Lamina cribrosa curvature in glaucoma patients, glaucoma suspects and healthy controls

Abstract

Purpose : To compare the mean lamina cribrosa curvature between glaucoma patients, patients with glaucomatous optic disc appearance (GODA) and healthy controls.

Methods : 255 subjects were recruited from the Glaucoma Clinic at the Department of Ophthalmology, Wroclaw Medical University. Patients were divided into three groups: 92 patients with open angle glaucoma (POAG), 77 GODA suspects and 86 healthy controls (HC). Images of the optic nerve head were obtained using spectral-domain optical coherence tomography (SD-OCT) with the enhanced depth imaging technique. A fully automated algorithm for delineating the lamina cribrosa from a set of OCT B-scans was used and the 3D lamina estimate was fitted with a parametric function. Additionally, intraocular pressure (IOP, Goldman), central corneal thickness (CCT), visual field (VF), Heidelberg Retina Tomograph (HRT) and OCT retinal nerve fiber layer (RNFL) parameters were measured. Nonparametric ANOVA was used to test for differences between the groups. Post-hoc analysis included the Kramer-Tukey correction factor.

Results : There were no statistically significant differences between the three groups of subjects in age, CCT and IOP. There were statistically significant differences in VF mean deviation (MD) between POAG patients (-9.3±7.4 dB), GODA subjects (-0.3±1.1 dB) and HC subjects (-0.4±1.0 dB) (p<0.001). HRT parameters rim area (RA) and rim volume (RV) were also statistically significantly different: RA=0.9±0.3 mm² for POAG, RA=1.2±0.2 mm² for GODA and RA=1.6±0.3 mm² for HC (p<0.001); RV=0.17±0.1 mm³ for POAG, RV=0.26±0.1 mm³ for GODA and RV=0.42±0.1 mm³ for HC (p<0.001). Average RNFL thickness was significantly different across all three groups: 63±12µm for POAG, 85±10µm for GODA and 98±9µm (p<0.001). The parameters of the delineated lamina cribrosa showed statistically significant differences (p<0.001), particularly in the second (parabolic) and fourth order powers. A post hoc analysis indicated statistically significantly differences between POAG and HC and GODA and HC but not between POAG and GODA.

Conclusions : Similarity of the mean lamina cribrosa curvature for the POAG and GODA groups suggests that the glaucomatous appearance of the optic disc, observed during slit-lamp fundus examination and the traditional imaging of the optic nerve head, in the group of suspects extends to the lamina cribrosa.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.