optical coherence tomography

OBJECTIVE

To assess the ability of optic nerve head (ONH) parameters, peripapillary retinal nerve fiber layer (pRNFL), and macular ganglion cell layer (GCL) thickness measurements with swept-source optical coherence tomography (SS-OCT), to discriminate between glaucomatous and non-glaucomatous optic neuropathy (GON and NGON).

METHODS

This retrospective cross-sectional study involved 189 eyes of 189 patients, 133 with GON and 56 with NGON. The NGON group included ischemic optic neuropathy, previous optic neuritis, and compressive, toxic-nutritional, and traumatic optic neuropathy. Bivariate analyses of SS-OCT pRNFL and GCL thickness and ONH parameters were performed. Multivariable logistic regression analysis was employed to obtain predictor variables from OCT values, and the area under the receiver operating characteristic curve (AUROC) was calculated to differentiate between NGON and GON.

RESULTS

Bivariate analyses showed that the overall and inferior quadrant of the pNRFL was thinner in the GON group (P=0.044 and P<0.01), while patients with NGON had thinner temporal quadrants (P=0.044). Significant differences between the GON and NGON groups were identified in almost all the ONH topographic parameters. Patients with NGON had thinner superior GCL (P=0.015), but there were no significant differences in GCL overall and inferior thickness. Multivariate logistic regression analysis demonstrated that vertical cup-to-disc ratio (CDR), cup volume, and superior GCL provided independent predictive value for differentiating GON from NGON. The predictive model of these variables along with disc area and age achieved an AUROC=0.944 (95% CI 0.898-0.991).

CONCLUSIONS

SS-OCT is useful in discriminating GON from NGON. Vertical CDR, cup volume, and superior GCL thickness show the highest predictive value.

Prediction of visual field progression in glaucoma: existing methods and artificial intelligence

Timely treatment is essential in the management of glaucoma. However, subjective assessment of visual field (VF) progression is not recommended, because it can be unreliable. There are two types of artificial intelligence (AI) strong and weak (machine learning). Weak AIs can perform specific tasks. Linear regression is a method of weak AI. Using linear regression in the real-world clinic has enabled analyzing and predicting VF progression. However, caution is still required when interpreting the results, because whenever the number of VF data sets investigated is small, the predictions can be inaccurate. Several other non-ordinal, or modern AI methods have been constructed to improve prediction accuracy, such as clustering and more modern AI methods of Analysis with Non-Stationary Weibull Error Regression and Spatial Enhancement (ANSWERS), Variational Bayes Linear Regression (VBLR), Kalman Filter and sparse modeling (The least absolute shrinkage and selection operator regression: Lasso). It is also possible to improve the prediction performance using retinal thickness measured with optical coherence tomography by using machine learning methods, such as multitask learning.

Importance of Pattern Standard Deviation of Humphrey 10-2 Visual Field to Evaluate Central Visual Function in Patients with Early-Stage Glaucoma

To explore various parameters that can evaluate the central visual impairment in patients with early-stage glaucoma, we included patients into a study with central visual impairments with an MD value greater than -6.0 dB on the 24-2 VF test. A possible association between structural parameters acquired by OCT and functional parameters of VF and PERG was determined. A total of 70 eyes of patients with suspected glaucoma or NTG underwent VF, OCT, and PERG examinations. The patients were classified into two groups according to the MD of the 24-2 VF test. We used Pearson correlation analysis to evaluate the relationships between GCIPL thickness/RNFL thickness and visual functional parameters, such as PERG and perimetry. Linear regression analyses were conducted to evaluate the significant factors affecting the PSD of VF 10-2. In the low MD group, the P50 amplitude presented significant correlations (r = 0.346, p = 0.048) with GCIPL thickness. In the correlation analysis of the high MD group, it was found that only the PSD of 10-2 uniquely presented borderline significant correlations with GCIPL thickness (r = -0.327, p = 0.055), and no other functional parameter showed significant correlation. Univariate and multivariate analyses revealed that GCIPL thickness was significantly associated with a PSD of 10-2 VF (p < 0.001 and 0.013, respectively). Among various parameters, the P50 amplitude and 10-2 PSD demonstrated statistically borderline significant structure-function relationships with GCIPL thickness in early-stage glaucoma.

Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression

Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.

Quantitatively Evaluating the Relationships between Insulin Resistance and Retinal Neurodegeneration with Optical Coherence Tomography in Early Type 2 Diabetes Mellitus

INTRODUCTION

The aim of this study was to quantitatively assess retinal neurodegenerative changes with optical coherence tomography (Cirrus HD-OCT) in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR) and evaluate their relationships with insulin resistance (IR) and associated systemic indicators.

METHODS

102 T2DM patients without DR and 48 healthy controls were included in this observational cross-sectional study. The OCT parameters of macular retinal thickness (MRT) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were evaluated between diabetic and normal eyes. The receiver operating characteristics (ROC) curve was generated to evaluate the discrimination power of early diabetes. Correlation and multiple regression analysis were performed between ophthalmological parameters and T2DM-related demographic and anthropometric variables, and serum biomarkers and homeostasis model assessment of insulin resistance (HOMA-IR) scores.

RESULTS

MRT and GCIPL thicknesses showed significant thinning in patients, especially in inferotemporal area. High body mass index (BMI) correlated with decreased GCIPL thicknesses and elevated intraocular pressure (IOP). A negative correlation between waist-to-hip circumference ratio (WHR) and GCIPL thicknesses was also found. High-density lipoprotein (HDL) and fasting C-peptide (CP0) were associated with GCIPL thickness but only in inferotemporal region (r = 0.20, p = 0.04; r = -0.20, p = 0.05, respectively). Multiple regression analysis showed that increased HOMA-IR scores independently predicted both average (β = -0.30, p = 0.05) and inferotemporal (β = -0.34, p = 0.03) GCIPL thinning.

