Comparing the Rates of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Loss in Healthy Eyes and in Glaucoma Eyes

Detection of Longitudinal Ganglion Cell/Inner Plexiform Layer Change: Comparison of Two Spectral-Domain Optical Coherence Tomography Devices

PURPOSE

We compared rates of change of macular ganglion cell/inner plexiform (GCIPL) thickness and proportion of worsening and improving rates from 2 optical coherence tomography (OCT) devices in a cohort of eyes with glaucoma.

DESIGN

Longitudinal cohort study.

METHODS

In a tertiary glaucoma clinic we evaluated 68 glaucoma eyes with ≥2 years of follow-up and ≥4 OCT images. Macular volume scans from 2 OCT devices were exported, coregistered, and segmented. Global and sectoral GCIPL data from the central 4.8 × 4.0-mm region were extracted. GCIPL rates of change were estimated with linear regression. Permutation analyses were used to control specificity with the 2.5 percentile cutoff point used to define "true" worsening. Main outcome measures included differences in global/sectoral GCIPL rates of change between 2 OCT devices and the proportion of negative vs positive rates of change (P < .05).

RESULTS

Average (standard deviation) 24-2 visual field mean deviation, median (interquartile range) follow-up time, and number of OCT images were -9.4 (6.1) dB, 3.8 (3.3-4.2) years, and 6 (5-8), respectively. GCIPL rates of thinning from Spectralis OCT were faster (more negative) compared with Cirrus OCT; differences were significant in superonasal (P = .03) and superotemporal (P = .04) sectors. A higher proportion of significant negative rates was observed with Spectralis OCT both globally and in inferotemporal/superotemporal sectors (P < .04). Permutation analyses confirmed the higher proportion of global and sectoral negative rates of change with Spectralis OCT (P < .001).

CONCLUSIONS

Changes in macular GCIPL were detected more frequently on Spectralis' longitudinal volume scans than those of Cirrus OCT. OCT devices are not interchangeable with regard to detection of macular structural progression.

Ganglion cell complex and macular thickness layers in primary open-angle glaucoma, pseudoexfoliation glaucoma and healthy eyes: A comparative study

PURPOSE

To investigate the differences in the ganglion cell complex (GCC) and macular thickness measurements between primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PXG), and healthy eyes with optical coherence tomography (OCT)optovue.

METHODS

In this non-randomized comparative cross-sectional study, 43 healthy eyes, 68 POAG eyes, and 57 PXG eyes were included. Patients were matched for age and disease severity. OCT angiography images were obtained for automated measurement of the GCC and macular thickness layers (inner and outer).

RESULTS

All GCC parameters were significantly difference between healthy and glaucomatous eyes (mild, and moderate to severe disease).There were no significant differences in GCC parameters between POAG and PXG patients except focal loss volume (FLV) after adjustment. Moderate to severe PXG eyes exhibited significantly lower GCC, larger global loss volume (GLV) values, and FLV values when compared with mild PXG eyes (p<= 0.05). We found significant thinning patterns in inner retinal thickness (fovea, parafovea, and perifovea), and total retinal thickness (parafovea, and perifovea) in moderate to severe PXG eyes when comparing with POAG eyes. Patients with moderate to severe PXG also showed significantly thinning patterns in inner retinal layers (fovea, parafovea and perifovea) and total retinal thickness (nasal parafovea) in compared to mild PXG.

CONCLUSION

It appears that GCC thickness is not significantly different between POAG and PXG except FLV. Despite similar retinal thickness in mild disease, a significant reduction in total and inner retinal thickness was demonstrated in moderate to severe PXG compared to moderate to severe POAG, in fovea, parafovea and perifovea region.

Circumpapillary OCT-focused hybrid learning for glaucoma grading using tailored prototypical neural networks

Glaucoma is one of the leading causes of blindness worldwide and Optical Coherence Tomography (OCT) is the quintessential imaging technique for its detection. Unlike most of the state-of-the-art studies focused on glaucoma detection, in this paper, we propose, for the first time, a novel framework for glaucoma grading using raw circumpapillary B-scans. In particular, we set out a new OCT-based hybrid network which combines hand-driven and deep learning algorithms. An OCT-specific descriptor is proposed to extract hand-crafted features related to the retinal nerve fibre layer (RNFL). In parallel, an innovative CNN is developed using skip-connections to include tailored residual and attention modules to refine the automatic features of the latent space. The proposed architecture is used as a backbone to conduct a novel few-shot learning based on static and dynamic prototypical networks. The k-shot paradigm is redefined giving rise to a supervised end-to-end system which provides substantial improvements discriminating between healthy, early and advanced glaucoma samples. The training and evaluation processes of the dynamic prototypical network are addressed from two fused databases acquired via Heidelberg Spectralis system. Validation and testing results reach a categorical accuracy of 0.9459 and 0.8788 for glaucoma grading, respectively. Besides, the high performance reported by the proposed model for glaucoma detection deserves a special mention. The findings from the class activation maps are directly in line with the clinicians' opinion since the heatmaps pointed out the RNFL as the most relevant structure for glaucoma diagnosis.

Estimated Utility of the Short-term Assessment of Glaucoma Progression Model in Clinical Practice

IMPORTANCE

Clinical trials of glaucoma therapies focused on protecting the optic nerve have required large sample sizes and lengthy follow-up to detect clinically relevant change due to its slow rate of progression. Whether shorter trials may be possible with more frequent testing and use of rate of change as the end point warrants further investigation.

OBJECTIVE

To describe the design for the Short-term Assessment of Glaucoma Progression (STAGE) model and provide guidance on sample size and power calculations for shorter clinical trials.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study of patients with mild, moderate, or advanced open-angle glaucoma recruited from the Diagnostic Innovations in Glaucoma Study at the University of California, San Diego. Enrollment began in May 2012 with follow-up for every 3 months for 2 years after baseline examination. Follow-up was concluded in September 2016. Data were analyzed from July 2019 to January 2021. Visual fields (VF) and optic coherence tomography (OCT) scans were obtained at baseline and for 2 years with visits every 3 months.

EXPOSURES

Glaucoma was defined as glaucomatous appearing optic discs classified by disc photographs in at least 1 eye and/or repeatable VF damage at baseline.

MAIN OUTCOMES AND MEASURES

Longitudinal rates of change in retinal nerve fiber layer (RNFL) thickness and VF mean deviation (MD) are estimated in study designs of varying length and observation frequency. Power calculations as functions of study length, observation frequency, and sample size were performed.

RESULTS

In a total referred sample of 97 patients with mild, moderate, or advanced glaucoma (mean [SD] age, 69 [11.4] years; 50 [51.5%] were female; 19 [19.6%]), over the 2-year follow-up, the mean VF 24-2 MD slope was -0.32 dB/y (95% CI, -0.43 to -0.21 dB/y) and the mean RNFL thickness slope was -0.54 μm/y (95% CI, -0.75 to -0.32 μm/y). Sufficient power (80%) to detect similar group differences in the rate of change in both outcomes was attained with total follow-up between 18 months and 2 years and fewer than 300 total participants.

CONCLUSIONS AND RELEVANCE

In this cohort study, results from the STAGE model with reduction of the rate of progression as the end point, frequent testing, and a moderate effect size, suggest that clinical trials to test efficacy of glaucoma therapy can be completed within 18 months of follow-up and with fewer than 300 participants.

Optical coherence tomography: a window to the brain?

First described in 1991 and introduced into clinical practice in 1996, optical coherence tomography (OCT) now has a very extensive role in many different areas of ophthalmological practice. It is non-invasive, cheap, highly reproducible, widely available and easy to perform. OCT also has a role in managing patients with neurological disorders, particularly idiopathic intracranial hypertension. This review provides an overview of the technology underlying OCT and the information it can provide that is relevant to the practising neurologist. Particular conditions discussed include papilloedema, optic disc drusen, multiple sclerosis and neuromyelitis optica, other optic neuropathies, compression of the anterior visual pathway and various neurodegenerative conditions.

Comparison of ganglion cell-inner plexiform layer thickness in exfoliative glaucoma and primary open-angle glaucoma

PURPOSE

To determine and compare the thickness of the ganglion cell-inner plexiform layer (GCIPL), the thickness of the retina nerve fiber layer (RNFL), and the parameters of the optic nerve head (ONH) in exfoliative glaucoma (XFG), primary open-angle glaucoma (POAG), and control eyes using optical coherence tomography (OCT).

METHODS

The study was a retrospective observational cross-sectional study of 43 eyes of patients with XFG, 44 eyes of patients with POAG, and 37 eyes of healthy participants. Visual acuity, intraocular pressure, central corneal thickness, rim-area, disc-area, average cup/disc ratio, vertical cup/disc ratio, cup volume, average RNFL thickness, and GCIPL (average, minimum, superior, superotemporal, superonasal, inferior, inferotemporal, and inferonasal) thicknesses were determined.

RESULTS

RNFL thicknesses were similar in the XFG and POAG groups (p = 0.065), and both glaucoma groups had significantly thinner RNFLs than the controls (p = 0.002). The XFG group had significantly thinner average and minimum GCIPLs compared to the POAG and control groups (p = 0.027, p < 0.001 for average thickness and p = 0.038, p < 0.001 for minimum thickness, respectively). No significant difference was found in the ONH parameters among the three groups except for rim-area and cup volume (p > 0.05 for all ONH parameters, p < 0.001 for rim-area, and p = 0.003 for cup volume). Mean visual field mean deviation was -11.6 ± 8.2 dB in the XFG group and -10.4 ± 9.3 dB in the POAG group (p = 0.453).

CONCLUSION

Eyes with XFG were found to have a thinner GCIPL (minimum and average) than eyes with POAG or from healthy controls, although the RNFL measurements were similar to those of eyes with POAG. GCIPL thickness may be a more valuable indicator than RNFL thickness in patients with XFG for early detection of glaucoma and/or for glaucoma progression measurement. There is still some debate in the literature about whether decreases in GCIPL thickness and RNFL thickness (and/or ONH parameter change) are the best indicators for early detection and progress measurement of glaucoma.

Correlation of Ocular Biometric Parameters and Macular Ganglion Cell Layer in Normal Eyes

PURPOSE

To determine the association between ocular biometric parameters and macular ganglion cell layer (MGCL) thickness in normal eyes.

