Early detection of eye diseases

Many severe eye diseases are not detected by standard methods, such as automated visual field testing, until some loss in vision already has occurred. Researchers from the department of ophthalmology at the University of Michigan in Ann Arbor now have discovered a noninvasive way to detect eye diseases at a very early stage.

Howard R. Petty, Victor M. Elner and their colleagues developed a method to detect flavoprotein autofluorescence in the affected eyes of women with pseudotumor cerebri — a condition primarily affecting young overweight women, that closely mimics the symptoms of a brain tumor and that can cause permanent visual loss.

The researchers understood that it was possible to detect fluorescence in diseased cells that experience severe metabolic stress. Flavoprotein autofluorescence had been used in animals to detect impaired cell function from cardiovascular disease. They wanted to see, however, whether the method could help detect when human retinal cells begin to dysfunction and die.

They tested six women who had been newly diagnosed with the ocular disease and six healthy women for comparison. The women first underwent standard automated visual field tests, which revealed that they all had either no signs of any dysfunction or only subtle abnormalities.

As reported in the February issue of Archives of Ophthalmology, the researchers dilated the patients’ pupils and obtained three 3° images from their eyes with a camera from Carl Zeiss of Oberkochen, Germany. The camera had been modified by inserting excitation and emission filters made by Omega Optical Inc. of Brattleboro, Vt. They also attached a Photometrics back-illuminated electron-multiplying CCD camera. Customized imaging software enabled them to detect any visual dysfunction. The test time for each patient was less than 6 min.

The patients with pseudotumor cerebri had an average of 60 percent higher flavoprotein autofluorescence values in the affected eye. Moreover, there was no significant difference between the eyes of the healthy women.

The researchers believe that the results suggest that flavoprotein autofluorescence imaging may be an effective diagnostic tool for ocular disease.