Intraocular lens power calculation in eyes with previous corneal refractive surgery

Abstract

Intraocular lens (IOL) power calculation after corneal refractive surgery (CRS) becomes an expanding challenge for ophthalmologists as more and more cataract surgeries after CRS are required. These patients typically also have high expectations as to visual performance. Conventional IOL power calculation schemes frequently provide inaccurate results in these cases. This review aims to summarize and recommend currently available IOL power calculation methods for eyes with the most common CRS methods: radial keratotomy (RK), photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE). To this end, biometry measuring methods and IOL formulas will be explained and combinations of both are proposed. In synopsis, it is evident that the latest generation of vergence formulas exhibit favorable IOL power prediction accuracy in post-CRS eyes, even though the predictive precision of methods in eyes without CRS is not attained. Ray tracing computation, intraoperative aberrometry, and machine learning–based formulas hold potential to further improve refractive outcomes in post-CRS eyes.

Impact of Single Constant Optimization on the Precision of IOL Power Calculation

“…This demonstrated improvement is particularly evident when compared to traditional vergence-based formulas like SRK/T, Haigis, Holladay, Hoffer Q, Potvin–Hill, and Barrett. 16 – 19 These conventional methods, which estimate corneal power based on the anterior corneal radius and keratometric index, appear less effective in comparison. In our study, we strategically chose to keep all variables constant, with the exception of the one.…”

An update on intraocular lens power calculations in eyes with previous laser refractive surgery

“…The mechanisms through which LRS induces errors in biometry and IOL power calculations are well documented [1–4]. In essence, LRS can adversely affect refractive outcomes by causing inaccuracies in measuring the physical dimensions of the eye and by challenging the assumptions frequently utilized in IOL power calculations.…”

Online intraocular lens calculation

“…When an eye has had any previous corneal refractive procedure, the IOL power calculation becomes more challenging [21]. The ASCRS calculator is one option, which offers up to seven formula results if no prior refractive history is known, and 14 if preoperative data is available.…”