Reliability And Repeatability Study Of The Tori-Check Measuring Device And Various Manufacturers Of Toric Hydrogel Lenses.

A frequent problem among eyecare professionals has been the accurate power measurement of a hydrogel contact lens. The water content and nature of the lens material makes the traditional lensmeter measurement difficult. Other difficulties include poor handling, lens dehydration and finally draping the lens over a dirty lens stop in an attempt to obtain a reasonable approximation of the true power. A device called the Tori-check was developed in 1986 by General Ophthalmics Inc.. The Tori-check is primarily a lens holding and positioning device for power measurement of soft contact lenses. It is used to position spherical or toric lenses on the lens support of a lensmeter. Positioning of toric lenses includes rotational orientation for proper axis measurement . The device may also be used for holding soft lenses for inspection. The first goal of this report was to determine how consistant the Tori-check device is at measuring contact lenses using various lensmeters. That is, what effect, if any, do stop distance variations and lensmeter designs affect Tori-check's ability to accurately measure a lens. The second goal of the study was to determine how closely the lens power and axis as measured with the aid of the Tori-check compared to the parameters the manufacturer printed on the vial. An informal poll of several contact lens educators, authors and lecturers recently showed that from 10 to as high as 35 percent of soft toric contact lenses are not as labeled (including problems with fit, power, axis or markings).