Abstract
Purpose :
Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are the two most common disorders encountered by retinal specialists. Though the exact mechanisms that initiate and render DR and AMD are not clear, there is evidence to suggest that both low-grade inflammation and vasculopathy have an imporant role in these conditions. As suggested by previous studies, ocular hemodynamics can be represented indirectly by measuring the ocular surface temperature (OST).We investigated the ocular thermographic profile of patients with AMD and DR to better understand the pathophysiology of these conditions
Methods :
Subjects diagnosed with DR or AMD treated at the Goldschleger Eye Institute retinal clinic were recruited. Subjects without any ocular disease were used as controls. Therm-App thermal imaging camera was used for OST acquisition. Room and body temperature were recorded and the mean temperature of the medial cantus, lateral cantus and cornea was calculated using an image processing software (figure 1).
Results :
Thermographic images were obtained from 133 subjects (260 eyes, 97 DR, 163 AMD) and 48 controls (55 eyes). Both room and body temperature correlated significanly (P<0.01) with OST measurements, however there were no differences between groups. No significant differences were observed based on sex, lens status or treatment with intravitreal injections). As depicted in figure 2a, OST was higher in the AMD group and lowest in the DR group (P<0.001, adjusted for age, room and body temperature). Subgroup analysis revealed that eyes with diabetic macular edema (DME) had significanly higher OST than DR eye without DME, and very similiar to that in the AMD group (figure 2b). There were no differences in OST between neovascular AMD and non-neovascular AMD eyes (figure 2c)
Conclusions :
Although both AMD and DR are considered posterior segment conditions, their effect on OST found here implies that the entire globe is involved. The differences in OST suggest that inflammation has a greater role than ischemia in the pathophysiology of AMD and DME and the opposite in NPDR and PDR. Future longitudinal studies might establish a potential prognostic value for thermographic evaluations in both DR and AMD patients.
This is a 2020 ARVO Annual Meeting abstract.