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[Prevalence and severity of dry eye syndrome in myopic candidates for laser in situ keratomileusis].

PURPOSE
To assess the prevalence and severity of dry eye syndrome (DES) in patients with myopia being evaluated for laser in situ keratomileusis (LASIK).


MATERIAL AND METHODS
The prospective, non-interventional, cross-sectional study involving 9 Russian ophthalmic centers included 400 patients with myopia (aged 29.7 years in average). Among them, 145 (36.2%) wore contact lenses, and 81 (20.2%) used locally administered drugs for treatment of DES. The examination included Shirmer I test, tear film break-up test (TBUT), staining with lissamine green and fluorescein (Oxford scale), Ocular Surface Disease Index (OSDI) questionnaire, and classification of the disease according to dry eye workshop (DEWS).


RESULTS
Average Shirmer test result was 15.2 mm; 36.5% of patients had signs of tear deficiency (Shirmer test ≤10 mm). Average TBUT was 11.7 seconds; the tear film of 10.1% of patients was unstable (TBUT <5 seconds). Lissamine green staining was classified as insignificant or higher (degree ≥I) in 62.3% of patients and mild or higher (degree ≥II) - in 22.8%. Mean score of the OSDI questionnaire was 20.4 indicating mild vision impairment. Dry eye severity according to DEWS classification 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.


CONCLUSION
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.