A simple computer program to quantify red desaturation in patients with optic neuritis

Purpose: Red desaturation is a subjective, sensitive test for patients with optic nerve disease. There is no quantitative clinical test to measure the severity of color desaturation. The current study introduces a simple PowerPoint presentation for quantification of red desaturation in patients with optic neuritis. Methods: A Microsoft Office PowerPoint presentation was designed. A red square is shown on each half of the screen. The degree of desaturation on one side is increased in each successive slide. The patient holds a black cardboard divider between his/her eyes, such that each eye can see one-half of the screen. The patient uses the mouse to forward through the slides, thereby gradually increasing the desaturation of the red square presented to the normal eye until it matches the color of the red square seen with the tested eye. Desaturation is graded by the number of slide changes needed until subjective equal color between the eyes is perceived. The test was presented to normal volunteers and to patients with optic neuritis. The difference in saturation levels between the right and the left eyes in patients with optic neuritis vs controls was compared. Results: A total of 83 patients were included. Patients with optic neuritis had significantly increased desaturation compared to controls (6.17±3.3 vs 0.24±2.8 respectively; p<0.0001). Conclusions: This test is easy to create and efficiently quantifies the severity of red desaturation.