Ocular Surface Temperature Differences in Retinal Vascular Diseases.

PURPOSE To define the effect of age-related macular degeneration (AMD) and diabetic retinopathy (DR) on the ocular thermographic profile. METHODS This retrospective cross-sectional study included subjects diagnosed with DR or AMD between January and April 2019. Individuals without ocular disease served as controls. Thermal imaging camera was used for ocular surface temperature (OST) acquisition. The mean temperatures of the medial cantus, lateral cantus, and cornea were calculated. RESULTS Thermographic images were obtained from 133 subjects (260 eyes, 97 DR, 163 AMD) and 48 controls (55 eyes). OST was higher among AMD patients and lowest among DR patients (P < 0.001). A subgroup analysis revealed that eyes with diabetic macular edema (DME) had significantly higher OSTs than DR eyes without DME. Moreover, the OST in eyes with DME was similar to the measurements of the AMD group. There were no differences in OSTs between neovascular and non-neovascular AMD eyes. CONCLUSIONS Although AMD and DR are considered posterior segment conditions, their effect on OST implies that the entire globe is involved. While both conditions result from similar multifactorial pathophysiologic changes, the differences in OST between DR and AMD might be due to dissimilarity in the balance of pathologic processes involved in each condition. Further research is required to better understand the pathophysiology of these diseases and their effect on OST as well as determine the effect of vasculature, circulation and tissue metabolism on ocular temperature.