The LRI System Study was conducted by a collaboration effort between MMD and Dr. Ray T. Oyakawa. It was a perspective study of the effectiveness of LRIs at the time of cataract surgery using the PalmScan P2000 Vector-adjustment of the Nichamin Age Pachymeter Adjusted nomogram (NAPA).
Patients that underwent cataract surgery with a 0.5 or greater astigmatism measured by the IOL Master k had calculations done to determine surgically induced changes in axis and astigmatism. All had topography.
A 0.5 D SIA (surgical induced astigmatism) was used for the first 14 eyes. The next 14 eyes used 0.3 D SIA after determining SIA in non LRI eyes by using Dr. Warren Hill’s SIA calculator.
Using the 50 MHz probe of the PalmScan, peripheral cornea thickness measurements were done at the slit lamp in eyes that had been determined to have astigmatism >0.75 diopters. The PalmScan built-in vector NAPA program was then used to determine the depth and axis.
A total of 28 eyes of 20 patients, 12 male and 8 female, were observed for the study. The age range of the patients was 50 to 84, with an average age of 72. It was found that vector-adjusted, NAPA LRIs are 96% effective and safe in treating preoperative astigmatism when done concurrently with cataract extraction.