Green disease in optical coherence tomography diagnosis of glaucoma

Intraocular pressure and optical coherence tomography concerning visual field outcomes in "green" patients: An observational study

This study investigates the relationship between intraocular pressure (IOP), optical coherence tomography (OCT) parameters, and visual field (VF) outcomes in 'Green' patients-those with normal OCT findings but potential VF abnormalities. Understanding this relationship is crucial for improving early detection and management strategies for glaucoma, especially in patients who show functional loss despite normal structural findings on OCT. A cross-sectional study was conducted at Taipei City Hospital, Renai Branch, Taiwan, from July 1, 2015, to July 1, 2023. Participants were referred for suspected glaucoma and included based on normal OCT parameters ('green' coding) and completed VF tests. Patients with any ocular disease that could confound results were excluded. Logistic regression models were used to assess relationships between IOP, OCT parameters (rim area, disc area, retinal nerve fiber layer thickness, cup-to-disc ratios, and cup volume), and VF outcomes. Age, sex, and IOP status (normal or ocular hypertension) were also included in the analysis. All data were analyzed using Statistical Package for the Social Sciences version 23.0. Larger disc area was a significant predictor of VF abnormalities, with an adjusted OR of 3.72 (95% confidence interval [CI], 1.14-12.15). Neither normal IOP nor ocular hypertension significantly predicted VF loss (adjusted OR = 0.89; 95% CI, 0.27-2.96). Female sex was associated with a higher likelihood of VF abnormalities (adjusted OR = 5.68; 95% CI, 1.03-31.25). Other OCT parameters, including retinal nerve fiber layer thickness and cup-to-disc ratios, were not significantly associated with VF outcomes. Disc area plays a critical role in predicting VF abnormalities in "green" patients, suggesting the importance of integrating disc size into screening and monitoring protocols. These findings challenge the reliance on IOP alone for predicting VF loss and support the need for more comprehensive assessments. Future research should explore longitudinal studies to further assess the predictive value of disc area and investigate additional factors, such as vascular and biomechanical influences, that may contribute to VF deterioration in this population.

Evaluation of lamina cribrosa curvature index in different types of glaucoma

OBJECTIVE

The aim of this study was to evaluate the lamina cribrosa curvature index in different types of glaucoma in comparison with clinical findings and conventional measurement methods.

MATERIAL AND METHOD

Patients older than 18 years who were followed up in Glaucoma Unit of Department of Ophthalmology at Fırat University Faculty of Medicine, whose disease had been under control at least for 1 year, who had at least three reliable visual fields, whose refractive error was between - 6 and + 5 diopter and who did not have any disease other than glaucoma that would affect the visual field, were included in the study. Clinical and demographic characteristics, visual field, optical coherence tomography and lamina cribrosa curvature index (LCCI) results were evaluated. The study patients were divided into six groups: early-stage primary open-angle glaucoma (POAG) as group 1 and intermediate-advanced stage POAG as group 2, pseudo-exfoliation glaucoma (PEXG) as group 3, normal tension glaucoma (NTG) as group 4, ocular hypertension patients whom subsequently developed POAG as group 5 and healthy control as group 6.

RESULTS

A total of 189 eyes of 101 patients were included in our study. Forty-seven patients were male (46.5%) and 54 were female (53.5%). The mean age was 62.43 ± 1.49 years. LCCI, mean deviation (MD), visual field index (VFI), pattern standard deviation (PSD) and retinal nerve fiber layer thickness (RNFL) values were analyzed in all groups and Pearson correlation analysis showed statistically significant correlation between PSD and RNFL measurements with LCCI values in all groups. MD value was correlated with LCCI in groups 2, 3 and 4, while VFI value was correlated with LCCI in all groups except group 5. When the groups were compared with each other according to the Post-Hoc Tamhane test, LCCI measurement showed statistically significant results in accordance with MD, VFI, PSD and RNFL values.

CONCLUSION

The LCCI assessment is mostly consistent with conventional tests. In this study, in which different types of glaucoma and healthy subjects were examined simultaneously, LCCI shows promise as a detailed and reliable assessment method.

