Article
Clinical evaluation of three autorefractometers, applicable in children and uncooperative patients
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Published: | September 22, 2004 |
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Outline
Text
Objective
To determine the accuracy of three autorefractometers that are suitable for refraction of children and uncooperative patients: Retinomax (Nikon), SureSight (Welch Allyn), and PowerRefractor (Plusoptix).
Methods
With the three autorefractometers 245 eyes of 125 patients (1 to 81 years) were examined with cycloplegia (CP) and 104 of these eyes also without CP. The parameters were: spherical equivalent, cylinder power, and (weighted) axis position. The results were compared to cycloplegic retinoscopy being the gold standard. A parameter was said to be correctly measured if the deviation was <0.5 D.
Results
The hit ratios in percent for Retinomax/SureSight/PowerRefractor were: spherical equivalent: with CP 82/68/52, without CP 56/33/37. Cylinder power: with CP 81/86/66, without CP 84/84/82. Weighted axis position: with CP 67/62/61, without CP 73/75/80.
Conclusions
With cycloplegia, Retinomax yielded the best results in terms of spherical equivalent, followed by SureSight and PowerRefractor. Without cycloplegia substantial error due to accomodation was encountered in all devices especially in younger patients. Conversely, astigmatism was more accurately measured in miosis.