Myopes show increased susceptibility to nearwork aftereffects

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Accommodation, the eye's ability to adjust focus, may differ between myopes, emmetropes, and hyperopes.
• Myopes show a greater initial accommodative adaptation in the dark after near work.
• Assessing accommodative aftereffects under natural viewing conditions is crucial for understanding clinical myopia.

Purpose of the Study:

• To investigate the accommodative aftereffect and its decay in myopes, emmetropes, and hyperopes.
• To determine if accommodative aftereffects are linked to myopia onset and progression.

Main Methods:

• Adult subjects included early-onset myopes (n=13), late-onset myopes (n=11), emmetropes (n=11), and hyperopes (n=9).
• Distance refractive state was measured using an autorefractor before and after a 10-minute, 5-diopter near task.
• Accommodative aftereffect magnitude and decay rate were analyzed.

Main Results:

• Myopes exhibited the most significant near-work accommodative aftereffect, averaging 0.35 D initially.
• Early-onset myopes showed faster decay (35 seconds) compared to late-onset myopes (63 seconds).
• No significant accommodative aftereffect was observed in emmetropes or hyperopes.

Conclusions:

• Myopes demonstrate heightened susceptibility to accommodative aftereffects from near work.
• Transient pseudomyopia, suggested by these aftereffects, may precede or contribute to myopia development.
• Increased retinal defocus over time, leading to axial elongation, is a proposed mechanism for myopia progression.