The manifestation of noncycloplegic refractive state in pre-school children is dependent on autorefractor design.
OBJECTIVE
To investigate the factors that govern the manifestation of hyperopic refractive errors of pre-school children when tested with and without the application of cycloplegics.


METHODS
Forty-three pre-school children (mean age, 3.68 +/- 0.59 years) were tested before and during cycloplegia in the following order: retinoscopy with optical fogging; Retinomax K plus; Welch Allyn SureSight (DAV SureSight), and PowerRefractor. In the case of the PowerRefractor, the children viewed a difference of Gaussian target (0.20 cpd) at 3.5 m in addition to viewing the instrument LED sources.


RESULTS
Instruments with close working distances (Retinomax) showed the greatest underestimation of hyperopia and the largest variation, followed by the instruments having a greater working distance (PowerRefractor LED view and retinoscopy). The addition of a far target (PowerRefractor difference of Gaussian view) showed the least underestimation, whereas DAV SureSight showed a mean overestimation of the refractive state.


CONCLUSIONS
When autorefractors are applied to vision screening of pre-school children without the use of cycloplegics, autorefractor designs must be developed that both stabilize and relax the child's accommodation. Our results suggest that designs should include large working distances and distant fixation targets.
Suryakumar
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School of Optometry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. rsuryku@uwaterloo.ca
Bobier
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WR
D000065:Accommodation, Ocular; D001251:Astigmatism / Q000175:diagnosis; D002675:Child, Preschool; D004867:Equipment Design; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis*; D009184:Mydriatics; D009887:Ophthalmoscopy; D015351:Vision Screening / Q000295:instrumentation*
D009184:Mydriatics