METHODS

This observational cohort study was conducted with 76 eyes of 76 healthy subjects. Keratometry, pachymetry, corneal volume, iridocorneal angle were measured with Sirius (CSO, Florence, Italy); axial length, anterior chamber depth, anterior chamber volume, corneal diameter were measured with IOL Master (Carl Zeiss Meditec, Dublin, California). For all participants, serial horizontal Spectralis Domain Optical Coherence Tomography (SD-OCT, Heidelberg Engineering, GmbH, Dossenheim, Germany) scans of the macula and peripapillary retinal nerve fiber layer (RNFL) analysis were obtained using SD-OCT. The relationship between numerical variables was given by Pearson correlation coefficient.

RESULTS

The mean age of the subjects was 36.3 ± 11.9 years (between 19 and 70 y). Fifty-one patients were female (67.1%) and twenty-five patients were male (32.9%). MGCL was found to be correlated with anterior chamber depth, anterior chamber volume, iridocorneal angle, axial length and white to white (p = .015 r = 0.594, p = .002 r = 0.365, p = .013 r = 0.299, p = .004 r = 0.335, p = .013 r = 0.289, respectively). In addition, MGCL was correlated positively with the mean global and superotemporal RNFL (p ≤ 0.005). However, neither central corneal thickness nor keratometry values were found to be correlated with MGCL.

CONCLUSION

The results of this study showed that MGCL thickness is affected by ocular biometric parameters. Therefore, these parameters should be taken into consideration when interpreting MGCL thickness measurements in the diagnosis of glaucoma.

Ageing and glaucoma progression of the retinal nerve fibre layer using spectral-domain optical coherence tomography analysis

PURPOSE

To compare the effects of ageing and glaucoma progression on the thickness of the circumpapillary retinal nerve fibre layer (cpRNFL) and to evaluate the performance of a set of optical coherence tomography (OCT) progression analyses.

METHODS

The cpRNFL was measured twice by OCT at each of two visits made 10 years apart in 69 healthy individuals and 49 glaucoma patients. Both visits also included Humphrey 24-2 SITA standard testing. The change in cpRNFL thickness was analysed by linear regression, and a sub-analysis was performed on glaucoma patients with a perimetric mean deviation better than -10 dB at the first visit. The proportion of individuals whose OCT progression analyses indicated progression was also evaluated for the same groups.

RESULTS

The average cpRNFL thickness deteriorated by a mean of -0.16 μm/year in the healthy cohort, increased by 0.03 μm/year in the glaucoma cohort, and deteriorated by -0.24 μm/year in eyes with less severe glaucoma; there were no statistically significant differences between the groups. For 17 (30%) of 56 healthy individuals, at least one of the three different OCT progression analyses incorrectly indicated progression.

CONCLUSIONS

No significant differences in change of cpRNFL thickness between visits were found when comparing healthy subjects with glaucoma patients. Also, further cpRNFL thinning was not observed in glaucomatous eyes in which at least one-third of the visual field had been lost. The OCT progression analyses generated a relatively high proportion of false positives. Using OCT for glaucoma follow-up may not be entirely straightforward.

Long-term structural and functional outcomes of primary congenital glaucoma

PURPOSE

To investigate the clinical characteristics and long-term outcomes of primary congenital glaucoma (PCG) patients.

METHODS

In this retrospective, longitudinal, cohort study, PCG patients with reliable visual field (VF) tests and optical coherence tomography (OCT) were included. Disease progression was detected using guided progression analysis with OCT and the change analysis of mean deviation (MD) slope with VF tests. Factors associated with the disease progression and visual prognosis were analyzed.

RESULTS

Twenty-nine eyes from 11 bilateral and 7 unilateral PCG patients were enrolled. LogMAR visual acuity declined (0.15 vs. 0.40, P < 0.001). The change rate of the average retinal nerve fiber layer thickness was - 0.83 ± 1.45 µm/year, and 28% of eyes showed glaucoma progression on OCT. The median of the MD slope was 0.16 (- 1.19 to 1.07) dB/year, and 14% of eyes showed glaucoma progression on the VF test. Higher average intraocular pressure (IOP) (P = 0.046) and IOP fluctuation (P = 0.031) predicted disease progression. None of the fellow eyes of unilateral PCG patients developed glaucoma during the follow-up. At last, 59% of eyes had visual acuity > 20/70, and 31% had MD >  - 6 dB. Patients with worse baseline visual acuity (P = 0.027), worse baseline MD (P < 0.001), and smaller neuroretinal rim area (P < 0.001) showed worse final MD values.

CONCLUSIONS

Aggressive IOP control is necessary to prevent structural and functional decline in PCG patients. Their fellow eyes are not at risk of glaucoma. Baseline neuroretinal rim area can predict the functional outcome.

Long-term effects of trabeculectomy in primary open-angle glaucoma on segmented macular ganglion cell complex alterations

PURPOSE

The aim of this study is to compare, using optical coherence tomography (OCT), the changes in the thickness of the macular nerve fiber layer (mNFL), macular ganglion cell layer (mGCL), macular inner plexiform layer (mIPL) and peripapillary global retinal nerve fiber layer (gRNFL) (in a span of 3 years) in surgically treated eyes with primary open-angle glaucoma (POAG).

METHODS

The medical records of 32 consecutive POAG patients who underwent trabeculectomy with mitomycin-C, between January 2013 and December 2014, were retrospectively reviewed. Pre- and postoperative measurements of IOP and OCT were analyzed 1, 2 and 3 years after the operation.

RESULTS

Among all patients, no significant changes in the thickness of the mNFL, mGCL or mIPL were found, with a significant reduction observed only in the IOP values and peripapillary gRNFL thickness during the 3-year postoperative period. In a subgroup analysis based on the preoperative peak IOPs (median value:41 mmHg), the thickness of the mNFL, mGCL and mIPL in the 3-year postoperative period increased significantly in the lower preoperative peak IOP group (IOP < 41 mmHg), whereas the macular OCT parameters in the 3-year postoperative period decreased in the higher preoperative peak IOP group.

CONCLUSIONS

Eyes exhibiting lesser preoperative peak IOP demonstrated greater preservation of the layer-by-layer segmented macular ganglion cell complex thickness as compared to eyes exhibiting greater preoperative peak IOP; also when the IOPs determined for the two groups in the period of follow-up were quite comparable.

The Paediatric Glaucoma Diagnostic Ability of Optical Coherence Tomography: A Comparison of Macular Segmentation and Peripapillary Retinal Nerve Fibre Layer Thickness

Simple Summary

Optical coherence tomography (OCT) is an established ophthalmologic diagnostic tool to visualise vital retinal structures. In glaucoma, it is used to quantify the thickness decrease in the peripapillary retinal nerve fibre layer (pRNFL) and in the macula. While glaucoma management in adults incorporates traditional clinical parameters as well as instrumental methods such as OCT, guidelines for paediatric glaucoma focus on conventional methods. Even though some reports encouraging a broader use of OCT in children are present, its diagnostic potential in this particular population has still not been sufficiently analysed. To address this, the present study compares the glaucoma discriminative ability of OCT measurements of the pRNFL and macular layers in a paediatric population. The results indicate a reduction of the pRNFL and of inner macular layer thickness in glaucoma eyes, as well as a high correlation with the presence of glaucoma. The glaucoma discriminative ability can be maximised combining either all pRNFL sectors or the thickness results of the three innermost macular layers, even though sensitivity remains moderate. In conclusion, the OCT measurements of the pRNFL and macular thickness have a strong ability to diagnose paediatric glaucoma. However, OCT should be used in addition to conventional diagnostic tools rather than as a standalone method.

Abstract

Paediatric glaucoma leads to a decreased thickness of the peripapillary retinal nerve fibre layer (pRNFL) and of the macula. These changes can be precisely quantified using spectral domain-optical coherence tomography (SD-OCT). Despite abundant reports in adults, studies on the diagnostic capacity of macular SD-OCT in paediatric glaucoma are rare. The aim of this study was to compare the glaucoma discriminative ability of pRNFL and macular segment thickness in paediatric glaucoma patients and healthy children. Data of 72 children aged 5–17 years (glaucoma: 19 (26.4%), healthy: 53 (73.6%)) examined with SD-OCT (SPECTRALIS^®, Heidelberg Engineering) were analysed retrospectively. The thickness of pRNFL sectors and of macular segment subfields were compared between diseased and healthy participants. Areas under the receiver-operating characteristic curves (AUC), sensitivity, and specificity from logistic regression were used to evaluate the glaucoma discriminative capacity of single and combined pRNFL and macular segments’ thickness. The results revealed a reduced thickness of the pRNFL and of the three inner macular layers in glaucoma patients, which correlates highly with the presence of glaucoma. The highest glaucoma discriminative ability was observed for the combination of pRNFL sectors or inner macular segments (AUC: 0.83 and 0.85, respectively), although sensitivity remained moderate (both 63% at 95% specificity). In conclusion, while confirmation from investigations in larger cohorts is required, SD-OCT-derived pRNFL and macular thickness measurements seem highly valuable for the diagnosis of paediatric glaucoma.

Early localized alterations of the retinal inner plexiform layer in association with visual field worsening in glaucoma patients

Glaucoma is a chronic neurodegenerative disease of the optic nerve and a leading cause of irreversible blindness, worldwide. While the experimental research using animal models provides growing information about cellular and molecular processes, parallel analysis of the clinical presentation of glaucoma accelerates the translational progress towards improved understanding, treatment, and clinical testing of glaucoma. Optic nerve axon injury triggers early alterations of retinal ganglion cell (RGC) synapses with function deficits prior to manifest RGC loss in animal models of glaucoma. For testing the clinical relevance of experimental observations, this study analyzed the functional correlation of localized alterations in the inner plexiform layer (IPL), where RGCs establish synaptic connections with retinal bipolar and amacrine cells. Participants of the study included a retrospective cohort of 36 eyes with glaucoma and a control group of 18 non-glaucomatous subjects followed for two-years. The IPL was analyzed on consecutively collected macular SD-OCT scans, and functional correlations with corresponding 10–2 visual field scores were tested using generalized estimating equations (GEE) models. The GEE-estimated rate of decrease in IPL thickness (R = 0.36, P<0.001) and IPL density (R = 0.36, P<0.001), as opposed to unchanged or increased IPL thickness or density, was significantly associated with visual field worsening at corresponding analysis locations. Based on multivariate logistic regression analysis, this association was independent from the patients’ age, the baseline visual field scores, or the baseline thickness or alterations of retinal nerve fiber or RGC layers (P>0.05). These findings support early localized IPL alterations in correlation with progressing visual field defects in glaucomatous eyes. Considering the experimental data, glaucoma-related increase in IPL thickness/density might reflect dendritic remodeling, mitochondrial redistribution, and glial responses for synapse maintenance, but decreased IPL thickness/density might correspond to dendrite atrophy. The bridging of experimental data with clinical findings encourages further research along the translational path.

