Quantitative evaluation of "sunset glow" fundus in Vogt-Koyanagi-Harada disease

Abstract

Purpose: To evaluate the color of the fundus quantitatively, especially the "sunset glow" fundus, in patients with Vogt-Koyanagi-Harada (VKH) disease.

Methods: The fundus of 39 patients (13 men and 26 women) who were diagnosed with VKH disease were photographed. The photographs were scanned by a film scanner and the amount of red, green, and blue pixels making up the image was determined by image analyzing software. A "sunset glow" index, the ratio of the number of red pixels to the total number of pixels, was determined for all patients as well as 31 normal controls.

Results: In comparison to the controls, the "sunset glow" indices at 3 months after onset of the "sunset glow" fundus showed significant increases in VKH patients. Six months after onset, the "sunset glow" indices showed further significant increases and continued to increase during the course of the disease.

Conclusions: The depigmentary changes can be found earlier by using our method rather than ophthalmoscopy. Because our method is more sensitive for slight depigmentary changes, the pigmentary changes in the fundus could be found in all the VKH patients. This quantitative evaluation of the fundus makes a correct diagnosis possible even in patients who do not demonstrate the "sunset glow" fundus by normal ophthalmoscopic examinations.