Abstract
Purpose:
To compare ocular UV exposure in Asian and Western facial contours.
Methods:
Mannequins, simulating facial skeletons of Western and Asian females aged 40s, embedded with UV-AB sensors (sensitivity 280-400 nm, ALGAN, Japan) at top of head, forehead, and eyes (nasal, center, temporal) with facial reliefs (distance perpendicular to a line connecting forehead and cheek from corneal surface) of 5 mm and 10 mm for Asian and Western, respectively, were set on a grey urethane-coated concrete surface, (UV reflectance approx. 10% comparable to asphalt) and measurement in 8 azimuths were performed from 0° to 40° of solar altitude per 5° on Kanazawa Medical University roof (lat.36.66°N, long. 136.65°E, alt. 50 m), October 1, 2013.
Results:
UV exposure doses at top of head for both facial contours were 8-10 mW/cm2 at 40° solar altitude (culmination). Maximum ocular doses from the average of 8 azimuths were around 2 mW/cm2 and 1 mW/cm2 in Asian and Western, respectively. When facing the sun, ocular dose in Asian showed a bimodal curve of about 4 mW/cm2 at maximum at around 30° solar altitude, and in Western a chevron curve of 1.7 mW/cm2 at maximum at culmination. Ocular exposure at 10°, 20°, 30°, and 40° of solar altitude in the average of 8 azimuths in Western showed 41%, 47%, 63%, 65% dose of Asian. Even facing the sun, Western eyes were shadowed due to skeletal geometry at about 10° or more of solar altitude.
Conclusions:
Due to differences in facial skeletal geometry, ocular exposure to UV in Asians is greater than in Westerners.
Keywords: 670 radiation damage: light/UV •
445 cataract •
419 anatomy