Making the switch from single vision lenses (SVLs) to progressive additional lenses (PALs) can increase working distance for pre-presbyopic adult computer users, a recent study found. Researchers from Hong Kong prescribed SVLs and PVLs designed for handheld digital device use for pre-presbyopic computer users from two age groups: 18 to 25 and 30 to 40. They then measured working distance and refractive shift while the patients played a video game immediately after lens delivery and again one month later.

One month after switching from SVLs to PALs, working distance results increased in both age groups, and there was a small but notable positive refractive shift in the older age group. The study found the changes in working distance were correlated with myopic error, while the positive refractive shift in the older group was correlated with amplitude of accommodation both immediately and one month later.

“Interestingly, those who preferred PALs or SVLs at the end of the wearing period also rated PALs as causing less ‘eye pain,’ ‘eye redness’ and ‘increased sensitivity to light,’” the study said. “However, these ratings should be interpreted carefully when prescribing spectacle lenses in ophthalmic practice because higher subjective ratings for PALs are associated with different sets of biometric parameters in the two age cohorts.”

Going forward, the researchers believe future studies should address “whether these impacts of lens design could interfere with the effectiveness of optical intervention on myopia development.”