Progressive Thinning of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer in Glaucoma Eyes with Disc Hemorrhage

PURPOSE

To evaluate the thinning of the circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) in primary open-angle glaucoma eyes with and without a history of disc hemorrhage (DH).

DESIGN

Observational cohort study.

PARTICIPANTS

Thirty-nine 39 eyes (34 participants) with DH and 117 eyes (104 participants) without DH from the Diagnostic Innovations in Glaucoma Study and the African Decent and Glaucoma Evaluation Study.

METHODS

Participants had at least 1.5 years of follow-up, with a minimum of 3 visits with biannual spectral-domain OCT cpRNFL and mGCIPL thickness measurements and visual fields (VFs). The rates of cpRNFL and mGCIPL thinning were calculated using mixed-effects models. The dynamic range-based normalized rates of cpRNFL and mGCIPL thinning were calculated and compared between the DH and non-DH groups.

MAIN OUTCOME MEASURES

Rates of cpRNFL and mGCIPL thinning.

RESULTS

The rate of mGCIPL thinning was significantly faster in the DH group compared with the non-DH group (-0.62 μm/year vs. -0.38 μm/year; P = 0.024). The rate of cpRNFL thinning in the DH quadrant and rate of mGCIPL thinning in the inferotemporal sector in the DH group were faster than the corresponding regions in the non-DH group after adjusting for intraocular pressure (-1.33 μm/year vs. -0.58 μm/year; P = 0.053) and race (-0.82 μm/year vs. -0.44 μm/year; P = 0.048). In the DH group, percent rate of loss was significantly faster for the mGCIPL than the cpRNFL (-1.59 %/year vs. -1.31 %/year; P = 0.046). Rates of mGCIPL thinning were associated weakly with mean deviation slope, VF index slope, and guided progression analysis (GPA). The areas under the receiver operating characteristic curve for VF progression were 0.75 for mGCIPL and 0.56 for cpRNFL in the DH group.

CONCLUSIONS

The rate of mGCIPL and cpRNFL thinning was faster in DH eyes than non-DH eyes. Compared with cpRNFL, mGCIPL showed higher proportional rates of thinning and greater association with functional progression. In addition to cpRNFL, clinicians should consider incorporating mGCIPL imaging to monitor glaucoma progression, especially in glaucoma eyes with DH.

Detection of Glaucoma Deterioration in the Macular Region with Optical Coherence Tomography: Challenges and Solutions

PURPOSE

Macular imaging with optical coherence tomography (OCT) measures the most critical retinal ganglion cells (RGCs) in the human eye. The goal of this perspective is to review the challenges to detection of glaucoma progression with macular OCT imaging and propose ways to enhance its performance.

DESIGN

Perspective with review of relevant literature.

METHODS

Review of challenges and issues related to detection of change on macular OCT images in glaucoma eyes. The primary outcome measures were confounding factors affecting the detection of change on macular OCT images.

RESULTS

The main challenges to detection of structural progression in the macula consist of the magnitude of and the variable amount of test-retest variability among patients, the confounding effect of aging, lack of a reliable and easy-to-measure functional outcome or external standard, the confounding effects of concurrent macular conditions including myopia, and the measurement floor of macular structural outcomes. Potential solutions to these challenges include controlling head tilt or torsion during imaging, estimating within-eye variability for individual patients, improved data visualization, the use of artificial intelligence methods, and the implementation of statistical approaches suitable for multidimensional longitudinal data.

CONCLUSIONS

Macular OCT imaging is a crucial structural imaging modality for assessing central RGCs. Addressing the current shortcomings in acquisition and analysis of macular volume scans can enhance its utility for measuring the health of central RGCs and therefore assist clinicians with timely institution of appropriate treatment.

Rates of Glaucomatous Structural and Functional Change From a Large Clinical Population: The Duke Glaucoma Registry Study

PURPOSE

To investigate rates of structural and functional change in a large clinical population of glaucoma and glaucoma suspect patients.

DESIGN

Retrospective cohort.

METHODS

Twenty-nine thousand five hundred forty-eight spectral-domain optical coherence tomography (OCT) and 19,812 standard automated perimetry (SAP) tests from 6138 eyes of 3669 patients with ≥6 months of follow-up, 2 good quality spectral-domain OCT peripapillary retinal nerve fiber layer scans, and 2 reliable SAP tests were included. Data were extracted from the Duke Glaucoma Registry, a large database of electronic health records of patients from the Duke Eye Center and satellite clinics. Rates of change for the 2 metrics were obtained using linear mixed models, categorized according to pre-established cutoffs, and analyzed according to the severity of the disease.

RESULTS

Average rates of change were -0.73 ± 0.80 μm per year for global retinal nerve fiber layer thickness and -0.09 ± 0.36 dB per year for SAP mean deviation. More than one quarter (26.6%) of eyes were classified as having at least a moderate rate of change by spectral-domain OCT vs 9.1% by SAP (P < .001). In eyes with severe disease, 31.6% were classified as progressing at moderate or faster rates by SAP vs 26.5% by spectral-domain OCT (P = .055). Most eyes classified as fast by spectral-domain OCT were classified as slow by SAP and vice versa.

CONCLUSION

Although most patients under routine care had slow rates of progression, a substantial proportion had rates that could potentially result in major losses if sustained over time. Both structural and functional tests should be used to monitor glaucoma, and spectral-domain OCT still has a relevant role in detecting fast progressors in advanced disease.

Local Glaucomatous Defects of the Circumpapillary Retinal Nerve Fiber Layer Show a Variety of Patterns of Progression

PRECIS

The region of glaucomatous progression, seen on optical coherence tomography (OCT) images of the circumpapillary retinal nerve fiber layer (cRNFL), increases in width and depth in all eyes, but shows a variety of different patterns of loss across eyes.

PURPOSE

The purpose of this study was to examine the patterns of cRNFL loss secondary to glaucomatous progression in a region associated with the superior hemifield of the 24-2/30-2 visual field (VF).

METHODS

Twenty-four eyes (20 patients) with a diagnosis of glaucoma and evidence of progression on OCT had OCT disc cube scans on at least 3 separate visits (mean follow-up 7.4 y; range: 3.9 to 11.4). Circumpapillary b-scans were derived after enface images were aligned to assure that the study region (ie, 0 to -135 degrees, where 0 degree is 9 o'clock, on a right eye) coincided. Within this region, a region of progression (ROP) was defined based on the loss in cRNFL thickness between the first and subsequent visits. The width of the ROP was determined, along with the locations of its leading (close to fixation) and trailing edges. In addition, for each ROP, the location and depth at the point of maximal loss, total loss, and average remaining retinal nerve fiber layer were measured.

RESULTS

The ROP proceeded both toward and away from fixation. Across eyes, the ROP varied widely in width (32 to 131 degrees, mean 82.7 degrees), location, and loss at point of deepest loss (22 to 99 μm, mean 52.9 μm), as well as total cRNFL loss.

CONCLUSIONS

All eyes showed a widening and deepening of the ROP, but a variety of different patterns of progressive cRNFL loss. Thus, one should expect considerable variation in patterns of VF loss. Furthermore, conventional metrics (global or quadrant cRNFL thickness) do not fully depict the progressive changes that can be appreciated by inspecting OCT images.

Macular imaging with optical coherence tomography in glaucoma

With the advent of spectral-domain optical coherence tomography, imaging of the posterior segment of the eye can be carried out rapidly at multiple anatomical locations, including the optic nerve head, circumpapillary retinal nerve fiber layer, and macula. There is now ample evidence to support the role of spectral-domain optical coherence tomography imaging of the macula for detection of early glaucoma. Macular spectral-domain optical coherence tomography measurements demonstrate high reproducibility, and evidence on its utility for detection of glaucoma progression is accumulating. We present a comprehensive review of macular spectral-domain optical coherence tomography imaging emerging as an essential diagnostic tool in glaucoma.

Custom extraction of macular ganglion cell-inner plexiform layer thickness more precisely co-localizes structural measurements with visual fields test grids

We aimed to evaluate methods of extracting optical coherence tomography (OCT)-derived macular ganglion cell-inner plexiform layer (GCIPL) thickness measurements over retinal locations corresponding to standard visual field (VF) test grids. A custom algorithm was developed to automatically extract GCIPL thickness measurements from locations corresponding to Humphrey Field Analyser 10-2 and 30-2 test grids over Goldmann II, III and V stimulus sizes from a healthy cohort of 478 participants. Differences between GCIPL thickness measurements based on VF test grids (VF-based paradigms) and the 8 × 8 grid, as per instrument review software, were analyzed, as were impacts of fovea to optic disc tilt and areas over which GCIPL thickness measurements were extracted. Significant differences between the VF-based paradigms and the 8 × 8 grid were observed at up to 55% of locations across the macula, with the greatest deviations at the fovea (median 25.5 μm, 95% CI 25.24–25.72 μm, P < .0001). While significant correlations with fovea to optic disc tilt were noted at up to 33% of locations distributed 6°–8° from the foveal center, there were no marked differences in GCIPL thickness measurements between VF-based paradigms using different stimulus sizes. As such, standard high-density OCT measurement paradigms do not adequately reflect GCIPL measurements at retinal locations tested with standard VF patterns, with the central macular region contributing most to the observed differences and with further correction required for fovea to optic disc tilt. Spatial direction of GCIPL thickness measurements will improve future comparisons of structure and function, thereby improving methods designed to detect pathology affecting the inner retina.

