Prevalence of pinguecula and pterygium in patients with thyroid orbitopathy.

PURPOSE: To determine the prevalence of pinguecula and pterygium in patients with thyroid orbitopathy (TO) and to evaluate its correlation with clinical findings. METHODS: All patients underwent a thorough ophthalmic examination, including tear function analysis using tear film breakup time (BUT) measurement. For patients with TO, lid retraction, Hertel exophthalmometry, and clinical activity scores were also measured. All patients were evaluated for the presence of pinguecula and pterygium. RESULTS: The groups were age (P = 0.15) and gender matched (P = 0.2). The prevalence of pinguecula was significantly higher in group 1 (196 patients, 98%) than in group 2 (23 patients, 46%) and group 3 (64 patients, 32%) (P < 0.001). In group 1, lid retraction was significantly correlated with pinguecula prevalence (P < 0.001), whereas there was no correlation between pinguecula prevalence and BUT values (P = 0.624), clinical activity score levels (P = 0.325), or exophthalmometer findings (P = 0.155) In groups 2 and 3, pinguecula was seen more frequently in patients with subnormal BUT measurements (P < 0.001). Pterygium was seen at very low rates in all groups and analysis could not be performed. CONCLUSIONS: Pinguecula was seen more frequently in patients with TO than in both control groups. Lid retraction was the only clinical factor determined with significant impact on the prevalence of pinguecula in patients with TO. Impaired tear function did not influence pinguecula prevalence in patients with TO, in contrast to both control groups. Increased exposure to UV light because of lid retraction may be the major underlying causative factor on pinguecula prevalence in patients with TO, compared with tear dysfunction in both control groups.