The Association of Subretinal Hyper-Reflective Material (SHRM) and Visual Acuity in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

Abstract

 

Purpose

 

To evaluate the association of SHRM characteristics with visual acuity (VA) in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

 

Methods

 

Masked readers graded 1185 CATT participant images for scar, geographic atrophy (GA) (fundus photography) and SHRM (TD- or SD-OCT) at 104 weeks after the initiation of anti-VEGF treatment. VA was measured (in letters) using a standardized electronic testing system. Participants with SD-OCT at 56 weeks had quantitative grading of SD-OCT at 56 (n=76) and 104 (n=66) weeks. Maximum height and width of SHRM lesions were measured in three grading areas: under the fovea, within the center 1mm², or outside the center 1mm². SHRM was classified as distinguishable from the underlying RPE elevation or not (Figure 1).

 

Results

 

Among all CATT participants, SHRM was present more often in eyes with scar (66% vs 31%; p<0.0001) and in eyes with GA (53% vs 43%; p=0.03) at week 104. Among 66 eyes with detailed evaluation of SHRM at week 104, SHRM was present at the foveal center in 19 (34%), within the central 1mm in 30 (45%) and outside the central 1mm² in 38 (58%). When SHRM was present, the median height in u (1^st quartile, 3^rd quartile) under the fovea, within the central 1 mm² and outside the central 1mm² was 86 (49, 120); 120 (81, 171); and 122 (84, 180), respectively. Mean [SE] VA letters decreased from 73.5 [2.8] when no SHRM was present to 63.9 [3.7] when it was under the fovea to 65.3 [3.5] when it was within the center 1mm² to 73.1 [3.4] when it was outside the center 1mm² (Table 1). Comparing each of the three grading areas in eyes with and without SHRM, VA reduction was directly associated with presence and size of SHRM (either height or width) (p <0.05; Table 1). VA did not depend on whether the SHRM was clearly differentiated from the underlying RPE elevation.

 

Conclusions

 

The presence and greater dimensions of SHRM were associated with worse VA, particularly when SHRM was in the foveal center. Eyes with scar or GA were more likely to have SHRM than other eyes. Combination treatment with agents that reduce this sub-retinal tissue component may result in better VA than treatment with anti-VEGF alone.  

 

Figure 1. A) Average size subfoveal SHRM (86um) that is distinguishable from the underlying RPE layer. B) SHRM (100um) that is indistinguishable from RPE layer.