This article is more than 5 years old. Information may no longer be current.
Empiric predictive model for IOL estimations shows promise
Click Here to Manage Email Alerts
NEW ORLEANS — A purely refractive algorithm to predict IOL power intraoperatively without the need for axial length and keratometry measurements has been developed, a speaker here said. This approach shows promise for bypassing some of the difficulties that have been encountered in predicting IOL power after refractive surgery, he said.
“If we have to go to emmetropic nirvana, how do we get there?” Tsontcho Ianchulev, MD, MPH, asked during the refractive surgery subspecialty day at the American Academy of Ophthalmology meeting. “Do we need better oil or a new engine?”
The challenge for cataract surgeons in the future will be IOL power prediction in the 1 million or so patients who have undergone LASIK and will eventually need cataract surgery.
In a pilot study, Dr. Ianchulev and colleagues used “spot optical refractive biometry” for modeling in 22 cataract cases and an additional 16 cases for validation. Of the 16 eyes, six were post-LASIK, he said.
The spherical equivalent of the intraoperative aphakic autorefraction correlated linearly with the emmetropic IOL power after adjustment for postoperative outcomes, he said.
“For the eyes that had undergone LASIK, 83% were within 1 D [of emmetropia]; 100% of the normal eyes using the conventional methodology were within 1 D,” he said.
Using conventional methodology, 67% of the LASIK eyes and 100% of the normal eyes were within 1 D of emmetropia, he said.
“The relationship was sustained over an axial length range of 21.43 mm to 25.25 mm and an IOL power implant range of 12 D to 25.5 D,” Dr. Ianchulev said.