[Analysis of the results of modified personalized topographically and tomographically oriented technique of ultraviolet corneal collagen crosslinking]. / Analiz rezul'tatov modifitsirovannoi personalizirovannoi topograficheski i tomograficheski orientirovannoi metodiki ul'trafioletovogo krosslinkinga rogovichnogo kollagena.

PURPOSE: The study aims to develop a modified personalized topographically and tomographically oriented technique of ultraviolet corneal collagen cross-linking (UVCXL) to affect the area of the cornea with weakest biomechanical properties as determined by mathematical modeling. MATERIAL AND METHODS: Modeling of the biomechanics of keratoconic cornea under conditions of external diagnostic action was done using COMSOL Multiphysics® software. Finite-element analysis procured 3D images of stress/deformation distribution pattern throughout the cornea. Matching these 3D images with primary topographic and tomographic Pentacam AXL maps and Corvis ST findings allowed determining localization and dimensions of impaired regions of the cornea. The acquired data helped develop the modified corneal collagen cross-linking technique, which was applied in the treatment of 36 persons (36 eyes) with degrees I and II keratoconus. RESULTS: Uncorrected and best-corrected visual acuity (UCVA and BCVA logMAR) in all patients after modified UVCXL increased after the follow-up period lasting 6-12 months by 0.2±0.19 (23%) and 0.1±0.14 (29%) (p<0.05), respectively, in comparison with preoperative values. Maximum keratometry (Kmax) decreased by 1.35±1.63% (3%; p<0.05) in all cases at 6-12 months follow-up. Improvement of corneal biomechanical strength was determined by statistically significant increase in corneal stiffness index (SP-A1) and corneal stress-strain index (SSI) measured with Pentacam AXL and Corvis ST at 6-12 months follow-up by 15.1±5.04 (18%) and 0.21±0.20 (23%) (p<0.05), respectively. Effectiveness of the developed UVCXL technique is also confirmed by the appearance of a characteristic morphological marker - «demarcation line¼ at the cross-linking site in keratoconus projection at the depth of 240±10.2 µm. CONCLUSION: The developed personalized topographically and tomographically oriented UVCXL technique provides an evident stabilizing effect on the cornea in the form of an increase in its biomechanical strength, improvement of clinical, functional indicators and safety of keratoconus treatment.

[Optimization of methodology and extension of indications for beta therapy of neoplasms of the eyelids, conjunctiva and cornea]. / Optimizatsiia metodiki i rasshirenie pokazanii dlia beta-terapii pri novoobrazovaniiakh vek, kon''iunktivy i rogovitsy.

The paper offers a theoretical foundation and results after clinical approbation of the method developed by the authors for beta therapy by enlarged single doses using, if necessary, a speeded-up fractionating and split courses of radiation. Beta therapy was used in 220 patients with tumors of the eye lids, conjunctiva and cornea, single doses of radiation, 40 Gr daily or each other day. By their morphologic type the tumors were mostly malignant epithelial and pigmented new-formations (sarcoma, melanoma). In the follow-up period, from 1 to 6 years, the following results were recorded: the treatment proved effective for epithelial tumors in 97%, melanocytic--in 73%; recurrences appeared in 3%; the number of postradiation complications made up 6.6%, of them disturbances in visual functions--2%: death from metastases in melanoma--8.7% of cases. The proposed method of radiation allowed to increase indications for beta therapy of this pathology to 5-6 mm of the tumor protrusion, to decrease the number of complications and terms of treatment. As a result of computer analysis of clinical results, a new method for calculation of optimal summary doses of beta radiation was worked out, that can be used by practitioners in conducting beta therapy for tumors of the eye lids, conjunctiva and cornea.

[The potential for organ-preserving treatment in large uveal melanoma]. / Vozmozhnost' organosokhrannogo lecheniia uveal'nykh melanom bol'shikh razmerov.

As compared with enucleation, organ-preserving treatment (photocoagulation, local excision, radiotherapy) of uveal melanoma doesn't worsen the prognosis for the patient's life. However, it was used chiefly for tumors of stages T1-T2, the prominence of the tumor not exceeding 4-5 mm. The purpose of the present communication was a study of the possibility of organ-preserving beta radiotherapy for treatment of uveal melanomas T3, the prominence of the tumor exceeding 5 mm. A new Soviet beta applicator (ruthenium-106, rhodium-106) was used for treatment of 21 patients with melanoma T3N0M0, who had refused enucleation. Average summary doses on the surface of the sclera were 1561 +/- 41 Gr. Clinical results (the follow-up period ranging from 12 to 20 months) were the following: total resorption of the tumor--3 cases; the volume of the tumor reduced by 1/2 and more--9 cases, by less than 1/2--7 cases; the size of the tumor remained unchanged--2 cases. Enucleation was made in 2 patients 3 and 4 months after radiation. The results obtained have shown beta therapy to be effective in some cases of uveal melanoma T3, this allowing to widen indications to organ-preserving treatment.