Nearwork-induced transient myopia in preadolescent Hong Kong Chinese

James S. Wolffsohn*, Bernard Gilmartin, Roger Wing-hong Li, Marion Hastings Edwards, Sandy Wing-shan Chat, John Kwok-fai Lew, Bibianna Sin-ying Yu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

PURPOSE. To compare the magnitude and time course of nearwork-induced transient myopia (NITM) in preadolescent Hong Kong Chinese myopes and emmetropes. METHOD. Forty-five Hong Kong Chinese children, 35 myopes and 10 emmetropes aged 6 to 12 years (median, 7.5), monocularly viewed a letter target through a Badal lens for 5 minutes at either 5.00- or 2.50-D accommodative demand, followed by 3 minutes of viewing the equivalent target at optical infinity. Accommodative responses were measured continuously with a modified, infrared, objective open-field autorefractor. Accommodative responses were also measured for a countercondition: viewing of a letter target for 5 minutes at optical infinity, followed by 3 minutes of viewing the target at a 5.00-D accommodative demand. The results were compared with tonic accommodation and both subject and family history of refractive error. RESULTS. Retinal-blur-driven NITM was significantly greater in Hong Kong Chinese children with myopic vision than in the emmetropes after both near tasks, but showed no significant dose effect. The NITM was still evident 3 minutes after viewing the 5.00-D near task for 5 minutes. The magnitude of NITM correlated with the accommodative drift after viewing a distant target for more than 4 minutes, but was unrelated to the subjects' or family history of refractive error. CONCLUSIONS. In a preadolescent ethnic population with known predisposition to myopia, there is a significant posttask blur-driven accommodative NITM, which is sustained for longer than has previously been found in white adults.

Original languageEnglish
Pages (from-to)2284-2289
Number of pages6
JournalInvestigative Ophthalmology and Visual Science
Volume44
Issue number5
DOIs
Publication statusPublished - May 2003

Bibliographical note

Copyright © Association for Research in Vision and Ophthalmology. Creative Commons Attribution Non-Commercial No Derivatives License

Keywords

  • transient myopia
  • Hong Kong
  • retinal-blur-driven

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