Risk of ocular exposure to biologically effective UV radiation in different geographical directions

Assessing Human Eye Exposure to UV Light: A Narrative Review

Exposure to ultraviolet light is associated with several ocular pathologies. Understanding exposure levels and factors is therefore important from a medical and prevention perspective. A review of the current literature on ocular exposure to ultraviolet light is conducted in this study. It has been shown that ambient irradiance is not a good indicator of effective exposure and current tools for estimating dermal exposure have limitations for the ocular region. To address this, three methods have been developed: the use of anthropomorphic manikins, measurements through wearable sensors and numerical simulations. The specific objective, limitations, and results obtained for the three different methods are discussed.

Photokeratitis induced by ultraviolet radiation in travelers: A major health problem

Ultraviolet (UV) irradiation is one of the several environmental hazards that may cause inflammatory reactions in ocular tissues, especially the cornea. One of the important factors that affect how much ultraviolet radiation (UVR) humans are exposed to is travel. Hence, traveling is considered to include a more acute UVR effect, and ophthalmologists frequently evaluate and manage the ocular manifestations of UV irradiation, including UV-induced keratitis. The purpose of this paper is to provide an evidence-based analysis of the clinical effect of UVR in ocular tissues. An extensive review of English literature was performed to gather all available articles from the National Library of Medicine PubMed database of the National Institute of Health, the Ovid MEDLINE database, Scopus, and ScienceDirect that had studied the effect of UVR on the eye and its complications, between January 1970 and June 2014. The results show that UVR at 300 nm causes apoptosis in all three layers of the cornea and induces keratitis. Apoptosis in all layers of the cornea occurs 5 h after exposure. The effect of UVR intensity on the eye can be linked to numerous factors, including solar elevation, time of day, season, hemisphere, clouds and haze, atmospheric scattering, atmospheric ozone, latitude, altitude, longitudinal changes, climate, ground reflection, and geographic directions. The most important factor affecting UVR reaching the earth's surface is solar elevation. Currently, people do not have great concern over eye protection. The methods of protection against UVR include avoiding direct sunlight exposure, using UVR-blocking eyewear (sunglasses or contact lenses), and wearing hats. Hence, by identifying UVR intensity factors, eye protection factors, and public education, especially in travelers, methods for safe traveling can be identified.

Personal ultraviolet Radiation exposure in a cohort of Chinese mother and child pairs: the Chinese families and children study

BACKGROUND

Few studies in China have examined personal ultraviolet radiation (UVR) exposure using polysulfone dosimetry.

METHODS

In this study, 93 mother and adolescent child pairs (N = 186) from two locations in China, one rural (higher latitude) and one urban (lower latitude), completed 3 days of personal UVR dosimetry and a sun/clothing diary, as part of a larger pilot study.

RESULTS

The average daily ambient UVR in each location as measured by dosimetry was 20.24 Minimal Erythemal Doses (MED) in the rural location and 20.53 MED in the urban location. Rural mothers had more average daily time outdoors than urban mothers (5.5 h, compared with 1.5 h, in urban mothers) and a much higher daily average personal UVR exposure (4.50 MED, compared with 0.78 MED in urban mothers). Amongst adolescents, rural males had the highest average daily personal UVR exposure, followed by rural females, urban females and urban males (average 2.16, 1.05, 0.81, and 0.48 MED, respectively).

CONCLUSIONS

Although based on small numbers, our findings show the importance of geographic location, age, work/school responsibilities, and sex of the adolescents in determining personal UVR exposure in China. These results suggest that latitude of residence may not be a good proxy for personal UVR exposure in all circumstances.