Anterior lamina cribrosa surface position in idiopathic intracranial hypertension and glaucoma

To compare the anterior lamina cribrosa (LC) surface position in patients with idiopathic intracranial hypertension (IIH), primary open-angle glaucoma (high-tension glaucoma [HTG] and normal-tension glaucoma [NTG]), and healthy controls using enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT).

This was a retrospective, cross-sectional observational study of 11 eyes with IIH, 20 eyes with HTG, 20 eyes with NTG, and 37 control eyes. Serial horizontal B-scans of the optic nerve head were obtained using EDI-OCT. The LC depth, defined as the distance from the Bruch membrane opening plane to the anterior LC surface, was manually measured on selected B-scans covering the central three-quarters of the optic nerve head in each eye.

Mean LC depth in patients with IIH (325.2 ± 92.1 µm) was significantly (p<0.01) decreased compared to control subjects (387.8 ± 53.9 µm). In HTG, the mean LC depth (493.0 ± 115.2 µm) was significantly increased compared to NTG (376.6 ± 27.1 µm, p<0.05) and control subjects (332.7 ± 53.1 µm, p<0.001). The trans-LC pressure difference (TLPD) (intraocular pressure - cerebrospinal fluid pressure) was positively correlated with the LC depth (r = 0.96, p<0.001) and inversely correlated with visual field perimetric mean deviation in patients with IIH (r = -0.88, p<0.001).

The LC is positioned anteriorly in patients with IIH and posteriorly in glaucomatous eyes compared to normal controls. The positional changes of the LC could be a result of the TLPD between the intraocular and intracranial pressure compartments.