Comparison Of Different Corneal Power Measurement Methods For Iol Power Calculation Across Several Formula Categories
Published 2026 - 44th Congress of the ESCRS
Reference: POCAT588 | Type: Free paper | DOI: 10.82333/ttj8-3920
Authors: Dr Ferdinando Cione* 1 , A/Prof. Maddalena De Bernardo 2 , Dr Aniello La Marca 3 , Dr Benedetta Cioffi 4 , Dr Isabella Pellegrino 4 , Dr Matteo Savo 4 , Dr Marco Gioia 5 , A/Prof. Nicola Rosa 2
1University Eye Clinic,AOU San Giovanni di Dio e Ruggi D'Aragona,Salerno,Italy, 2Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana,University of Salerno,Salerno,Italy;University Eye Clinic,AOU San Giovanni di Dio e Ruggi D'Aragona,Salerno,Italy, 3Department of Ophthalmology,Vimercate Hospital,Vimercate (MB),Italy, 4Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana,University of Salerno,Salerno,Italy, 5Ophthalmological Unit,PO Maria SS Addolorata,Eboli (SA),Italy
Purpose
To compare the reliability of simulated keratometry (SimK) obtained from a Scheimpflug-based corneal tomographer with conventional automatic keratometry (aK) from optical biometer for IOL power calculation.
Setting
University Eye Clinic, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Italy
Methods
Two-hundred-thirty-one eyes of 231 patients that underwent cataract surgery at the University Hospital of Salerno were recruited. Refractive prediction errors (PEs) using both aK obtained by IOLMaster and SimK obtained by Pentacam-HR were calculated with Barrett Universal II, Cooke K6, EVO 2.0, Hoffer Q, Hoffer QST, Holladay 1, Pearl-DGS, SRKT, and T2 formulas, by using both IOLCon lens factors, and optimized constants through zeroing out the mean error (ME). Mean absolute error (MAE), median absolute error (MedAE) and percentage of eyes within ±0.50 and ±1.00 diopters (D) of PE were evaluated.
Results
With IOLCon constants, ME obtained with SimK were equal to zero for most formulas (p>0.05), with exclusion of Hoffer- , Hoffer QST, Kane. With IOLCon constants, using aK, MedAE were respectively 0.39D, 0.40D, 0.48D, 0.41D, 0.37D with Cooke K6, EVO 2.0, Hoffer Q, Holladay 1 and T2, while using SimK they were respectively 0.36D, 0.38D, 0.37D, 0.37D, 0.34D, all significantly lower (p<0.05). Other formulas showed a better trend with SimK, even if not significant. After lens constants optimization: Hoffer Q had lower MedAE using SimK compared to aK (p<0.05). Similar percentages of eyes with PE within ±0.50/±1.00D were obtained between aK and SimK both with IOLCon and optimized constants. (p>0.05)
Conclusions
SimK can be used instead of aK for IOL power calculation. In case of non-availability, a correction factor could be applied to preoperative aK to improve PEs.