Breakdown of the blood-retinal barrier after radiofrequency-induced ocular hyperthermia

To study the possible application of hyperthermia in the treatment of proliferative vitreoretinopathy (PVR), we induced hyperthermia in 15 normal rabbit eyes by a radiofrequency capacitive heating device. The retinal surface of each eye was warmed to a presumed temperature of 41 or 43 degrees C for 30 min. The thermal effect on the blood-retinal barrier (BRB) was evaluated before and 2 h after the hyperthermic regimen by means of vitreous fluorophotometry. Heat treatment to 43 degrees C at the retinal surface for 30 min increased the fluorescein leakage compared with the 41 degrees C treatment. This finding suggests that retinal hyperthermia at 43 degrees C for 30 min may cause breakdown of the BRB.