Patterns of Vision Loss in Idiopathic Intracranial Hypertension: The Central vs. Peripheral Visual Field

Abstract

Purpose : The peripheral visual field is largely unexplored with static threshold automated perimetry. We performed a cross-sectional clinical study to both characterize visual field defects and evaluate structure-function correlation in idiopathic intracranial hypertension (IIH) subjects.

Methods : 60 control subjects with normal vision were tested twice with a new perimetry test of the central and far peripheral visual field. After creating a normative database for full field perimetry from the control subjects, the 95^th, 98^th and 99^th percentiles for abnormality were determined for those with IIH. 22 patients seeking care for IIH at the University of Iowa Hospitals and Clinics were then recruited and underwent perimetry on the full visual field. All subjects were also tested on the Cirrus Optical Coherence Tomography (OCT) machine to determine retinal nerve fiber layer (RNFL) thickness. We then 1) characterized the visual field defects found testing the full visual field, and 2) analyzed the OCT structural data alongside vision function and determined the level of structure-function correlation.

Results : The most common defects found in the peripheral visual fields were infero-temporal wedge defect (68% – see figure), infero-nasal loss (55%), and supero-nasal loss (50%). For those with infero-temporal visual field defects in the periphery (n=15), (53%) had corresponding RNFL OCT thinning of the border of the superior and nasal optic disc that sends axons to this area. None of the subjects had thinning of the supero-nasal disc sector without a corresponding infero-temporal visual field defect. Additionally, 27% of subjects had normal central visual field examinations with an abnormality in the peripheral visual field.

Conclusions : We found temporal wedge defects to be common in IIH patients, a defect that has only been rarely reported in IIH. Additionally, this particular defect showed good correlation with OCT structural data. Another important finding was that 6 of the 22 subjects (27%) had normal central visual field testing with a visual field defect present in the far periphery. Testing the largely unexplored far peripheral visual field may be important for clinically following patients with IIH.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.