Recent studies have reported choroidal thickness measurements based on FD-OCT images. Lamina fusca (LF) is the natural anatomical outer boundary of the choroid. Unfortunately, LF is not always clearly visible in OCT images. The goal of this study is to assess the difference between LF boundary and posterior choroidal vessel (PCV) boundary.Methods:
In a retrospective case review study, Horizontal B-Scan images, through the center of the fovea were reviewed and 96 eyes were included. The eyes were divided into 3 categories based on the characteristics of the choroid-sclera junction: SCS if suprachoroidal space is visible as a dark strand, LF if lamina fusca is visible as a bright strand, and PVC if only posterior vessel cavity boundary is visible.Results:
For the 48 eyes in either SCS or LF, choroid thickness measurement differ by 26.9μm on average, ranging from 8 to 85 μm in individuals between the two boundaries.Conclusions:
Choroid thickness measurement could be affected by boundary criteria. Posterior vessels boundary is the best method in 50% of cases but the presence of Supra Choroidal Space must be remembered. A common posterior boundary definition may be necessary to avoid significant bias in further studies.