Optical Coherence Tomography Can Be Used to Assess Glaucomatous Optic Nerve Damage in Most Eyes With High Myopia.

PRECIS: It is generally assumed that optical coherence tomography (OCT) cannot be used to diagnose glaucomatous optic neuropathy (GON) in high myopes. However, this study presents evidence that there is sufficient information in OCT scans to allow for accurate diagnosis of GON in most eyes with high myopia. PURPOSE: The purpose of this study was to test the hypothesis that glaucomatous damage can be accurately diagnosed in most high myopes via an assessment of the OCT results. PATIENTS AND METHODS: One hundred eyes from 60 glaucoma patients or suspects, referred for OCT scans and evaluation, had corrected spherical refractive errors worse than -6 D and/or axial lengths ≥26.5 mm. An OCT specialist judged whether the eye had GON, based upon OCT circle scans of the disc and cube scans centered on the macula. A glaucoma specialist made the same judgement using all available information (eg, family history, repeat visits, intraocular pressure, 10-2 and 24-2 visual fields, OCT). A reference standard was created based upon the glaucoma specialist's classifications. In addition, the glaucoma specialist judged whether the eyes had peripapillary atrophy (PPA), epiretinal membrane (ERM), tilted disc (TD), and/or a paravascular inner retinal defect (PIRD). RESULTS: The OCT specialist correctly identified 97 of the 100 eyes using the OCT information. In 63% of the cases, the inner circle scan alone was sufficient. For the rest, additional scans were requested. In addition, 81% of the total eyes had: PPA (79%), ERM (18%), PIRD (26%), and/or TD (48%). CONCLUSIONS: For most eyes with high myopia, there is sufficient information in OCT scans to allow for accurate diagnosis of GON. However, the optimal use of the OCT will depend upon training to read OCT scans, which includes taking into consideration myopia related OCT artifacts and segmentation errors, as well as PPA, ERM, PIRD, and TD.

Association of Macular Visual Field Measurements With Glaucoma Staging Systems.

Importance: Macular function is important for daily activities but is underestimated when tested with 24-2 visual fields, which are often used to classify glaucoma severity. Objective: To test the hypothesis that current glaucoma staging systems underestimate glaucoma severity by not detecting macular damage. Design, Setting, and Participants: This cross-sectional study was carried out in a glaucoma referral practice. The eyes of participants with manifest glaucoma and 24-2 mean deviation (MD) better than -6 dB were included. All participants were tested with 24-2, 10-2 visual fields, and spectral-domain optical coherence tomography of the optic disc and macula. Exposures: Macular damage was based on the topographic agreement between visual field results and retinal ganglion cell plus inner plexiform layer probability plots. Classifications from the Hodapp-Parrish-Anderson (HPA), visual field index (VFI), and Brusini staging systems were examined and compared with visual field and spectral-domain optical coherence tomography results. Main Outcomes and Measures: The association between the presence of macular damage and glaucoma severity scores. Results: Fifty-seven eyes of 57 participants were included; 33 participants (57%) were women, and 43 (75%) were white. Their mean (SD) age was 57 (14) years. Forty-eight of the eyes (84% [95% CI, 72%-92%]) had macular damage by the study definition. These had a 24-2 MD mean (SD) of -2.5 (1.8); corresponding results for the 10-2 MD were -3.0 (2.4) dB and for the VFI were 94.2% (4.5%). The HPA system classified 70% (95% CI, 55%-83%) of eyes with macular damage as having early defects; the VFI system classified 81% (95% CI, 67%-91%) of eyes with macular damage as having early defects, and the Brusini system 68% (95% CI, 53%-81%). Conclusions and Relevance: These findings suggest that current glaucoma staging systems based on 24-2 (or 30-2) visual fields underestimate disease severity and the presence of macular damage. If these results are confirmed and generalizable to other participants, new systems using macular measures (from 10-2 and spectral-domain optical coherence tomography results) might improve staging of glaucoma severity.

Progression of Local Glaucomatous Damage Near Fixation as Seen with Adaptive Optics Imaging.

PURPOSE: Deep glaucomatous defects near fixation were followed over time with an adaptive optics-scanning light ophthalmoscope (AO-SLO) to better understand the progression of these defects and to explore the use of AO-SLO in detecting them. METHODS: Six eyes of 5 patients were imaged with an AO-SLO from 2 to 4 times for a range of 14.6 to 33.6 months. All eyes had open-angle glaucoma with deep defects in the superior visual field (VF) near fixation as defined by 10-2 VFs with 5 or more points less than -15 dB; two of the eyes had deep defects in the inferior VF as well. AO-SLO images were obtained around the temporal edge of the disc. RESULTS: In 4 of the 6 eyes, the edge of the inferior-temporal disc region of the retinal nerve fiber (RNF) defect seen on AO-SLO moved closer to fixation within 10.6 to 14.7 months. In 4 eyes, RNF bundles in the affected region appeared to lose contrast and/or disappear. CONCLUSIONS: Progressive changes in RNF bundles associated with deep defects on 10-2 VFs can be seen within about 1 year with AO-SLO imaging. These changes are well below the spatial resolution of the 10-2 VF. On the other hand, subtle thinning of regions with RNF bundles is not easy to see with current AO-SLO technology, and may be better followed with OCT. TRANSLATIONAL RELEVANCE: AO-SLO imaging may be useful in clinical trials designed to see very small changes in deep defects.

Optical Coherence Tomography and Glaucoma Progression: A Comparison of a Region of Interest Approach to Average Retinal Nerve Fiber Layer Thickness.

