Purpose: To evaluate our newly developed infrared heater (IRH) and compare it to a broad-spectrum heater (BSH) for warming the eyelids.
Materials and methods: Ten normal subjects were enrolled in this study. All measurements were recorded in a room with temperature 23 degrees C, 40% humidity, and no wind. The IRH is composed of two hard eye patches that have light-emitting diodes (LEDs) emitting near-infrared radiation. We first compared the temperature rises in the cornea, lacrimal gland, and eyelids after warming through closed eyelids with the IRH for 5 and 10 min. Next, we compared warming with the IRH or BSH for 30 min. We then used the IRH for 5 min with the eyes open to confirm its safety. Finally, we determined subjective feeling after warming the eyes.
Results: Direct comparison of 5 versus 10 min of warming with the IRH showed no significant differences in temperature rises in the upper eyelid (p = 0.09). The IRH caused significantly more heating (p < 0.05) than did the BSH everywhere except the cornea. The temperatures never rose above 37.7 degrees C for either heater during 30 min or with the IRH with the eyes open for 5 min. The subjects' comfort level rose significantly (p < 0.05) after treatment with the IRH.
Conclusions: Our study showed the efficacy and safety of warming the eyelids with a newly developed IRH. Only 5 min is necessary to increase ocular temperature and enhance comfort.