Abstract
Purpose :
Studies in dermatology have reproduced the finding of an increased frequency of skin cancers on the left side of the body compared to the right, and authors have intriguingly proposed that ultraviolet irradiation through sunlight exposure is a plausible explanation. No existing study has examined a possible asymmetry regarding pterygium between the right and left eye. Thus, we aimed to determine if pterygium preferentially affects the right or left eye in a subject population of known drivers.
Methods :
Following IRB approval, subjects ≥18 years were retrospectively identified at a primary eye clinic in Maricopa County, Arizona for pterygium based on International Classification of Diseases (ICD) diagnosis codes (H11.0 and 372.4). Pterygium presence was then verified by manual medical record examination and adjudicated among investigators. Subject records were inspected for smoking status, ethnicity, and the presence of a driver’s license in the electronic chart. Data were recorded and statistical analyses for differences in right and left eye, sex, smoking status, and ethnicity were performed with the chi-square test for categorical variables.
Results :
239 subjects with a total of 351 pterygia were enrolled. 147 subjects had a single unilateral pterygium, and 3 of these subjects had pterygia both nasally and temporally in a single eye. 92 subjects had bilateral or multiple pterygia present (173 nasal and 28 temporal). The mean subject age was 61.6 (standard deviation 13.8), 117 (49%) were female, and 45 (20%) were Hispanic. Pterygium showed a significant predilection for the left eye with 59% of the unilateral pterygium sample (87 left and 60 right eye, P=0.021). When known drivers with unilateral pterygium were analyzed (n=121), left eye pterygium was significantly more common (79 and 42, P<0.001).
Conclusions :
Though not without its limitations, this epidemiological study demonstrated that pterygium in this population appears to have a predilection for the eye nearest to the left automobile window, an effect greatly enhanced among known drivers. Out of concern that cumulative ultraviolet exposure is not only associated with pterygium but may lead to more deleterious ocular and non-ocular consequences, wearing sunglasses inside automobiles is recommended as a method of primary disease prevention. For clinicians in climates with a high ultraviolet light index, methods to avert ocular sunlight exposure should be considered and encouraged.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.