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Updated: Feb 9, 2026

Measuring the Behavioral Effects of Intraocular Scatter
Published on: February 18, 2021
Refractive outcomes of intraocular lens power calculation using different corneal power measurements with a new
Giacomo Savini1, Kazuno Negishi1, Kenneth J Hoffer1
1From the G.B. Bietti Foundation IRCCS (Savini, Schiano Lomoriello), Rome, Italy; the Department of Ophthalmology (Negishi), Keio University School of Medicine, Hospital, Tokyo, Japan; Stein Eye Institute (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center (Hoffer), Santa Monica, California, USA.
Purpose:
To evaluate the results of intraocular lens (IOL) power calculation using different corneal power measurements provided by an optical biometer combined with a dual Scheimpflug analyzer and a Placido disk topographer (Galilei G6).
Setting:
G.B. Bietti Foundation, Rome, Italy, and Keio University Hospital, Tokyo, Japan.
Design:
Evaluation of diagnostic technology.
Methods:
Consecutive patients having cataract surgery were enrolled. The IOL power was calculated with the Barrett Universal II, Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Different options were used to calculate the corneal power: simulated keratometry (K) based on anterior corneal surface measurements only and total corneal power (TCP) based on ray tracing through both corneal surfaces. Three TCP measurements (TCP1, TCP2, and TCP-IOL) were evaluated.
Results:
The study analyzed 118 eyes. The mean values of simulated K (43.74 diopters [D] ± 1.40 [SD]), TCP1 (43.13 ± 1.35 D), TCP2 (41.87 ± 1.30 D), and TCP-IOL (42.62 ± 1.35 D) were significantly different (P < .0001). The best results were obtained using simulated K: the median absolute error ranged between 0.22 D and 0.29 D and the percentage of eyes with a prediction error of ±0.50 D or less, between 76.2% and 84.7%, depending on the formula. After constant optimization, the results using any TCP value and simulated K were similar with no statistically significant differences.
Conclusions:
Biometric measurements provided by the Scheimpflug-Placido optical biometer can be used to accurately calculate the IOL power. Simulated K and TCP led to similar outcomes after constant optimization.
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