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

Purpose: 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.