Conjunctival ultraviolet autofluorescence area is predictive of pterygium onset in young adults

Abstract

Purpose : Conjunctival ultraviolet autofluorescence (CUVAF) area has been associated with ocular ultraviolet (UV) radiation exposure and time spent outside. CUVAF area is also associated with greater risk of pterygium on cross-sectional studies; however, longitudinal data is lacking. We investigated the relationship between CUVAF area measured at 20 years of age and incident pterygium over a 7- to 8-year follow-up period.

Methods : Data from the 20-year (age range 19-22 years), 27-year (age range 25-28 years) and 28-year (age range 27-30 years) follow-ups of the Raine Study generation 2 birth cohort were used for this study. CUVAF images were taken at the 20-year follow-up and CUVAF area measured by a single grader using a custom-built software. Pterygium was defined as a wing-shaped fibrovasular growth crossing the limbus and was assessed by a single grader from colour photographs captured at the 20-, 27- and 28-year follow-ups. Participants without CUVAF images taken at the 20-year follow-up or who had a pterygium at the 20-year follow-up were excluded from the analysis. The primary outcome was incident pterygium in either eye. Cox regression was used for statistical analysis.

Results : Of the 1344 participants of the 20-year follow-up, 1313 (97.7%) had CUVAF data and 1298 (96.6%) did not have a pterygium. Of these, 970 (74.7%) had colour photos taken at either the 27- (n=907) or 28-year (n=712) follow-ups and incident pterygia in either eye were present in 13 (1.4%) participants. Of 159 (15%) of participants who reported smoking cigarettes at the 20-year follow-up, none had an incident pterygium. On Cox regression, total CUVAF area (of both eyes) was strongly associated with risk of incident pterygium (per 10mm² increase, hazard ratio [HR]=1.38, 95% confidence interval [CI]: 1.21, 1.57) and remained strongly associated with incident pterygium after adjusting for sex and self-reported time spent outside in summer (HR=1.45, 95% CI: 1.21, 1.73). The area under the ROC curve for total CUVAF area alone was 0.81. Sex, axial length, 25-hydroxyvitamin D concentration and self-reported family history of pterygium were not associated with risk of incident pterygium.

Conclusions : CUVAF area at 20 years was a strong predictor of subsequent development of pterygium and may be useful in identifying patients at high risk of pterygium.

This is a 2021 ARVO Annual Meeting abstract.