Photochromic glass for sunglasses

Abstract

The present study addressed the investigation of the effect of wearing glasses on the human eyes' temperature distribution in different ambient conditions. Besides, the effect of variations of ambient temperature, convection coefficient of ambient air, blinking, and body's temperature on the human eye's temperature distribution was investigated. Three scenarios (without glasses, wearing medical glasses, and wearing sunglasses) have been considered. The weather information for summer and winter for Divandarreh, Kurdistan province, Iran, has been used as the inputs. The sunlight intensity reaching the eye in three scenarios for both winter and summer was measured experimentally. In scenario 1 (without glasses), for the maximum radiation intensity, the Corneal temperature increased by 5 °C, which can cause cataracts in the long term. The results show that by wearing sunglasses in winter, the Corneal temperature reduced by 4 °C that may lead to blurred and diplopia visions. It was observed that by increasing the temperature difference between the sides of the Anterior chamber, the Aqueous Humor (AH) circulation speed increases. Also, it was found that the AH's circulation pattern in summer is clockwise, while in winter, it is counterclockwise. The results highlighted the significant effect of the convection coefficient of air ambient on the Corneal temperature. The results show that depending on the ambient temperature, blinking has a significant effect on eye temperature. Moreover, in the summer and scenario1, the difference in maximum temperature of the Cornea between normal and fever conditions is 1.01 °C. On the other hand, the difference in maximum temperature of the Cornea between normal and hypothermia conditions is 1.51 °C.