Features of Hemodynamics of Retinal Vessels in Hypermetropic and Myopic Defoci during Treatment with Orthokeratological Lenses

Abstract

Conduct a study of the hemodynamics of retinal vessels in eyes with myopia with hypermetropic and myopic defocuses: 60 eyes (30 patients) with mild myopia and 100 eyes (50 patients) with moderate myopia were examined. The average age of the patients was 12.0±0.38 years. The average degree of myopia was — (−) 2.2±0.25 D with a mild degree; (−) 4.7±0.22 D at average; The control group consisted of 40 eyes (20 patients) with emmetropia, average age -13.0±0.27 years. Along with generally accepted research methods, the following were carried out: autorefractometry, ophthalmometry, biometry, keratotopography, binocular ophthalmoscopy, OST of the optic disc and macula, OST-A with calimetry, ultrasound of the vessels of the central nervous system and central veins. All patients were fitted with orthokeratological lenses of reverse geometry Moonlens from Sky Optix, with repeated examinations after 1-3-6-12-24 months. With a weak degree of myopia, a narrowing of the caliber of the vessels of the central nervous system was revealed to 71.0±0.60 µm in 14.8% with hypermetropic defocus, with the absence of narrowing of these vessels with myopic defocus. With an average degree of myopia, narrowing of the vessels of the central nervous system to 66.1±0.60 μm was detected in 55% (55 eyes) with hypermetropic defocus, versus 35.8% (36 eyes) with the caliber of the vessels of the central nervous system — 68.6±0.57 μm (P <0.05). Along with this, in patients with an average degree of myopia, a narrowing of the vessels of the central vein with hypermetropic defocus was found to 93.1±0.59 μm in 72.7% (73 eyes), versus 56.4% (56 eyes) with myopic defocus. In both groups, normalization of LBF in the central vascular system to 5.8±0.59 cm/sec and 5.3±0.63 cm/sec with myopic defocus was revealed, and LBF in the central vein to 15.3±0.64 cm/sec. sec with average degree of myopia (P <0.05). In both groups, an increase in the resistivity coefficient (RI) was found to 0.85±0.54 (P <0.01). Conducted studies of OCT-A with calimetry of the vessels of the central nervous system and central nervous system in moderate myopia revealed a significant decrease in the frequency of vasoconstriction in myopic defocus. When examining vessels using ultrasound, a significant normalization of LBF in the central nervous system and central veins was revealed, with myopic defocus with mild and moderate myopia during treatment with orthokeratological lenses. Accordingly, the state of eye hemodynamics may be one of the factors in the effectiveness of treating myopia with orthokeratological lenses.