CONCLUSION

Retinal thinning in early T2DM was associated with obesity-related metabolic disorders. IR as an independent risk factor for retinal neurodegeneration may increase the risk of developing glaucoma.

Analysis of Plasma Metabolic Profile on Ganglion Cell-Inner Plexiform Layer Thickness With Mortality and Common Diseases

Importance

The neural retina is considered a unique window to systemic health, but its biological link with systemic health remains unknown.

Objective

To investigate the independent associations of retinal ganglion cell-inner plexiform layer thickness (GCIPLT) metabolic profiles with rates of mortality and morbidity of common diseases.

Design, Setting, and Participants

This cohort study evaluated UK Biobank participants enrolled between 2006 and 2010, and prospectively followed them up for multidisease diagnosis and mortality. Additional participants from the Guangzhou Diabetes Eye Study (GDES) underwent optical coherence tomography scanning and metabolomic profiling and were included for validation.

Main Outcomes and Measures

Systematic analysis of circulating plasma metabolites to identify GCIPLT metabolic profiles; prospective associations of these profiles with mortality and morbidity of 6 common diseases with their incremental discriminative value and clinical utility.

Results

Among 93 838 community-based participants (51 182 [54.5%] women), the mean (SD) age was 56.7 (8.1) years and mean (SD) follow-up was 12.3 (0.8) years. Of 249 metabolic metrics, 37 were independently associated with GCIPLT, including 8 positive and 29 negative associations, and most were associated with the rates of future mortality and common diseases. These metabolic profiles significantly improved the models for discriminating type 2 diabetes over clinical indicators (C statistic: 0.862; 95% CI, 0.852-0.872 vs clinical indicators only, 0.803; 95% CI, 0.792-0.814; P < .001), myocardial infarction (0.792; 95% CI, 0.775-0.808 vs 0.768; 95% CI, 0.751-0.786; P < .001), heart failure (0.803; 95% CI, 0.786-0.820 vs 0.790; 95% CI, 0.773-0.807; P < .001), stroke (0.739; 95% CI, 0.714-0.764 vs 0.719; 95% CI, 0.693-0.745; P < .001), all-cause mortality (0.747; 95% CI, 0.734-0.760 vs 0.724; 95% CI, 0.711-0.738; P < .001), and cardiovascular disease mortality (0.790; 95% CI, 0.767-0.812 vs 0.763; 95% CI, 0.739-0.788; P < .001). Additionally, the potential of GCIPLT metabolic profiles for risk stratification of cardiovascular diseases were further confirmed in the GDES cohort using a different metabolomic approach.

Conclusions and Relevance

In this prospective study of multinational participants, GCIPLT-associated metabolites demonstrated the potential to inform mortality and morbidity risks. Incorporating information on these profiles may facilitate individualized risk stratification for these health outcomes.

Agreement of Diagnostic Classification Between Structural Parameters in Pre-Perimetric and Early Perimetric Glaucoma

PRCIS

In both pre-perimetric and early perimetric glaucoma, the diagnostic agreements between optic disk, retinal nerve fiber layer, and ganglion cell-inner plexiform layer parameters based on Cirrus HD-OCT normative database classification were mostly fair, suggesting that abnormal classification in 1 anatomic area may suffice for the diagnosis of glaucoma in early stages.

PURPOSE

To evaluate the agreement of normative database diagnostic classification between optic disk, retinal nerve fiber layer (RNFL), and ganglion cell-inner plexiform layer (GCIPL) in patients with early glaucoma.

METHODS

Retrospective cross-sectional study involving 66 eyes (66 patients) with pre-perimetric and 97 eyes (97 patients) with early perimetric glaucoma. Normative database diagnostic classifications were retrieved from Cirrus HD-OCT scans of 1 eye per participant. An eye was considered abnormal if any of the optic disk, RNFL, or GCIPL was abnormal (yellow or red color-coded classification). For combined parameters, the eye had to be flagged as abnormal by both classifications, regardless of the parameters that were abnormal (global or sectorial). The agreement was assessed with Cohen's Kappa statistics.

RESULTS

The agreement between RNFL and GCIPL was fair in both pre-perimetric (κ=0.25) and perimetric glaucoma (κ=0.21). Agreements between RNFL or GCIPL and optic nerve head parameters (rim area and vertical cup-to-disk ratio; VCDR) were inconclusive due to insufficient data ( P >0.05). Combining GCIPL and rim area agreed fairly with RNFL both in pre-perimetric (κ=0.21) and perimetric glaucoma (κ=0.33). The best classification agreement (moderate) was achieved with the comparison of RNFL-rim area versus VCDR (κ=0.48 in pre-perimetric, 0.45 in perimetric glaucoma). There were no significant differences between pre-perimetric and perimetric glaucoma coefficients of classification agreement.

CONCLUSIONS

The normative database diagnostic agreements between optic disk, RNFL, and GCIPL were mostly fair in both pre-perimetric and early perimetric glaucoma. Clinicians should not wait for multiple structures to show abnormality on OCT to diagnose early glaucoma.

Visual Outcomes and Optical Coherence Tomography Biomarkers of Vision Improvement in Patients With Leber Hereditary Optic Neuropathy Treated With Idebenone

PURPOSE

To assess the relationship of demographics, clinical characteristics and structural optical coherence tomography (OCT) findings to long-term visual outcomes in patients with Leber hereditary optic neuropathy (LHON) treated with idebenone.

DESIGN

Retrospective, interventional, noncomparative clinical cohort study.

METHODS

In this study, a total of 17 participants (34 eyes) with LHON treated with idebenone therapy within 1 year after disease onset and 2 years (24 months) of regular follow-ups were retrospectively enrolled. At baseline, structural OCT volume scans of the macula and optic nerve were reviewed to measure metrics reflecting neuronal loss (ie, macular ganglion cell and inner plexiform layer [GC-IPL] and peripapillary retinal nerve fiber layer [RNFL] thicknesses). Stepwise multiple regression analyses were computed to assess associations between final best-corrected visual acuity (BCVA) at 2 years and change in BCVA from baseline at 2 years as dependent variables with demographics, clinical characteristics, and OCT metrics at baseline (visit before the initiation of treatment).

