Impact Of Total Keratometry On Toric Iol Power Selection: A Comparison Of Standard And Measured Posterior Corneal Astigmatism In A Croatian Caucasian Cohort
Published 2026 - 44th Congress of the ESCRS
Reference: POCAT627 | Type: Poster | DOI: 10.82333/rc2j-dd05
Authors: Dr Niko Tomljanovic* 1 , Dr Lorena Karla Šklebar 2 , Dr Ivan Škegro 2 , Dr Sanja Masnec 2 , Dr Sonja Jandroković 2 , Dr Božana Mrvelj 2 , Dr Leon Artuković 2 , Prof. Dr Miro Kalauz 2
1Department of Ophthalmology,Ghetaldus Eye Clinic,Zagreb,Croatia;Department of Ophthalmology,UHC Zagreb,Zagreb,Croatia, 2Department of Ophthalmology,UHC Zagreb,Zagreb,Croatia
Purpose
To evaluate the clinical impact of incorporating measured posterior corneal astigmatism using Total Keratometry (TK) on toric intraocular lens (IOL) power selection. Standard keratometry assumes a fixed anterior–posterior corneal relationship, whereas TK directly measures posterior corneal curvature. We assessed how often TK would alter toric cylinder power and axis selection compared with the Barrett Universal II formula in a Croatian Caucasian population.
Setting
Single-centre retrospective study conducted at a tertiary referral ophthalmology department in Croatia.
Methods
Thirty-seven eyes implanted with a toric IOL were analysed. For each eye, toric cylinder power and axis were calculated using Barrett Universal II (standard keratometry) and Barrett TK (Total Keratometry). The paired difference in recommended cylinder power (ΔCylinder) and minimal angular axis difference were determined. A clinically relevant change in cylinder power was predefined as a ≥0.50 D difference. The proportion of eyes in which TK would have resulted in a different toric IOL selection was calculated.
Results
Median recommended toric cylinder power was 1.0 D (IQR 0.5) with both calculation methods. The median ΔCylinder (TK–K) was 0.00 D (IQR 0.00), with a maximum observed difference of 0.75 D. A clinically relevant cylinder difference (≥0.50 D) was identified in 4 of 37 eyes (10.8%). Differences in suggested cylinder axis were minimal, with a median angular difference of 2° (IQR 1°); in 31 of 37 eyes, axis variation was ≤3°.
Conclusions
In this Croatian Caucasian cohort, incorporation of measured posterior corneal astigmatism using Total Keratometry resulted in a different toric IOL cylinder power recommendation in approximately one in ten eyes, while axis differences were generally minimal. Although toric planning remained unchanged in the majority of cases, posterior corneal measurement influenced surgical decision-making in a meaningful subset of patients. These findings support a selective but clinically relevant role of Total Keratometry in toric IOL planning.