Idiopathic intracranial hypertension: relation between obesity and visual outcomes

Increased body mass index (BMI) has been associated with increased risk of idiopathic intracranial hypertension (IIH), but the relationship of BMI to visual outcomes in IIH is unclear.

A retrospective chart review of all adult cases of IIH satisfying the modified Dandy criteria seen at our institution between 1989 and 2010 was performed. Demographics, diagnostic evaluations, baseline visit and last follow-up examination data, treatment, and visual outcome data were collected in a standardized fashion. Groups were compared, and logistic regression was used to evaluate the relationship of BMI to severe visual loss, evaluating for interaction and controlling for potential confounders.

Among 414 consecutive IIH patients, 158 had BMI ≥40 (World Health Organization Obese Class III) and 172 had BMI 30-39.9. Patients with BMI ≥40 were more likely to have severe papilledema at first neuro-ophthalmology encounter than those with a lower BMI (P = 0.02). There was a trend toward more severe visual loss in 1 or both eyes at last follow-up among those patients with BMI ≥40 (18% vs 11%, P = 0.067). Logistic regression modeling found that 10-unit (kilogram per square meter) increases in BMI increased the odds of severe visual loss by 1.4 times (95% confidence interval, 1.03-1.91, P = 0.03) after controlling for sex, race, diagnosed hypertension, and diagnosed sleep apnea.

Our finding of a trend for severe papilledema and visual loss associated with increasing BMI suggests that very obese IIH patients should be closely monitored for progression of visual field loss.