Objectives: To evaluate the association between obesity and idiopathic intracranial hypertension (IIH) and establish whether there is a relationship with visual outcome. To calculate the prevalence and degree of obesity in a group of patients with IIH.
Methods: 34 patients (31 female and 3 male) were recruited between 1993 - 1997 with a diagnosis of IIH. Assessment included visual acuity, visual field assessment (Humphrey automated and Goldmann manual perimetry), fundus assessment and measurement of body mass index (BMI). Obesity was defined as a BMI of 30 kg/m2.
Results: 70.5% of patients were obese. The relative risk for obesity and IIH was significant at 8 (95%CI: 2,29). This increased to 17 (95%CI: 5,62) for obese females aged 16 to 24 years and 10 (95%CI: 3,35.5) for obese females aged 25 to 34 years. Morbid obesity (BMI > 40) was significantly associated with poor visual outcome. Serial obesity measures showed generally little change in weight over time and there was no correlation between weight change and visual improvement.
Conclusions: This study has documented a relationship between obesity and IIH. A high degree of obesity was associated with a poor visual function and identified as a risk factor for poor outcome. Obesity may be an aetiological factor in this condition although it is unlikely to be the sole cause but more probably a precipitating factor. Weight loss is recommended although failure to lose weight is common. Any weight reduction programme must therefore be actively encouraged and monitored.