Induced bifocal soft contact lenses with the addition of 4.0 D myopic defocus in the near periphery of the retina and its effect on the progression of myopia

AIM: To evaluate the dynamics of axial and peripheral refraction in the near periphery of the retina in eyes with myopia against the background of wearing bifocal soft contact lens (BSCL) with the addition of 4 D.

MATERIAL AND METHODS: Forty-three patients (84 eyes) with myopia from −0.5 to −6.5 D (average −3.53±0.19 D) aged 7–15 (average 11.3±0.27) years were examined before and 6 months after the start of wearing Prima BIO Bifocal BSCL (Okey Vision Retail, Russia). Visual acuity without correction, with optimal correction, and in BSCL, cycloplegic refraction, eye length, keratotopography, and peripheral defocus (PD) at 5°, 10°, and 15° to the nose and temple from the center of the fovea with and without lenses were assessed.

RESULTS: After 6 months of wearing BSCL, the subjective refraction increased by 0.04 D, cycloplegic refraction by 0.18 D, and average BSCL strength by 0.01 D. The axial length increased by 0.03 mm (p >0.05). The initial PD without lenses was hypermetropic in all zones, and in BSCL, it was myopic in zones T5°, T10°, T15°, and N15° and hypermetropic in zones N5° and N10°. After 6 months of PD without correction, hypermetropic defocus tended to decrease in zones N10° and N15° and myopic defocus appeared in N5° (p >0.05); with lenses, myopic defocus increased in zones T5°, T10°, T15°, and N15°, and in N5° and N10°, it did not change and remained hypermetropic.

CONCLUSION: BSCLs provide total correction of myopia and high distant and near visual acuity in children, induce myopic defocus in the near periphery, and contribute to the inhibition of the progression of myopia in the traced period.