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

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

METHODS: 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.

RESULTS: 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.

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