Evaluation of choroidal thickness and anatomical and optical parameters of the eye in the early period after orthokeratology myopia correction

Purpose: to evaluate subfoveal choroidal thickness (SFCT) and other anatomical parameters of the eye in the early stages after orthokeratological correction of myopia. Material and Methods. The study was conducted on 20 myopic Caucasian patients (40 eyes) with moderate myopia. The main group consisted of 10 children with myopia -4.5 ± 1.03 D aged 11 ± 2.26 years, who were examined before the correction with orthokeratological lenses (OK-lenses) ESA-DL (Dr Lens Tehno, Russia) and 3 weeks after it. The control group comprised 10 patients (20 eyes) with myopia -3.84 ± 1.12 D aged 11.6 ± 1.17 years, who wore monofocal glasses as a correction. SFCT was measured with RS-3000 Advance optical coherent tomograph (OCT) (Nidek, Japan), while axial length (AL), peripheral eye length (PEL), and anterior chamber depth (ACD) was measured with IOL Master 500 optical biometer (Carl Zeiss, Germany), and central cornea thickness (CCT), epithelial thickness (ET) and corneal stroma (ST) thickness, with OCT Avanti Rtvue XR (Optovue, USA). All patients were tested before and 3 weeks after the start of wearing lenses or glasses. Results. SFCF increased by 24.25 ± 19 μm as compared with changes in the control group (p < 0.001) after 3 weeks of wearing OK-lenses. A notable negative correlation of changes in AL and SFCT was revealed in the main group (r = -0.48). CCT decreased by 14.6 ± 2.54 μm in the group wearing OKlenses. The main OK-lens contribution to the statistically significant change in the CCT concerned the epithelium, whose thickness showed a 12.7 ± 1.58 μm (22.6 %) change as compared with the initial data (p < 0.001) and with the change in the control group (p < 0.001). The decrease in AL showed an insignificant correlation with the decrease in the CCT: r = 0.16. ACD, PEL and ST did not change significantly (p > 0.05). Conclusion. SFCT shows an increase in the early stages after OK correction. When controlling the growth of the eye in patients with OK lenses, we need to take into account the impact of the choroid on the results of AL measurement.