Reticular Pseudodrusen in Early Age-Related Macular Degeneration is Associated with Choroidal Thinning

Abstract

 

Purpose

 

To compare subfoveal choroidal thickness (SFCT) measurements in early age-related macular degeneration (AMD) between patients with and without reticular pseudodrusen (RPD) using spectral-domain optical coherence tomography (SDOCT).

 

Methods

 

This cross-sectional study examined 84 AMD patients (40 RPD, 44 non-RPD) who were age- and gender-matched (RPD: 32 of 40 (80%) were female, mean age 76.9 years ± 7.5 SD; non-RPD: 32 of 44 (73%) were female, mean age 73.9 years ± 7.8 SD). 63 RPD eyes and 75 non-RPD eyes were included in the analysis. Exclusion criteria included late AMD (geographic atrophy greater than 500 microns² or history of choroidal neovascularization), myopia greater than -6 diopters, central serous chorioretinopathy, or past vitreoretinal surgery. Color fundus photographs and scanning laser ophthalmoscopy (including autofluorescence and infrared imaging) were graded in a masked fashion by three retinal specialists (SY, SB, MO) to identify RPD and non-RPD groups. SDOCT was used to measure choroidal thickness for all eyes. For each eye, the best SDOCT image with a clear posterior margin of choroid was chosen for analysis. Enhanced depth imaging spectral-domain optical coherence tomography (EDI-SDOCT) was used when available (20 of 138 eyes). SFCT was measured using Heidelberg Eye Explorer interactive software.

 

Results

 

Mean SFCT of RPD eyes (176.3 microns ± 60.5 SD) was significantly less than that of non-RPD eyes (216.5 microns ± 70.3 SD) by the Student’s t-test for independent samples (p = 0.0005).

 

Conclusions

 

These results support previous smaller studies that have shown RPD is associated with a thinner choroid. As RPD has been associated with increased risk of advanced AMD, SFCT may be integral to understanding the RPD process, as well as stratifying risk of AMD progression.

 

 

Images of an AMD patient without RPD. EDI-SDOCT (top) shows a SFCT of 451 microns. Infrared (middle) and autofluorescence (bottom) imaging depict absence of RPD.

 

 

Images of an AMD patient with RPD. SDOCT (top) shows a very thin SFCT of 32 microns. Infrared (middle) and autofluorescence (bottom) imaging support the presence of RPD throughout the fundus.

 

Keywords: 412 age-related macular degeneration • 452 choroid • 464 clinical (human) or epidemiologic studies: risk factor assessment