Abstract
Purpose :
While prominent degenerative retinal changes have been characterized in atrophic and exudative advanced AMD, it is less understood whether degenerative changes occur in eyes with early to intermediate AMD . Characterization of non-advanced AMD progression has largely focused on drusen and pigmentary changes, and changes in retinal thickness are not well characterized. We examined eyes with non-advanced AMD to discover AMD-related factors influencing macular thickness and thickness change over a 4-year period.
Methods :
143 eyes of 143 patients >50 years old ranging from no to intermediate AMD were imaged with optical coherence tomography with and without enhanced depth imaging at study baseline and 79 of these were re-imaged at 4 years. Macular thickness within the ETDRS fields, choroidal thickness (CT), and choroidal vascularity index (CVI) were measured. Study eyes were stratified into the following groups: control eyes with no large drusen (Group 1, N=35), eyes with large drusen but none in the fellow eye (Group 2, N=27), eyes with large drusen and large drusen or advanced AMD in the fellow eye (Group 3, N=60), eyes with SDD (Group SDD, N=20). Multivariate analyses using mixed models were performed to study the association between macular thickness, demographics and AMD features.
Results :
On cross-sectional analyses , decreased macular thicknesses in the central 1mm and 3mm diameter areas were significantly associated with increased age and female sex. Group 3 (P<0.05) and Group SDD (P<0.01) had macular thickness measures that were significantly less than those of control eyes (Group 1). On longitudinal analyses, macular thinning in the central 1mm and 3mm diameter areas (measured as % decrease over 4 years) was greater in Group 3 (P<0.01) and Group SDD (P<0.001) relative to control Group 1 eyes . Macular thickness measures were not associated with choroidal parameters in multivariate analyses.
Conclusions :
Decreases in macula thickness is not limited to eyes with advanced AMD but can occur during intermediate AMD. Rate of thinning is significantly accelerated with greater AMD severity and SDD presence but is independent of choroidal status. Macular thinning in intermediate AMD may be revealing of AMD pathobiology and constitute an outcome measure for clinical trials of AMD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.