Article review data
August 2024
Article publication date
June 2024
ARPANSA summary
This cohort study, conducted in the USA, examined the impact of ambient ultraviolet radiation (UVR) on the incidence of ocular melanoma. The study included 18,089 cases of ocular melanoma collected from 21 of the Surveillance, Epidemiology, and End Results (SEER) population-based cancer registries from 2000-2019. Cases were stratified by county of residence, sex, age at diagnosis and year of diagnosis (2000–2003, 2004–2007, 2008–2011, 2012–2015, 2016–2019). The UVR exposure used in the study was based on cloud adjusted UVR measurements from 2000 different locations that are meant to represent high population areas.
The authors reported no association for the highest quartile of UVR exposure and total ocular melanoma (UVR Q4 versus Q1 incidence rate ratio (IRR) = 0.98; 95% confidence interval (CI):0.94-1.03). However, there was an association for the highest quartile of UVR exposure and ocular melanoma in ciliary body/iris cases specifically (IRR = 1.63; 95%CI:1.43-1.87). The authors concluded there was association between solar UVR and ocular melanoma in the ciliary body/iris, but not for all anatomical sites when using the highest exposed category of solar UVR.
Link to study
Ambient ultraviolet radiation and ocular melanoma incidence in the United States, 2000−2019
Published in
Eye
ARPANSA commentary
This study indicated an association between high solar UVR exposure and ocular melanoma in the ciliary body/iris. For the highest exposed category there was no association for total ocular melanoma cases. The observed lack of an association is contrary to the well-established link between UVR and skin melanoma (Olsen et al 2015). The lack of an association in total ocular melanoma could be due to a number of confounders relating to the lack of individualised exposure assessment in this study. The actual ocular UVR a person is exposed to could deviate significantly from the UVR depending on how much time they spend outside each day, usage of eye protection (sunglasses) and their occupation. None of these factors were considered by the authors. This could result in misclassification bias where the people in the low exposure group could have high exposure and those in the high exposure group could have low exposure. While the study does provide interesting results for how solar UVR might impact ocular melanoma no firm conclusions can be drawn from their findings. An Australian study that looked at ocular melanoma reported a higher age-standardized incidence rate in people 55 and older between 2008-2013 (ASR) in Queensland (ASR 3.9, 95% CI 3.3–4.5) that has a higher average UV index compared to Victoria (ASR 2.8, 95% CI 2.4–3.1) (Chalada et al 2021). However, this study also suffers from misclassification bias as it also does not present individual exposure data or account for sun protective behaviours.