From the past to the present, optical coherence tomography in glaucoma: a practical guide to a common disease

Glaucoma comprises a group of disorders of the optic nerve that cause degenerative optic neuropathy, characterised by failure of neuroretinal rim tissue in the optic nerve head, retinal nerve fibre layer, and retinal ganglion cells. Glaucoma imposes a serious epidemiological threat, with an steady increase in the global number of cases. In the current ophthalmological practice, glaucoma is diagnosed via a series of examinations, including routine funduscopic examination, ocular tonometry, gonioscopy, measurement of the visual field, and assessment using the optical coherence tomography (OCT) technique. Nowadays, the OCT technique helps in systematising the diagnostic pathway and is a basic diagnostic tool for detection of early glaucomatous eye changes. It is also vital in assessing progression and monitoring treatment results of patients. The aim of this review was to present the OCT technique as a main tool in diagnosing and monitoring glaucoma.

Glaucoma Detection Using Optical Coherence Tomography: Reviewing the Pitfalls of Comparison to Normative Data

PRCIS

Optical coherence tomography is essential in managing glaucoma. This review describes various artifacts that originate from using a normative database to compare the individual's scans. This is a review paper regarding artifacts in optical coherence tomography imaging for glaucoma arising from using a normative database as a reference for healthy retinal nerve fiber layer and ganglion cell layer.

Optical Coherence Tomography (OCT): A Brief Look at the Uses and Technological Evolution of Ophthalmology

Medical imaging is the mainstay of clinical diagnosis and management. Optical coherence tomography (OCT) is a non-invasive imaging technology that has revolutionized the field of ophthalmology. Since its introduction, OCT has undergone significant improvements in image quality, speed, and resolution, making it an essential diagnostic tool for various ocular pathologies. OCT has not only improved the diagnosis and management of ocular diseases but has also found applications in other fields of medicine. In this manuscript, we provide a brief overview of the history of OCT, its current uses and diagnostic capabilities to assess the posterior segment of the eye, and the evolution of this technology from time-domain (TD) to spectral-domain (SD) and swept-source (SS). This brief review will also discuss the limitations, advantages, disadvantages, and future perspectives of this technology in the field of ophthalmology.

Performance of neuroretinal rim thickness measurement by Cirrus high-definition optical coherence tomography in myopic eyes

Neuroretinal rim (NRR) measurement can aid the diagnosis of glaucoma. A few studies reported that Cirrus optical coherence tomography (OCT) had NRR segmentation errors. The current study investigated segmentation success of NRR in myopic eyes using the Cirrus built-in software and to determine the number of acquisitions required to identify NRR thinning. Right eye of 87 healthy adult myopes had an optic disc scanned using Cirrus HD-OCT for five successive acquisitions. A masked examiner evaluated 36 radial line images of each scan to screen for segmentation errors using the built-in software at the Bruch's membrane opening (BMO) and/or internal limiting membrane (ILM). Participants with three accurate NRR acquisitions had their average NRR thickness determined. This result was compared with average of the two acquisitions and the first acquisition. Among 435 OCT scans of the optic disc (87 eyes × 5 acquisitions), 129 (29.7%) scans had segmentation errors that occurred mainly at the ILM. The inferior-temporal and superior meridians had slightly more segmentation errors than other meridians, independent of axial length, amount of myopia, or presence of peripapillary atrophy. Sixty-five eyes (74.7%) had at least three accurate NRR measurements. The three acquisitions had high reliability in NRR thickness in the four quadrants (intraclass correlation coefficient > 0.990, coefficient of variation < 3.9%). NRR difference between the first acquisition and the average of three acquisitions was small (mean difference 2 ± 13 μm, 95% limits of agreement within ± 30 μm) among the four quadrants. Segmentation errors in NRR measurements appeared regardless of axial length, amount of myopia, or presence of peripapillary atrophy. Cirrus segmentation lines should be manually inspected when measuring NRR thickness.

