[Intraocular lens power calculation after corneal refractive surgery]

Area of Science:

• Ophthalmology
• Refractive Surgery
• Biomedical Engineering

Background:

• Calculating intraocular lens (IOL) power after laser-assisted in situ keratomileusis (LASIK) presents challenges due to altered corneal curvature.
• Accurate IOL power calculation is crucial for achieving desired refractive outcomes after cataract surgery in patients with prior refractive procedures.

Purpose of the Study:

• To investigate and validate an effective method for calculating intraocular lens power retrospectively in eyes that have undergone LASIK previously.
• To assess the accuracy of a specific formula for IOL power calculation in post-LASIK cataract surgery cases.

Main Methods:

• A retrospective case series of 40 eyes from 28 patients who underwent phacoemulsification after LASIK.
• Data collected included pre-LASIK and post-LASIK refraction, axial length, corneal curvature (K values), and visual acuity.
• Comparison of two methods (K1 and K2 using IOLmaster) for calculating target refraction.

Main Results:

• The study analyzed data from patients with a history of LASIK, with pre-LASIK spherical equivalents ranging from -3.13 to -18.00 D.
• Two methods for calculating target refraction (K1 and K2) showed a significant difference (P = 0.02).
• Post-phacoemulsification refraction outcomes were evaluated, with best-corrected visual acuity generally maintained or improved.

Conclusions:

• The formula utilized in this study for intraocular lens power calculation in post-LASIK eyes is accurate and effective.
• The validated method aids in achieving predictable refractive results for cataract surgery patients with prior LASIK.