Keratoconus is one of the topical problems in modern ophthalmology. Among the currently used treatment methods is intralamellar keratoplasty that utilizes allomaterials or homotransplants. The surgery technique has obvious advantages over penetrating and deep anterior lamellar keratoplasty. There is no risk of tissue incompatibility, the recovery period is shorter, and prolonged use of corticosteroids is not necessary. In recent years, technological development has made the application of femtosecond laser a standard procedure for various surgical interventions on the cornea, particularly for creation of intrastromal tunnels and corneal bags. This article presents an analysis of the modern literature data about different intralamellar keratoplasty techniques for treatment of keratoconus. The described techniques show its great clinical possibilities, especially the intrastromal keratoplasty variant with implantation of biological tissues. One of such techniques was developed and tried by a group of specialists at Research Institute of Eye Diseases in 2014. It involves recovery of corneal thickness in the ectatic area by intralamellar transplantation of a layered transplant of adequate size, which acts as a bandage. The surgery simultaneously affects the stabilization action, corrects refractive errors and eliminates the structural changes; it was accordingly named bandage therapeutic-optical keratoplasty (BTOK). The indication for its usage is progressing keratoconus in stage II–III patients. Among the described outcomes are cease of the disease progression in long-term follow-up, improvement of corrected and uncorrected visual acuity. The foreign analogue of the technique is Corneal Allogenic Intrastromal Ring Segments (CAIRS) by Jacob S. et al. His study included 20 patients with stages I to IV keratoconus; all patients undergone corneal cross-linking as the first stage, then they had CAIRS implanted into the intrastromal tunnels prepared with femtosecond laser. In both methods, the authors point at the improvement of corrected and uncorrected visual acuity. None of the patients had implant dislocation or keratoconus progression during the follow-up period.

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Purpose — to evaluate the functional results of bandage therapeutic-optical keratoplasty (BTOK) in keratoconus eyes after implantation of intrastromal corneal ring segments (CRS). Material and methods. The study included 18 patients with stage II and III keratoconus (as per Amsler-Krumeich classification) who had underwent implantation of CRS with unsatisfactory long-term outcomes. The patients were divided into two groups. The first group consisted of 7 patients (7 eyes) of 27 ± 3 years old with had past history of CRS implantation followed by the absence of predicted improvement of visual acuity during the observation period of up to 18 months. The second group included 11 patients (11 eyes) who had visual acuity improvements after CRS implantation, but had regression in the long-term follow-up of 2 to 5 years. The surgical algorithm consisted of two steps: first, all 18 patients had the intrastromal ring segments removed; second, 3 months later they underwent BTOK. Outcomes. After the removal of CRS, patients of both groups showed improvements in central corneal refraction, their visual acuity decreased to 0.07 ± 0.02 and 0.09 ± 0.04, respectively. The 36 months follow-up after BTOK revealed significant improvements in visual acuity — up to 0.48 ± 0.04 and 0.54 ± 0.11, respectively — in all patients in both group due to marked flattening of the cornea in the optical zone. Conclusion. Bandage therapeutic-optical keratoplasty allows treatment of patients with complicated or who had unsatisfactory results after implantation of intrastromal ring segments. The surgery leads to stabilization of keratectasia in keratoconus patients and significantly increases uncorrected visual acuity.

Introduction: penetrating keratoplasty (PK) is an effective method for the surgical treatment of corneal failure and its layers and low visual acuity. It is well-known that the graft degrades over time, it is associated with “chronic immune destruction”. Rekeratoplasty is conducted in case of rapid decrease of transplant functions, but even with multiple rekeratoplasty iterations, the result can be unstable.Patient and methods. Patient D., 42 years old, complaints to low vision of left eye — arm movement 10 cm on face. Both eyes have been previously surgically operated for the last 10 years. Two iterations of an artificial iris transplantation in combination with IOL implantation, and Ahmed drainage implantation and five rekeratoplasty on the left eye were conducted. Corneal graft failure with transplant thickness — 802 μm. The patient suffers from Mediterranean fever and polyarthritis. We conducted a course of conservative therapy, which increased visual acuity to 0.05. Then we performed a surgical procedure for hybrid type of keratotransplantation. The following procedures were gradually conducted: mechanical removal of epithelium, femto-laser formation in a recipient’s replaceable corneal disk formation with 500 μm thick and a diameter of 7.0 mm, removal of disk, femto-laser formation of a central penetrating hole with a diameter of 3 mm opposite the artificial pupil, placing of the hydrogel graft 60 μm thick on the bottom of the bed. Hydrogel graft was covered by a donor corneal graft, which was fixed by interrupted sutures and soft contact lens.Results: Visual acuity of the left eye after 1 day after keratoplasty — 0.2; after 1 month — 0.3, the transplant was transparent; after 4 months — 0.4 with complex correction — 0.7, the transplant was transparent, the thickness of the donor disc — 275 μm.Conclusion. After multiple rekeratoplasty iterations the presented method of combined keratotransplantation allows to obtain a non-permanent effective result. At the same time, the polymer metabolism is preserved, since it has a circulation with the front camera. The case requires further observation.

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