Differential refractive susceptibility to sustained nearwork.

摘要: Abstract Purpose: A possible role for nearwork-induced transient myopia (NITM) (i.e. at distance following sustained nearwork) in the development and/or progression of permanent has been suggested. If certain refractive groups are more susceptible to NITM than others, then measures may be implemented prevent or retard occurrence these individuals. In a recent study (Ciuffreda and Wallis, 1998), it was found that young-adult late-onset myopes (LOM) early-onset (EOM) were highly this accommodative after-effect, while emmetropes (EMMs) only moderately susceptible, hyperopes (HYP) particularly insusceptible, short periods (10 min) nearwork very close (20 cm, 5 D). current study, extended encompass much longer period under naturalistic conditions. Methods: Young-adult subjects (n = 16) performed reading task continuous 4 h their habitual working conditions, i.e. binocular viewing with blur-related visual feedback present. Distance state (binocular viewing) assessed objectively using Canon R-1 autorefractor immediately before (pre-task), every hour during task, after (post-task) assess its subsequent decay pre-task levels. Subjects divided into four subgroups as above, which each equal size (n = 4). Results: The induced all subjects, except there hyperopic shift. LOMs (0.12 D) EOMs (0.13 D) HYPs especially insusceptible (0.44 D hyperopia), EMMs (0.09 D). Conclusions: present our earlier investigation by demonstrating differential susceptibility over nearwork, result reduced sympathetic activation. It speculated factor myopigenesis, mechanism being time-integrated increased retinal defocus from both near, conjunction normal lag accommodation thereby causing axial elongation. Hence, future longitudinal specifically targeting hypothesis is warranted.