Intraocular lens (IOL) calculation formulas used with the smallaperture IC-8 IOL appear to address challenges associated with patients who have a history of hyperopic and myopic LASIK, according to Australian researchers Assoc. Prof. Smita Agarwal and Dr. Erin Thornwell.
Patients who have undergone refractive procedures often require cataract surgery at an early age; however, postoperative results are compromised. The researchers explained this is because a higher amount of central corneal ablation results in a greater discrepancy between the anterior and posterior corneal curvature. This can make the central corneal power more difficult to calculate in eyes that have had myopic LASIK, resulting in a higher incidence of postoperative hyperopia after subsequent cataract surgery than in eyes that have had hyperopic LASIK. Additionally, hyperopic LASIK can induce negative spherical aberration and more coma-like aberrations than myopic LASIK.
Assoc. Prof. Agarwal reported on patients, 64 to 70 years, who had a small aperture IOL implanted in the nondominant eye, and a clear aspheric monofocal IOL in the dominant eye.
Visual performance, assessed between one and six months after surgery, found all patients had good simultaneous near, intermediate, and distance visual acuities while maintaining stereoacuity and mesopic contrast sensitivity. No patients experienced subjective visual aberrations (eg, dysphotopsia) and the majority were able to do away with spectacles to perform routine day to day activities.
Findings were published in Journal of Cataract & Refractive Surgery.