Cardiovascular Disease Predicts Structural and Functional Progression in Early Glaucoma

PURPOSE

To investigate the association between cardiovascular disease and baseline structural defects and disease progression in glaucoma.

DESIGN

Prospective, longitudinal study of preperimetric and perimetric glaucoma.

PARTICIPANTS

Two thousand six hundred twenty-eight eyes from 1314 participants recruited to the Progression Risk of Glaucoma: Relevant SNPs with Significant Association (PROGRESSA) study were evaluated for baseline and longitudinal structural thinning using spectral-domain OCT and for visual field progression on Humphrey visual field (HVF) assessment.

METHODS

Patients were classified as either predominantly macula ganglion cell-inner plexiform layer (mGCIPL), predominantly peripapillary retinal nerve fiber layer (pRNFL), or both mGCIPL and pRNFL structural change at enrollment, and then evaluated for longitudinal OCT or HVF progression. Cardiovascular disease and medication characteristics of the participants were compared with a reference group of stable patients.

MAIN OUTCOME MEASURES

OCT and HVF baseline status and longitudinal progression.

RESULTS

After accounting for age and cardiovascular characteristics, patients with predominantly mGCIPL thinning at baseline showed a higher prevalence of hypertension (odds ratio [OR], 2.70; 95% confidence interval [CI], 1.66-4.41; P < 0.001), antihypertensive use (OR, 2.03; 95% CI, 1.20-3.46; P = 0.008), and statin use (OR, 1.98; 95% CI, 1.07-3.66; P = 0.029) than reference patients. Patients with predominantly pRNFL thinning exhibited a comparable prevalence of cardiovascular disease or medication with reference patients. Review of longitudinal OCT and HVF data (mean follow-up, 5.34 ± 1.29 years) showed that hypertension was associated with an increased risk of both OCT (OR, 1.79; 95% CI, 1.17-2.75; P = 0.006) and HVF progression (OR, 1.92; 95% CI, 1.18-3.15; P = 0.013). A 1-standard deviation (approximately 21 mmHg) increase in systolic blood pressure at baseline was associated with a greater risk of OCT progression (OR, 1.27; 95% CI, 1.01-1.63; P = 0.041) and HVF progression (OR, 1.32; 95% CI, 1.01-1.73; P = 0.043). The association between systolic blood pressure and structural progression was comparable to that observed between intraocular pressure and structural progression (OR, 1.30; 95% CI, 1.01-1.67; P = 0.039).

CONCLUSIONS

Cardiovascular disease is an important risk factor for glaucoma progression.

Longitudinal changes in the thickness of the ganglion cell-inner plexiform layer in patients with hypertension: a 4-year prospective observational study

PURPOSE

Hypertension (HTN) is expected to accelerate age-related ganglion cell-inner plexiform layer thickness (GC-IPLs) reduction, but there is limited information on the reduction rate of GC-IPLs in HTN patients. We investigate longitudinal changes in the thickness of GC-IPL in patients with HTN.

METHODS

We performed a prospective, longitudinal and observational study design. Participants were divided into two groups: HTN group (49 eyes) and control group (56 eyes). After the initial visit, GC-IPLs were measured four times at 1-year intervals using spectral-domain optical coherence tomography. The GC-IPL reduction rate was estimated using a linear mixed model and compared between the two groups. Univariate and multivariate generalized linear mixed models were used to identify factors associated with reductions in GC-IPLs over time.

RESULTS

In a linear mixed model, the GC-IPL reduction rates for the HTN and control groups were -0.64 (p < 0.001) and -0.19 (p < 0.001) μm/year, respectively, and the interaction between group and follow-up duration was significant (p < 0.001). In the HTN group, all sectors exhibited significant reductions over time (all p < 0.001). Results from univariate and multivariate linear mixed model analyses revealed that age and IOP were significantly associated (p = 0.009 and 0.047, respectively) with reductions in GC-IPLs in HTN patients.

CONCLUSION

Patients with HTN exhibited a significant reduction in GC-IPLs compared to normal subjects. Additionally, age and IOP affected the reduction rate of GC-IPLs in HTN patients. In various ophthalmic diseases, physicians should consider the longitudinal effect of HTN on GC-IPLs.

Wide-field Trend-based Progression Analysis of Combined Retinal Nerve Fiber Layer and Ganglion Cell Inner Plexiform Layer Thickness: A New Paradigm to Improve Glaucoma Progression Detection

OBJECTIVE

Evaluation of glaucoma progression with OCT has been centered on the analysis of progressive retinal nerve fiber layer (RNFL) thinning over the parapapillary region and/or progressive ganglion cell inner plexiform layer (GCIPL) thinning over the macula. We investigated (1) whether combining the RNFL and GCIPL as a single layer (i.e., RNFL-GCIPL) for wide-field progression analysis outperforms wide-field progression analysis of the RNFL or the GCIPL, and (2) whether eyes with progressive RNFL-GCIPL thinning are at risk of visual field (VF) progression.

DESIGN

Prospective, longitudinal study.

PARTICIPANTS

A total of 440 eyes from 236 glaucoma patients; 98 eyes from 49 healthy individuals.

METHODS

OCT RNFL/GCIPL/RNFL-GCIPL thickness and VF measurements were obtained at ∼4-month intervals for ≥3 years. Progressive changes of the RNFL/GCIPL/RNFL-GCIPL thicknesses were analyzed over a wide field (12×9 mm²) covering the parapapillary region and the macula with trend-based progression analysis (TPA) controlled at a false discovery rate of 5%. VF progression was determined by the Early Manifest Glaucoma Trial criteria.

MAIN OUTCOME MEASURES

Proportions of eyes with progressive RNFL/GCIPL/RNFL-GCIPL thinning; hazard ratios (HRs) for development of VF progression.

RESULTS

More eyes showed progressive RNFL-GCIPL thinning (127 eyes; 28.9%, 95% confidence interval [CI]: 23.9%-33.8%) than progressive RNFL thinning (74 eyes; 16.8%, 95% CI: 13.1%-20.6%) and progressive GCIPL thinning (26 eyes; 5.9%, 95% CI: 3.7%-8.1%) in the glaucoma group over the study follow-up. Progressive RNFL-GCIPL thinning was almost always detected before or simultaneously with progressive RNFL thinning or progressive GCIPL thinning. The specificity of TPA (estimated from the healthy group) for detection of progressive RNFL-GCIPL thinning, progressive RNFL thinning, and progressive GCIPL thinning was 83.7% (95% CI: 74.9%-92.4%), 94.9% (95% CI: 90.6%-99.2%), and 96.9% (95% CI: 93.5%-100.0%), respectively. Eyes with progressive RNFL-GCIPL thinning had a higher risk to develop possible (HR: 2.4, 95% CI: 1.2-5.0) or likely (HR: 4.6, 95% CI: 1.5-14.0) VF progression, with adjustment of covariates, compared with eyes without progressive RNFL-GCIPL thinning.

CONCLUSIONS

Progression analysis of RNFL-GCIPL thickness reveals a significant portion of progressing eyes that neither progression analysis of RNFL thickness nor GCIPL thickness would identify. Wide-field progression analysis of RNFL-GCIPL thickness is effective to inform the risk of VF progression in glaucoma patients.

Focal alteration of the intraretinal layers in neurodegenerative disorders

Focal intraretinal alterations have been studied to advance our understanding of the pathology of neurodegenerative diseases. The current literature involving focal alterations in the intraretinal layers was reviewed through PubMed using the search terms "focal alteration", "region of interest", "optical coherence tomography", "glaucoma", "multiple sclerosis", "Alzheimer's disease", "Parkinson disease", "neurodegenerative diseases" and other related items. It was found that focal alterations of intraretinal layers were different in various neurodegenerative diseases. The typical focal thinning might help differentiate various ocular and cerebral diseases, track disease progression, and evaluate the outcome of clinical trials. Advanced exploration of focal intraretinal alterations will help to further validate their clinical and research utility.

Posture-related ocular cyclotorsion during cataract surgery with an ocular registration system

Ocular cyclotorsion when a patient changes from seated to supine position in cataract surgery and factors predicting the amount of cyclotorsion were investigated using VERION system. Variables analyzed were age, gender, preoperative visual acuity, axial length, laterality of eyes, operative duration, and the direction and degree of cyclotorsion. The mean cyclotorsion of 107 eyes of 93 cataract patients was 0.98 ± 4.85 degrees (median, 1 degree; range, -11 to 12 degrees), and the median absolute value was 4 degrees (mean, 4.05 ± 2.82 degrees; range, 0 to 12 degrees). Cyclotorsion was ≥3 degrees in 68 (63.6%) eyes. Excyclotorsion occurred more frequently than incyclotorsion (50.5% vs. 43.0%). There was no cyclotorsion in seven (6.5%). Multiple regression analysis showed that gender was a significant predictive factor for the absolute value of cyclotorsion (β = 1.06, P = 0.041); however, the other variables had no effect on cyclotorsion. The absolute value of cyclotorsion was significantly larger in female than in male patients [median, 4 degrees and 3 degrees, respectively; mean, 4.66 ± 3.02 degrees and 3.44 ± 2.52 degrees, respectively (P = 0.039)]. In conclusion, cataract patients had significant posture-related ocular cyclotorsion. The amount of cyclotorsion was larger for female than male patients.

Ganglion Cell-Inner Plexiform Layer and Retinal Nerve Fiber Layer Changes in Glaucoma Suspects Enable Prediction of Glaucoma Development

PURPOSE

To investigate whether progressive macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thinning predict development of visual field (VF) defects in glaucoma suspects.

DESIGN

Retrospective cohort study.

METHODS

This study included 541 eyes of 357 glaucoma suspects with a mean follow-up of 5.7 years. Progressive GCIPL and RNFL thinning were determined using Guided Progression Analysis (GPA) in optical coherence tomography (OCT). The development of VF defect was defined as the presence of three consecutive abnormal VFs. The risk of developing VF defect was evaluated using Cox proportional hazard models.

