Relative Ellipsoid Zone Reflectivity in Macular Telangiectasia Type 2.

Purpose: The relative ellipsoid zone reflectivity (rEZR) has been proposed as an innovative biomarker for photoreceptor integrity. This study evaluates the rEZR in macular telangiectasia type 2 (MacTel) eyes of different disease stages. Methods: The mean rEZR (ratio ellipsoid zone [EZ]/external limiting membrane [ELM] reflectivity [arbitrary units {AUs}], grey level range = 0-1) was analyzed for an entire spectral domain optical coherence tomography volume scan (global) and for each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid (topographic) in patients with MacTel and controls. MacTel disease severity was classified according to Gass and Blodi. Results: Linear mixed-model analysis of 145 eyes of 74 patients and 50 eyes of 25 controls revealed globally lower, yet not statistically significant, rEZR values in MacTel eyes. Topographically, most pronounced decreases were found in stages 3 and 4/5 for the temporal inner (coefficient estimates [CEs] = -25.4 [-38.2; -12.6] and -34.1 [-48.7; -19.6] AU, both: P < 0.001), the inferior inner (-29.9 [-44.6; -15.6] and -35.3 [-52.1; -18.5] AU, both: P < 0.001), the nasal inner (-21.5 [-35.52; -7.4] and -31.6 [-47.6; -15.6] AU, P = 0,003 and P < 0.001), and in the superior inner subfield of stage 4/5 (-25.0 [-42.0; -7.9] AU, P = 0.004). Conclusions: The rEZR showed association with disease severity and the predilection area of MacTel. Given the current understanding of the pathophysiological concept of MacTel, these findings underscore the value of the rEZR as a potential novel biomarker for outer retinal integrity. Longitudinal studies are demanded to better characterize its value as a biomarker for early photoreceptor alterations and disease progression in MacTel.

Relative ellipsoid zone reflectivity and its association with disease severity in age-related macular degeneration: a MACUSTAR study report.

Quantification of the relative ellipsoid zone reflectivity (rEZR) might be a structural surrogate parameter for an early disease progression in the context of age-related macular degeneration (AMD). Within the European multicenter, cross-sectional MACUSTAR study, we have devised an automatic approach to determine the mean rEZR [arbitrary units, AU] at two independent visits in SD-OCT volume scans in study participants. Linear mixed-effects models were applied to analyze the association of AMD stage and AMD associated high-risk features including presence of pigmentary abnormalities, reticular pseudodrusen (RPD), volume of the retinal-pigment-epithelial-drusenoid-complex (RPEDC) with the rEZR. Intra-class correlation coefficients (ICC) were determined for rEZR reliability analysis. Within the overall study cohort (301 participants), we could observe decreased rEZR values (coefficient estimate ± standard error) of - 8.05 ± 2.44 AU (p = 0.0011) in the intermediate and of - 22.35 ± 3.28 AU (p < 0.0001) in the late AMD group. RPD presence was significantly associated with the rEZR in iAMD eyes (- 6.49 ± 3.14 AU; p = 0.0403), while there was a good ICC of 0.846 (95% confidence interval: 0.809; 0.876) in the overall study cohort. This study showed an association of rEZR with increasing disease severity and the presence of iAMD high-risk features. Further studies are necessary to evaluate the rEZR's value as a novel biomarker for AMD and disease progression.

Natural History of the Relative Ellipsoid Zone Reflectivity in Age-Related Macular Degeneration.

