Prediction Accuracy Of Intraocular Lens Formulas With Keratometry Measurements From Swept Source Oct-Based Biometer Or Scheimpflug Tomography In Post-Laser Vision Correction Eyes
Published 2023 - 41st Congress of the ESCRS
Reference: FP05.11 | Type: Free paper | DOI: 10.82333/armv-zv68
Authors: Ashvin Agarwal* 1 , Haripriya Aravind 2 , Sri Ganesh 3 , Sheetal Brar 3 , Shail Vasavada 4 , Abhay Vasavada 4
1Dr Agarwal’s Eye Hospital and Eye Research Centre,Chennai,India, 2Aravind Eye Hospital,Chennai,India, 3Nethradhama Superspeciality Eye Hospital,Bangalore,India, 4Raghudeep Eye Hospital,Ahmedabad,India
Purpose
To evaluate the prediction accuracy of various IOL formulas used for IOL power calculations in eyes that have undergone myopic corneal refractive surgery.
Setting
Ambispective, Multicenter study.
Methods
This study included post-refractive surgery eyes that underwent cataract surgery with the implantation of monofocal IOL. Keratometry measurements were obtained from IOLMaster 700 (IOLM 700) or Pentacam HR (PHR). Other biometry measurements were obtained from IOLMaster 700. Predicted refraction with 1) Barrett True K total keratometry (TK) (IOLM 700), 2) Barrett True K conventional K (IOLM 700), 3) Barrett True K Sim K (PHR), 4) Haigis TK (IOLM 700), and 5) Haigis L conventional K (IOLM 700) for the final IOL power implanted were noted. The mean prediction error and the proportion of eyes with prediction error within 0.5 D and 1.0 D calculated for all the study formulas at postoperative 3 to 6 weeks were compared.
Results
These are the initial results of 35 eyes available for analysis. Post-operative clinical assessment was evaluated 3-6 weeks after planned cataract surgery. The mean prediction error, absolute prediction error, and proportion of eyes within 0.5 D and 1.0 D of predicted post-operative spherical equivalent for Barrett True K total keratometry (TK) (IOLM 700), Barrett True K conventional K (IOLM 700), Haigis L conventional K (IOLM700), Barrett True K Sim K (PHR), and Haigis TK (IOLM 700) was evaluated. Results from parametric or non-parametric tests depending on the distribution of data, will be provided.
Conclusions
The Barrett True K TK formula showed the least mean absolute prediction error in post-myopic laser vision correction eyes. The proportion of eyes with absolute prediction error within 0.5 D was ~11% better when using the Barrett True K formula with total keratometry readings or conventional K readings from IOLMaster 700 than when using SimK readings from PHR. Among the five study formulas, the Barrett True K formula with TK/conventional K readings achieved the greatest prediction accuracy in post-myopic refractive surgery eyes.