PURPOSE: To determine whether the change in the retinal nerve fiber layer (RNFL) thickness in a region of interest (ROI) is a better measure of glaucoma progression than the change in average circumpapillary (cp) RNFL thickness. METHODS: Disc cube scans were obtained with frequency domain optical coherence tomography from 60 eyes of 60 patients (age, 61.7±12.7 y) with early or suspected glaucoma and controlled intraocular pressure. The average time between 2 test dates was 3.2±1.8 years. En-face images of the scans from the 2 tests were aligned based on the blood vessels, and cp images were derived for an annulus 100 µm wide and 3.4 mm in diameter, centered on the disc. An ROI was defined as the portion of the circumpapillary retinal nerve fiber layer (cpRNFL) plot within the temporal disc that extended below the 1% confidence interval for ≥5 degrees. Trend analysis using multilevel mixed-effects models was used to compare the rates of change between ROI width and average cpRNFL thickness. RESULTS: In total, 26 of the 60 eyes had a total of 33 ROIs. The ROI width significantly increased between the 2 test dates (median, 4.9 degrees; Q1=1.03 degrees, Q3=10.5 degrees). In comparison, the average cpRNFL thickness did not decrease significantly over the same period (median, -0.7 µm; Q1=-2.7 µm, Q3=2.7 µm). Mixed-effects linear models confirmed significant ROI progression (P=0.015), but not average cpRNFL (P=0.878). CONCLUSIONS: In this population, RNFL thinning in a ROI is a better measure of progression than is average cpRNFL thickness change.

A Single Wide-Field OCT Protocol Can Provide Compelling Information for the Diagnosis of Early Glaucoma.

PURPOSE: To evaluate a report for glaucoma diagnosis based on a single optical coherence tomography (OCT) protocol. METHODS: A wide-field (9 × 12 mm) swept-source (SS) OCT scan, encompassing the macula and disc, was obtained on 130 eyes (patients) with or suspected open-angle glaucoma, a mean deviation greater than or equal to -6 dB on a 24-2 visual field (VF), and spherical refractive error between ± 6 diopters (D). The single-page report contained a circumpapillary retinal nerve fiber layer (cpRNFL) thickness plot; retinal ganglion cell layer and retinal nerve fiber layer (RNFL) thickness and probability plots of the macula and optic nerve; and an enface slab image of the optic nerve. A report specialist judged each eye as healthy (H); probably healthy (PH); forced-choice healthy (FC-H); optic neuropathy (ON); probably ON (PON); forced-choice optic neuropathy (FC-ON). Two glaucoma specialists made similar judgments about the presence of glaucomatous damage. The glaucoma specialists had 24-2 and 10-2 VFs, fundus photos, patient chart information, and the single-page report including the report specialist's interpretation. RESULTS: The reference standard consisted of 57 eyes judged as glaucomatous (ON or PON) and 45 eyes judged as healthy (H or PH) by both glaucoma specialists. The report specialist identified 56 of the glaucomatous eyes as optic neuropathy (i.e., ON, PON, or FC-ON), and 44 of the healthy eyes as healthy (i.e., H, PH, or FC-H), an accuracy of 98.0%. CONCLUSIONS: A single-page report based upon a single, wide-field OCT scan has the information needed to diagnose early glaucoma with excellent sensitivity/specificity. TRANSLATIONAL RELEVANCE: It is possible that screening for glaucoma can be effective with only a single OCT protocol.

A Region-of-Interest Approach for Detecting Progression of Glaucomatous Damage With Optical Coherence Tomography.

IMPORTANCE: Detecting progression of glaucomatous damage is often challenging. OBJECTIVE: To test the feasibility of using frequency-domain optical coherence tomography (FD-OCT) and a region-of-interest (ROI) approach to measure progressive changes in glaucomatous damage. DESIGN, SETTING, AND PARTICIPANTS: Among a group of patients in an institutional glaucoma practice who were likely to show glaucoma progression, eyes with a history of an optic disc hemorrhage (DH) confirmed by stereophotography were followed up with FD-OCT cube scans of the optic disc. All patients underwent FD-OCT scans on at least 2 occasions separated by at least 1 year (mean, 3.45 years; range, 1.42-6.39 years). Because we were not studying the effects of an optic DH, no constraint was placed on the time between the documentation of an optic DH and the first scan used in the analysis. MAIN OUTCOMES AND MEASURES: After en face images of the FD-OCT scan were aligned based on the blood vessels, circumpapillary images were derived for an annulus 100 µm in width, and the retinal nerve fiber layer (RNFL) thickness profiles were plotted for the first and last visits. The ROI width associated with the optic DH was defined as the region of the RNFL profile below the 1% CI based on healthy norms. The change in the ROI width was compared with the change in the global RNFL thickness, which was obtained by averaging the circumpapillary RNFL thickness. RESULTS: The change in the ROI width (mean [SD], 8.0° [6.4°]; 95% CI, 4.9° to 11.1°; range, -0.7° to 19.3°) was significant (P < .001, 2-tailed t test) while the change in the global thickness (mean [SD], 2.40 [5.87] µm; 95% CI, -0.48 to 5.28 µm) was not significant (P > .12, 2-tailed t test). Although 15 of the 16 ROIs increased in width between visits, only 11 showed a decrease in the global RNFL thickness. CONCLUSIONS AND RELEVANCE: For detecting progression of local RNFL damage in patients with glaucoma, an OCT ROI approach appears superior to the OCT global RNFL thickness measure typically used.