RESULTS

The BCVA was 1.6±0.8 logMAR (Snellen VA of ∼20/800) at baseline (visit before the initiation of treatment) and 1.0±0.7 logMAR (Snellen VA of 20/200) at the 2-year follow-up visit (P < .0001). Mean±SD change in BCVA from baseline at 2 years was -51.9%±35.9%. In multivariable analysis, the strongest associations with final BCVA were with baseline BCVA (P = .012), superior macular GC-IPL thickness (P = .044), superotemporal macular GC-IPL thickness (P = .010), and inferotemporal macular GC-IPL thickness (P = .015). Similarly, the strongest associations with delta BCVA were with superior macular GC-IPL thickness (P = .045), superotemporal macular GC-IPL thickness (P = .047), and inferotemporal macular GC-IPL thickness (P = .030).

CONCLUSION

We identified OCT biomarkers associated with long-term (ie, 2-year) visual outcomes in patients with LHON treated with idebenone therapy in the first year after disease onset. Thinning of the GC-IPL in the superior and temporal parafoveal regions was associated with worse long-term visual outcomes in these patients.

The Japan Glaucoma Society guidelines for glaucoma 5th edition

We are pleased to bring you the 5th edition of the Glaucoma Clinical Practice Guidelines. Clinical practice guidelines are based on evidence (scientific grounds). It is a document that presents the treatment that is the most appropriate for the patient. "Glaucoma Clinical Guidelines" was first published in 2003. This was the first guideline for glaucoma treatment in Japan. The principle of glaucoma treatment is to lower intraocular pressure. Means for lowering intraocular pressure includes drugs, lasers, and surgery; Glaucoma is a disease that should be considered as a complex syndrome rather than a single condition. Therefore, the actual medical treatment is not as simple as one word. This time we set the Clinical Questionnaire with a focus on glaucoma treatment. We hope that you will take advantage of the 5th edition.

Evaluation of Visual Acuity, Macular Thickness, and Level of Proteinuria in Children with Nephrotic Syndrome

PURPOSE

Macular edema, serous retinal detachment, and retinal pigment epithelial detachment have been reported in patients with nephrotic syndrome. However, there is limited data about macular thickness in children with nephrotic syndrome. The aim of this study was to compare the mean macular thickness in children with nephrotic syndrome and in a control group and to correlate it with visual acuity and level of proteinuria.

METHODS

The comparative cross-sectional study included 66 children aged 6 to 17 years with nephrotic syndrome and healthy control seen in two tertiary centers in Malaysia. We recorded demographic data, as well as visual acuity, level of proteinuria, and the mean macular thicknesses in both groups. The mean macular thickness was measured using Stratus optical coherence tomography according to nine areas of the Early Treatment Diabetic Retinopathy Study map.

RESULTS

The mean foveal thickness was 238.15 ± 22.98 µm for children with nephrotic syndrome and 237.01 ± 22.60 µm for the control group. There was no significant difference in the mean macular thickness between the groups (p = 0.843). A significant correlation with visual acuity was observed in the superior outer macula (r = -0.41, p = 0.019), the nasal outer macula (r = -0.41, p = 0.019), and the inferior outer macula (r = -0.40, p = 0.021). There was no significant correlation between the mean macular thickness and level of proteinuria (p = 0.338), although those with higher levels of proteinuria demonstrated a trend towards increased macular thickness.

CONCLUSIONS

The mean macular thickness in children with nephrotic syndrome was similar to that of healthy children. A significant correlation between the mean thickness of the outer macular layer and the presenting visual acuity was observed. There was no correlation between the mean macular thickness and the level of proteinuria.

Analysis of ganglion cell-inner plexiform layer thickness in retinal vein occlusion with resolved macular edema

PURPOSE

To analyze the retinal ganglion cell-inner plexiform layer (GCIPL) changes in retinal vein occlusion (RVO) eyes with resolved macular edema using optical coherence tomography.

METHODS

We compared the average and minimum GCIPL thickness in RVO eyes with fellow eyes and healthy controls including 40 unilateral RVO patients and 48 healthy subjects. The average GCIPL thickness in BRVO eyes was segmented into the affected and opposite area according to the site of lesion, comparing them with corresponding areas in fellow eyes. Furthermore, maximum central macular thickness (CMT), visual acuity (VA), and intravitreal injection times were recorded to investigate their relationship with the GCIPL thickness.

RESULTS

Despite no significant difference in CMT (P = 0.96), the average (P = 0.02 and P < 0.001, respectively) and minimum (both P < 0.001) GCIPL thicknesses were decreased in RVO eyes with resolved macular edema after treatment in comparison to fellow eyes and healthy eyes. Maximum CMT thickness was negatively correlated with the minimum GCIPL thickness (r = - 0.47, P = 0.003). VA and average GCIPL thickness were associated (r_s = - 0.49, P = 0.002). In a subgroup analysis that only included BRVO patients, the opposite area revealed no significant difference between two eyes (P = 0.91) although the affected area in BRVO eyes was decreased (P < 0.001).

CONCLUSIONS

A decrease of GCIPL thickness in RVO was observed even after anatomic restoration and associated with VA prognosis. These GCIPL defects could be attributable to systemic risks and RVO itself, not anti-VEGF effects.