PURPOSE: Relative ellipsoid zone reflectivity (rEZR) has been reported to be reduced in intermediate age-related macular degeneration (iAMD). However, longitudinal changes in rEZR remain unknown. This study investigated the natural history of rEZR in iAMD and its association with risk factors for disease progression, including the presence or extent of drusen volume, reticular pseudodrusen (RPD), and pigmentary abnormalities (PAs). DESIGN: Longitudinal observational study. PARTICIPANTS: Subjects with bilateral large drusen. METHODS: Spectral-domain (SD) OCT images of both eyes from each participant were obtained every 6 months for 3 years. Using an automated rEZR determination approach, the average rEZR of the central 20° macula was determined for each SD-OCT volume scan. Linear mixed models were used to determine the rate of change in rEZR with age (using the cross-sectional data at baseline) and over time (longitudinal data) and the interactions between the rate of rEZR changes with AMD risk factors at baseline. MAIN OUTCOME MEASURES: Relative ellipsoid zone reflectivity and its rate of change with age and over time. RESULTS: A total of 280 eyes from 140 individuals with bilateral large drusen were included in this study. Cross-sectional data showed that rEZR reduced with increasing age (-8.4 arbitrary units [AUs] per decade; 95% confidence interval [CI], -11.5 to -5.2; P < 0.001). Longitudinal data showed that, on average, rEZR declined at a rate of -2.1 AU per year (95% CI, -2.6 to -1.6 AU per year; P < 0.001). Larger RPD area (P = 0.042) at baseline was associated with a faster rate of rEZR decline over time, whereas the presence of PAs and the drusen volume at baseline showed no significant association with rEZR decline over time (P = 0.068 and P = 0.529, respectively). CONCLUSIONS: The rEZR significantly reduces over 3 years in subjects with iAMD, and both the presence and increasing extent of coexistent RPD at baseline are associated with a faster rate of decline. These findings warrant further studies to understand the value of rEZR as a biomarker of AMD progression.

Effect of subthreshold nanosecond laser on retinal structure and function in intermediate age-related macular degeneration.

BACKGROUND: Subthreshold nanosecond laser (SNL) treatment has been studied as a potential intervention in intermediate age-related macular degeneration (iAMD). This study investigated the effect of 100 SNL treatment spots on retinal structure and function. METHODS: A prospective single-arm interventional pilot study. SNL treatment was delivered as 100 spots around the retinal vascular arcades of the study eye (worst visual acuity) in a single session in subjects with iAMD. Multimodal retinal imaging and dark-adapted chromatic perimetry were performed at baseline and at 0.5, 3, 6 and 12 months post treatment. Post treatment changes in best corrected visual acuity (BCVA), retinal thickness, relative ellipsoid zone reflectivity (rEZR) and rod-mediated functional parameters were compared to baseline. RESULTS: Twenty-one subjects with iAMD were recruited. SNL treatment was associated with an increase in retinal thickness (p = 0.008) and decrease in rEZR (p < 0.001) at 2 weeks post laser. Recovery of retinal thickness and rEZR was observed at the 3-month post laser visit. A gradual improvement in BCVA was observed after laser treatment. The mean change in BCVA between baseline and 12-month visit was +1.9 ± 3.3 letters for the SNL treated eyes, compared to -0.4 ± 3.0 letters for the fellow eyes (p = 0.027). Rod-mediated function improved at 3 months post laser (p < 0.001) and returned to the baseline levels at 12 months post treatment. CONCLUSIONS: A single treatment with 100 SNL spots causes a short-term change in retinal structure and improvement in retinal function that are apparent at 3 months post treatment.

Validation of an Automated Quantification of Relative Ellipsoid Zone Reflectivity on Spectral Domain-Optical Coherence Tomography Images.

Purpose: Relative ellipsoid zone reflectivity (rEZR) represents a potential biomarker of photoreceptor health on spectral-domain optical coherence tomography (SD-OCT). Because manual quantification of rEZR is laborious and lacks of spatial resolution, automated quantification of the rEZR would be beneficial. The purpose of this study was to evaluate the reliability and reproducibility of an automated rEZR quantification method. Methods: The rEZR was acquired using a manual and an automated approach in eyes with age-related macular degeneration (AMD) and healthy controls. The rEZR obtained from both methods was compared and the agreement between the methods and their reproducibility assessed. Results: Forty eyes of 40 participants with a mean (± standard deviation) age of 65.2 ± 7.8 years were included. Both the manual and automated method showed that control eyes exhibit a greater rEZR than AMD eyes (P < 0.001). Overall, the limits of agreement between the manual and automated method were -7.5 to 7.3 arbitrary units (AU) and 95% of the data points had a difference in the rEZR between the methods of ±8.2%. An expected perfect reproducibility was observed for the automated method, whereas the manual method had a coefficient of repeatability of 6.3 arbitrary units. Conclusions: The automated quantification of rEZR method is reliable and reproducible. Further studies of the rEZR as a novel biomarker for AMD severity and progression are warranted. Translational Relevance: Automated quantification of SD-OCT-based rEZR allows for its comprehensive and longitudinal characterization evaluating its relevance as an in vivo biomarker of photoreceptor function and its prognostic value for AMD progression.