RAY-TRACING CALCULATION USING SCHEIMPFLUG TOMOGRAPHY FOR NONDIFFRACTIVE WAVEFRONT SHAPING EXTENDED DEPTH OF FOCUS IOLS FOLLOWING MYOPIC LASIK
Published 2023 - 27th ESCRS Winter Meeting
Reference: P085 | Type: Free Paper Submission | DOI: 10.82333/8gbk-av19
Authors: Thomas Kohnen* 1 , Titus Schug 1 , Christoph Lwowski 1
1Department of Ophthalmology,Goethe University,Frankfurt,Germany
Purpose
To evaluate intraocular lens (IOL) calculation using a ray-tracing formula of a new nondiffractive wavefront shaping extended depth-of-focus (EDoF) IOL after myopic laser in situ keratomileusis (LASIK) compared to formulas from an online calculator.
Setting
Department of Ophthalmology, Goethe University, Frankfurt, Germany.
Methods
This retrospective, consecutive case series included patients with a history of myopic LASIK after cataract surgery with implantation of a EDOF IOL (AcrySof IQ Vivity). Preoperatively, biometry (IOLMaster; Carl Zeiss Meditec) and corneal tomography (Pentacam; Oculus Optikgeräte GmbH) were assessed, including true net power (TNP). Evaluation of IOL calculation included the number of eyes within ±0.50, ±1.00, and ±2.00 diopters (D), as well as the mean prediction error, mean absolute prediction error and the median absolute prediction error for the formulas Haigis-L, Shammas and Barrett True K No History. These were compared to the Hill Potvin Shammas PM formula that uses TNP (Pentacam).
Results
Seventeen eyes matched our inclusion criteria. The preoperative mean spherical equivalent (SE) was -0.55 ± 0.7 diopters (D) and postoperative -0.3 ± 0.73 D. The mean difference from SimK and TNP was significantly different from zero (P < .001; -1.68 ± 0.21 D). Sorted by MedAE, the best formulas were Hill Potvin Shammas PM and Barrett True K (0.21 ± 0.59 D and 0.25 ± 0.55 D). Most eyes within ±0.50 D were achieved by the Hill Potvin Shammas PM formula (76%) and the Haigis-L formula (76%). For MAE and percentage of eyes within ±0.50 D, Hill Potvin Hammas PM, Barrett True K No History and Haigis-L were significantly better than Shammas (P < 0.5).
Conclusion
Our limited data suggests that using ray-tracing with the Hill Potvin Shammas PM formula for calculation of a nondiffractive wavefront shaping EDOF IOL after myopic LASIK yields good results. IOL calculation after myopic LASIK is still challenging.