Ganglion Cell Complex Analysis: Correlations with Retinal Nerve Fiber Layer on Optical Coherence Tomography

The aim of this review is to analyze the correlations between the changes in the ganglion cell complex (GCC) and the retinal nerve fiber layer (RNFL) on optical coherence tomography in different possible situations, especially in eyes with glaucoma. For glaucoma evaluation, several studies have suggested that in the early stages, GCC analysis, especially the thickness of the infero and that of the inferotemporal GCC layers, is a more sensitive examination than circumpapillary RNFL (pRNFL). In the moderate stages of glaucoma, inferior pRNFL thinning is better correlated with the disease than in advanced cases. Another strategy for glaucoma detection is to find any asymmetry of the ganglion cell-inner plexiform layers (GCIPL) between the two macular hemifields, because this finding is a valuable indicator for preperimetric glaucoma, better than the RNFL thickness or the absolute thickness parameters of GCIPL. In preperimetric and suspected glaucoma, GCC and pRNFL have better specificity and are superior to the visual field. In advanced stages, pRNFL and later, GCC reach the floor effect. Therefore, in this stage, it is more useful to evaluate the visual field for monitoring the progression of glaucoma. In conclusion, GCC and pRNFL are parameters that can be used for glaucoma diagnosis and monitoring of the progression of the disease, with each having a higher accuracy depending on the stage of the disease.

[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 1. Study methods, measurement variability and the role of age-related changes]

This paper reviews the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma and considers the significance of evaluating retinal nerve fiber layer and ganglion cell complex in assessment of glaucoma progression, variability and reproducibility of the method, as well as the influence of age-related retinal changes on the results, analyzes the role of OCTA in glaucoma monitoring. Optical coherence tomography is a modern standard for glaucoma diagnosis and monitoring, and OCTA shows high potential as an auxiliary diagnostic tool.

Gessesse G. Diagnostic performance of optical coherence tomography macular ganglion cell inner plexiform layer and retinal nerve fiber layer thickness in glaucoma suspect and early glaucoma patients at St. Paul's hospital millennium medical college, Addis Ababa, Ethiopia

PURPOSE

To evaluate glaucoma diagnostic performance of ganglion cell inner plexiform layer and retinal nerve fiber layer parameters measured with cirrus HD optical coherence tomography (OCT).

METHOD

Total of 188 eyes were included in our study. 49 eyes of healthy controls, 70 glaucoma suspect eyes and 69 early glaucomatous eyes. Complete ophthalmic examination was done including visual field test (with Humphrey field analyzer) and OCT scanning of ganglion cell inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) in different quadrants. Sensitivity, specificity and area under the receiver operating characteristic curve (AUROC) of each parameter was calculated to provide diagnostic ability between normal controls, glaucoma suspects or early glaucoma.

RESULT

GCIPL and RNFL parameters had strong power in discriminating early glaucoma from healthy controls with all having AUROC of above 0.76. Of all the GCIPL and RNFL parameters, the only variable that could discriminate between glaucoma suspect and healthy controls was the combined parameter by OR-logic approach. Of all the parameters, the average and nasal RNFL parameters had the strongest power in discriminating between the two with AUROC of 0.81. All parameters had an overall good diagnostic performance with excellent sensitivity but the specificity was relatively poor. The combined parameter had the best specificity (62.2%) with excellent sensitivity (93.5%).

CONCLUSION

Nasal RNFL parameters had the strongest power in discriminating between glaucoma suspect and healthy controls and the OR-logic combination of RNFL and GCIPL provides better diagnostic performance than single GCIPL, RNFL or ONH parameter.

Comparison of Ganglion Cell Layer and Ganglion Cell/Inner Plexiform Layer Measures for Detection of Early Glaucoma

PURPOSE

To test the hypothesis that macular ganglion cell layer (GCL) measurements detect early glaucoma with higher accuracy than ganglion cell/inner plexiform layer (GCIPL) thickness measurements.

DESIGN

Cross-sectional study.

PARTICIPANTS

The first cohort included 58 glaucomatous eyes with visual field mean deviation (MD) ≥ -6 dB and 125 normal eyes. The second cohort included 72 glaucomatous and 73 normal/glaucoma suspect (GS) eyes with scans able to create GCL/GCIPL deviation maps.

METHODS

In the first cohort, 8 × 8 GCL and GCIPL grids were exported and 5 superior and inferior sectors were defined. Global and sectoral GCL and GCIPL measures were used to predict glaucoma. In the second cohort, proportions of scan areas with abnormal (< 5% and < 1% cutoffs) and supernormal (> 95% and > 99% cutoffs) thicknesses on deviation maps were calculated. The extents of GCL and GCIPL abnormal areas were used to predict glaucoma.

MAIN OUTCOME MEASURES

Extents of abnormal GCL/GCIPL regions and areas under receiver operating characteristic curves (AUROC) for prediction of glaucoma were compared between GCL or GCIPL measures.

RESULTS

The average ± standard deviation MDs were -3.7 ± 1.6 dB and -2.7 ± 1.8 dB in glaucomatous eyes in the first and second cohorts, respectively. Global GCIPL thickness measures (central 18° × 18° macular region) performed better than GCL for early detection of glaucoma (AUROC, 0.928 vs. 0.884, respectively; P = 0.004). Superior and inferior sector 3 thickness measures provided the best discrimination with both GCL and GCIPL (inferior GCL AUROC, 0.860 vs. GCIPL AUROC, 0.916 [P = 0.001]; superior GCL AUROC, 0.916 vs. GCIPL AUROC, 0.900 [P = 0.24]). The extents of abnormal GCL regions at a 1% cutoff in the central elliptical area were 17.5 ± 22.2% and 6.4 ± 10.8% in glaucomatous and normal/GS eyes, respectively, versus 17.0 ± 22.2% and 5.7 ± 10.5%, respectively, for GCIPL (P = 0.06 for GCL and 0.002 for GCIPL). The extents of GCL and GCIPL supernormal regions were mostly similar in glaucomatous and normal eyes. The best performance for prediction of glaucoma in the second cohort was detected at a P value of < 1% within the entire scan for both GCL and GCIPL (AUC, 0.681 vs. 0.668, respectively; P = 0.29).

