Prevalence and severity of dry eye in candidates for laser in situ keratomileusis for myopia in Russia

PURPOSE: To assess the prevalence and severity of dry-eye disease in patients with myopia being evaluated for laser in situ keratomileusis. SETTING: Nine ophthalmology centers in Russia. DESIGN: Prospective noninterventional cross-sectional study. METHODS: The assessments included the Schirmer I test, tear breakup time (TBUT), lissamine green and fluorescein staining (Oxford grading scheme), Ocular Surface Disease Index (OSDI) questionnaire, and Dry Eye Workshop (DEWS) dry-eye severity grading. RESULTS: The study comprised 400 patients with myopia (mean age 29.7 years); 145 (36.2%) wore contact lenses, and 81 (20.2%) used topical dry-eye medication. The mean Schirmer test score was 15.2 mm; 36.5% of patients had evidence of tear-volume deficiency (Schirmer score ≤10 mm). The mean TBUT was 11.7 seconds; 10.1% of patients had tear-film instability (TBUT <5 seconds). Conjunctival (lissamine green) staining intensity was categorized as minimal or greater (grade ≥1) in 62.3% of patients and mild or greater (grade ≥2) in 22.8% of patients. The mean OSDI score was 20.4, indicating mild ocular disability. Dry-eye severity (DEWS grading) was mild/episodic in 66.2%, moderate in 29.5%, and severe in 4.3% of patients. No clear correlation was evident between the Schirmer/TBUT scores and the lissamine green/OSDI scores. CONCLUSIONS: The prevalence of dry eye in this population was estimated at approximately 10% to 40% (based on clinical signs) and 40% to 55% (based on symptoms); dry-eye severity was predominantly mild/episodic. The proportion of patients requiring dry-eye therapy (based on OSDI and DEWS severity findings) was almost 2 times higher than the proportion receiving treatment.