Change of the condition of the precorneal tear film at different stages of keratoconus

Relevance Keratoconus is an ectatic corneal disease of a degenerative-dystrophic nature, etiopathogenetically associated with a violation of the biomechanical properties of collagen fibers [1, 2]. Due to the violation of the framework properties of the cornea, progressive thinning and protrusion of its central part develop, which leads to the occurrence of irregular astigmatism and a significant decrease in visual functions. According to the observations of several authors, KE is often accompanied by symptoms of dry eye syndrome (DES), while the frequency of DES in keratectasia is higher than in the population of healthy individuals [3]. Objective Evaluation of changes in the state of the precorneal tear film according to the stages of keratectasia. Material and methods 50 patients (100 eyes) with bilateral unoperated KE from subclinical to stage IV were examined. For a comprehensive assessment of the tear film condition, the following methods were used: biomicroscopy of the anterior segment of the eye using vital dyes, functional tests (Norn, Schirmer, Jones tests), tiascopy with software processing of the results of the lipid layer of the tear film, OCT meniscometry, as well as filling out the OSDI questionnaire by patients. Results Depending on the progression of the clinical stage of keratoconus, significant changes were detected: an increase in the areas of staining of the ocular surface with vital dyes, a decrease in the results of the Norn functional test and OCT meniscometry, an increase in the area of ​​zones with a lower lipid thickness and zones of their complete absence according to tiascopy data, as well as an increase in the number of points on the OSDI questionnaire [4]. Conclusion The obtained results emphasize the importance of prescribing tear substitute and reparative therapy for keratoconus, which helps to improve the condition of the ocular surface and stabilize the precorneal tear film. Key words: keratoconus; dry eye syndrome; tear film