Abstract
Purpose :
Retinal thinning is associated with decreased visual acuity (VA) but the reasons are not clear. The relationship of choroidal morphology to retinal thickness is also poorly understood. We sought to determine the association between morphological parameters of retinal thinning, choroidal thickness (CT), and VA in CATT.
Methods :
Data at year 5 were analyzed from patients enrolled in CATT. Outcome measures included VA, various parameters of retinal thickness at the fovea, and CT as measured by enhanced depth imaging. Parameters of retinal thinning and choroidal morphology with mean VA was assessed using analysis of variance (univariate). The correlation between retinal thickness and CT was assessed with Spearman’s correlation coefficient (r).
Results :
VA data were available for 647 of 914 (71%) patients alive at 5 years. SD-OCT data were available for 523 of these patients (81%). The retina was abnormally thin (<120um) in 36% of eyes with mean VA 19 letters worse than eyes with normal retina thickness (50 vs 69; p<0.001). Mean VA was worse by at least 10 letters in eyes with thinning in the inner nuclear, outer plexiform, outer nuclear layers, and in eyes with retinal thinning affecting the external limiting membrane and ellipsoid zone (all with p<0.05), but not in eyes with retinal thinning in the nerve fiber layer/ganglion cell complex/inner plexiform layer (53 vs 61; p=0.15). Increasing subretinal tissue complex thickness (STCT) was associated with worse mean VA (57 vs 64; p=0.003). Thinner CT (stromal and vessel) was not associated with decreased VA (p>0.20) (Table 1). Greater STCT was associated with thinner choroid vessel thickness (r=-.10; p=0.03) and thinner choroid stromal layer thickness (r=-.10; p=0.04), but there were no significant correlations between CT (stromal and vessel) and foveal total thickness, retinal thickness or subretinal fluid thickness (|r|≤0.05 for all).
Conclusions :
Treatments to prevent retinal thinning in the middle and outer retina may help prevent VA loss in long-term AMD treatment. Therapy to reduce STCT, perhaps through preventing choroid stromal layer thinning, may also be beneficial although more studies are necessary to clarify how CT contributes and or responds to changes in retina morphology in AMD progression.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.