Abstract
Purpose :
To investigate the effect of incidental ultraviolet (UV) radiation exposure, in a location with high UV index (Brisbane, Australia), in otherwise healthy eyes on the signs of ocular surface and corneal inflammation.
Methods :
Fifty-two young healthy adults aged 18-35 years were enrolled in a cohort study. Participant’s demographics and sun exposure behavior were recorded using questionnaires. Images of the bulbar conjunctiva of the right eye were captured and analyzed for conjunctival ultraviolet autofluorescence (CUVAF) area. Ocular surface inflammation was assessed using OSDI questionnaire, Efron grading scales of bulbar redness and upper tarsal conjunctival (UTC) roughness. In vivo confocal microscopy (IVCM) was used to determine the presence of immature (iDC) and mature (mDC) dendritic cells in the central and peripheral cornea, and to image and measure central corneal nerve parameters. Comparisons were made between corneas with and without CUVAF (independent t-test) and relationships between CUVAF and other measures (Pearson correlation).
Results :
CUVAF was observed in 31 of 52 eyes (60%), with a mean (± SD) nasal, temporal and total CUVAF area of 5.4 ± 4.2 mm2, 4.3 ± 4.3 mm2, and 9.7 ± 7.0 mm2, respectively. Individuals with CUVAF had increased bulbar redness (p = 0.001), upper tarsal conjunctival (UTC) roughness (p = 0.001), and greater DC density (e.g., central mDC, p = 0.02; superior iDC, p = 0.009). Corneal nerve parameters were not affected (e.g., CNFD, p = 0.2; CNBD, p = 0.8). Greater CUVAF area was associated with greater iDC density in the superior (r = 0.36, p = 0.009) and nasal cornea (r = 0.42, p = 0.02). Larger CUVAF area was also correlated with greater mDC density (r = 0.40, p = 0.003) in the superior cornea.
Conclusions :
Greater ocular surface inflammation and higher corneal DC density were observed in individuals with CUVAF, a biomarker for UV exposure. This observation suggests that chronic low levels of UV exposure are harmful to the eye, triggering subclinical inflammatory processes.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.