Sources of refractive errors in calculating the optical power of intraocular lenses in the treatment of cataract patients

Abstract

Purpose: Cataract surgery is the most common surgical procedure worldwide, the goal of which is not only to restore the patient’s vision, but to obtain a perfect refractive result that meets the expectations of complete independence from glasses. Unexpected poor refractive outcome after cataract surgery (refractive error) is an unsolved problem, despite increasingly better postoperative outcomes. Improving the postoperative refractive outcome requires an analysis of the sources of refractive errors. This is also the purpose of the present study. Methods: The subject and object of the study were cataract patients with indications for surgical treatment by phacoemulsification (FE) and implantation of an artificial intraocular lens (IOL). The results of the operations of 235 eyes in 160 patients (80 women and 80 men) who underwent surgery in the eye clinic of the Academy of Medical Sciences-Sofia for the period 2018-2020 were analyzed. Results: Of all the measured keratometric parameters, only the value of the cylinder before phacoemulsification is a risk factor, as when it rises above ±1.0D, the risk doubles, and when the value exceeds 2.0D, it becomes 2.4 times greater. The ratio of POC to AL is a statistically significant risk factor for the occurrence of refractive error, with a ratio of POC/AL <0.30, the risk is 2.3 times greater. Conclusion: In the present study, in 62.6% of cases or 2/3 of the eyes, the set Target was successfully met with a minimum permissible refractive error of AE<±0.50D. This determines the effectiveness of the surgical procedure as high.