Purpose. Evaluation of the impact of the developed intracorneal gel stained implants for keratopigmentation based on various materials on the donor human cornea during organotypic cultivation. Material and methods. Three experimental samples of intracorneal gel stained implants were investigated: sample 1 based on sodium hyaluronate with organic pigment, sample 2 based on collagen hydrolyzate with inorganic pigment, and sample 3 based on hydroxypropyl methylcellulose (HPMC) with organic pigment. To determine the toxicity of the studied implants the apoptosis of keratocytes was determined in cryostat sections of the cornea. The method of immunohistochemistry was used to study apoptosis. Scanning electron microscopy was used to visualize the corneal structures in the presence of implants. Results. During the investigation we showed that a gel implant based on a collagen hydrolyzate and a pigment with an inorganic toner (28% in the composition) causes a weak expression of the initiator proteins of apoptosis Caspasa 8 and Cytochrome C, and there is no expression of the BAX and effector proteins Caspasa 3/7. It was revealed that samples No. 1 and No. 3 undergo partial dissolution and washout from the intrastromal tunnel, sample No. 2 based on collagen hydrolyzate has a dense structure and remains in the corneal tunnel throughout the entire cultivation period, for at least 7 days, which is showed using an electron-scanning microscopy. The proposed collagen hydrolyzate gel implant can be considered compact and non-toxic. Conclusion. As a result of organotypic cultivation for 7 days showed the best results intracorneal colored implant № 2 based hydrolyzate of collagen and inorganic toner. Intracorneal colored implant based on collagen hydrolyzate has a more compact and dense structure than the accompanying experimental samples. Key words: keratopigmentation, aniridia, intracorneal colored implant.

Purpose. Analyze of the long-term results of treatment of patients with progressive keratoconus initial stages performed according to the developed algorithm. Material and methods. Clinical studies were carried out on the basis of a retrospective analysis of three comparison groups, depending on the tactics of surgery. Group 1 consisted of 843 patients (1186 eyes) with progression of keratoconus who underwent crosslinking. Group 2 consisted of 1185 patients (1343 eyes) who underwent intrastromal keratoplasty with implantation of corneal segments (ISKP with implantation of RS) with a mechanical (1007 eyes) or femtolaser (336 eyes) method. Group 3 consisted of 912 patients (1270 eyes), these patients underwent combined treatment – ISKP+UV crosslinking. The observation was carried out for 10 years. Results. As a result of the observation of patients for 10 years from the moment of UV crosslinking, an increase in UCVA and BCVA was revealed 10 years after surgery by 0.33±0.05 and 0.2±0.04, respectively. There was a significant increase in the central thickness of the cornea, on average by 12.75±0.08µm after 10 years. When analyzing the results of the observation of group 2, an increase in UCVA and BCVA was observed by 3–6 months after MS implantation. Keratometry indices (Kmax) decreased by an average of 3.5±1.3 diopters after 10 years. There was an increase in the central corneal thickness by 19.25±2.2µm after 10 years. As a result of the observation of patients for 15 months after the combined treatment (UV-crosslinking+ISCP), an increase in UCVA and BCVA was revealed by 0.17±0.10 and 0.25±15, respectively. Keratometry indices (Kmax) decreased by an average of 4.1±0.9 diopters after 15 months. There was an increase in the central corneal thickness by an average of 15±6.2µm after 15 months. Conclusion. Our research has shown that after 6 years there is no need to repeat UV crosslinking. With the correct location of the corneal segments, the progression of ectasia stops, and the UCVA and BCVA increase. Differences were revealed in the dynamics of the postoperative course in patients with combined UV crosslinking and implantation of corneal segments, which is obviously associated with their mutual effect on the ectasized cornea. In order to improve the quality of life of patients with the initial stages of keratoconus, these methods of treating keratectasias can be used in wide clinical practice without the threat of a decrease in clinical and functional results over a long period of time. Key words: keratoconus, classification, algorithm, crosslinking, corneal segment

Aim: To develop a new surgical keratectasia classification. Materials and methods:We did analysis of existing variants of classification of keratectasia, discussion of newly appeared classifications. We discussed advantages and disadvantages of the presented information. We also discussed the decision of a question on creation of the optimum approach to surgical treatment of patients depending on a kind and a stage of keratectasia.Results: Keratectasias were classified according to the presence of the ectatic process progression (progressive and stable); type of ectasia (primary and secondary); ectasia symmetry (symmetrical and nonsymmetrical); stages (0, I, II, III and IV). The following are recommended for each stage: Subclinical stage 0: Observation and check-up every 6 months; stage I: Ultraviolet (UV) cross-linking; stage II: Intracorneal ring segments (ICRS) implantation, UV cross-linking only if residual ametropia correction by photorefractive keratectomy (PRK) or toric intraocular lenses (TIOL) implantation is planned; stage III: Deep anterior lamellar keratoplasty (DALK); stage IV: penetrating keratoplasty (PK). Conclusion:The presented keratectasia classification is based on modern diagnostic methods; it allows to determine the tactic of surgical treatment, depending on the type and stage of the pathological process.Clinical significance: Our classification helps doctors to easily put the stage of keratoconus process and decide on the following surgical treatment.

No abstract

The aim of the study was to assess the feasibility and outcomes of surgical interventions on the cornea in ex vivo experiments using the Femto Visum femtosecond laser system (Optosystems Ltd., Russia). Materials and Methods. This collective study was conducted by the S. Fyodorov Eye Microsurgery Federal State Institution together with the Scientific-Experimental Production "Eye Microsurgery" Ltd. We have developed a technology for surgical intervention on the cornea with the polymeric intrastromal ring implantation aimed to prevent post-keratoplastic astigmatism. To correct defects of the iris, an original colored gel implant was inserted into the corneal tunnel. With the participation of Optosystems Ltd., we developed an algorithm and related software for using femtolaser keratotomy in the treatment of progressive keratoconus. These interventions were performed with 23 donor (cadaver) eyes that had been earlier rejected for a possible use in human keratoplasty. To assess the feasibility of the posterior lamellar keratoplasty using Femto Visum, we tested the surface quality of the ultrathin grafts prepared from 10 isolated corneal flaps. Results. The proposed keratoplasty technology and the implantation of the intrastromal ring resulted in a complete corneal penetration free from adverse tissue bridges or adhesions. Following the kerato-pigmentation procedure, the gel-colored implant was found stably held in the preformed corneal tunnel; the remaining cornea areas remained intact. The femtolaser-assisted keratotomy resulted in radial incisions at the predetermined locations. According to the roughness parameter, the surface quality of the ultrathin grafts produced with the femtosecond laser assistance was similar to that of the standard samples produced with a mechanical microkeratome. Conclusion. The use of the Femto Visum femtosecond laser system in innovative areas of corneal surgery is effective and safe.