CONCLUSIONS

Macular GCL and GCIPL thicknesses are equivalent for identifying early glaucoma with current OCT technology. This is likely explained by limitations of inner macular layer segmentation and concurrent changes within the inner plexiform layer in early glaucoma.

Evaluation of ganglion cell complex and retinal nerve fiber layer in children with spina bifida using optical coherence tomography

PURPOSE

Spina bifida (SB) is a congenital disorder caused by the incomplete fusion of the embryonic neural tube during spinal cord development. In this study, we used Spectral Domain Optic Coherence Tomography (SD-OCT) for retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) analyses and compared the results of healthy children and SB patients in a similar age group.

METHODS

Our study was planned prospectively and conducted between June 2017 and July 2019. One hundred eyes of 50 participants, consisting of 28 SB patients and 22 healthy children were included. In all cases, RNFL and GCC measurements were undertaken using SD-OCT. The circumpapillary RNFL analysis was conducted by examining the circular area of 3.45 mm in diameter around the centre of the optic disc. GCC parameters were determined with MM7 protocols by taking 15 vertical sections from a 7-mm macular square centred in the fovea.

RESULTS

The mean GCC thickness of the participants was 91.120 ± 5.224 µm in the control group and 91.696 ± 7.410 µm in the SB group. The difference between the two groups was not statistically significant (p > 0.05). The mean RNFL thickness was 102.499 ± 11.250 µm in the control group and 99.549 ± 15.235 µm in the SB group. The mean RNFL thickness of the patients in the SB group was lower than that of the control group, but the difference was not statistically significant (p > 0.05).

CONCLUSIONS

In this study, the lack of a statistically significant difference in the RNFL and GCC values between the SB and control groups can be attributed to successful clinical management.

Patterns of Optical Coherence Tomography Imaging in Preperimetric Open Angle Glaucoma: A Comparative Study With Young-Age-Onset and Old-Age-Onset Eyes

PRCIS

Optic coherence tomography imaging in preperimetric open angle glaucoma (OAG) differed between young-age-onset and old-age-onset eyes. Inferior and superior quadrants were thinner in young and old-age-onset eyes, respectively. Understanding the specific patterns of early glaucomatous damage based on age-at-onset may improve glaucoma diagnosis and monitoring.

PURPOSE

To investigate the patterns of retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thinning in preperimetric OAG by optical coherence tomography based on age at onset ("young-age onset (<40 y)" vs. "old-age onset (≥40 y)".

MATERIALS AND METHODS

The RNFL and GCIPL deviation images were acquired by Cirrus HD-optical coherence tomography, and overlaid, thus converted to a "deviation frequency map", respectively. The topographic thinning patterns and parameters of RNFL and GCIPL thickness measurements were compared.

RESULTS

A total of 194 eyes of 194 patients with preperimetric OAG and 97 eyes of 97 age-matched normal subjects were analyzed. Young-age-onset eyes of preperimetric OAG mainly had RNFL defects inferotemporally (264-296 degrees) with GCIPL defects in the inferior region (213-357 degrees). Old-age-onset preperimetric OAG eyes had RNFL defects inferotemporally (266-294°) and superotemporally (33-67 degrees), with GCIPL defects in the inferior and superior regions (206-360 degrees, 0-22 degrees). The inferior quadrant of RNFL and GCIPL thicknesses were significantly thinner in young-age-onset eyes compared with old-age-onset eyes ( P =0.012, 0.016), while the superior quadrant of those were significantly thinner in the old-age-onset eyes ( P =0.003, 0.005).

CONCLUSION

Young-age-onset and old-age-onset eyes of preperimetric OAG present different specific patterns of RNFL and GCIPL thinning.

Evaluation of University of North Carolina OCT Index for Diagnosis of Early Glaucoma

PURPOSE

To evaluate the diagnostic performance of the University of North Carolina (UNC) OCT Index based on Cirrus high-definition OCT to discriminate early glaucomatous eyes from normal eyes in clinical practice.

DESIGN

Evaluation of diagnostic test or technology.

PARTICIPANTS

Ninety-eight patients with early glaucoma and 98 age-matched normal subjects.

METHODS

Macular ganglion cell-inner plexiform layer (GCIPL) thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head parameters were measured in each subject. The measurements were run through the UNC OCT algorithm to compare their diagnostic abilities.

MAIN OUTCOME MEASURES

Area under the curve (AUC) of the receiver operating characteristic and sensitivity at 95% specificity.

RESULTS

The AUC of the UNC OCT Index was 0.974. The best AUCs of the single parameters were those of the minimum GCIPL (0.926) of the macular GCIPL, average RNFL (0.916) of the peripapillary RNFL, and rim area (0.964) of the optic nerve head. The AUC of the UNC OCT Index was significantly greater than those of the minimum GCIPL and average RNFL (all P values < 0.05), and also outperformed the rim area. The sensitivity value of the UNC OCT Index (90.8) was greater than that of single OCT parameters (minimum GCIPL, 42.9; average RNFL, 64.3; rim area, 84.7) at 95% specificity.

CONCLUSIONS

The diagnostic performance of the UNC OCT Index in discriminating early glaucomatous eyes from normal eyes is high and exceeds the best optic nerve head, peripapillary RNFL, and macular GCIPL parameters in clinical practice.

Pattern Electroretinogram Parameters and their Associations with Optical Coherence Tomography in Glaucoma Suspects

Aim

To investigate whether steady state pattern electroretinogram (ssPERG) could identify retinal ganglion cell (RGC) dysfunction, and to assess the relationship between ssPERG with optical coherence tomography (OCT) measurements in glaucoma suspects (GS).

