Correction of peripheral myopic defocus with HAL spectacle lenses

Current methods to slow myopia progression based on the theory of peripheral defocus have shown their efficacy when used as spectacle, contact, and orthokeratology lenses. Spectacle lenses with highly aspherical microlenslets (Stellest®) were introduced into clinical practice in 2020, and their efficacy was rated highly in different studies. AIM: To investigate peripheral defocus imposed by Stellest® spectacle lenses in myopic children. MATERIAL AND METHODS: Peripheral refraction (PR) was evaluated in 42 children (84 eyes) with low-to-moderate myopia. Patients of Group 1 (42 eyes) were examined under cycloplegic conditions, without correction and with HAL spectacle lenses, in the primary position and different directions of gaze, 15° and 30° temporally (T) and nasally (N) from the fovea. Patients of Group 2 (42 eyes) were examined under mydriatic conditions, without correction and with HAL spectacle lenses, 5°, 10°, 15° nasally and temporally from the fovea, in the different directions of gaze. PR was measured using the Grand Seiko WAM-5500 open-field binocular autorefractor. To calculate peripheral defocus, central (axial) refraction was subtracted from the peripheral spherical equivalent taking into account the +/− sign. RESULTS: HAL spectacle lenses reduced hyperopic defocus and imposed a myopic one in all tested areas of the near retinal periphery; the differences at N5 and N10 points were statistically significant (р 0.05). At N15 point ocular movements imposed myopic defocus of −0.26 D (р 0.05). There is also a trend towards a decrease in hyperopic defocus at T15 and N30 points. CONCLUSION: The first study of peripheral refraction with HAL spectacle lenses (Stellest®) helped demonstrate that the lenses imposed myopic defocus on the retinal periphery, with the greatest defocus on the near nasal periphery.