Intraocular lens power calculation after myopic excimer laser surgery: Selecting the best method using available...

To compare the results of methods to calculate intraocular lens (IOL) power after myopic excimer laser surgery.

G.B. Bietti Foundation-IRCCS, Rome, Italy.

Prospective interventional case series.

Eyes were classified into 4 groups: Group 1 (preoperative keratometry available, refractive change known), Group 2 (preoperative keratometry available, refractive change uncertain), Group 3 (preoperative keratometry unavailable, refractive change known), and Group 4 (preoperative keratometry unavailable, refractive change unknown). The IOL power was calculated by 19 methods. The median absolute error in refraction prediction and the percentage of eyes with a refraction prediction error within ±0.50 diopter (D) were calculated.

In Group 1 (n = 30), the Savini, Seitz/Speicher/Savini, and Masket methods provided the lowest median absolute error (0.29 D, 0.35 D, and 0.34 D, respectively), with more than 70% of eyes within ±0.50 D of the predicted refraction. In Group 2 (n = 16), the Seitz/Speicher method achieved the best result (median absolute error 0.37 D), with 75% of eyes within ±0.50 D of the predicted refraction. In Group 3 (n = 18), the Masket method provided the lowest median absolute error (0.24 D), with 72.2% of eyes within ±0.50 D of the predicted refraction. In Group 4 (n = 6), the Shammas no-history method had the lowest median absolute error (0.31 D), with 83% of eyes within ±0.50 D of the predicted refraction.

Intraocular lens power can be accurately calculated in post-laser surgery eyes when the preoperative corneal power and refractive change are known and when they are not.

Dr. Hoffer receives book royalties for IOL Power and formula royalties from all manufacturers using the Hoffer Q formula to ensure it is programmed correctly. No other author has a financial or proprietary interest in any material or method mentioned.