Correlation between Optical Coherence Tomography Ganglion Cell Layer Analysis and Visual Field in Cases of Benign Intracranial Hypertension

Abstract

Background: Benign intracranial hypertension (BIH) is a condition in which there is excessive cerebral spinal fluid (CSF) pressure in the subarachnoid space that surrounds the brain and spinal cord (intracranial pressure (ICP)) owing to an unexplained cause. It affects 1:100,000 persons yearly with a 20 times greater prevalence in young, obese girls. We wanted to correlate between optical coherence tomography ganglion cell layer analyses and visual field in patients of benign intracranial hypertension.
 Methods: This cross-sectional clinical study that was carried out on 30 patients (60 eyes) who all had a recently diagnosed papilledema due to first episode of IIH. Goal of the study, and applied tests was done before obtaining an informed consent. Personal history, past medical and ocular history, possible risk factors for IIH were taken. Full ophthalmological examination including best corrected visual acuity (BCVA), intraocular pressure (IOP), color perception, pupillary reflexes, slit lamp bio microscopy examination including assessment of papilledema grade, blood pressure check and body mass index (BMI). All patients underwent automated perimetry in dim light to evaluate their visual field using SITA fast Standard 30-2 protocol by Humphrey Field Analyzer (Humphrey Field Analyzer I Carl Zeiss AG – Oberkochen – Germany).
 Results: Average RNFL thickness had significant positive correlation with rim area (r=0.654, P<0.001) and disc area (r=0.665, P<0.001). Average RNFL thickness had no correlation with VA, IOP and average CD.
 Average GCL complex had significant negative correlation with rim area (r= -0.283, P=0.028) and disc area (r= -0.328, P=0.01). Average GCL complex had no correlation with VA, IOP and average CD. Minimum GCL complex had significant negative correlation with rim area (r= -0.272, P=0.036) and disc area (r= -0.315, P=0.014). Minimum GCL complex had no correlation with VA, IOP and average CD. Papilledema grading had significant positive correlation with average RNFL thickness (r=0.461, P<0.001). Papilledema grading had no correlation with average GCL complex, minimum GCL complex, VFI, MD and PSD.
 Conclusions: There is a strong structure-function link between visual field indices and OCT parameters such as RNFL and GCC.