Study of lamina cribrosa depth and optic nerve in patients with spontaneous intracranial hypotension

The aim of this study is to analyze the lamina cribrosa depth and to study the optic nerve in patients with spontaneous intracranial hypotension.A total of 10 eyes of the patients with spontaneous intracranial hypotension with unknown etiology (study group) and 10 eyes of healthy patients without any ophthalmological or neurological pathologies (control group) were included. The subjects were submitted to ophthalmological examination with the evaluation of visual acuity, spherical equivalent, applanation tonometry, pachymetry, axial length, retinography, computerized static perimetry (Humphrey 30-2 SITA-Standard), and OCT Spectralis with enhanced depth image, to calculate the depth of the anterior surface of the lamina cribrosa and to measure the nerve fiber layer thickness of the optic nerve. All of these parameters were compared between the two groups.Mean anterior surface of the lamina cribrosa depth was 447.96 ± 118.51 (313.30-632.0) μm for the spontaneous intracranial hypotension group and 292.56 ± 40.71 (247-387) μm for the control group, with a statistically significant difference between them (p = 0.001). The thickness of the nerve fiber layer did not differ significantly in the temporal (p = 0.94), nasal (p = 0.173), superior (p = 0.41), central (p = 0.36) or inferior (p = 0.5) sectors. Four eyes of patients with spontaneous intracranial hypotension showed a marked reduction in the temporal nerve fiber layer. Pachymetry (p = 0.16), axial length (p = 0.71), and intraocular pressure (p = 0.6) did not differ significantly between groups, whereas spherical equivalent (p = 0.03) was significantly different. Visual fields were normal in both groups.The translaminar gradient is determinant in the structure of the lamina cribrosa. Low intracranial pressure associated with a high translaminar gradient leads to an increased lamina cribrosa depth similar to that observed in glaucoma patients.