Detecting disease progression in mild, moderate and severe glaucoma

PURPOSE OF REVIEW

The purpose of this review is to examine contemporary techniques for detecting the progression of glaucoma. We provide a general overview of detection principles and review evidence-based diagnostic strategies and specific considerations for detecting glaucomatous progression in patients with mild, moderate and severe disease.

RECENT FINDINGS

Diagnostic techniques and technologies for glaucoma have dramatically evolved in recent years, affording clinicians an expansive toolkit with which to detect glaucoma progression. Each stage of glaucoma, however, presents unique diagnostic challenges. In mild disease, either structural or functional changes can develop first in disease progression. In moderate disease, structural or functional changes can occur either in tandem or in isolation. In severe disease, standard techniques may fail to detect further disease progression, but such detection can still be measured using other modalities.

SUMMARY

Detecting disease progression is central to the management of glaucoma. Glaucomatous progression has both structural and functional elements, both of which must be carefully monitored at all disease stages to determine when interventions are warranted.

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.

Comparison of Diagnostic Ability Between Wide-Field Swept-Source Optical Coherence Tomography Imaging Maps and Heidelberg Retina Tomograph 3 Optic Nerve Head Assessment to Discriminate Glaucomatous and Non-glaucomatous Eyes

Background

In this study, we aimed to determine the diagnostic performance of optic nerve head (ONH), macular, and circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements of wide-field maps (12 × 9 mm) using swept-source optical coherence tomography (SS-OCT) compared to measurements of the ONH and RNFL parameters measured by Heidelberg Retina Tomograph (HRT3).

Methodology

This case-control study included 39 eyes of 39 glaucoma patients and 36 eyes of 36 normal subjects (control group). All participants underwent standard automated perimetry (SAP) as well as structural measurements by SS-OCT (DRI-OCT, Triton; Topcon Inc., Tokyo, Japan) and HRT3 (Heidelberg Engineering, Heidelberg, Germany). The abilities of the continuous parameters to discriminate between glaucoma and control groups were assessed using areas under the receiver operating characteristic curves (AUCs). To assess the glaucoma diagnostic abilities of each of the categorical variables, sensitivity, specificity, positive predictive value, and negative predictive value were tested.

Results

The highest sensitivities were achieved by the DRI-OCT categorical parameters of Superpixel-200 map and cpRNFL (12 sectors) thickness analysis. The best performing HRT3 continuous parameter was rim volume (AUC = 0.829, 95% confidence interval (CI) = 0.735-0.922), and the best continuous parameter for DRI-OCT wide-field was vertical cdr (AUC = 0.883, 95% CI = 0.805-0.951), followed by total cpRNFL thickness (AUC = 0.862, 95% CI = 0.774-0.951). AUCs for disc area, rim area, linear cdr, and RNFL thickness were not significantly different between the two technologies. Using either the most or the least specific criteria, SuperPixel-200 map always showed the highest sensitivity among the categorical parameters of both technologies (82.1% and 89.7%, respectively). The highest sensitivity among HRT3 classification parameters was shown by MRA and GPS classification algorithms.

Conclusions

Both wide-field DRI-OCT maps and HRT3 showed good diagnostic performance in discriminating glaucoma. Although DRI-OCT thickness values and normative diagnostic classification showed the best performance, more studies are required to determine the clinical role of wide-field DRI-OCT scan in glaucoma diagnosis.

Hyperglycemia induces retinal ganglion cell endoplasmic reticulum stress to the involvement of glaucoma in diabetic mice

Glaucoma is a neurodegenerative disease leading to visual loss. Since glaucoma is associated with chronic renal diseases (RDs) their rate is higher in patients with RDs, and end-stage RDs (ESRDs) than in the general population and kidney transplant recipients.

OBJECTIVE

To explore the molecular mechanism of diabetic internal environment in regulating the endoplasmic reticulum stress of the retinal ganglion cells (RGCs).

