Lamina Cribrosa Depth Variation Measured by Spectral-Domain Optical Coherence Tomography Within and Between Four Glaucomatous Optic Disc Phenotypes.

Abstract

To study lamina cribrosa (LC) depth variation measured by spectral-domain optical coherence tomography (SD-OCT) in four glaucomatous optic disc phenotypes. In this cross-sectional study, 59 normal eyes and 180 open-angle glaucoma (OAG) eyes were grouped into 56 focally injured discs (FI), 30 generalized enlargement of the optic cup discs (GE), 69 myopic glaucomatous discs (MY), and 25 senile sclerotic discs (SS). They were imaged by enhanced depth imaging SD-OCT, obtaining multiple horizontal and vertical optic disc B-scans. Mean and maximum LC depths were measured relative to Bruch's membrane opening (BMO) and the anterior sclera (AS) reference planes. Lamina cribrosa depths were compared between and among the normal and OAG group disc phenotypes. Lamina cribrosa depth differences within groups were examined as well as the overlap between them. Mean and maximum LC depths relative to the BMO and AS reference planes were greater in the OAG group than in the normal group (P < 0.0001). Among glaucomatous phenotypes, the GE group had the greatest (P < 0.001) and the SS group had the smallest (P < 0.05) mean and maximum LC depths. There was a wide range of LC depth overlap between the normal and SS groups, and a high proportion of SS eyes had LC depths within the 95% confidence interval of the normal group. The LC was displaced posteriorly in OAG group compared to the normal group. The LC depth was significantly different among four glaucomatous disc phenotypes. The LC depth of the SS group was similar to the normal group.