Combined approach to cataract surgery in keratoconus

Relevance Keratoconus (KC) is a chronic dystrophic non-inflammatory disease of the cornea, leading to its thinning and cone-shaped deformation. The disease manifests itself at a young age, stabilizes by 40-45 years, when the risk of cataract development increases [1, 2]. Cataracts in KC occur more often and earlier than in people without KC, and worsen the decline in visual function, worsening the quality of life [3]. Risk factors for early cataracts are surgical treatment of KC and glucocorticosteroid therapy. Standardized methods of cataract phacoemulsification (PEC) and IOL calculation are not suitable for patients with KC for the following reasons: • corneal features reduce the reliability of IOL calculation; • there is no universal formula for calculating postoperative refraction; • the progressive nature of KC and the effect of PEC can worsen long-term results. Objective To create and introduce into clinical practice a new approach to the treatment of cataracts combined with progressive keratoconus. Material and methods The study includes 11 eyes: 4 eyes with stage II keratoconus and 7 eyes with stage III keratoconus according to Amsler and a history of immature cataract. Results A new approach to the treatment of cataracts combined with progressive keratoconus was tested and introduced into clinical practice at the M.M. Krasnov Research Institute of Eye Diseases. To stabilize keratoconus, regularize the corneal surface and improve visual functions, intrastromal keratoplasty with allograft implantation using a femtosecond laser is performed at the first stage, which leads to thickening and strengthening of the cornea in the ectasia zone [4, 5]. Then, in the second stage, after 6-12 months, PE is performed with IOL implantation, the calculation of which is performed using the Barrett Toric Calculator formula. The progressive nature of CC became the basis for two-stage treatment. As a result, a decrease in keratometric parameters and an increase in UCVA and KOVA were achieved (Table 1). Conclusion The implementation of the approach proposed by us in patients with CC in combination with cataract is an effective option for treating corneal ectasia with an increase in visual functions and allows for an increase in the accuracy of calculating the optical power of the IOL, reducing the discrepancy between the calculated and actual refraction after PE. Key words: keratoconus; cataract; cataract phacoemulsification; allograft; intrastromal keratoplasty; IOL; bandage therapeutic optical keratoplasty