Widefield Choroidal Thickness Maps in Dry Age Related Macular Degeneration with and without Reticular Pseudodrusen

Abstract

 

Purpose

 

To obtain and compare choroidal thickness maps of eyes with dry Age Related Macular Degeneration (AMD) over extended retinal regions.

 

Methods

 

Twenty patients with a diagnosis of dry AMD were imaged using a prototype swept source OCT system from Carl Zeiss Meditec (Dublin, CA). The OCT system had a central wavelength of 1050nm and supported acquisition of 12mmx12mmx3mm raster scans. Each scan used a 512x512 homogeneous sampling scheme. A novel algorithm was developed to segment the anterior a posterior boundaries of the choroid over the full OCT datasets.

 

Results

 

Pointwise thickness maps of the choroid were obtained over the scan area using the automated algorithm. Using the associated OCT fundus images, as well as other en face OCT images, choroidal thickness information can be correlated to retinal landmarks. In particular we examined the relationship between the choroidal thickness and features like geographic atrophy, reticular pseudodrusen, and drusen. The choroid is in general thinner in eyes with reticular pseudodrusen than in eyes without reticular pdeudodrusen, but the precise patterns of choroidal thickness vary significantly across different eyes.

 

Conclusions

 

There can be considerable variability in choroidal thickness at different retinal locations, in eyes with dry AMD. Also the relationship between local choroidal thickness and other features of dry AMD can assume different patterns in different eyes. The detailed quantitative descriptions of choroidal thickness over extended regions have the potential to improve our understanding of retinal pathology.