Drug treatment and weight loss restores vision in a blinding disorder linked to obesity
June 06, 2014
As many as 100,000 Americans suffer from a disorder called pseudotumor cerebri or idiopathic intracranial hypertension that can cause permanent blindness and chronic headaches. The disease primarily strikes obese women of reproductive age with symptoms of daily headaches, visual symptoms including transient blurring or blindness, double vision, and pulsating noises in one’s head. Up to 5-10% of these patients may have permanent visual loss due to optic nerve damage.
A recent national trial funded by the National Institute of Health’s National Eye Institute has shown that a common water pill, acetazolamide, combined with a moderate but comprehensive dietary and lifestyle modification plan can restore and preserve vision in women with this disease. I was one of the local investigators for this trial along with Dr. Eugene May.
The symptoms of pseudotumor cerebri are thought to be due to high spinal fluid pressure around the optic nerves and brain due to impaired reabsorption of spinal fluid that is continuously being produced within the brain. This results in chronic headaches and swelling of the optic nerves that can lead to permanent blindness if left untreated. Patients typically are women with a body mass index (BMI) of 30 or greater as primary risk factor between the ages of 20 and 50. Only 5% of patients with pseudotumor cerebri are male. Diagnosis is made by finding swelling of the optic nerves or papilledema on a dilated eye examination in an obese patient with chronic headaches and visual symptoms. A brain MRI scan is performed to rule out a tumor, and typically a diagnostic spinal tap is performed to measure the opening pressure of the spinal fluid and rule out infection.
In this National Institute of Health funded trial, 161 women and 4 men with this diagnosis were enrolled with mild visual loss at 38 clinical sites nationally. All participants were put on a lifestyle modification program with diet and weight loss counseling with a goal of 6% weight loss over 6 months. Half the patients were assigned placebo, and the other half a common water pill called acetazolamide or Diamox in varying doses. After 6 months, both groups improved on visual tests including assessment of swelling of the optic nerves and visual field testing. The groups assigned to acetazolamide improved twice as much as those on placebo with visual field testing. Quality of life responses were also greater in those treated with medication than weight loss alone. The study confirmed that acetazolamide is a very useful medication in preserving vision and quality of life in this small group of obese women with optic nerve swelling at risk of losing vision. The study is continuing as a long-term follow up of participants with annual monitoring at all clinical sites, including Swedish. The six-month initial results have just been published in the Journal of the American Medical Association. The study is currently closed to recruitment but future results will be published as they become available.
Normal appearing optic nerve (image source). Swollen optic nerve as seen in pseudotumor cerebri (image source).