Visual Field Pointwise Analysis of the Idiopathic Intracranial Hypertension Weight Trial (IIH:WT)

PURPOSE: This study was designed to determine if point analysis of the Humphrey visual field (HVF) is an effective outcome measure for people with idiopathic intracranial hypertension (IIH) compared with mean deviation (MD). METHODS: Using the IIH Weight Trial data, we performed a pointwise analysis of the numerical retinal sensitivity. We then defined a medically treated cohort as having MDs between −2 dB and −7 dB and calculated the number of points that would have the ability to change by 7 dB. RESULTS: The HVF 24-2 mean ± SD MD in the worse eye was −3.5 ± 1.1 dB (range, −2.0 to −6.4 dB). Total deviation demonstrated a preference for the peripheral and blind spot locations to be affected. Points between 0 dB and −10 dB demonstrated negligible ability to improve, compared with those between −10 dB and −25 dB. For the evaluation of the feasibility for a potential medical intervention trial, only 346 points were available for analysis between −10 dB and −25 dB bilaterally, compared with 4123 points in baseline sensitivities of 0 to −10 dB. CONCLUSIONS: Patients with IIH have mildly affected baseline sensitivities in the visual field based on HVF analyzer findings, and the majority of points do not show substantial change over 24 months in the setting of a randomized clinical trial. Most patients with IIH who are eligible for a medical treatment trial generally have the mildest affected baseline sensitivities. In such patients, pointwise analysis offers no advantage over MD in detection of visual field change.