METHODS

Thirty-six SPF grade type 2 diabetes models were divided into 3 groups: Diabetes mellitus (DM), DM + glaucoma and 4-phenylbutyric acid-DM (4-PBA-DM) + glaucoma group. C57BL6 mice of the same week age were taken as the negative control (NC) group. The morphology of RGCs and their axon in the 4 groups were labeled by fluorescent reactive dye Dil. The apoptosis situation of RGCs was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. The protein expression values of RTN4IP1, Protein kinase R-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2A (eIF2a) and X-box-binding Protein 1 (XBP1) were determined by western blot. The relative mRNA levels of cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP), Caspase12 and Bax were determined by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Glaucoma promotes the apoptosis of RGCs. The protein expression values of RTN4IP1, PERK and XBP1 in DM mouse models with glaucoma were much higher compared to only DM mouse models. Further injection of endoplasmic reticulum stress inhibitor 4-PBA decreased the expression values. The relative mRNA levels of CHOP, Cysteine aspartic acid specific protease12 (Caspase12) and BCL2-associated X protein (Bax) in DM + glaucoma were significantly higher compared to those in DM group. Further injection of endoplasmic reticulum stress inhibitor 4-PBA decreased the mRNA levels.

CONCLUSION

Endoplasmic reticulum stress (ERS) is the underlying cause of glaucoma, which could promote the apoptosis of RGCs in diabetic mice.

Detection of Early Glaucomatous Damage: Performance of Summary Statistics From Optical Coherence Tomography and Perimetry

Purpose

To evaluate the diagnostic performance of optical coherence tomography (OCT) and visual field (VF) summary statistics (metrics) that are available in OCT and VF reports.

Methods

OCT disc and macular scans and 24-2 and 10-2 VFs were obtained from 56 healthy control (HC) eyes/participants and 61 eyes/patients with 24-2 mean deviation of better than –6 dB. All metrics were obtained from OCT radial, circle, and posterior pole cube scans and 24-2 and 10-2 VFs. Their diagnostic performances were evaluated, in isolation and in combinations. For specificity, the 56 HC eyes were used. For sensitivity, 40 of the 61 patient eyes were deemed likely glaucomatous based on an automated topographic method that evaluates structure–function (S–F) agreement. Any 1 of these 40 eyes not judged as abnormal by any given metric was considered a false negative.

Results

All single OCT and VF metrics misclassified HCs as glaucomatous and missed likely glaucomatous eyes. The best performing single metric was the temporal inferior thickness of the 3.5-mm circle scan, with 96% specificity and 83% sensitivity. Combinations of OCT–OCT and OCT–VF metrics markedly improved specificity. A newly proposed metric that evaluates structure–structure (S–S) agreement at a hemifield level had the highest accuracy. This S–S metric had 98% specificity and 80% sensitivity.

Conclusions

OCT and VF metrics, single or in combinations, have only moderate sensitivity for eyes with early glaucoma.

Translational Relevance

OCT and VF metrics combinations evaluating S–S or S–F agreement can be highly specific, which is an important implication for clinical and research purposes.

Evaluation of Average Retinal Nerve Fiber Layer Measurement in Eyes with Refractive Errors

SIGNIFICANCE

Optical coherence tomography (OCT) measurements of peripapillary retinal nerve fiber layer (pRNFL) play an important role in the diagnosis of glaucoma and optic atrophy. However, the interpretation of these measurements in patients with refractive errors, especially of a high degree, presents great difficulties. Optical coherence tomography instruments from most manufacturers do not take into account the effect of refractive errors, especially of a high degree, on quantitative measurements of pRNFL.

PURPOSE

The aim of this study was to develop a simple and easy method for evaluation of average pRNFL in eyes with refractive errors.

METHODS

Average pRNFL was measured by Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA) in 183 healthy White subjects (183 eyes) older than 40 years, with an axial length of the eye from 22.5 to 24.5 mm and spherical equivalent of refraction from -1.63 to 2.0 D.

RESULTS

For an average pRNFL, normative database of eyes with refraction close to emmetropia was constructed. The calculated first and fifth percentiles for age groups 41 to 50, 51 to 60, 61 to 70, and 71 to 85 years were 81 and 83, 79 and 81, 78 and 80, and 76 and 79 μm, respectively. Littmann-Bennett formula was modified to calculate a table containing first and fifth percentiles for eyes with axial lengths of 19 to 30 mm in the same age groups.

