Refractive Outcomes after Cataract Surgery

Abstract

A post-operative manifest refractive error as close as possible to target is key when performing cataract surgery with intraocular lens (IOL) implantation, given that residual astigmatism and refractive errors negatively impact patients’ vision and satisfaction. This review explores refractive outcomes prior to modern biometry; advances in biometry and its impact on patients’ vision and refractive outcomes after cataract surgery; key factors that affect prediction accuracy; and residual refractive errors and the impact on visual outcomes. There are numerous pre-, intra-, and post-operative factors that can influence refractive outcomes after cataract surgery, leaving surgeons with a small “error budget” (i.e., the source and sum of all influencing factors). To mitigate these factors, precise measurement and correct application of ocular biometric data are required. With advances in optical biometry, prediction of patient post-operative refractory status has become more accurate, leading to an increased proportion of patients achieving their target refraction. Alongside improvements in biometry, advancements in microsurgical techniques, new IOL technologies, and enhancements to IOL power calculations have also positively impacted patients’ refractory status after cataract surgery.

Theoretical Relationship Among Effective Lens Position, Predicted Refraction, and Corneal and Intraocular Lens Power in a Pseudophakic Eye Model

“…The purpose of intraocular lens (IOL) power calculation formulas is to determine the refractive power of an implant that will allow the operated eye to achieve the target refraction. 1 The formula precision and accuracy depend on the reliability of the preoperative biometric measurements, the difference between the achieved versus predicted effective lens position (ELP), and possible postoperative fluctuations in corneal power. 2 – 4 The quality of the postoperative ELP prediction is the most critical factor in controlling residual refractive error.…”

Saving of Time Using a Software-Based versus a Manual Workflow for Toric Intraocular Lens Calculation and Implantation

“…The best indicator of toric intraocular lens calculation accuracy is the prediction error (PE) of residual astigmatism. Depending on the formula used to calculate toric intraocular lenses, different anatomical parameters are considered [ 5 ]. The most important parameters of all formulas are the keratometry values of the cornea since they have the greatest influence on the required toricity of IOL for neutralizing corneal astigmatism [ 4 ].…”

A systemic review and network meta-analysis of accuracy of intraocular lens power calculation formulas in primary angle-closure conditions

“…Compared with cataract surgery in normal population, a range of publications have suggested that similar procedures in PACD patients often resulted in inaccurate refractive outcomes [3,5]. According to current studies, for simple cataract patients, the percentage of postoperative refractive error within ±0.50 D varied between 73% and 88%, while the percentage dropped to 50%~68% for PACD patients [5,6], indicating extra inaccuracy in terms of IOL power prediction in PACD patients, which had drawn ophthalmologists' attention. Along with well-accepted precision of ocular biometry, accuracy of manufacturer IOL power quality control and the now-mature surgical techniques, the accuracy of IOL power calculation becomes the most essential factor for achieving the target refraction post-operatively.…”