Optic nerve compression: the role of the lamina cribrosa and translaminar pressure

To describe the morphological changes of the lamina cribrosa (LC) in patients with optic nerve compression.

Cross-sectional study. Twenty eyes with optic nerve compression, affected by Graves' ophthalmopathy (GO) were compared with 18 refractive error-matched healthy eyes. The following examinations were performed: best-corrected visual acuity (BCVA), intraocular pressure, optic nerve echography, visual field, SD-OCT including the retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and LC thickness and extent.

A-scan revealed significant differences in the subarachnoid space (SAS) between the affected and control groups. LC thickness and LC area were 233 µm (SD 23) and 0.41 mm² (SD 0.19), respectively. Average GCC thickness (P=0.0005), LC thickness (P=0.001), MD (P=0.001) and PSD (P=0.001) differed significantly between the two groups; whereas LC area (P=0.2) and average RFNL (P=0.1) did not.

Optic nerve compression reduces the SAS thereby altering the morphology of LC thickness and causing GCC damage.