Four-step treatment of keratoconus associated with high refractive ametropia

Abstract

Relevance. Today, the problem is particularly relevant for cases of keratoconus combined with high refractive ametropia. An extensive review of protocols for the combined use of corneal cross-linking (CXL) in combination with photorefractive keratotomy (PRK), phototherapeutic keratectomy (FTC), IRS, and phakic intraocular lens implantation shows that these protocols require further research to prove the best treatment options. Purpose. To evaluate the effectiveness of the fourstage model of surgical treatment of keratoconus in combination with high refractive ametropia. Material and methods. Between 2016 and 2019, 16 patients (22 eyes) aged 18 to 40 years were operated on using the four-step procedure including intrastromal corneal segments (ICRS) implantation, CXL the next day after the surgery, phakic toric lens implantation (Visian ICL STAAR, implantable collamer lens) 8 months after the surgery, and transepithelial topographic PRK 6 months after the surgery. The study group included patients with keratoconus stage II–III according to the classification of Amsler M. (1961). Patients were examined before, 10 days, 1, 3, 6, 8 and 12 months after the surgery according to a unified program, including determination of visual acuity without (NCVA) and with maximum correction (MCVA), autorefractometry (TOMEY RC-5000), non-contact tonometry (TOMEY FT-1000), Pentacam corneal topography, Wavelight Oculyzer (ALCON), Topolyzer VARIO tomography (ALCON), OCT of the anterior segment Cirrus HD-OCT 5000 (Zeiss, Germany). Results. Indicators of NCVA (M±SD) before and after the 1st operation were 0.02±0.015 and 0.08±0.022 (p=0.05). After the 2nd operation, the NCVA (0.10±0.025) didn‘t change significantly, after the 3rd operation its value increased more than 4 times (0.42±0.11). After the 4th operation, a statistically significant increase in NCVA was observed (0.58±0.12). Conclusion. In patients aged 18 to 40 years with progression of keratoconus, with high myopia, due to the inexpediency of excimer laser operations and where the depth of the anterior chamber isn‘t less than 3 mm, the combined four-stage method of treating keratoconus can be performed as a more effective method. This method allows to avoid keratoplasty, preserving and correcting the irregularity of the own cornea. Key words: keratoconus, refractive surgery, Visian ICL STAAR, topographic PRK, CXL