Macular Morphology and Visual Acuity in the Second Year of the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

Abstract

 

Purpose

 

To evaluate the morphologic features on fundus photography (FP) and optical coherence tomography (OCT) associated with visual acuity in the second year of the Comparison of Age-related Macular Degeneration (AMD) Treatments Trials (CATT).

 

Methods

 

Eligibility criteria required evidence on fluorescein angiography and OCT of choroidal neovascularization (CNV) secondary to AMD and visual acuity (VA) between 20/25 and 20/320 in the study eye. Treatment was assigned randomly to either ranibizumab or bevacizumab and to 3 different dosing regimens over a 2-year period. A linear regression model was used to provide estimates of mean VA adjusted for all significant morphologic features.

 

Results

 

Among 1185 CATT participants, 993 (84%) had fluid on OCT at baseline and 2-year follow up data. At 2 years, the mean VA (letters) of eyes varied substantially by the type of subfoveal pathology on FP: 70.6 for no pathology, 74.1 for fluid only, 73.3 for CNV or pigment epithelial (RPE) detachment, 68.4 for non-geographic atrophy, 62.9 for geographic atrophy (GA), hemorrhage, RPE tear, or blocked fluorescence and 62.9 for scar (p<0.0001). Eyes with subretinal fluid (SRF) in the foveal center on OCT had better mean VA than eyes with no fluid (70.9 vs. 67.0 letters, p=0.006). Eyes with intraretinal fluid (IRF) in the foveal center had worse mean VA than eyes without any IRF (59.9 vs. 70.9 letters, p<0.0001). Eyes with retinal thickness <120 microns had worse VA compared to eyes with retinal thickness 120 to 212 microns and retinal thickness >212 microns (59.4 vs. 71.3 vs. 70.3 letters, p<0.0001). Greater subretinal tissue complex thickness (p=0.03) and greater CNV lesion area (p<0.0001) were associated with worse VA. Figure 1 shows the relationship between VA and retinal thickness at baseline and follow up through year 2.

 

Conclusions

 

The associations between VA and morphologic features previously identified through year 1 were maintained or strengthened during year 2. Eyes with foveal IRF, abnormally thin retina, and those developing subfoveal GA or scar had the worst VA. SRF was associated with better VA while greater thickness of the subretinal tissue complex was associated with worse VA.

 

 

Fig 1: Relationship between retinal thickness and VA at baseline and follow-up: foveal total thickness (A), retinal thickness (B), SRF thickness (C) and subretinal tissue complex thickness (D).

 

Keywords: 412 age-related macular degeneration • 748 vascular endothelial growth factor • 466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials