Optical Coherence Tomography Characteristics of the Choroid Underlying Congenital Hypertrophy of the Retinal Pigment Epithelium

Abstract

This study evaluates and characterizes the choroid underlying congenital hypertrophy of the retinal pigment epithelium (CHRPE). Methods: Retrospective observational study of CHRPE at least 2 mm in diameter. Choroidal vascular architecture was qualitatively examined. Choroidal thickness was measured by 2 independent observers using enhanced depth imaging spectral domain optical coherence tomography. Results: Forty-six eyes of 46 patients with CHRPE were included. Thirty-two lesions had imaging sufficient for analysis. Haller's layer was healthy in 18 (56%), thin in 13 (41%), and absent in 1 (2%). Sattler's layer was atrophic in 30 (94%), and choriocapillaris was atrophic in 31 (97%). CHRPE with thinned Haller's layer had significantly larger diameter. The mean sub-CHRPE choroidal thickness was 82.4 ± 7.9 µm, compared to a thickness of 148.4 ± 9.6 µm in the normal adjacent choroid (p < 0.0001). Mean retinal thickness overlying the CHRPE was 77.3 ± 4.3 µm, compared to a retinal thickness of 137.8 ± 2.9 µm overlying the normal adjacent choroid (p < 0.0001). Sub-CHRPE choroidal thickness was a mean of 56.2 ± 3.1% of the adjacent normal choroidal thickness. Conclusion: The underlying choroid CHRPE is thinner than the adjacent normal choroid. All layers of the choroid can be thin with a preference of the inner Sattler's and choriocapillaris layers.