Retinal nerve fiber layer analysis in idiopathic intracranial hypertension

Abstract

Background: The chronic nature of idiopathic intracranial hypertension (IIH) represents a risk factor for progressive optic nerve damage and structural abnormalities of the retina. Aim: We measured the retinal nerve fiber layer (RNFL) thickness in patients followed with the diagnosis of IIH who had no or mild visual impairment to search for possible structural alterations in the retina for diagnostic and prognostic purposes. Settings and Design: Case-control prospective study. Materials and Methods: The study group consisted of 12 women followed and treated with the diagnosis of IIH in our clinic. The selection criteria were the, normal optic nerve, normal visual fields or mild visual field defects (Grade 1-3) by Humphrey perimeter. Randomly assigned, age-matched 12 healthy women were taken as the control group. Retinal nerve fiber layer thickness was evaluated with scanning laser polarimetry and both eyes were studied for each case in both groups. Statistical Analysis Used: Mann-Whitney U test. Results: The mean ages of the patient and the control groups were 34.58 +/- 4.2 and 34.42 +/- 5.7 years respectively (P=0.87). The mean duration of disease was 5.5 +/- 3 years. Some parameters related to RNFL thickness were found to differ significantly between patients with IIH and control subjects. Namely superior ratio (P=0.007), inferior ratio (P=0.039), superior-nasal ratio (P=0.025), maximum modulation (P=0.01) and symmetry (P=0.006) were lower in the patient group than controls. Conclusion: Scanning laser polarimetry might be a good adjunct for determining possible structural affects of IIH on the retina in patients with no or mild visual impairment.