RESULTS

A total of 74 eyes (13.7%) and 87 eyes (16.1%) showed progressive GCIPL and RNFL thinning by OCT GPA, respectively, and 40 eyes (7.4%) developed VF defects. Eyes with progressive GCIPL (hazard ratio [HR], 7.130; 95% confidence interval [CI], 3.137-16.205) and RNFL (HR, 7.525; 95% CI, 3.272-17.311) thinning showed a significantly higher risk of developing VF defects. The rate of change in the average GCIPL and RNFL thickness was significantly higher in the eyes that developed VF defects (-0.71 and -1.13 μm/y, respectively) than the eyes that did not (-0.19 and -0.27 μm/y, respectively; all P < 0.05). Progressive GCIPL (43.1 vs. 63.1 months, respectively; P < 0.001) and RNFL (50.9 vs. 66.7 months, respectively; P < 0.001) thinning were detected significantly earlier than the development of VF defects.

CONCLUSIONS

Monitoring progressive change in GCIPL, as well as RNFL, effectively predicts the development of VF defects in glaucoma suspects.

Ganglion Cell - Inner Plexiform Layer Damage in Diabetic Patients: 3-Year Prospective, Longitudinal, Observational Study

Diabetes is expected to accelerate age-related ganglion cell–inner plexiform layer (GC-IPL) loss, but there is limited information on the rate of reduction in GC-IPL thicknesses. We aimed to evaluate the reduction rate of GC-IPL thickness in diabetic patients, and to compare the rates between patients without and with diabetic retinopathy (DR). We included 112 eyes of 112 patients with diabetes [49 eyes without DR (no-DR group) and 63 eyes with mild to moderate non-proliferative DR (NPDR group)] and 63 eyes of 63 normal controls (control group) in this study. Macular GC-IPL thickness in all participants was measured for 3 years at 1-year intervals. The reduction rates of GC-IPL thickness were determined by linear mixed models and compared among the three groups. The estimated reduction rates of the average GC-IPL thickness in the no-DR (−0.627 μm/year) and NPDR (−0.987 μm/year) groups were 2.26-fold (p = 0.010) and 3.56-fold (p = 0.001) faster, respectively, than the control group (−0.277 μm/year). Age, duration of diabetes, and baseline average GC-IPL thickness were associated with longitudinal changes in average GC-IPL thickness. The GC-IPL reduction rate was significantly faster in diabetic patients, with and without DR. Physicians should therefore be aware that GC-IPL damage continues even if there is no DR.

Ganglion Cell Complex Thickness and Macular Vessel Density Loss in Primary Open-Angle Glaucoma

PURPOSE

To characterize the change rate of ganglion cell complex (GCC) thickness and macular vessel density in healthy, preperimetric glaucoma and primary open-angle glaucoma (POAG) eyes.

DESIGN

Prospective, longitudinal study.

PARTICIPANTS

One hundred thirty-nine eyes (23 healthy eyes, 36 preperimetric glaucoma eyes, and 80 POAG eyes) of 94 patients who had at least 3 visits were included from the Diagnostic Innovations in Glaucoma Study. The mean follow-up was 2.0 years for healthy eyes, 2.6 years for preperimetric glaucoma eyes, and 2.6 years for POAG eyes.

METHODS

OCT angiography (OCTA)-based vessel density and OCT-based structural thickness of the same 3×3-mm² GCC scan slab were evaluated. The dynamic range-based normalized rates of vessel density and thickness change were calculated and compared within each diagnostic group. The association between the rates of thickness and vessel density change and potential factors were evaluated.

MAIN OUTCOME MEASURES

The rates of GCC thinning and macular vessel density loss.

RESULTS

Significant rates of GCC thinning and macular vessel density decrease were detectable in all diagnostic groups (all P < 0.05). In healthy eyes and preperimetric glaucoma eyes, the normalized rates of GCC thinning and macular vessel density decrease were comparable (all P > 0.1). In contrast, the normalized rate (mean, 95% confidence interval) of macular vessel density decrease in the POAG eyes (-7.12 [-8.36, -5.88]%/year) was significantly faster than GCC thinning (-2.13 [-3.35, -0.90]%/year; P < 0.001). In the POAG group, more than two thirds of the eyes showed faster macular vessel density decrease than GCC thinning; faster macular vessel density decrease rate was associated significantly with worse glaucoma severity (P = 0.037). The association between GCC thinning rate and glaucoma severity was not significant (P = 0.586). Intraocular pressure during follow-up significantly affected the rate of GCC thinning in all groups (all P < 0.05) but showed no association with the rate of macular vessel density decrease.

CONCLUSIONS

Both GCC thinning and macular vessel density decrease were detectable over time in all diagnostic groups. In POAG eyes, macular vessel density decrease was faster than GCC thinning and was associated with severity of disease. Macular vessel density is useful for evaluating glaucoma progression, particularly in more advanced disease.

Risk factors associated with progressive nerve fiber layer thinning in open-angle glaucoma with mean intraocular pressure below 15 mmHg

The purpose of this study was to identify risk factors associated with progressive retinal nerve fiber layer(RNFL) thinning of open-angle glaucoma(OAG) in patients whose intraocular pressure(IOP) was maintained low with medical treatment. Based on a retrospective review of medical records, OAG patients with ≥60 months of follow-up and mean IOP below 15 mmHg were recruited. All eyes underwent IOP measurement with Goldmann applanation tonometer(GAT), standard automated perimetry(SAP), and cirrus optical coherence tomography(cirrus OCT) at 6 month or 1 year intervals. RNFL thinning was assessed using the Guided Progression Analysis(GPA) software. Forty-one eyes of 41 patients (mean age 54.9 ± 13.5) were followed up for 77.8 ± 7.8 months. GPA detected 20 eyes (48.8%) with progressive RNFL thinning(−1.5 ± 0.5 um/year), who were subsequently classified as the ‘rapid progression group.’ Those whose rate of change in RNFL thickness was slower than −1.00 µm/year was classified as the ‘slow progression group’ (n = 21, −0.0 ± 0.4 um/year, P < 0.001). Mean IOP after initiating therapy was 13.2 ± 1.1 mmHg in the rapid progression group and 13.1 ± 1.3 mmHg in the slow progression group (P = 0.300; 14.8 ± 10.0% vs. 19.6 ± 12.4% reduction, P = 0.155). Disc hemorrhage was found to more frequently occur in the rapid progression group (P = 0.001). Multivariate logistic regression analysis showed that patients with disc hemorrhage were at a higher risk for progressive RNFL thinning in OAG (OR 37.529 95% CI 2.915–483.140) after adjusting for baseline co-variates (P = 0.005). In conclusion, disc hemorrhage is associated with progressive RNFL thinning in OAG with well-maintained IOP. Factors other than IOP appear to also play a role in OAG progression.

Development of a Spatial Model of Age-Related Change in the Macular Ganglion Cell Layer to Predict Function From Structural Changes

PURPOSE

To develop location-specific models of normal, age-related changes in the macular ganglion cell layer (GCL) from optical coherence tomography (OCT). Using these OCT-derived models, we predicted visual field (VF) sensitivities and compared these results to actual VF sensitivities.

DESIGN

Retrospective cohort study.

METHODS

Single eyes of 254 normal participants were retrospectively enrolled from the Centre for Eye Health (Sydney, Australia). Macular GCL measurements were obtained using Spectralis OCT. Cluster algorithms were performed to identify spatial patterns demonstrating similar age-related change. Quadratic and linear regression models were subsequently used to characterize age-related GCL decline. Forty participants underwent additional testing with Humphrey VFs, and 95% prediction intervals were calculated to measure the predictive ability of structure-function models incorporating cluster-based pooling, age correction, and consideration of spatial summation.

RESULTS

Quadratic GCL regression models provided a superior fit (P value <.0001-.0066), establishing that GCL decline commences in the late 30s across the macula. The equivalent linear rates of GCL decline showed eccentricity-dependent variation (0.13 μm/yr centrally vs 0.06 μm/yr peripherally); however, average, normalized GCL loss per year was consistent across the 64 macular measurement locations at 0.26%. The 95% prediction intervals describing predicted VF sensitivities were significantly narrower across all cluster-based structure-function models (3.79-4.99 dB) compared with models without clustering applied (5.66-6.73 dB, P < .0001).

CONCLUSIONS

Combining spatial clustering with age-correction based on regression models allowed the development of robust models describing GCL changes with age. The resultant superior predictive ability of VF sensitivity from ganglion cell measurements may be applied to future models of disease development to improve detection of early macular GCL pathology.

Longitudinal Macular Structure-Function Relationships in Glaucoma and Their Sources of Variability

PURPOSE

To review central structure-function (SF) relationships in glaucoma; to compare contributions of within-session and between-session variability to total variability of macular optical coherence tomography (OCT) thickness measurements; and to test the hypothesis that longitudinal within-eye variability of central SF relationships is smaller than between-individual variability.

METHODS

We reviewed the pertinent literature on central SF relationships in glaucoma. Thirty-eight eyes (20 normal or glaucoma subjects) had ×3 macular images per session over 3 sessions, and superpixels thickness measurements for ganglion cell layer (GCL), ganglion cell/inner plexiform layer (GCIPL), ganglion cell complex (GCC), and full macular thickness (FMT) were exported. Linear mixed models were used for estimating contributions of between- and within-session variability to total thickness variability. One hundred twenty eyes with ≥3 10° visual fields (VFs)/OCT images were enrolled for the longitudinal study. We investigated within-eye longitudinal SF relationships (GCIPL thickness vs VF total deviations) with a change-point regression model and compared within-eye to between-individual variabilities with components-of-variance models.

RESULTS

In the cross-sectional study, the between-session component contributed 8%, 11%, 11%, and 36% of total variability for GCL, GCIPL, GCC, and FMT, respectively. In the longitudinal study, between-individual variability explained 78%, 77%, and 67% of total SF variability at 3.4°, 5.6°, and 6.8° eccentricities, respectively (P < .05). SF relationships remained stable over time within individual eyes.

