Purpose: to study the effect of bifocal soft contact lens (BSCL) with an ADD of 4 diopters on peripheral refraction (PR), optical and ergonomic eye parameters in children with myopia.Patients and methods. 26 patients (52 eyes) with myopia –3.09 ± 1.13 diopters at the age of 10.04 ± 1.5 years without correction and with correction by BSCL Prima BIO Bi-focal ( Okay Vision Retail, Russia). All patients underwent a horizontal and vertical PR study on an open field autorefractometer Grand Seiko WAM-5500 (Japan), wavefront aberrations were studied on OPD-Scan III aberrometer (Nidek, Japan), contrast sensitivity under mesopic conditions were studied on a Mesotest 2 instrument (Oculus, Germany) and visual productivity was studied using test tables.Results. The visual acuity of the distance with a BSCL correction of 0.98 ± 0.04 did not differ (p = 0.26) from the maximum visual acuity corrected by spherocylindrical glasses of 0.99 ± 0.04. BSCL induces myopic defocus in all peripheral zones, with a maximum value of 15° and a sharp decrease of 30°. Peripheral myopic defocus induced by the lens at a horizontal and vertical angle of 15 degrees did not depend on the initial degree of myopia. BSCL increases the total RMS from 0.07 ± 0.02 μm to 0.19 ± 0.07 μm in the 3 mm zone (p < 0.01) and from 0.27 ± 0.09 μm to 1.18 ± 0, 23 μm in the 6 mm zone (p < 0.01), mainly due to an increase in spherical aberration from –0.0005 ± 0.006 μm to 0.06 ± 0.01 μm (p < 0.01) and from 0.01 ± 0.09 μm to 0.58 ± 0.14 μm (p < 0.01) in the 3 mm and 6 mm zones, respectively. An increase in the overall RMS in BSCL reduces the quality of eye optics and contrast sensitivity under mesopic conditions, but does not impair visual productivity.Conclusion. BSCLs with a high ADD of 4 diopters are capable of inducing significant myopic peripheral defocus due to the induction of spherical aberration, while maintaining high visual acuity and not changing ophthalmic ergonomics, which makes them a pathogenetically substantiated method for correcting myopia and preventing its progression in children and adolescents.
Purpose: to evaluate dynamics of subjective and objective accommodation in children wearing bifocal soft contact lenses (BSCLs) for myopia control with +4.00 D addition power. M e t h o d s: the study involved 22 patients (44 eyes).Mean age amounted to 10.1 ± 1.46 years and mean myopic refraction amounted to –3.21 ± 1.23 D. Patients were fitted Prima BIO Bi-focal BSCLs (OKVision Retail, Russia). All patients underwent cycloplegic refraction assessed with Auto Ref/Keratometer ARK 530A (Nidek, Japan), had axial length measured with IOL Master 500 optical biometry device (Carl Zeiss, Germany), had positive relative accommodation (PRA) assessed with and without lenses and had binocular (BAR) and monocular (MAR) accommodative response assessed at a distance of 33 cm with WAM-5500 Binocular Accommodation Auto Ref/Keratometer (Grand Seiko, Japan) prior to wearing BSCLs as well as 3, 6 and 12 months after wearing BSCLs.Results: neither MAR nor BAR measured without lenses changed after 3, 6 and 12 months of wearing BSCLs (p >0,05). A change in PRA evaluated without lenses was noted after 12 months (p < 0,05). PRA evaluated with lenses after 3, 6 and 12 months differed from baseline significantly (p < 0,001). Over 12 months of wearing BSCLs, changes in AL (0.09 ± 0.17 mm) and cycloplegic refraction (0.3 ±0.43 D) correlated with baseline BAR and MAR loosely. C o n c l u s i o n: objective accommodation (MAR and BAR) did not change in the course of wearing BSCLs with +4.00 D addition power. Increase in PRA evaluated without BSCLs may be associated with improvement of accommodation due to a full correction in the optic zone. The gradual increase in PRA evaluated with BSCLs probably indicates an adaptation of patients to addition zone in near vision conditions.
Экспериментальные исследования на животных представили убедительные доказательства возможности -посредством манипуляции с дефокусом различного знака -замедлять или ускорять рост глаза. Ведущим механизмом в ряде современных оптических стратегий профилактики прогрессирования миопии является наведение (индукция) миопического дефокуса на периферию сетчатки или уменьшение гиперметропического дефокуса. В обзоре проанализированы сведения о периферической рефракции при ортокератологической, мультифокальной контактной и мультифокальной очковой коррекции. Показана эффективность данных методов коррекции в контроле прогрессии миопии у детей и подростков. Ключевые слова: миопия; периферическая рефракция; ортокератология; мультифокальные мягкие контактные линзы; мультифокальные очки; очки «Перифокал» Конфликт интересов: отсутствует. Прозрачность финансовой деятельности: никто из авторов не имеет финансовой заинтересованности в представленных материалах или методах. Для цитирования: Милаш С.В., Епишина М.В., Толорая Р.Р. Современные оптические методы коррекции периферического дефокуса. Российский офтальмологический журнал. 2019; 12 (4): 92-8.Experimental animal studies proved that by manipulating with the defocus one can slow down or speed up the eye growth. The leading mechanism among modern optical strategies of myopia progression treatment is to induce myopic defocus to retinal periphery or decrease the hyperopic defocus. This review sums up the data on peripheral refraction in orthokeratological, multifocal contact, and multifocal spectacle correction. The effectiveness of these methods in myopia control in children and teenagers is shown.
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.
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