CONCLUSIONS

For the correct interpretation of the measurements of pRNFL in patients with refractive errors, an original table was proposed, which provides a quick assessment of the results obtained on the Cirrus HD-OCT device. The proposed new formulas make it easy to calculate a similar table for any optical coherence tomography device using existing databases or after collecting a normative database of eyes with refraction close to emmetropia.

Artifacts and Anatomic Variations in Optical Coherence Tomography

In recent years, ophthalmologists widely depend on optical coherence tomography (OCT), which is an objective, reliable, and repeatable structural test for both early diagnosis of glaucoma and detecting progression of the disease. Using this technology, it is now possible to take measures of various anatomic structures and layers of the optic nerve head, peripapillary retinal nerve fiber layer, and macular area. Although OCT has these powerful capabilities in general, anatomical variations, artifacts related to the ocular pathologies, and issues with image acquisition can be present in up to one-third of scans. These anatomical variations and artifacts can be misleading to an interpreter and may lead to erroneous conclusions. This review focuses on the realization and prevention of most common anatomical variations and artifacts observed with OCT imaging. The concepts of floor effect and red and green diseases are also investigated.

A Simple Subjective Evaluation of Enface OCT Reflectance Images Distinguishes Glaucoma From Healthy Eyes

Purpose

We present a subjective approach to detecting glaucomatous defects in enface images and assess its diagnostic performance. We also test the hypothesis that if reflectivity changes precede thickness changes in glaucoma there should be reduced correlation between the modalities in glaucoma compared to controls.

Methods

Twenty glaucoma participants and 20 age-matched controls underwent high-resolution OCT scans of one eye. 4 µm-thick enface slabs were constructed through the retina. Enface indices were depths of first gap in visible retinal nerve fiber bundles (RNFBs) and last visible bundle, subjectively evaluated in six sectors of a 3.5 mm circle around the optic disc. Retinal nerve fiber layer thickness (RNFLT) along the same circle was extracted at angles corresponding to enface indices. Between-group differences were tested by linear mixed models. Diagnostic performance was measured by partial receiver operating characteristic area (pAUC).

Results

First gap and last visible bundle were closer to the inner limiting membrane in glaucoma eyes (both P < 0.0001). Enface indices showed excellent diagnostic performance (pAUCs 0.63-1.00), similar to RNFLT (pAUCs 0.63-0.95). Correlation between enface and RNFLT parameters was strong in healthy (r = 0.81-0.92) and glaucoma eyes (r = 0.73-0.80).

Conclusions

This simple subjective method reliably identifies glaucomatous defects in enface images with diagnostic performance at least as good as existing thickness indices. Thickness and reflectivity were similarly related in healthy and glaucoma eyes, providing no strong evidence of reflectivity loss preceding thinning. Objective analyses may realize further potential of enface OCT images in glaucoma.

Translational Relevance

Novel enface OCT indices may aid glaucoma diagnosis.

Cut-Off Values of Foveal Vascular Indices in Exfoliation Glaucoma

PURPOSE

To compare the vascular measurements obtained from fovea including foveal avascular zone (FAZ) with optical coherence tomography angiography (OCTA) between patients with exfoliation glaucoma (XFG) and healthy controls.

METHODS

This cross-sectional comparative study included 54 XFG patients and 94 healthy subjects. All subjects were given a complete ophthalmological examination including visual field testing, retinal nerve fiber layer and macular ganglion cell complex analysis. OCTA was performed to evaluate the vascular features of fovea including FAZ. The measurements of vessel density (VD), perfusion density (PD) and FAZ values were segmented and calculated using the inbuilt software on OCTA. Receiver operating characteristic (ROC) analyses were performed to determine the best cut-off values to detect the disease.