Materials and methods

This was a prospective cohort study of GS, identified based on suspicious optic disk appearance and glaucoma risk factors. Complete eye exam, Standard automated perimetry, OCT, and ssPERG were performed. Magnitude (Mag), Magnitude D (MagD), and MagD/Mag ratio were subsequently used in the correlation and linear regression analyses between ssPERG parameters and the RNFL, GCL/IPL, and macular thicknesses measurements.

Results

Forty-nine eyes of 26 patients were included. Mag and MagD were significantly correlated with the superior, inferior, and average RNFL thicknesses (avRNFLT). All ssPERG parameters were significantly correlated with the average and minimum GCL/IPL thicknesses and the inner macular sector thicknesses. Mag and MagD significantly predicted the superior, inferior, and avRNFLT in the regression analysis. All ssPERG parameters were predictive of GCL/IPL thickness in all sectors as well as the average and minimum GCL/IPL thicknesses. All ssPERG parameters were predictive of all inner macular sector thicknesses and MagD was also predictive of some outer macular sector thicknesses as well.

Conclusion

ssPERG has significant correlations with and is predictive of RNFL, GCL/IPL, and macular thicknesses in glaucoma suspects.

Clinical significance

ssPERG may serve as a useful objective functional tool for identifying and following the progression of disease in glaucoma suspects.

How to cite this article

Tirsi A, Wong A, Zhu D, et al. Pattern Electroretinogram Parameters and their Associations with Optical Coherence Tomography in Glaucoma Suspects. J Curr Glaucoma Pract 2022;16(2):96-104.

Macular Layer Thickness and Effect of BMI, Body Fat, and Traditional Cardiovascular Risk Factors: The Tromsø Study

Purpose

The purpose of this study was to investigate associations between cardiovascular risk factors and the thickness of retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), and outer retina layers (ORL).

Methods

In this population-based study, we included participants from the Tromsø Study: Tromsø6 (2007 to 2008) and Tromsø7 (2015 to 2016). Persons with diabetes and/or diagnosed glaucoma were excluded from this study. Retinal thickness was measured on optical coherence tomography (Cirrus HD-OCT) macula-scans, segmented on RNFL, GCIPL, and ORL and associations were analyzed cross-sectionally (N = 8288) and longitudinally (N = 2595). We used directed acyclic graphs (DAGs) for model selection, and linear regression to adjust for confounders and mediators in models assessing direct effects. Factors examined were age, sex, blood pressure, daily smoking, serum lipids, glycated hemoglobin, body mass index (BMI), total body fat percentage (BFP), and the adjustment variables refraction and height.

Results

The explained variance of cardiovascular risk factors was highest in GCIPL (0.126). GCIPL had a strong negative association with age. Women had thicker GCIPL than men at higher age and thinner ORL at all ages (P < 0.001). Systolic blood pressure was negatively associated with RNFL/GCIPL (P = 0.001/0.004), with indication of a U-shaped relationship with GCIPL in women. The negative association with BMI was strongest in men, with significant effect for RNFL/GCIPL/ORL (P = 0.001/<0.001/0.019) and in women for GCIPL/ORL (P = 0.030/0.037). BFP was negatively associated with GCIPL (P = 0.01). Higher baseline BMI was associated with a reduction in GCIPL over 8 years (P = 0.03).

Conclusions

Cardiovascular risk factors explained 12.6% of the variance in GCIPL, with weight and blood pressure the most important modifiable factors.

Widefield OCT Imaging for Quantifying Inner Retinal Thickness in the Nonhuman Primate

Purpose

To determine the agreement and repeatability of inner retinal thickness measures from widefield imaging compared to standard scans in healthy nonhuman primates.

Methods

Optical coherence tomography (OCT) scans were acquired from 30 healthy rhesus monkeys, with 11 animals scanned at multiple visits. The scan protocol included 20° × 20° raster scans centered on the macula and optic nerve head (ONH), a 12° diameter circular scan centered on the ONH, and a 55 × 45° widefield raster scan. Each scan was segmented using custom neural network–based algorithms. Bland–Altman analysis were used for comparing average circumpapillary retinal nerve fiber layer (RNFL) thickness and ganglion cell inner plexiform layer (GCIPL) thickness for a 16° diameter region. Comparisons were also made for similar 1° × 1° superpixels from the raster scans.

Results

Average circumpapillary RNFL thickness from the circular scan was 114.2 ± 5.8 µm, and 113.2 ± 7.3 µm for an interpolated scan path from widefield imaging (bias = −1.03 µm, 95% limits of agreement [LOA] −8.6 to 6.5 µm). GCIPL thickness from standard raster scans was 72.7 ± 4.3 µm, and 73.7 ± 3.7 µm from widefield images (bias = 1.0 µm, 95% LOA −2.4 to 4.4 µm). Repeatability for both RNFL and GCIPL standard analysis was less than 5.2 µm. For 1° × 1° superpixels, the 95% limits of agreement were between −13.9 µm and 13.7 µm for RNFL thickness and −2.5 µm and 2.5 µm for GCIPL thickness.

Conclusions

Inner retinal thickness measures from widefield imaging have good repeatability and are comparable to those measured using standard scans.

Translational Relevance

Monitoring retinal ganglion cell loss in the non-human primate experimental glaucoma model could be enhanced using widefield imaging.

Reproducibility of Neuroretinal Rim Measurements Obtained from High-Density Spectral Domain Optical Coherence Tomography Volume Scans

Purpose

To compare the reproducibility of two-dimensional (2D) peripapillary retinal nerve fiber layer (RNFL) thickness and three-dimensional (3D) neuroretinal rim measurements using spectral domain optical coherence tomography (SDOCT) in normal and glaucoma subjects.

Methods

One eye per subject for 27 normal and 40 glaucoma subjects underwent repeat SDOCT RNFL thickness scans and optic nerve volume scans on the same day. From the volume scan, custom software calculated five neuroretinal rim parameters: 3D minimum distance band (MDB) thickness, 3D MDB area, 3D rim volume, 2D rim area, and 2D rim thickness. Within-subject variance (Sw), coefficient of variation (CV), and intraclass correlation coefficient (ICC) were analyzed.

