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Factors Affecting Visual Field Outcomes in the Idiopathic Intracranial Hypertension Treatment Trial

Cello, Kimberly E. BS; Keltner, John L. MD; Johnson, Chris A. PhD; Wall, Michael MD; for the NORDIC Idiopathic Intracranial Hypertension Study Group

Journal of Neuro-Ophthalmology: March 2016 - Volume 36 - Issue 1 - p 6–12
doi: 10.1097/WNO.0000000000000327
Original Contribution

Background: To determine the prevalence of visual field (VF) performance failures (PF) and treatment failures (TFs), and identify factors associated with PFs in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).

Methods: A total of 165 participants from 38 sites with idiopathic intracranial hypertension (IIH) and mild visual loss were randomized to either acetazolamide-plus diet or placebo-plus diet. The IIHTT Visual Field Reading Center evaluated 2950 Swedish Interactive Threshold Algorithm Standard 24-2 VFs from the enrolled participants. A TF was defined when the participant's VF mean deviation (MD) worsened ≥2 to 3 dB from the average baseline MD (range of −2 to −7 dB) with a second retest confirming the visual deterioration. A PF was determined when the participant's: 1) VF results met TF criteria but were not confirmed on retest, 2) deterioration was confirmed on retest but the IIHTT Adjudication Committee concluded a TF was clinically unlikely.

Results: TF was detected in 7/165 (4%) of the participants and PF was detected in 35/165 (21%) of the participants on at least 1 examination. Four of the 35 PFs were adjudicated for TF, however based on clinical review by the adjudication committee and a third retest, they were judged as PFs. Of the 2,950 total IIHTT VF examinations, 2.7% met PF criteria.

Conclusions: PF was confirmed in 21% of subjects and in 2.7% of the total number of VF examinations and was reversible on repeat testing. We recommend retesting when perimetric worsening occurs in otherwise clinically stable or improving IIH patients.

Departments of Ophthalmology and Vision Science (KEC), and Neurology and Neurological Surgery (JLK), University of California Davis, California; Department of Ophthalmology and Visual Sciences (CAJ), University of Iowa, Iowa City, Iowa; and Department of Neurology and Ophthalmology (MW), College of Medicine, University of Iowa, Iowa City, Iowa.

Address correspondence to Kimberly E. Cello, BS, Department of Ophthalmology and Vision Science, University of California Davis, 4860 Y Street, Suite 2400, Sacramento, CA 95817; E-mail: kecello@ucdavis.edu

Supported by National Institutes of Health Grants 1U10EY017281-01A1 (NORDIC), 1U10EY017387-01A1 (Data Coordinating and Biostatistical Center), 3U10EY017281-01A1S1 (American Recovery and Reinvestment Act for NORDIC), 1U10EY017387-01A1S1 (Data Coordinating and Biostatistical Center), and 3U10EY017281-01A1S2 (supplements for NORDIC), and was supported in part by an Unrestricted Grant from Research to Prevent Blindness, New York, New York to the Department of Ophthalmology at University of Rochester. Trial Registration: clinicaltrials.gov identifier: NCT01003639 on 10/28/09.

The authors report no conflicts of interest.

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© 2016 by North American Neuro-Ophthalmology Society