Functional results of the optimized aspherical technology using nomogram in comparison with aspherical and standard algorithm in patients with myopia in application of the domestic excimer laser unit «MicroScan-Vizum»

• Main Authors: I. A. Mushkova, A. N. Karimova, E. G. Pogodina, V. G. Movshev
• Format: Article
• Language: Russian
• Published: Publishing house "Ophthalmology" 2020-01-01
• Series: Офтальмохирургия
• Subjects: aspheric ablation; conic constant; excimer laser correction of myopia; nomogram
• Online Access: https://www.ophthalmosurgery.ru/jour/article/view/544
• ISSN: 0235-4160; 2312-4970

Purpose. Comparison of FOZ (Functional-Optical Zone), Spatial-Contrast Sensitivity (SCS) under various illumination conditions, evaluation of efficacy, safety, predictability and stability in correction of myopia using the MicroScan-Visum unit in patients of comparative, control and main study groups.Material and methods. The results of FemtoLasik operations were analyzed in 78 patients with myopia (130 eyes), which were divided into the following groups: ≪Nomogram≫ (50 eyes) – the calculation was made according to the nomogram developed by the authors; ≪Aspheric≫ (30 eyes), where Q was 0.2; ≪Standard≫ (50 eyes) – using the standard method.Results. In the Nomogram group, the uncorrected visual acuity (UCVA) was 1.08±0.04, the Aspheric group – 1.06±0.02, the Standard group – 1.04±0.03. In the Nomogram group, average FOZ (functional-optical zone) value was 5.71±0.09 mm, in the Aspheric group – 5.61±0.12 mm, in the Standard group – 5.38±0,75 mm. Statistically significant differences in FOZ values between the Aspheric and Nomogram groups in the area of moderate and high myopia were 5.18±0.12 mm and 5.52±0.08 mm, respectively. The visual acuity in all light conditions by 6th month was higher than the preoperative one in all the groups except the Standard group. In the SCS analysis under photopic conditions with and without light a growth of indicators in all groups at all frequencies was observed. By 6th month under mesopic conditions without light for the Aspheric and Nomogram groups a SCS recovery was noted, with difference at 18 cyclo/deg frequency, with a slight decrease for the Aspheric group, and an increase for the Nomogram group. In the mesopic conditions with light in the Aspheric and Nomogram groups, the SCS values increased on high frequencies almost twice as opposed to the preoperative level, and also the values of the Nomogram group increased twofold as opposed to those of the Aspheric group.Conclusion. The Nomogram group showed the best characteristics of efficiency, safety, predictability and stability as opposed to the comparative and control groups.