CONCLUSIONS

Within-session variability accounts for most of macular thickness variability over time. Longitudinal within-eye SF variability is smaller than between-individual variability. Study of within-eye SF relationships could help clinicians better understand SF linking in glaucoma and help refine progression algorithms. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Thinning rates of retinal nerve layer and ganglion cell-inner plexiform layer in various stages of normal tension glaucoma

AIMS

To compare the changes in the macular retinal nerve fibre layer (mRNFL), macular ganglion cell layer and inner plexiform layer (mGCIPL), and circumpapillary retinal nerve fibre layer (cpRNFL) in various stages of normal tension glaucoma (NTG) using spectral domain optical coherence tomography.

METHODS

Eyes with NTG (n=218) were assigned into three groups based on initial mean deviation (MD) as follows: mild (MD>-6 dB), moderate (-6 dB≥MD≥-12 dB) and severe (-12 dB>MD>-20 dB). Annual rates of change in mRNFL, mGCIPL and cpRNFL thickness were calculated by linear regression analysis.

RESULTS

Age, gender, spherical equivalent, and average intraocular pressure during follow-up were not significantly different among the three groups. There were significant differences in the mRNFL, mGCIPL and cpRNFL among the three groups at baseline (p<0.0001 in all sectors except for the mRNFL in the superonasal sector). The average thinning rates of the mRNFL, mGCIPL and cpRNFL were -0.38±0.32 µm/year, -0.62±0.46 µm/year and -0.86±0.83 µm/year, respectively. No significant difference in the rates of change in the mRNFL and mGCIPL were found among the groups in any sector. However, there was a significant difference in the rate of change in the cpRNFL among the groups (in all sectors: p<0.0001).

CONCLUSIONS

Changes in the mRNFL and mGCIPL can reflect the progression of NTG even in its advanced stage. However, careful interpretation of changes in the cpRNFL in the advanced stage of glaucoma is warranted due to a potential floor effect.

Serial Combined Wide-Field Optical Coherence Tomography Maps for Detection of Early Glaucomatous Structural Progression

Importance

Both parapapillary and macular areas are important in determining the progression of early glaucoma. However, no attempt has been made to assess the progression of glaucoma in images that combine the 2 areas.

Objective

To evaluate the potential usefulness of serial analysis of combined wide-field optical coherence tomography (OCT) maps for detection of structural progression in patients with early glaucoma.

Design, Setting, and Participants

Retrospective observational study. Patients with early primary open-angle glaucoma with a minimum of 3-year follow-up involving serial spectral-domain OCT measurement were analyzed. Patients were divided into a nonprogressor group (n = 47) and a progressor group (n = 47) on the basis of serial stereo disc photography and red-free photography. Serial combined wide-field OCT maps integrating parapapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) maps were generated with the embedded software of serial spectral-domain OCT. Glaucoma specialists then assessed the structural progression detection ability of those serial wide-field OCT maps for early glaucomatous eyes and compared their sensitivity with those of RNFL and GCIPL guided progression analyses (GPAs).

Main Outcomes and Measures

The diagnostic ability of the serial wide-field OCT maps for early glaucomatous structural progression.

Results

Ninety-four patients (mean [SD] age, 51.4 [12.3] years; 48 [51.1%] women; all Korean) were included. The serial wide-field OCT map analysis showed good agreement for detection of structural progression between the 2 glaucoma graders (wide-field OCT thickness map: κ = 0.649; wide-field OCT deviation map: κ = 0.833). These maps showed early glaucomatous structural progression detection abilities comparable with those of RNFL and GCIPL GPAs (sensitivities of wide-field OCT thickness map, wide-field OCT deviation map, RNFL GPA, and GCIPL GPA = 63.8%, 83.0%, 83.0%, and 66.0%, respectively, all P > .05; specificities of wide-field OCT thickness map, wide-field OCT deviation map, RNFL GPA, and GCIPL GPA = 93.6%, 95.7%, 84.8%, and 93.6%, respectively, all P > .05).

Conclusions and Relevance

The serial combined wide-field OCT maps integrating RNFL and GCIPL maps performed well in detecting structural progression in early glaucomatous eyes. Confirmation in an independent prospective study might provide greater confidence in this conclusion.

Assessment of Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer Changes following Cataract Surgery in Patients with Pseudoexfoliation Glaucoma

Purpose

To assess eye pressure, ganglion cell complex, and retinal nerve fiber layer changes following cataract surgery in patients with pseudoexfoliation glaucoma.

Methods

Eighty-five patients with pseudoexfoliation glaucoma (PEXG) were included in the study. They were divided into two groups; the first group included patients with PEXG and cataract who underwent phacoemulsification (pseudophakic group; n = 40 eyes). The second group included patients with PEXG without cataract (control group; n = 45 eyes). Both groups were on antiglaucoma treatment. IOP changes after surgery and the ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) thicknesses were evaluated in patients underwent cataract extraction surgery compared to controls that did not have cataract, nor underwent surgery. Both groups were followed up postoperatively for 18 months.

Results

There was no difference in the mean age and glaucoma stage in both groups (P=0.242 and 0.70, respectively). In the pseudophakic group, the mean IOP significantly dropped from 20.43 ± 0.90 to 17.00 ± 2.75 mmHg at the end of the follow-up period (P ≤ 0.001). Slight decrease (≈3 μm) was recorded in the mean GCC thickness of the pseudophakic patients from the baseline at the end of the follow-up period. This decrease was lower than that of the controls (≈5 μm). No significant pRNFL changes were recorded all over the postoperative visits (88.78 ± 22.55 μm at 3 months, 88.67 ± 23.14 μm at 6 months, 87.62 ± 23.04 μm at 12 months, and 87.32 ± 22.61 μm at 18 months) as compared to preoperative value (90.28 ± 22.31 μm) with P=0.335, 0.387, 0.158, and 0.110, respectively, or controls (89.69 ± 21.76 μm, 88.73 ± 21.08 μm, 87.33 ± 20.67 μm, and 87.23 ± 20.54 μm with P=0.850, 0.990, 0.951, and 0.984).

Conclusion

Phacoemulsification and IOL implantation may aid in managing pseudoexfoliation glaucoma by lowering IOP and slowing the rate of GCC and pRNFL losses over a short-term period.

Longitudinal Changes in the Peripapillary Retinal Nerve Fiber Layer Thickness of Patients With Type 2 Diabetes

Importance

Type 2 diabetes is expected to accelerate age-related peripapillary retinal nerve fiber layer (pRNFL) loss, but limited information on the rate of reduction in pRNFL thicknesses in patients with type 2 diabetes is available.

Objective

To investigate longitudinal changes in pRNFL thickness in patients with type 2 diabetes, with or without diabetic retinopathy (DR).

Design, Setting, and Participants

A total of 164 eyes of 63 healthy individuals and 101 patients with type 2 diabetes (49 patients without DR [non-DR group] and 52 patients with mild to moderate nonproliferative DR [NPDR group]) were enrolled in this prospective, longitudinal, observational study from January 2, 2013, through February 27, 2015. Participants were followed up for 3 years, and the peripapillary mean and sector RNFL thicknesses were measured at 1-year intervals. The mean rate of pRNFL loss was estimated using a linear mixed model and compared among the 3 groups. Follow-up was completed on March 16, 2018, and data were analyzed from April 2 through July 27, 2018.

Exposure

Type 2 diabetes.

Main Outcomes and Measures

The rate of reduction in pRNFL thickness in patients with type 2 diabetes.

Results

A total of 164 participants (88 women [53.7%]; mean [SD] age, 58.2 [8.7] years) were included in the study analysis. The mean (SD) age of the control group was 56.5 (9.3) years (39 women [61.9%]); the non-DR group, 59.1 (9.4) years (26 women [53.1%]); and the NPDR group, 59.4 (11.0) years (23 women [44.2%]). Mean (SD) duration of type 2 diabetes was 7.1 (4.4) years in the non-DR group and 13.2 (8.4) years in the NPDR group. The baseline mean (SD) pRNFL thickness was 96.2 (11.0) μm in the control group, 93.5 (6.4) μm in the non-DR group, and 90.4 (7.9) μm in the NPDR group. During 3 years of follow-up, these values decreased to 95.0 (9.2) μm in the control group, 90.3 (6.4) in the non-DR group, and 86.6 (7.9) μm in the NPDR group. In a linear mixed model, the estimated mean pRNFL loss was -0.92 μm/y in the non-DR group (P < .001) and -1.16 μm/y in the NPDR group (P < .001), which was 2.9-fold (95% CI, 1.1-14.8; P = .003) and 3.3-fold (95% CI, 1.4-18.0; P < .001) greater, respectively, than that of the control group (-0.35 μm/y; P = .01).

Conclusions and Relevance

Progressive reduction of pRNFL thickness was observed in healthy controls and patients with type 2 diabetes without and with DR; however, type 2 diabetes was associated with a greater loss of pRNFL regardless of whether DR was present. These findings suggest that pRNFL loss may occur in people with type 2 diabetes even in the absence of DR progression.

Topographic correlation and asymmetry analysis of ganglion cell layer thinning and the retinal nerve fiber layer with localized visual field defects

Purpose

To evaluate the accuracy of the measurement of the ganglion cell layer (GCL) of the posterior pole analysis (PPA) software of the Spectralis spectral-domain (SD) optical coherence tomography (OCT) device (Heidelberg Engineering, Inc., Heidelberg, Germany), the asymmetry of paired GCL sectors, the total retinal thickness asymmetry (RTA), and the peripapillary retinal nerve fiber layer (pRNFL) test to discriminate between healthy, early and advanced glaucoma eyes.

Methods

Three hundred eighteen eyes of 161 individuals with reliable visual fields (VF) were enrolled in this study. All participants were examined using the standard posterior pole and the pRNFL protocols of the Spectralis OCT device. VF impairment was graded in hemifields, and the GCL sectors were correlated with this damage. Thicknesses of each GCL, the GCL map deviation asymmetry and the pRNFL were compared between control and glaucomatous eyes. The area under the receiver operating characteristic curve (AUC) of these analyses was assessed.

Results

Fourteen of the 16 sectors of the GCL and pRNFL were significantly thinner in eyes with glaucoma than in control eyes (p<0.006). Similarly, the GCL map deviation showed a significant difference between these eyes and both the control eyes as well as the eyes with early glaucoma (p = 0.001 and p = 0.039, respectively). The highest values of AUC to diagnose both early and advanced glaucoma corresponded to the average pRNFL analysis and the GCL map deviation (AUC>0.823, p<0.040 and AUC>0.708, p<0.188, respectively).