RESULTS

In the XFG group, decreased VD, PD and FAZ values were observed. ROC analysis showed an obvious separation, differentiating the patients with XFG from the healthy controls at cut-off value of 19.55 with a sensitivity (sen) of 92.3% and a specificity (spe) of 81.9%) for VD total and 21.20 (sen:100 and spe:78.7) for VD parafoveal; 0.36 (sen:98.1and spe:76.6) for PDtotal and 0.378 (sen:96.2and spe:84) for PDparafoveal; 0.635 (sen: 79.3 and spe:72) for FAZ circulatory index.

CONCLUSION

The results support the findings of decreased microvascular density on foveal region in XFG. The cut off values of the changes in the foveal parameters in patients with exfoliation may be useful in evaluation of future glaucoma management to show how far a particular exfoliative eye is positioned from an healthy eye and how close to XFG.

Changes in Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer after Femtosecond Laser-Assisted Cataract Surgery Compared to Manual Phacoemulsification in Patients Receiving a Trifocal Intraocular Lens

Introduction

During femtosecond laser-assisted cataract surgery (FLACS), there is a significant increase in intraocular pressure, which might lead to ganglion cell damage. We aimed to determine whether there were differences in the changes produced in the ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) thickness, as evaluated with optical coherence tomography (OCT), between phacoemulsification and FLACS, after implantation of a trifocal intraocular lens (IOL).

Methods

Patients with no coexistent pathologies undergoing cataract surgery with implantation of a PanOptix IOL were explored with the Cirrus-OCT before and three months after surgery. GCC values were obtained from the built-in software. The differences between pre- and postoperative GCC and pRNFL thicknesses after phacoemulsification were compared to differences after FLACS.

Results

A total of 171 eyes were included, 74 undergoing FLACS and 97 phacoemulsification. For both groups, there was a statistically significant increase in GCC values after cataract surgery, except for the inferior and inferonasal sectors. There were no statistically significant differences between FLACS and phacoemulsification. Mean change in average GCC and minimum GCC were 1.08 ± 1.40 µm (range −1 to +6 µm) and 1.69 ± 2.54 µm (range −3 to +11 µm) after FLACS and 0.99 ± 1.67 µm (range −5 to +6 µm) and 2.02 ± 3.54 µm (−6 to +18 µm) after phacoemulsification. These values are similar to those previously reported after phacoemulsification with monofocal IOL implantation. No significant changes after surgery were detected for the pRNFL, with no differences between groups. Discussion. There were no differences in the changes produced by FLACS and phacoemulsification in either GCC or pRNFL values. Although mean change was small, the range of variation was wide. Therefore, it is necessary to establish a new baseline for GCC and pRNFL thicknesses after cataract surgery in order to monitor any subsequent changes.

Peripapillary Vessel Density In Unilateral Preperimetric Glaucoma

Purpose

To investigate vessel density (VD) of radial peripapillary capillaries (RPC) and structural alterations in patients with unilateral preperimetric glaucoma (PPG) using optical coherence tomography angiography (OCTA).

Methods

This cross-sectional observational study included 13 untreated patients with unilateral PPG. PPG eyes had larger excavation and abnormal thinning of retinal nerve fiber layer (RNFL) and/or ganglion cell complex (GCC) compared with fellow eyes (F). Both RNFL and GCC thickness in F were statistically within normal limits and/or borderline. The RPC VD on optic disc (idVD), of peripapillary (ppVD) and whole image (wiVD) scan area was measured. Twenty healthy eyes (H) served as controls. Structural and vascular parameters obtained by spectral-domain OCT/OCTA (Optovue; Fremont, CA) were compared between PPG, F and H.

Results

Mean RNFL and GCC average thickness in microns differed significantly (p<0.001) between PPG (82.4±7.1, 81.4±5.9), F (91.0±7.1, 88.5±3.8) and H (103.5±6.0, 99.3±5.7). PPG compared with F showed significantly (p<0.001) lower mean ppVD (43.8%±3.0% versus 47.8%±3.2%) and wiVD (45.9%±3.5% versus 50.1%±3.9%). Mean ppVD (49.7%±2.4%) and wiVD (52.6%±3.0%) in H were not significantly higher than in F. Mean idVD showed no significant differences among the 3 groups. Areas under the receiver operating characteristic curves (AUROCs) for RNFL, GCC, ppVD and wiVD between PPG and H were excellent (>0.9). AUROCs between F and H demonstrated an excellent diagnostic ability for structural parameters and a poor one (<0.7) for vascular parameters.

