The choroid is thicker in angle closure than in open angle and control eyes

Purpose. To study factors associated with choroidal thickness (CT) and to compare CT in angle closure (AC), open angle (OA), and normal eyes. Methods. Forty controls, 106 OA, and 79 AC subjects underwent measurements of posterior CT by spectral domain-optical coherence tomography, and of intraocular pressure (IOP), blood pressure, axial length (AL), and central corneal thickness (CCT). Results. CT was significantly greater in AC than in OA and normal eyes (HSD test, P < 0.05), but there was no significant difference between OA and normal CT; mean CT was 234, 235, and 318 um in the normal, OA, and AC groups, respectively. With multivariable analysis among all participants, thinner CT was associated with older age, longer AL, higher IOP, and thicker CCT (all P < 0.03, R² = 0.45). Adjusting for other relevant variables, the AC group had a significantly greater CT than either the normal or the OA group (P = 0.003 and 0.03, respectively). In multivariable analysis including only OA and AC patients, neither cup-to-disc ratio nor visual field mean deviation were significantly associated with CT. Multivariable analysis for CT among normal eyes found longer AL to be associated with thinner CT (P = 0.04). Conclusions. AC eyes had significantly thicker CT than OA and normal eyes, even after adjusting for the shorter AL in AC eyes, supporting hypotheses that choroidal expansion contributes to the development of AC disease. Age, AL, CCT, and IOP were also significantly associated with CT, while severity of glaucoma damage was not.