Abstract
Purpose:
Although a spatial relationship between RPE pathology and the corresponding choriocapillaris in dry AMD (dAMD) was found in the human retina, the dependence of morphological features of the choroidal vascular layers in relation to the fovea in dAMD patients has not been explored.
Methods:
A retrospective study of patients with dAMD (11 eyes) who underwent 5 line raster HD SD-OCT (Cirrus HD-OCT Model 4000) with Enhanced Depth Imaging (EDI) software, fundus autofluorescence (FAF) in selected cases, and fluorescein angiography (FA) from February 2012 to October 2013 was conducted. Two independent raters experienced in analyzing OCT images evaluated the choroidal thickness. The key parameters analyzed consisted of the contour and shape of the choroidoscleral interface (CSI), maximal thickness of the choroid (MTC) at the subfoveal area, and the combined choriocapillaris and medium choroidal vessel layer thickness (CCMVT). The location of the altered choroidal vascular layers relative to the fovea was calculated and compared to established controls.
Results:
In all identified dAMD eyes as compared with normal controls, the OCT showed the contour of the CSI at the subfoveal area (1.5mm) changed from the normal convex shape to an irregular undulated shape. The MTC was reduced and shifted away from the subfovealar area (beyond 0.35mm). The comparative analysis showed a gradual thinning of the CCMVT from the subfoveal rim (1.5mm) towards the subfovealar center. In all dAMD eyes, the spatial relationship between the irregular CSI and the overlaying RPE drusen was observed.
Conclusions:
The present report demonstrates alterations in the choroidal morphological features detected by OCT in eyes with dAMD. It is worth noticing that the reduction of the CCMVT is more significant below the foveola verses the entire subfoveal area in dAMD eyes. Therefore, the quantity and location of the CCMVT may be a determining factor to RPE pathology in dAMD.
Keywords: 585 macula/fovea •
452 choroid •
550 imaging/image analysis: clinical