Conclusion

Affected eyes of patients with unilateral PPG demonstrated significant RPC dropout. Clinically unaffected eyes showed thinner structural parameters but no significant microvasculature differences compared with non-glaucomatous eyes. Diagnostic ability of peripapillary vascular parameters was not superior to structural measurements. Microvascular dysfunction seems to be an early but not a primary event in glaucoma continuum at the stage of undetectable visual field loss. OCTA can be useful in early glaucoma diagnosis.

Exploring the gap between diagnostic research outputs and clinical use of OCT for diagnosing glaucoma

AIMS

To explore the gap between diagnostic research outputs and clinical use of optical coherence tomography (OCT) in glaucoma and assess the reliability of a specific reference database when applied to a morphological imaging parameter for diagnostic purposes.

METHODS

Consecutive subjects enrolled in the Multicenter Italian Glaucoma Imaging Study (MIGIS) have been included in this cross-sectional, comparative evaluation of diagnostic tests study. Patients underwent measurement of global and sectorial peripapillary retinal nerve fibre thickness (pRNFL) and minimum rim width (MRW) by OCT. The sensitivity and specificity of reference-database categorical classifications were calculated by means of 2×2 tables and sensitivity was compared with that of the corresponding continuous parameter extracted from the receiver operating characteristic (ROC) curves by matching the specificity.

RESULTS

280 Caucasian subjects have been included. At matched specificities, the sensitivity of pRNFL categorical classifications was statistically similar to that of the corresponding continuous parameters, whereas the sensitivity of the MRW categorical classifications was significantly lower than that of the corresponding continuous parameters.

CONCLUSIONS

The diagnostic accuracy of reference database classifications might be lower than that extrapolated from the ROC curves of continuous parameters used in diagnostic research. The gap between the accuracy of these two approaches may be used to estimate the reliability of a specific reference database when applied to a continuous parameter for diagnostic purposes.

The vitreopapillary interface in healthy and glaucoma: posterior vitreous detachment in the vitreopapillary interface study

PURPOSE

To investigate the vitreopapillary interface (VPI) in health and glaucoma according to the different stages of posterior vitreous detachment (PVD) formation.

METHODS

Prospective single centre study including healthy subjects and glaucoma patients. PVD staging was performed with spectral domain optical coherence tomography. Gender, age, lens status and refractive error were assessed in both groups. Glaucoma patients additionally had a comprehensive ophthalmological investigation including intraocular pressure measurement, visual field testing and confocal imaging of the optic nerve head.

RESULTS

Data on 523 subjects (993 eyes) were included from the VPI study (clinicaltrials.gov NCT02290795) database (493 eyes of 258 healthy subjects and 500 eyes of 265 glaucoma patients). Healthy subjects were significantly younger than primary open angle glaucoma patients (59.7 ± 14.81 versus 70.0 ± 10.78 years, p < 0.001), but were otherwise matched for refractive error and gender. Significantly more glaucomatous eyes were pseudophakic (26.6% versus 5.1%). Including only phakic nonoperated eyes from subjects between 50 and 80 years old decreased the age difference between healthy and open angle glaucoma (64.1 ± 8.0 versus 65.9 ± 6.7 years, p = 0.051). Comparing these subgroups rendered similar average ages for PVD stages 0 and 4, in contrast to the significant older age for the glaucoma subgroup in stage 1 (64.1 ± 6.01 versus 61.4 ± 8.38 years, p < 0.001) and a trend towards significance in stage 3 (70.8 ± 69.8 versus 67.5 ± 5.92 years, p = 0.051).

CONCLUSION

The VPI study is a large clinical trial investigating the VPI in health and glaucoma. A subset of glaucoma patients seems to experience stages 1-3 of PVD formation at older age compared to healthy subjects.