Conclusions

Although 16 central sectors of the GCL observed with PPA showed good correlation with VF damage, the pRNFL and the GCL map deviation were more effective for discrimination of glaucomatous damage.

Comparison of Associations with Different Macular Inner Retinal Thickness Parameters in a Large Cohort: The UK Biobank

PURPOSE

To describe and compare associations with macular retinal nerve fiber layer (mRNFL), ganglion cell complex (GCC), and ganglion cell-inner plexiform layer (GCIPL) thicknesses in a large cohort.

DESIGN

Cross-sectional study.

PARTICIPANTS

We included 42 044 participants in the UK Biobank. The mean age was 56 years.

METHODS

Spectral-domain OCT macular images were segmented and analyzed. Corneal-compensated intraocular pressure (IOPcc) was measured with the Ocular Response Analyzer (Reichert, Corp., Buffalo, NY). Multivariable linear regression was used to examine associations with mean mRNFL, GCC, and GCIPL thicknesses. Factors examined were age, sex, ethnicity, height, body mass index (BMI), smoking status, alcohol intake, Townsend deprivation index, education level, diabetes status, spherical equivalent, and IOPcc.

MAIN OUTCOME MEASURES

Thicknesses of mRNFL, GCC, and GCIPL.

RESULTS

We identified several novel independent associations with thinner inner retinal thickness. Thinner inner retina was associated with alcohol intake (most significant for GCIPL: -0.46 μm for daily or almost daily intake compared with special occasion only or never [95% confidence interval (CI), 0.61-0.30]; P = 1.1×10^-8), greater social deprivation (most significant for GCIPL: -0.28 μm for most deprived quartile compared with least deprived quartile [95% CI, -0.42 to -0.14]; P = 6.6×10^-5), lower educational attainment (most significant for mRNFL: -0.36 μm for less than O level compared with degree level [95% CI, -0.45 to 0.26]; P = 2.3×10^-14), and nonwhite ethnicity (most significant for mRNFL comparing blacks with whites: -1.65 μm [95% CI, -1.86 to -1.43]; P = 2.4×10^-50). Corneal-compensated intraocular pressure was associated most significantly with GCIPL (-0.04 μm/mmHg [95% CI, -0.05 to -0.03]; P = 4.0×10^-10) and was not associated significantly with mRNFL (0.00 μm/mmHg [95% CI, -0.01 to 0.01]; P = 0.77). The variables examined explained a greater proportion of the variance of GCIPL (11%) than GCC (6%) or mRNFL (7%).

CONCLUSIONS

The novel associations we identified may be important to consider when using inner retinal parameters as a diagnostic tool. Associations generally were strongest with GCIPL, particularly for IOP. This suggests that GCIPL may be the superior inner retinal biomarker for macular pathophysiologic processes and especially for glaucoma.

Rate of three-dimensional neuroretinal rim thinning in glaucomatous eyes with optic disc haemorrhage

Background

To investigate the thinning rate of three-dimensional neuroretinal rim thickness (3D-NRT) in glaucoma eyes with optic disc haemorrhage (DH) and its relationship to retinal nerve fibre layer thickness (RNFLT) progression.

Methods

Ninety-five (95) eyes of 95 glaucoma patients with initial DH in the inferotemporal (n=69) and superotemporal (n=26) regions and 48 eyes of 48 glaucoma patients without DH were retrospectively reviewed. The rates of change for 3D-NRT and RNFLT were compared by linear mixed-effect model. For the direct comparison between 3D-NRT and RNFLT, dynamic-range-based normalised coefficient was used. The effect of DH frequency on the rates of thinning of 3D-NRT and RNFLT was evaluated.

Results

During a mean 7-year follow-up, the rates of thinning of 3D-NRT (–5.69±4.88 µm/year) and RNFLT (–2.03±2.03 µm/year) at 7 o’clock were faster than those at other locations (all p<0.05) in DH eyes. The dynamic-range-based normalised rate of thinning was significantly faster for RNFLT (–2.06%±1.62%/year) than for 3D-NRT (–1.15%±1.10%/year, p<0.001) in DH eyes, but not in non-DH eyes (p=0.43). DH frequency in the inferotemporal region was associated with the thinning rate of 3D-NRT as well as RNFLT.

Conclusion

DH eyes are associated with the progression of both 3D-NRT and RNFLT, especially in the inferotemporal region. DH eyes show a relatively faster thinning rate of average RNFLT than 3D-NRT. The frequency of DH can affect the progression of 3D-NRT as well as RNFLT.

Long-term effect of intravitreal ranibizumab therapy on retinal nerve fiber layer in eyes with exudative age-related macular degeneration

PURPOSE

To investigate long-term effect (96 months) of intravitreal ranibizumab administered for exudative age-related macular degeneration (AMD) on retinal nerve fiber layer (RNFL) thickness when used following a pro re nata regimen.

METHODS

In this prospective study, 20 eyes of 20 patients diagnosed with exudative AMD were included. Contralateral non-exudative AMD eyes of nine of these patients were included as controls. Data on intraocular pressure (IOP) and number of injections were recorded. Spectralis optic coherence tomography (OCT) of the circumpapillary RNFL was performed under dilation when diagnosis was made and before the three loading injections. "Follow-up" software was selected to accurately compare baseline with subsequent images through the 8 years of the study.

RESULTS

Baseline IOP was 14.1 mmHg both in study (standard deviation, SD: 0.8) and control eyes (SD: 0.9) and remained unchanged during the study. Mean number of injections was 21 (SD: 2.8) at the end of the study. Mean average thickness of RNFL in the study eye group at the end of the study was 96.5 μm (SD: 2.1). Mean loss for the study period was 5.3 μm (SD: 0.7; p < 0.0001). Corresponding RNFL values for controls were 92.9 (SD: 3.2) and 5.8 μm (SD: 1.2; p < 0.001). Superior temporal sector had the greatest loss in both groups, followed by inferior and nasal sectors. No statistically significant differences were found when comparing losses in injected eyes versus control eyes.

CONCLUSIONS

RNFL thickness decreased both equally in injected eyes and control eyes. Thus, no long-term effects of intravitreal ranibizumab were observed on the retinal nerve fiber layer thickness.

Changes in fundus reflectivity during myopia development in chickens

Previous studies have shown that changes in functional activity in the retina can be visualized as changes in fundus reflectivity. When the image projected on the retina is low pass filtered or defocused by covering the eye with a frosted diffuser or a negative lens, it starts growing longer and develops myopia. We have tested the hypothesis that the resulting altered retinal activity may show up as changes in fundus reflectivity. Fundus reflectivity was measured in chickens in vivo, both in visible (400-800 nm, white) and near ultraviolet (UV) light (315-380 nm). Two CCD cameras were used; a RGB camera and a camera sensitive in near UV light (peak sensitivity at 360 nm). White and UV LEDs, respectively, placed in the center of the camera lens aperture, served as light sources. Software was written to flash the LEDs and record the average brightness of the pupil that was illuminated by light reflected from the fundus. The average pixel grey level (px) in the pupil was taken as a measure of the amount of reflected light while refractive errors were corrected by trial lenses after pupil brightness was corrected for pupil size. It was found that myopic eyes had brighter pupils in UV light, compared to eyes with normal vision, no matter whether myopia was induced by diffusers or negative lenses (48 ± 9 vs. 28 ± 3, p<0.001 and 47 ± 7 vs. 27 ± 2, respectively). Using SD-OCT in alert chickens it was found that the retinal nerve fiber layer (RNFL) and the retinal ganglion cell layer (RGCL) in the central retina became thinner already at early stages of myopia development, compared to controls (31.2 ± 5.8 µm vs. 43.9 ± 2.6 µm, p<0.001 and 36.9 ± 1.2 µm vs. 44 ± 0.5 µm, respectively). While the decrease in RNFL thickness occurred concomitantly with the increase in UV reflectivity, it remains unclear whether these changes were causally linked. Thinning of the RNFL could be due to reduced neural activity in retinal ganglion cells but also due to metabolic changes in the retina during myopia development.

Retinal Nerve Fiber Layer Features Identified by Unsupervised Machine Learning on Optical Coherence Tomography Scans Predict Glaucoma Progression

Purpose

To apply computational techniques to wide-angle swept-source optical coherence tomography (SS-OCT) images to identify novel, glaucoma-related structural features and improve detection of glaucoma and prediction of future glaucomatous progression.

Methods

Wide-angle SS-OCT, OCT circumpapillary retinal nerve fiber layer (cpRNFL) circle scans spectral-domain (SD)-OCT, standard automated perimetry (SAP), and frequency doubling technology (FDT) visual field tests were completed every 3 months for 2 years from a cohort of 28 healthy participants (56 eyes) and 93 glaucoma participants (179 eyes). RNFL thickness maps were extracted from segmented SS-OCT images and an unsupervised machine learning approach based on principal component analysis (PCA) was used to identify novel structural features. Area under the receiver operating characteristic curve (AUC) was used to assess diagnostic accuracy of RNFL PCA for detecting glaucoma and progression compared to SAP, FDT, and cpRNFL measures.

Results

The RNFL PCA features were significantly associated with mean deviation (MD) in both SAP (R² = 0.49, P < 0.0001) and FDT visual field testing (R² = 0.48, P < 0.0001), and with mean circumpapillary RNFL thickness (cpRNFLt) from SD-OCT (R² = 0.58, P < 0.0001). The identified features outperformed each of these measures in detecting glaucoma with an AUC of 0.95 for RNFL PCA compared to an 0.90 for mean cpRNFLt (P = 0.09), 0.86 for SAP MD (P = 0.034), and 0.83 for FDT MD (P = 0.021). Accuracy in predicting progression was also significantly higher for RNFL PCA compared to SAP MD, FDT MD, and mean cpRNFLt (P = 0.046, P = 0.007, and P = 0.044, respectively).

Conclusions

A computational approach can identify structural features that improve glaucoma detection and progression prediction.

Macula Vessel Density and Thickness in Early Primary Open-Angle Glaucoma

PURPOSE

To characterize and compare the ganglion cell complex (GCC) thickness and macula vessel density in preperimetric and early primary open-angle glaucoma (POAG) eyes.

