Association among pterygium, cataracts, and cumulative ocular ultraviolet exposure: A cross-sectional study in Han people in China and Taiwan

Abstract

Purpose Pterygium is an ocular surface disorder mainly caused by ultraviolet (UV) light exposure. This study explored the relationships between six cataract types with pterygium and UV exposure. Methods We have previously studied cataracts in residents of three regions in China and Taiwan with different UV intensities. From that study, we identified 1,547 subjects with information on the presence or absence of pterygium. Pterygium severity was graded by corneal progress rate. Cataracts were graded by classification systems as three main types (cortical, nuclear, posterior subcapsular) and three subtypes (retrodots, waterclefts, fiber folds) with high prevalence in middle-aged and elderly people. We calculated the cumulative ocular UV exposure (COUV) based on subject data and National Aeronautics and Space Administration data on UV intensities and used logistic regression to calculate odds ratios for the associations of COUV, cataract, and pterygium. Results We found an overall pterygium prevalence of 23.3%, with significant variation among the three regions. Four cataract types (cortical, nuclear, posterior subcapsular, and retrodots) were significantly associated with the presence of pterygium. Conclusions There was a significant association between COUV and pterygium, indicating that COUV is associated with the risk of pterygium development and that pterygium is useful as an index of UV exposure. Furthermore, the type of cataract in eyes with pterygium may indicate the level of UV exposure.

Refractive Outcomes of Simultaneous Pterygium and Cataract Surgery With Fibrin Glue

“…Exposure to UV light causes an increased incidence of cataract in patients with pterygium [5,11,12]. Cataract remains the leading cause of avoidable blindness worldwide [13].…”

Vision With Retrodots and Factors for Declining Visual Function

“…RDs were assessed using the World Health Organization classification system 18 and Kanazawa Medical University Cataract Classification and Grading system. 7 , 8 The BLS of the fetal nucleus was measured for each participant using EAS-1000 (Nidek Co., Ltd., Aichi, Japan); participants with macroscopically apparent nuclear cataract were excluded. Patients with eye diseases other than ametropia were excluded.…”

“…1 ). In the Kanazawa Medical University classification, 7 , 8 RDs are classified into four groups. Grade 1 is based on the number of RDs (1–4) within the pupil area of 3 mm.…”

“…The prevalence rate of RDs among older adults from the Han people in China and Taiwan was reported to be high. 7 , 8 Decreased visual acuity associated with lenticular changes is influenced by increased high-order aberrations (HOAs), 9 – 11 increased backward light scattering (BLS), 12 and increased forward light scattering. 13 , 14 Furthermore, increased straylight 15 , 16 is a factor that decreases visual function.…”

UV Protection in the Cornea: Failure and Rescue

“…In the case of the cornea, acute UV exposure is known to cause photokeratitis, a painful inflammation where the epithelium, stroma, and endothelium may be affected and which leads to clouding [ 26 , 27 , 28 , 29 ]. Chronic UV exposure usually leads to long term conditions such as tumours (squamous cell carcinomas, malignant melanomas, lymphoma of the conjunctiva [ 30 , 31 , 32 ]) or keratopathy (see Table 1 ) [ 33 , 34 , 35 ].…”