Validation of the UNC OCT Index for the Diagnosis of Early Glaucoma

Purpose

To independently validate the performance of the University of North Carolina Optical Coherence Tomography (UNC OCT) Index in diagnosing and predicting early glaucoma.

Methods

Data of 118 normal subjects (118 eyes) and 96 subjects (96 eyes) with early glaucoma defined as visual field mean deviation (MD) greater than -4 decibels (dB), aged 40 to 80 years, and who were enrolled in the Full-Threshold Testing Size III, V, VI comparison study were used in this study. CIRRUS OCT average and quadrants' retinal nerve fiber layer (RNFL); optic disc vertical cup-to-disc ratio (VCDR), cup-to-disc area ratio, and rim area; and average, minimum, and six sectoral ganglion cell-inner plexiform layer (GCIPL) measurements were run through the UNC OCT Index algorithm. Area under the receiver operating characteristic curve (AUC) and sensitivities at 95% and 99% specificity were calculated and compared between single parameters and the UNC OCT Index.

Results

Mean age was 60.1 ± 11.0 years for normal subjects and 66.5 ± 8.1 years for glaucoma patients (P < 0.001). MD was 0.29 ± 1.04 dB and -1.30 ± 1.35 dB in normal and glaucomatous eyes (P < 0.001), respectively. The AUC of the UNC OCT Index was 0.96. The best single metrics when compared to the UNC OCT Index were VCDR (0.93, P = 0.054), average RNFL (0.92, P = 0.014), and minimum GCIPL (0.91, P = 0.009). The sensitivities at 95% and 99% specificity were 85.4% and 76.0% (UNC OCT Index), 71.9% and 62.5% (VCDR, all P < 0.001), 64.6% and 53.1% (average RNFL, all P < 0.001), and 66.7% and 58.3% (minimum GCIPL, all P < 0.001), respectively.

Conclusions

The findings confirm that the UNC OCT Index may provide improved diagnostic perforce over that of single OCT parameters and may be a good tool for detection of early glaucoma.

Translational Relevance

The UNC OCT Index algorithm may be incorporated easily into routine clinical practice and be useful for detecting early glaucoma.

Glaucoma suspects: A practical approach

Glaucoma suspects are controversial clinical dilemmas. These individuals harbor certain risk factors or demonstrate some clinical features suggestive of an increased probability to develop glaucomatous optic atrophy in the future. These characteristics range from high intraocular pressure; optic disc, visual field, or retinal nerve fiber layer abnormalities; or abnormal angles to a positive family history of glaucoma and other risk factors. Individuals having these characteristics should be assessed diligently before a diagnosis of glaucoma is made. Glaucoma is a chronic, lifelong condition, having a negative impact on the quality of life, with an increased risk of medication-related side-effects, adverse economic impacts, and the need for lifestyle changes in the patient. Overdiagnosis and unnecessary treatment of such individuals is bereft of any advantage. This review aims to provide a practical blueprint for the proper diagnosis and management of such glaucoma suspects.

Will Perimetry Be Performed to Monitor Glaucoma in 2025?

Visual field testing has played an essential role in the diagnosis and management of glaucoma for more than a century. Methods to examine the visual field have been refined from early kinetic perimetry to current standard automated perimetry (SAP). Clinicians now use SAP for the diagnosis and management of glaucoma throughout the world. Various testing paradigms and analytic methods have been developed to simplify the diagnosis of glaucoma and the interpretation of progression. Moreover, strategies have been implemented to improve patient experience with visual field testing and to increase reliability. Objective functional tests, such as electroretinography, provide an alternative to subjective visual field testing but are not yet ready for widespread adoption. Standard automated perimetry is being adapted and improved constantly. New devices may allow patients to complete visual field tests at home, which could relieve patients and clinicians from in-office testing and allow for more frequent examinations. Glaucoma detection and progression analysis also are incorporating progressively more information and will be improved as deep learning strategies are applied. Finally, perimetric and structural testing likely will become more closely intertwined as testing platforms and progression analysis incorporate both of these measures. Visual field testing will continue to have an important role in the diagnosis and management of glaucoma.