An evaluation of the Hyde surgical astigmatic ruler.
The Hyde Ruler, a semi-quantitative intraoperative keratometric device, was compared with the Bausch and Lomb keratometer by taking 50 paired measurements of induced astigmatism on a model cornea. The correlation between the two instruments was 0.884, and regression of the Hyde Ruler estimates on the Bausch and Lomb keratometer readings produced a slope of 0.732 with an intercept of -0.150 D. From the regression equation, a correction was applied to the Hyde Ruler estimates, resulting in 68.2% of the latter falling within 1.22 D or less of the Bausch and Lomb readings. We consider this accuracy to be acceptable for a semi-quantitative intraoperative keratometer, and should allow appropriate suture tensioning during cataract surgery to aid in early visual rehabilitation of the patient.
House
P H
PH
Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
Chauhan
B C
BC
D001251:Astigmatism / Q000209:etiology / Q000517:prevention & control*; D002387:Cataract Extraction / Q000009:adverse effects / Q000295:instrumentation*; D003315:Cornea / Q000033:anatomy & histology*; D004867:Equipment Design; D006801:Humans; D007432:Intraoperative Period; D008961:Models, Structural