Choroidal thickness measured with swept source optical coherence tomography in posterior staphyloma strongly correlates with axial length and visual acuity

Purpose: To measure the choroidal thickness in patients with high myopia from staphyloma using swept source OCT (SS-OCT) in Early Treatment Diabetic Retinopathy Study (ETDRS) fields and compare to normal cohort. The study also evaluated the correlation between choroidal thickness with axial length and best-corrected visual acuity (BCVA). Methods: In this prospective cross sectional study, 37 eyes of 20 patients with high myopia from staphyloma and 86 eyes of 43 normal subjects were included. In each eye, horizontal scans centered on the fovea (12 × 9 mm) were performed using SS-OCT (DRI-OCT, Topcon, Japan). Choroidal thickness in 9 ETDRS subfields, including central subfield (CSF) was analyzed and correlated with axial length as well as BCVA. Results: The axial length and BCVA in the high myopia from staphyloma group ranged from 25.12 to 33.54 mm (28.4 ± 1.2) and 20/20–20/400, respectively. The choroidal thickness in staphyloma group was 85.53 ± 48.61 μm as compared to 250.24 ± 71.01 μm in the normal group (p < 0.0001). Stepwise regression analysis showed that axial length strongly correlated with decreased choroidal thickness (p < 0.001) in staphyloma group (r = 0.71, r₂ = 0.5). Refractive error and BCVA moderately correlated(r = − 0.47; r₂ = 0.22) with choroidal thickness (p < 0.001). Conclusion: Choroidal thickness in staphyloma (measured with novel technology of SS-OCT) patients is markedly reduced compared to normal controls. In addition, choroidal thickness strongly correlated with axial length of the eye and inversely correlated with visual acuity. This testing modality maybe used as a good predictor of visual acuity in patients with high myopia from staphyloma.