APR 03, 2009
Researchers assessed the accuracy and validity of the true net corneal power of the Pentacam system for keratometry measurement for calculating IOL power in postoperative keratorefractive eyes. The results indicated that true net corneal power appears to be a useful tool for determining keratometry in eyes with previous myopic keratorefractive surgery.
The authors compared target refraction values calculated with the SRK/T formula using Pentacam true net corneal power with postoperative manifest refraction values in 30 eyes of 27 patients undergoing cataract surgery that had previously undergone myopic LASIK, myopic photorefractive keratectomy or radial keratotomy. The Pentacam anterior segment imaging system uses a Scheimpflug camera that rotates around the center of the cornea, measures the anterior and posterior corneal curvatures and ascertains corneal power from anterior and posterior corneal surface measurements. The exact central value in the true net corneal power map of the Pentacam was used as the keratometry value.
Use of Pentacam true net corneal power resulted in a mean deviation of 0.47 from the desired postoperative targets. Seventy percent of eyes were within 0.50 D of intended correction and 93 percent were within 1.00 D.
Dr. Stahl is a consultant for AcuFocus, Inc.