Introduction. One important question for patients with both myopia and glaucoma is comparability of optical coherence tomography (OCT) data obtained before and after a significant change in eye refraction following cataract extraction surgery with implantation of intraocular lens (IOL). Purpose — to assess the impact of correcting moderate and high myopia during cataract phacoemulsification with IOL implantation (Phaco/IOL) on the parameters measured by OCT. Material and methods. OCT was performed in 31 patients (31 eyes) with axial eye length of more than 25.5 mm before and the day after Phaco/IOL. Changes in 17 parameters of the retina, retinal ganglion cells-inner plexiform layer (GCIPL), peripapillary retinal nerve fiber layer (RNFL) and optic nerve head (ONH) were analyzed. Results. Axial eye length was 26.94±1.09 mm in average (25.57—29.39 mm). The average refractive effect of the intervention was 8.44±4.16 D (3.75—19.0 Diopters). Signal strength in all OCT protocols was no lower than 5. Changes in the average values of OCT parameters after surgery were insignificant. They exceeded 1% of the pre-operation values only in 7 cases, including all 5 parameters of the ONH, and were significant only in 5 out of 17 parameters. For GCIPL and RNFL thickness, the changes on average did not exceed 0.9 μm, for retinal thickness in the macular area — 2.1 μm. In relative terms, the largest decrease (an average of –0.03 mm2; –2.5%) was in the optic disc area. Conclusion. In patients with high and moderate myopia, the parameters of the retina, RNFL, GCIPL, and ONH, as measured by OCT, changed insignificantly on the first day after Phaco/IOL (considering the signal strength of Cirrus HD-OCT device was not lower than 5).