Intraocular Lens Power Calculation And Cataract Surgery In Eyes With Previous Small Incision Lenticule Extraction

Published 2022 - 40th Congress of the ESCRS

Reference: FPT07.10 | Type: Free paper | DOI: 10.82333/mz60-z015

Authors: Nikolaus Luft* ¹ , Roman Lischke ¹ , Walter Sekundo ² , Rainer Wiltfang ³ , Martin Bechmann ³ , Thomas Kreutzer ¹ , Martin Dirisamer ¹ , Siegfried G. Priglinger ¹

¹Ludwig-Maximilians University,Munich,Germany, ²Philipps University, Marburg Germany,Marburg,Germany, ³Smile Eyes Munich,Munich,Germany

Purpose

Small incision lenticule extraction (SMILE), with over 5 million procedures globally performed, will challenge ophthalmologists in the foreseeable future with accurate intraocular lens (IOL) power calculation in an ageing population. After more than one decade since the introduction of SMILE, only one case report of cataract surgery with IOL implantation after SMILE is present in the peer-reviewed literature. Hence, the scope of the present multicenter study was to compare the IOL power calculation accuracy in post-SMILE eyes between ray tracing and a range of empirically optimized formulae available in the ASCRS post-keratorefractive surgery IOL power online calculator.

Setting

Multi-centric cross-sectional study (University Eye Hospital, Ludwig-Maximilians-University, Munich; Department of Ophthalmology, Philipps University, Marburg; Smile Eyes Clinic, Munich).

Methods

After uneventful cataract surgery with IOL implantation in 11 post-SMILE eyes of 7 patients, IOL power calculation was performed utilizing dedicated ray tracing software based on preoperative corneal tomography scans, preoperative optical biometry and anterior chamber depth. Moreover, a range of formulae accessible in the American Society of Cataract and Refractive Surgeons (ASCRS) post-keratorefractive surgery IOL power online calculator was used. The mean arithmetic error, mean absolute error and median absolute error was compared between formulae.

Results

Physical ray tracing showed the smallest mean absolute error (0.40D) and yielded the largest percentage of eyes within ±0.50/±1.00D (82/91%) from target refraction. The next best conventional IOL power calculation formula was the Potvin-Hill formula with a mean absolute error of 0.66D and an ±0.50 and ±1.00D accuracy of 45% and 73%, respectively.

Conclusions

Analyzing this first worldwide cohort of post-SMILE eyes undergoing cataract surgery and IOL implantation, ray tracing showed superior predictability in IOL power calculation over empirically optimized IOL power calculation formulae that were originally intended for use after Excimer-based keratorefractive procedures.