The effect of the use of scleral lenses on the course of dry eye syndrome in patients with keratoconus

Relevance Keratoconus (KC) is a chronic non-inflammatory dystrophic disease of the cornea, accompanied by its cone-shaped "bulging" in the central zone and thinning in the apex zone [1, 2]. It has also been proven that as the clinical stage of KC is expressed, significant changes occur in the precorneal tear film and cornea, which causes the appearance of dry eye syndrome (DES) [3, 4]. Objective Evaluation of changes in the state of the precorneal tear film in KC in combination with DES while wearing scleral contact lenses (SCL). Material and methods A total of 31 patients (62 eyes) were examined, who were fitted with individual SCLs for stabilized non-operated KC of various stages. A comprehensive assessment of the tear film condition included the following methods: anterior segment biomicroscopy using vital dyes, functional tests, OCT meniscometry, as well as the OSDI questionnaire and an oral survey. The studies were conducted before, after 1 and 3 months while wearing the lenses. Results Before fitting the SCL, the absence of staining of the ocular surface was recorded in 29% of cases, after 3 months - in 94% of cases. The data from the functional tests conducted before fitting the SCL showed a decrease in the stability of the precorneal tear film. As the period of wearing the lenses increased, the tear film breakup time increased significantly: after one month of wearing by 12%, after 3 months - by 27% of the initial values. An oral survey showed complete adaptation to the SCL and comfort when wearing it in 87% of cases. The following effects were noted while wearing the SCL: a decrease in the degree of epitheliopathy, an increase in the functional test results, which indicates the restoration of the normal function of the tear film. Conclusion The results of the study confirm the effectiveness of the use of SCL in the protection of the ocular surface in patients with keratoconus in combination with signs of dry eye syndrome. Keywords: keratoconus; dry eye syndrome; scleral rigid gas-permeable lenses; tear film