Results

MDB thickness and RNFL thickness have similar reproducibility among normal and glaucoma subjects (eg, global MDB thickness CVs of 2.4% and 3.6%, and global RNFL thickness CVs of 1.3% and 2.2%; P > 0.05 for both comparisons). Reproducibility of MDB thickness was lower in glaucoma patients for the superior and inferior quadrants compared to normal subjects (CVs of 9.6% versus 3.4% and 6.9% versus 2.7%; P < 0.05, respectively). There were no statistically significant differences between both groups for RNFL thickness in the four quadrants. For both patient groups and for all regions, MDB thickness had the lowest CVs among all five neuroretinal rim parameters (eg, global MDB thickness CVs of 2.4% and 3.6% versus 3.0% and 18.9% for the other four neuroretinal rim parameters).

Conclusion

Global MDB and global RNFL thickness are similarly reproducible among normal and glaucoma subjects, though MDB thickness for the superior and inferior quadrants is less reproducible among glaucoma subjects.

Comparison of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness Values Using Spectral-Domain and Swept-Source OCT

Purpose

To compare peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thickness measurements obtained with spectral domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) using an OCT-angiography scanning protocol, and their ability to distinguish among patients with glaucoma, glaucoma suspects (GS), and healthy controls (HC).

Methods

Cross-sectional study of 196 eyes (81 glaucoma, 48 GS, and 67 HC) of 119 participants. Participants underwent peripapillary and macular OCT with SD-OCT and SS-OCT. Parameters of interest were average and sector-wise pRNFL and mGCIPL thickness. Inter-device agreement was investigated with Bland-Altman statistics. Conversion formulas were developed with linear regression. Diagnostic performances were evaluated with area under the receiver operating characteristic curves.

Results

Both SD-OCT and SS-OCT detected a significant pRNFL and mGCIPL thinning in glaucoma patients compared to HC and GS for almost all study sectors. A strong linear relationship between the two devices was present for all quadrants/sectors (R2 ≥ 0.81, P < 0.001), except for the nasal (R2 = 0.49, P < 0.001) and temporal (R2 = 0.62, P < 0.001) pRNFL quadrants. SD-OCT and SS-OCT measurements had a proportional bias, which could be removed with conversion formulas. Overall, the two devices showed similar diagnostic abilities.

Conclusions

Thickness values obtained with SD-OCT and SS-OCT are not directly interchangeable but potentially interconvertible. Both devices have a similar ability to discriminate glaucoma patients from GS and healthy subjects.

Translational Relevance

OCT-Angiography scans can be reliably used to obtain structural metrics in glaucoma patients.

Diagnostic assessment of glaucoma and non-glaucomatous optic neuropathies via optical texture analysis of the retinal nerve fibre layer

The clinical diagnostic evaluation of optic neuropathies relies on the analysis of the thickness of the retinal nerve fibre layer (RNFL) by optical coherence tomography (OCT). However, false positives and false negatives in the detection of RNFL abnormalities are common. Here we show that an algorithm integrating measurements of RNFL thickness and reflectance from standard wide-field OCT scans can be used to uncover the trajectories and optical texture of individual axonal fibre bundles in the retina and to discern distinctive patterns of loss of axonal fibre bundles in glaucoma, compressive optic neuropathy, optic neuritis and non-arteritic anterior ischaemic optic neuropathy. Such optical texture analysis can detect focal RNFL defects in early optic neuropathy, as well as residual axonal fibre bundles in end-stage optic neuropathy that were indiscernible by conventional OCT analysis and by red-free RNFL photography. In a diagnostic-performance study, optical texture analysis of the RNFL outperformed conventional OCT in the detection of glaucoma, as defined by visual-field testing or red-free photography. Our findings show that optical texture analysis of the RNFL for the detection of optic neuropathies is highly sensitive and specific.

Associations between steady-state pattern electroretinography and estimated retinal ganglion cell count in glaucoma suspects

Purpose

To estimate retinal ganglion cell (RGC) count in glaucoma suspects (GS) and ascertain its relationships with steady-state pattern electroretinography (ssPERG) parameters.

Methods

In this prospective cross-sectional study, 22 subjects (44 eyes) were recruited at the Manhattan Eye, Ear, and Throat Hospital. Subjects underwent complete eye examinations, optical coherence tomography, standard automated perimetry, and ssPERG testing. Eyes were divided into two groups based upon clinical data: healthy subjects and GS. RGC count was estimated using the combined structure–function index.

Results

Estimated RGC count, average retinal nerve fiber layer thickness (ARNFLT), and average ganglion cell layer and inner plexiform layer thickness (GCIPLT) were reduced in GS eyes (p ≤ 0.001 for all parameters). Pearson correlations revealed that ssPERG magnitude and magnitudeD correlated with ARNFLT (r ≥ 0.53, p < 0.001), GCIPLT (r > 0.38, p < 0.011), and estimated RGC count (r > 0.46, p < 0.002). Six mediation analyses revealed that estimated RGC count mediated the relationships among ssPERG parameters, ARNFLT, and GCIPLT.

Conclusion

Steady-state PERG parameters demonstrated linear correlations with estimated RGC count. The associations among ssPERG parameters and structural measures were mediated by estimated RGC count.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10633-022-09869-9.

Ganglion Cell Layer Thickness Variance Using SPECTRALIS Optical Coherence Tomography

BACKGROUND

To determine the normal variance of the mean macular ganglion cell layer (GCL) volume among subjects without significant ocular pathology using SPECTRALIS optical coherence tomography (OCT).

