Related Experiment Video
Updated: Aug 16, 2026
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Nomogram-based intraocular lens power adjustment after myopic photorefractive keratectomy and LASIK: a new approach
Vahid Feiz1, Majid Moshirfar, Mark J Mannis
1Department of Ophthalmology, University of California, Davis Medical Center, Sacramento, California 95817, USA. Vfeiz@ucdavis.edu
Purpose:
(1) To evaluate the accuracy of nomogram-based adjustment of intraocular lens (IOL) power to achieve a desired refractive target after cataract surgery in postmyopic LASIK and photorefractive keratectomy (PRK) eyes and (2) to compare the accuracy of the nomogram-based method with the clinical history method.
Design:
Multicenter, retrospective, interventional, noncomparative case series.
Subjects:
Fourteen patients (19 eyes) after myopic LASIK or PRK with visually significant cataracts.
Intervention:
All eyes underwent cataract extraction and posterior chamber intraocular lens implantation. In each case, IOL power was determined with standard keratometry and biometry. Power adjustment was made by use of a theoretical nomogram followed by implantation.
Main Outcome Measures:
(1) Final refraction and spherical equivalent after cataract surgery and (2) deviation of the final spherical equivalent from the refractive target.
Results:
After cataract extraction, by use of nomogram adjustment, 63.2% of eyes were within 0.5 D of the intended spherical equivalent, 84.2% were within 1.0 diopter of the intended spherical equivalent, and 100% were within 1.5 D of the intended spherical equivalent. The clinical history method was accurate in predicting the correct IOL power in 37.5% of cases, regardless of whether spectacle or corneal plane refraction was used.
Conclusions:
(1) Given the change in spherical equivalent induced by myopic LASIK/PRK, IOL power can be adjusted accurately to avoid undercorrection without the need for the prerefractive surgery corneal power. (2) The nomogram-based method was more accurate than the clinical history method.