DESIGN

Cross-sectional study.

METHODS

Fifty-seven healthy, 68 preperimetric, and 162 early POAG eyes enrolled in the Diagnostic Innovations in Glaucoma Study. Optical coherence tomography angiography (OCT-A)-based superficial macula vessel density and OCT-based GCC thickness were evaluated simultaneously. Percent loss from normal of GCC thickness and macula vessel density was compared. Area under the receiver operating characteristic curve was used to describe the diagnostic utility.

RESULTS

Both GCC thickness and vessel density were significantly lower in preperimetric and early POAG eyes compared to healthy eyes. Compared to the preperimetric POAG group, the early POAG group showed larger GCC thickness percent loss (whole image 4.72% vs 9.86%; all P < .01) but similar vessel density percent loss (whole image 4.97% vs 6.93%; all P > .05). In preperimetric POAG, GCC thickness and vessel density percent losses were similar (all P > .1). In contrast, in early POAG, GCC thickness percent loss was larger than that of vessel density (all P ≤ .001). To discriminate preperimetric or early glaucoma eyes from healthy eyes, GCC thickness and macula vessel density showed similar diagnostic accuracy (all P > .05).

CONCLUSIONS

Both GCC thinning and macula vessel density dropout were detectable in preperimetric and early POAG eyes. GCC loss was greater than macula vessel density loss in early perimetric POAG. However, OCT-A and OCT measurements showed similar efficiency to detect early glaucoma.

Evaluation of the retinal nerve fiber layer and ganglion cell complex thicknesses in patients with exfoliation syndrome

Background/aim

This study aimed to evaluate retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thicknesses using spectral domain optical coherence tomography (SD-OCT) in both unilateral and bilateral exfoliation syndrome (XFS) patients

Materials and methods

Twenty-four patients with unilateral XFS, 20 patients with bilateral XFS, and 23 healthy subjects were enrolled in this study. Eyes with XFS were compared with both fellow eyes and age-matched control subject eyes in terms of mean and segmental RNFL thickness and minimum, mean, and segmental GCC thickness.

Results

In the bilateral XFS group, minimum GCC of the right eye (75.80 ± 11.6 μm) was significantly thinner compared with the right eyes of the control group (81.83 ± 6.6 μm) (P < 0.05). Also, superior RNFL was thinner in the right eye (106.90 ± 16.7 μm) compared with left eye (114.15 ± 18.1 μm) in the bilateral XFS group (P < 0.05). No significant differences in the unilateral XFS group were detected in GCC and RNFL analysis.

Conclusion

Minimum GCC value may be the first parameter affected in the conversion of XFS to exfoliative glaucoma followed by RNFL changes.

Inner retinal thickening in newly diagnosed choroidal neovascularization

PURPOSE

Automated segmentation of retinal layers by spectral-domain optical coherence tomography (SD-OCT) is usually erroneous in the presence of retinal diseases. The purpose of this study is to report the changes in ganglion cell complex (GCC) comprising retina nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) in neovascular age-related macular degeneration (AMD) patients by manually correcting the automated segmentation errors.

METHODS

Thirty eyes of 30 patients with new-onset choroidal neovascularization secondary to neovascular AMD and 30 eyes of 30 healthy subjects were included. The inner retinal thicknesses were measured using early treatment diabetic retinopathy circle in the central 1 mm (fovea) and surrounding 3 mm diameter (parafovea) after checking the accuracy of automated segmentation lines. Manual segmentation was done to ensure the accurate segmentation, when needed.

RESULTS

Neovascular AMD patients had thicker mean RNFL, GCL, IPL, and GCC thicknesses within the fovea compared to healthy eyes (p = 0.04, p = 0.001, p = 0.032, and p = 0.005, respectively). In the parafoveal area, among the thickness-related measurements, the only significant difference was a thicker mean RNFL (p = 0.002).

CONCLUSION

Diffuse thickening of inner retinal layers in neovascular AMD may overestimate actual GCC thickness within fovea. This pseudo-increase in GCC thickness and inner retinal layers in general likely does not reflect more cells or tissue, but rather diffuse edema which leads to a falsely increased reading of layer thickness. Such false readings may also make the assessment of other conditions that lead to reduced inner retinal layer thickness such as glaucoma, optic nerve disease, or retinovascular occlusions more difficult.

Progression of Primary Open-Angle Glaucoma in Diabetic and Nondiabetic Patients

PURPOSE

To compare the rates of visual field (VF) loss and retinal nerve fiber layer (RNFL) thinning in primary open-angle glaucoma (POAG) patients with or without type 2 diabetes mellitus (DM).

DESIGN

Cohort study.

METHODS

A total of 197 eyes (55 eyes of 32 POAG patients with DM in POAG/DM group and 142 eyes of 111 age-matched POAG patients without DM in POAG/DM- group) were included from the Diagnostic Innovations in Glaucoma Study (DIGS). Type 2 DM participants were defined by self-report of DM history and use of antidiabetic medication. The rates of VF loss and RNFL loss were compared in POAG eyes with and without DM using univariate and multivariable mixed-effects models.

RESULTS

The median (interquartile range) follow-up was 5.7 years (4.0, 6.4). The mean rate of global RNFL loss in the POAG/DM group was 2-fold slower than in the POAG/DM- group overall (-0.40 μm/year vs -0.83 μm/year, respectively P = .01). Although a slower rate of VF mean deviation and pattern standard deviation loss was found in the POAG/DM group compared to the POAG/DM- group, the difference was not statistically significant.

CONCLUSIONS

POAG patients with treated type 2 DM, who had no detectable diabetic retinopathy, had significantly slower rates of RNFL thinning compared to those without diagnosed DM.

Comparison of Changes in Macular Ganglion Cell-Inner Plexiform Layer Thickness Between Medically and Surgically Treated Eyes With Advanced Glaucoma

PURPOSE

To compare changes in the macular ganglion cell layer and inner plexiform layer (mGCIPL) thickness over 5 years between surgically treated eyes (STE) and medically treated eyes (MTE) with advanced glaucoma.

DESIGN

Retrospective, comparative case series.

METHODS

Eighty-six patients comprising 43 with open-angle glaucoma (OAG) with trabeculectomy and 43 with medically treated OAG. The mGCIPL thickness was measured more than 5 times during follow-up by optical coherence tomography. Main outcome measure was differences in mGCIPL thickness thinning rate between the groups.

RESULTS

The mean age at study initiation was 62.5 ± 9.2 years in STE and 62.7 ± 9.5 years in MTE. The mean deviations (MD), according to the Humphrey Field Analyzer central program 30-2, and the mGCIPL thickness in each sector showed no significant differences at initial measurement. The averaged intraocular pressure (IOP) throughout follow-up was 10.5 ± 2.0 mm Hg in STE and 10.8 ± 0.8 mm Hg in MTE (P = .429; Mann-Whitney U test). There was no significant difference in the MD changes over 5 years between the 2 groups (P = .405; Mann-Whitney U test). Changes in the mGCIPL thickness over 5 years in MTE were significantly greater than that in STE in all sectors (all 6 sectors P < .0001, Mann-Whitney U test). The IOP fluctuation over 5 years in STE was significantly less than that in MTE (P < .0001, Mann-Whitney U test).

CONCLUSIONS

The structure of the mGCIPL was better preserved in STE than in MTE, even when the IOPs during follow-up were similar.

Integrating Macular Ganglion Cell Inner Plexiform Layer and Parapapillary Retinal Nerve Fiber Layer Measurements to Detect Glaucoma Progression

PURPOSE

To investigate the temporal relationship among progressive macular ganglion cell inner plexiform layer (GCIPL) thinning, progressive parapapillary retinal nerve fiber layer (RNFL) thinning, and visual field (VF) progression in patients with primary open-angle glaucoma (POAG).

DESIGN

Prospective study.

PARTICIPANTS

One hundred thirty-six POAG patients (231 eyes) followed up for ≥5 years.

METHODS

OCT imaging of the macular GCIPL and parapapillary RNFL and perimetry were performed at ∼ 4-month intervals. Progressive GCIPL and RNFL thinning were determined by Guided Progression Analysis (GPA) of serial GCIPL and RNFL thickness maps. The specificities of GPA were calculated from the proportions of eyes with progressive GCIPL or RNFL thinning in 67 eyes of 36 healthy individuals followed up for ≥5 years. Visual field progression (likely or possible) was determined by the Early Manifest Glaucoma Trial criteria.

MAIN OUTCOME MEASURES

Hazard ratios for VF progression, progressive RNFL thinning, and progressive GCIPL thinning, as determined by time-varying Cox models.

RESULTS

GPA detected 57 eyes (24.7%) with progressive GCIPL thinning and 66 eyes (28.6%) with progressive RNFL thinning at a specificity of 95.5% and 91.0%, respectively. Thirty-five eyes (15.2%) demonstrated progressive RNFL and GCIPL thinning, whereas 53 eyes (22.9%) demonstrated progressive RNFL or GCIPL thinning. Eyes with progressive GCIPL thinning had a higher risk for progressive RNFL thinning (HR, 5.27; 95% confidence interval [CI], 2.89-9.62), whereas eyes with progressive RNFL thinning were also at a higher risk for progressive GCIPL thinning (HR, 2.99; 95% CI, 1.48-6.02), after adjusting for baseline covariates. The HRs for likely and possible VF progression were 3.48 (95% CI, 1.51-8.01) and 2.74 (95% CI, 1.26-5.98), respectively, on detection of progressive GCIPL thinning and 3.66 (95% CI, 1.68-7.97) and 2.54 (95% CI, 1.23-5.21), respectively, on detection of progressive RNFL thinning after adjusting for baseline covariates. Eyes with VF progression were not at risk of progressive RNFL or GCIPL thinning (P ≥ 0.493).

CONCLUSIONS

Progressive macular GCIPL thinning and progressive parapapillary RNFL thinning are mutually predictive. Because progressive RNFL thinning and progressive GCIPL thinning are both indicative of VF progression, integrating macular GCIPL and parapapillary RNFL measurements is relevant to facilitate early detection of disease deterioration in glaucoma patients.