Article

Refractive outcomes of intraocular lens power calculation using different corneal power measurements with a new optical biometer

Savini, Giacomo MD^*; Negishi, Kazuno MD; Hoffer, Kenneth J. MD, FACS; Lomoriello, Domenico Schiano MD

From 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

^*Corresponding author: Giacomo Savini, MD, Fondazione G.B. Bietti Foundation IRCCS, Via Livenza 3, Rome, Italy.

E-mail: [email protected]

Submitted November 27, 2017; revised March 16, 2018; accepted March 20, 2018.

The contribution of G.B. Bietti Foundation IRCCS was supported by the Italian Ministry of Health and Fondazione Roma, Rome, Italy.

Graham D. Barrett, MD, optimized the lens factor of the Barrett Universal II formula.

Journal of Cataract & Refractive Surgery 44(6):p 701-708, June 2018. | DOI: 10.1016/j.jcrs.2018.03.027

Abstract

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.

Secondary Logo

Journal Logo

Refractive outcomes of intraocular lens power calculation using different corneal power measurements with a new optical biometer