Highly aspheric lenslets (HAL) and slightly aspheric lenses (SAL) used for myopia control do not influence accommodation, phoria (except for larger micro fluctuations), or long-term scotopic and low-contrast visual acuity, according to research published in Eye and Vision.
Researchers obtained data from 161 children with myopia and randomly assigned them to treatment with HAL (n=54; mean age, 10.65±1.15 years; 28 girls), SAL (n=55; mean age, 10.17±1.24 years; 37 girls), or single vision spectacle lenses (SVL; n=52; mean age, 10.37± 1.27 years; 23 girls). Patients underwent distance and near visual acuity (VA) measurements at high (100%) and low (10%) contrast under both photopic and scotopic conditions. Phoria, stereoacuity, accommodative lag, micro fluctuations (AMFs), and amplitude of accommodation (AA) were also measured. Investigators obtained measurements after 10 minutes, 6 months, and 12 months of wear.
After 10 minutes of wear, visual acuity worsened in individuals in the HAL (0.03 to 0.08 logarithm of the minimum angle of resolution [logMAR]) and SAL groups (0.01 to 0.04 logMAR) while improving slightly among individuals in the SVL group. Both HAL and SAL group participants experienced VA improvements over the course of the study and VA was not different among the 3 groups at 12 month follow-up. No significant differences in accommodative lag, AA, or phoria were noted between the groups.
The report states that there were significant differences in AMFs between the groups at each visit (all P <.01), with the HAL and SAL groups having greater AMFs compared with SVL group participants.
“The results showed that the 2 different aspherical lenslet designs had no clinically meaningful influence on near phoria, accommodative lag, or amplitude,” according to the researchers. “SAL and HAL exhibited a slightly lower performance than SVL in scotopic and low-contrast VA at the initial use, but after 12 months, VA was recovered to be comparable to SVL in all conditions.”
Study limitations include failure to measure pupil distance and missing data due to computer difficulties.
References:
Huang Y, Li X, Wang C, et al. Visual acuity, near phoria and accommodation in myopic children using spectacle lenses with aspherical lenslets: results from a randomized clinical trial. Eye and Vision. Published online September 1, 2022. doi:10.1186/s40662-022-00304-3