[Deep anterior lamellar keratoplasty in extrusion of an incomplete intrastromal corneal ring segment (clinical observation)]. / Glubokaya perednyaya posloinaya keratoplastika pri ekstruzii nepolnogo intrastromal'nogo kol'tsa (klinicheskoe nablyudenie).

Intrastromal corneal ring segments (ICRS) of in various shapes are used to correct structural changes in the cornea and improve visual acuity in keratoconus (KC). The most serious complications of the technology infection, vascular ingrowth, and extrusion. In this study a 44-year-old patient underwent deep anterior lamellar keratoplasty (DALK) 5 years after implantation of ICRS in the shape of an incomplete ring to treat its extrusion of up to 30%, vascular ingrowth into the cornea and corneal syndrome. The following DALK technique was used: excision of the free part of the corneal segment, removal of the remaining part of the corneal segment, excision of 80% of thickness of the corneal block with a 8.5-mm trepan, pneumatic dissection of the stroma down to the Descemet membrane (DM), removal of the remaining stroma on the viscoelastic pillow, laying and suture fixation of the donor graft. There were no complications during the postoperative period, the graft remained transparent for up to 10 months. Uncorrected visual acuity (UCVA) increased from 0.01 to 0.4, best corrected visual acuity (BCVA) increased from 0.3 to 0.7. The number of endothelial cells decreased from 2980 to 2670 cells/mm2 (10.4%). This clinical case demonstrates that DALK surgery can be a reliable method of patient rehabilitation in cases of extrusion of ICRS in the shape of an incomplete ring and vascular ingrowth.

[Long-term outcomes of bandage therapeutic-optical keratoplasty in the treatment of keratoconus]. / Otdalennye rezul'taty bandazhnoi lechebno-opticheskoi keratoplastiki pri lechenii progressiruyushchego keratokonusa.

Intrastromal keratoplasty has recently been widely used in the surgical treatment of keratoconus (KC). In 2013, a new type of interlamellar keratoplasty operation was developed - bandage therapeutic-optical keratoplasty (BTOK). PURPOSE: Evaluation of the long-term outcomes of surgical treatment of stages II and III progressive KC with BTOK technique. MATERIAL AND METHODS: The study included 107 patients (126 eyes): group 1 with stage II KC - 78 eyes, 100% of these patients were observed for 1 year, 52 eyes (66%) for 3 years, and 18 eyes (23%) for 5 years; group 2 - 48 eyes with stage III KC, with 100% of them observed for 1 year, 39 eyes (81%) for 3 years, and 12 eyes (25%) - 5 years. All patients received a customized allograft in the form of an intrastromal corneal ring segment (ICRS). RESULTS: During the first year after BTOK surgery, the uncorrected and corrected visual acuity (UCVA and CVA) in the first group increased by 0.5±0.04 (p<0.05) and 0.2±0.02 (p<0.05), respectively, in the second group - by 0.46±0.05 (p<0.05) and 0.47±0.05 (p<0.05) due to a decrease in refractive indices in the central 3.0 mm zone. In the first group, mean refraction in the central 3.0 mm zone (Km) was within 45±3.75 (p<0.05), in the second - 48.63±.2 diopters (p<0.05), while maximum refraction in the central 3.0 mm zone (Kmax) decreased from 50.02±2.20 (p<0.05) to 44.61±1.03 diopters (p<0.05) in the first group, from 58.21±3.43 (p<0.05) to 50.45±3.46 diopters (p<0.05) in the second group. The values of UCVA, CVA and refractive indices of the central corneal zone in the first and second groups did not change statistically significantly after three and five years. Minimum corneal thickness in the first group increased from 476.23±13.35 to 485.08±15.80 µm (p<0.05), in the second - from 412.73±38.63 to 422.00±42.25 µm (p<0.05). CONCLUSION: BTOK surgery can be used in patients with stages II and III KC to improve the visual functions, strengthen the ectatic cornea and stop the progression of the disease.

[Experimental studies of the biomechanical properties of the cornea]. / Eksperimental'nye issledovaniya biomekhanicheskikh svoistv rogovitsy.

The review presents the results of experimental studies of the biomechanical properties of the cornea. Selective evaluation of the individual corneal structures (for example, limiting membranes) using classical mechanical tests is to a certain extent limited due to the rather small thickness of these structures and the related difficulties in sample fixation. In real practice, the use of a method better adapted for conducting such studies - atomic force microscopy (AFM) - remains promising, since on the one hand it eliminates the need for mechanical capture and retention of the sample, and on the other - provides the capability for studying its segments separately.

[On the issue of allocating the pre-Descemet's layer in the corneal structure]. / K voprosu o vydelenii predestsemetovogo sloya v strukture rogovitsy.

Selective keratoplasty is known to be based on surgical manipulations aimed at dosed isolation of layered grafts in the corneas of the donor and the recipient. Some technological features of obtaining transplants have served as the basis for expanding the understanding of the corneal structure. Thus, analysis of the process of corneal stroma pneumodissection for isolation of the Descemet's membrane led to a suggestion that there was another layer in the cornea, it was designated as the pre-Descemet's layer. This article discusses the practicability of separating the pre-Descemet's layer from the perspective of structural, functional and surgical anatomy.