Study shows decline in refractive prediction error after cataract surgery

J Cataract Refract Surg. 2008;34(11):1935-1939.

The mean absolute prediction error for postoperative refraction after cataract surgery diminished significantly during a 5-year period in a Swedish population, according to a prospective study.

Data from the Swedish National Cataract Register were collected between 2000 and 2005; the study included 23,244 patients treated at 49 centers.

"The mean absolute prediction error was related to study year and became smaller the more recent the surgery was performed," the study authors said. "This may imply that a better technique and modern equipment can improve the refraction outcome."

Improved IOL power calculations, personalized IOL constants and improved surgical technique should yield spherical equivalent refraction within ±1 D of targeted refraction in 90% of patients, the authors said, but this can be hard to achieve in cataract surgery.

Data showed 13,580 patients (58.4%) within ±0.5 D of the difference between targeted refraction and final postop refraction; 19,489 patients (83.8%) were within ±1 D of the difference between targeted refraction and postop refraction.

Mean absolute prediction error was higher in women than in men (P < .001). Lower preoperative visual acuity corresponded with larger mean absolute prediction error. Patients with glaucoma had a higher mean prediction error.