METHODS

Fifty subjects underwent a baseline scan using SPECTRALIS OCT followed by 2 more studies with (reg-ON) and without (reg-OFF) eye registration all taken at the same session. The mean GCL volume was measured using built-in SPECTRALIS software. Eyes with macular pathology were excluded. The reproducibility of the measurements of the GCL volume was evaluated with Bland-Altman plots and limits of agreement, intraclass correlation coefficient (ICC), and the coefficient of repeatability (CR).

RESULTS

A total of 98 eyes met criteria for the analysis. The mean GCL volume difference was 0.0002 ± 0.029 and -0.0005 ± 0.035 mm3 for scans 1 versus 2 (baseline vs reg-ON) and 3 (baseline vs reg-OFF), respectively. The ICCs were 0.985 and 0.977 for the baseline vs reg-ON and reg-OFF groups. The CR for baseline vs reg-ON was 0.056 while CR for baseline vs reg-OFF was 0.069. Ninety percent of eyes fell within 0.04 mm3 of test-retest reliability.

CONCLUSIONS

Our model found a predictable threshold of 0.07 mm3 or less for SPECTRALIS OCT mean GCL volume variance, which did not significantly change with eye registration in eyes without macular pathology. Clinicians may also consider a threshold of 0.04 mm3 when determining stable vs progressive changes in mean GCL volume using this device.

Comparative Evaluation of Two SD-OCT Macular Parameters (GCC, GCL) and RNFL in Chiasmal Compression

Purpose

To evaluate the relationship between different macular thickness parameters analyzed by SD-OCT and the central visual field (VF) evaluated with automated kinetic perimetry in a cohort of patients with pituitary tumors.

Methods

Data from patients with pituitary adenoma treated at Reims University Hospital between October 1st, 2017, and May 31st, 2018 were collected. All patients underwent an automated kinetic perimetry and a SD-OCT to map the ganglion cell complex (GCC), the ganglion cell layer (GCL) thickness and the retinal nerve fiber layer (RNFL) using devices from two different manufacturers. Univariate and multivariate analysis were used to evaluate the correlation between the area of central VF in square degrees (deg2) and the SD-OCT parameters (μm).

Results

Eighty-eight eyes were included in the analysis. All the thickness parameters measured in SD-OCT decreased with the visual field alteration. The best correlation was observed between superior thickness parameters (GCC, GCL) and the inferior central visual field. The most pertinent predictive factors for visual field loss were the inferior central GCL and the nasal RNFL (both AUC=0.775) with a sensitivity respectively of 86% and 70%.

Conclusion

This study suggests that both GCC, GCL thickness parameters could be reliable predictors of central visual field impairment in patients with pituitary tumors. There was no significative difference between both devices.

Retinal nerve fibre layer/ganglion cell-inner plexiform layer thickness ratio in patients with systemic hypertension

PURPOSE

Acute and chronic hypertension may have different pathophysiological mechanisms in the retina. Here, we compared the retinal nerve fibre layer (RNFL)/ganglion cell-inner plexiform layer (GC-IPL) thickness ratios of patients with 'relieved' severe hypertensive retinopathy (relieved HTNR) and chronic hypertension without retinopathy (chronic HTN) to those of normal controls.

METHODS

We performed cross-sectional study. The eyes were divided into the following groups: normal controls (Group A, age ≥50 years; Group D, age <50 years); chronic HTN (Group B, <10 years of HTN; TNHT; Group C, ≥10 years of HTN); and relieved HTNR (previously diagnosed with grade IV HTNR and relieved retinopathy for >1 year; Group E), and the RNFL/GC-IPL thickness ratio was compared among Groups A-C and between Groups D and E.

RESULTS

A total of 379 eyes were included in this study. Groups A-E consisted of 145, 59, 63, 60 and 52 eyes, respectively. The RNFL/GC-IPL thickness ratios were 1.161 ± 0.093, 1.158 ± 0.082 and 1.162 ± 0.089 in groups A-C, respectively, and did not showed a statistically difference (p = 0.966). The RNFL/GC-IPL thickness ratio of groups D and E were 1.169 ± 0.080 and 1.221 ± 0.080, respectively, and showed a statistically difference (p = 0.001).

CONCLUSIONS

The RNFL/GC-IPL thickness ratios of the chronic HTN group did not show a difference compared with the normal controls. However, relieved HTNR patients showed a higher ratio than the normal controls. Physicians should be aware that acute hypertensive injury could affect the RNFL/GC-IPL thickness ratio.

Predictive value of OCT and MRI for postoperative visual recovery in patients with chiasmal compressive lesions

PURPOSE

We aimed to investigate the predictive value of retinal thickness measured by optical coherence tomography (OCT) and mass biometrics measured using magnetic resonance image (MRI) for visual recovery after surgery for removal of a mass compressing the optic chiasm.

METHODS

Consecutive patients who showed typical temporal visual field defect (VFD) with respect to the vertical meridian due to a chiasmal compressive mass and who underwent mass removal surgery were recruited. Ophthalmic examination was performed preoperatively and postoperatively. Retinal thickness was measured by the Cirrus OCT. The height and size of the mass and suprasellar extension (SSE) in both the sagittal and coronal planes were evaluated. Patients were divided into two groups based on the improvement in VFD (mean deviation [MD] change ≥ 5 dB: group R; others: group NR) and clinical characteristics were compared.

RESULTS

Fifteen patients were included in the study. Eight (53.3%) patients were allocated into group R and others (7 patients, 46.7%) into group NR. Age, sex, initial visual acuity, initial MD was not different between the two groups. The retinal thicknesses were not different while tumor height, volume, and both sagittal and coronal SSE were significantly different between the two groups. (p = 0.029, 0.014, <0.001, and <0.001, respectively) All MRI parameters showed significant predictive value for the degree of MD recovery.

CONCLUSION

MRI showed better predictive value than OCT in predicting postoperative VFD recovery in patients with temporal VFDs due to chiasmal compressive disorder.