METHOD FOR DETERMINATION OF DIFFERENTIATED INDICATIONS TO EXCIMER-LASER CORRECTION OF POST-CARATHOTOMIC REFRACTIVE DISORDERS Russian patent published in 2017 - IPC A61F9/00 A61F9/08 

FIELD: medicine.

SUBSTANCE: autorefractokeratometry and visometry are performed with and without correction. The maximum corrected visual acuity (MCVA) is determined. Biomicroscopy is performed to assess the condition of the eye and lens anterior segment. Computer keratotopography is performed on a TMS-4 device (Tomey, Japan) to obtain keratotopographic indices: Surface Asymmetry Index (SAI) and Surface Regularity Index (SRI). Confocal microscopy is performed on a Confoscan 4 device (Nidek, Japan). If the patient is diagnosed with hypermetropic refraction, the MCVA before surgery is below or equal to 0.6, the biomicroscopy revealed no lens opacifications, according to computer keratotopography data, corneal topogram asymmetry is observed, the SAI index is greater than 0.5, the SRI index is greater than 1.0, According to confocal microscopy, the keratotomic scar is a dense fibrous tissue with no signs of diastasis, then the patient is prescribed two-stage treatment. The first stage includes restoration of corneal surface regularity by the method of topographically oriented laser intrastromal keratomileusis (LASIK). The second stage, with stabilisation of refraction, keratometry and keratotopography indices, includes spherocylindrical correction by sublamellar ablation after lifting of the valve formed at the first stage. If the patient is diagnosed with hypermetropic refraction, the MCVA before surgery is higher than 0.6, the biomicroscopy revealed no lens opacifications, according to computer keratotopography data, corneal surface is regular, the SAI index is below or equal to 0.5, the SRI index is below or equal to 1.0, according to confocal microscopy, the keratotomic scar is a dense fibrous tissue with no signs of diastasis, then correction of refractive disorders by the LASIK method with a spherical cylindrical ablation algorithm is prescribed. If the patient is diagnosed with hypermetropic refraction and/or mixed astigmatism, the biomicrocoscopy reveals lens opacifications, according to computer keratotopography data, corneal topogram asymmetry is observed, the SAI index is greater than 0.5, the SRI index is greater than 1.0, the confocal microscopy reveals keratotomic scar structure violation, namely, the signs of diastasis and incomplete scarring with individual fibrous elements, then two-stage treatment is prescribed. The first stage includs lens replacement with an intraocular optical lens with expectation of myopic refraction. The second stage, with the stabilisation of refraction, keratometry and keratotopography indices, includes elimination of refractive disorders and corneal irregularity by the method of topographically oriented FRK.

EFFECT: method allows to reduce the chance of complications, obtain the highest possible visual acuity after excimer laser postkeratotomy refractive violations correction through a comprehensive assessment of the most significant indicators.

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