98th Annual Meeting DOG 2000

K 539

How accurate does the new autorefractor "Power Refractorâ " work?

M. Schittkowski, P. Kruse, S. Hucks-Sievers

Background: The Power Refractorâ is a new autorefractometer which is now commercially available. The aim of this study is to analyze its benefits and limitations as a measuring tool.

Patients / Method: The refractive status of 75 patients (150 eyes) was measured under cycloplegic conditions with the portable Power Refractorâ , the hand-held Retinomax (Nikon), the table-top mounted Canon RK-5 and retinoscopy (one observer). Another 75 patients (150 eyes) were measured under the same conditions and additionally with the Power Refractorâ under non-cycloplegic conditions.

Results: The spherical values differed in the range ± 2 dpt up to 1 dpt. Extreme differences up to 10 dpt were found in single cases. The measurement errors were more pronounced in astigmatism, resulting in a difference of the cylindrical corrections (artificial astigmatism) up to 6 dpt. Without cycloplegia, Power Refractorâ is able to measure spherical value, cylinder power and axis with a better but not the same reproducibility as the other tested methods.

Conclusions: The accuracy of measurement of Power Refractorâ is not as good as of the other tested devices. The obtained data from the Retinomax, the Canon RK-5 and retinoscopy are comparable.

The Power Refractorâ may be a usefull device for screening small children because of the one meter observing distance, but for a precise refraction and for a prescription of spectacles a supplemental retinoscopy under cycloplegic conditions is still necessary.

Rostock University, Department of Ophthalmology, Doberaner Straße 140, D-18057 Rostock