The impact of spectacle lenses for myopia control on visual functions

Abstract

Purpose Spectacle lenses containing multiple small peripheral elements have been developed for myopia control in children. It is important that their effect on vision be quantified by (i) fixation through the peripheral portion, thereby using foveal vision and (ii) by fixation through the central portion and presentation of peripheral targets. Methods The above approaches were used in five studies to evaluate two novel spectacle lens designs: spectacle lenses with Highly Aspherical Lenslets (HAL) and Slightly Aspherical Lenslets (SAL). A single vision lens served as a control. Visually normal adults participated in each study. The first two studies had subjects fixate through the periphery of the lenses. High and low (10%) contrast visual acuity was measured with the Freiburg Vision Test and reading speed for high and low contrast words measured with a sentence generator. The other three studies assessed peripheral vision while subjects fixated through the central portion of the lens. Peripheral contrast sensitivity was measured using two cycles per degree drifting Gabor stimuli. Peripheral motion perception was further evaluated using random dot stimuli. Finally, attention was measured using an established test of useful field of view with three levels of complexity. Results The periphery of the HAL lens significantly reduced low contrast visual acuity, but not high contrast visual acuity, while the effect of the SAL lens was not significant for either. Neither test lens affected reading speed for high contrast words, but the HAL lens significantly affected performance for low contrast words. Neither test lens affected peripheral motion perception or useful field of view. Conclusions Low contrast visual acuity and reading was slightly reduced while high contrast visual acuity was unaffected when fixating through the periphery of the novel lens designs. None of the peripheral measures of vision was affected by the novel lens designs.

Spectacles with highly aspherical lenslets for myopia control do not change visual sensitivity in automated static perimetry

“…In previous studies (Gao et al, 2021;Li et al, 2021), the HAL lens was found to have only a small impact on visual acuity. When looking directly through the lenslets, high contrast VA was reduced by HAL for 0.07 logMAR, which is only slightly more than half a line, in children (Li et al, 2021); for adults (Gao et al, 2021), high contrast VA was also reduced by 0.07 logMAR and low contrast VA was reduced by 0.14 logMAR. Another myopia control spectacle lens with a honeycomb configuration of spherical lenslets (HC) was found to reduce VA for about one line (Li et al, 2021).…”

“…HC was found to influence CS to a larger degree in various conditions (Li et al, 2021). The study conducted on adults (Gao et al, 2021) found that HAL had no significant impact on peripheral visual functions including useful field of view (UFOV), peripheral motion detection, and peripheral coherent motion direction discrimination.…”

Visual acuity, near phoria and accommodation in myopic children using spectacle lenses with aspherical lenslets: results from a randomized clinical trial

“…When the subjects first used the HAL and SAL at baseline, it could be that the participants did not fixate completely through the center of the lens (without lenslets area) but partly through the central area and partly through the peripheral aspherical lenslets area. A previous study found that low-contrast scotopic VA was reduced when fixating through the lenslets area of HAL and SAL [ 23 ]. Therefore, during the 1-year wearing period, children learned to use the lenses (find the clear center area), the influence of aspherical lenslets was reduced, and the VA improved significantly.…”

“…The 1-year results showed 0.11 mm and 0.33 D decreases in axial length (AL) elongation and spherical equivalent refraction (SER) progression in the spectacle lenses with slightly aspherical lenslets (SAL) group compared with the SVL group and 0.23 mm and 0.53 D decreases in AL and SER progression in the spectacle lenses with highly aspherical lenslets (HAL) group compared with the SVL group [ 21 ]. Two studies have shown that HAL and SAL have low impact on short-term visual acuity and contrast sensitivity in children and adult population [ 23 , 24 ]. However, the long-term impacts on various aspects of visual function and visual quality of HAL and SAL in myopic children are yet to be investigated, which is the aim of this study.…”

Spectacles and orthokeratology lenses as non‑operative management in myopia: a brief review

“…However, the use of this therapy shows a longer correction time. Therefore, this therapeutic option tends to be more recommended as an optical tool to slow the development and progression of myopia patients [37].…”