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ARTICLE
Comparison of various intraocular lens
formulas using a new high-resolution
swept-source optical coherence tomographer
Eszter Szalai, MD, PhD, Noemi Toth, MD, Zsofia Kolkedi, MD, Csaba Varga, MD, Adrienne Csutak, MD, PhD
Purpose: To compare vergence, artificial intelligence, and com-
bined intraocular lens (IOL) calculation formulas using a new swept-
source optical coherence tomographer (SS-OCT) and to analyze
their performance based on manifest and estimated refractive
outcomes of cataract surgery.
Setting: Department of Ophthalmology, University of P ´ ecs Med-
ical School, P ´ ecs, Hungary.
Design: Retrospective data analysis.
Methods: Optical biometry readings of patients who underwent
uneventful cataract removal and implantation of a monofocal
acrylic IOL were used to predict IOL power with Barrett Universal
II (BUII), Haigis, Hoffer Q, Holladay 1, Radial Basis Function (RBF)
2.0, Kane, Ladas Super Formula, and SRK/T. All the implanted
IOLs were calculated by using the Haigis formula. The arithmetic
prediction error and median and mean absolute refractive errors
for all formulas were computed. The percentage of eyes within
±0.25 diopters (D), ±0.50 D, and ±1.0 D of prediction error was
calculated.
Results: A total of 95 eyes of 95 patients with a mean age of 68.80
± 7.57 years were included. There was a statistically significant
difference in absolute prediction error across the 8 IOL calculation
formulas (P < .0001). Haigis showed the lowest mean absolute
error, and it differed significantly from the BUII, Hoffer Q, Holladay 1,
Ladas, RBF 2.0, and SRK/T formulas (P < .05). In terms of eyes
within ±0.25 D, ±0.50 D, and ±1.0 D of prediction error, the Haigis
formula showed the overall best performance.
Conclusions: The results indicated that a recently developed SS-
OCT provided accurate ocular biometry measurements before
cataract surgery, and the Haigis formula incorporated in its software
enabled precise calculation of IOL refractive power.
J Cataract Refract Surg 2020; 46:1138–1141 Copyright © 2020 Published
by Wolters Kluwer on behalf of ASCRS and ESCRS
I
nstrumentation and preoperative planning of cataract
surgery have changed profoundly since its first in-
troduction in 1949. Accurate calculation of the intraocular
lens (IOL) is one of the most important determinants of
surgical outcome and patient satisfaction. Performance of IOL
power calculation formulas has been evolving rapidly from the
refraction-based methods to the artificial intelligence–based
formulas.
1,2
Variables used in these formulas are axial length
(AL), keratometry (K), anterior chamber depth (ACD, mea-
sured from the epithelium to the anterior lens surface), lens
thickness (LT), central corneal thickness (CCT), corneal di-
ameter (CD), patient age, and gender. The most recent third-
generation optical biometers using swept-source optical co-
herence tomography (SS-OCT) technology are able to provide
data on corneal surfaces, anterior chamber parameters,
thickness of the crystalline lens, and corneal pachymetry.
3
The purpose of this study was to compare third- and fourth-
generation vergence, artificial intelligence, and combined IOL
power calculation formulas using a recently developed mul-
timodal high-resolution SS-OCT and to analyze their per-
formance based on manifest and estimated refractive outcomes
of cataract surgery.
METHODS
Study Design
Retrospective data analysis was performed on 95 eyes of 95 patients
(54 women [57%]; 51 left eyes [54%]). All patients had a negative
history of ocular disease (other than refractive errors excluding
corneal ectasias), trauma, or previous ocular surgery. Biometry was
performed preoperatively using a recently introduced high-
wavelength swept-source anterior segment OCT (ANTERION,
Heidelberg Engineering GmbH). All patients underwent uneventful
phacoemulsification and implantation of a monofocal acrylic IOL.
The implanted IOLs were Medicontur 690AB (Medical Engineering
Ltd.) in 39 eyes (41.05%), Akreos Adapt AO (Bausch & Lomb, Inc.)
in 30 eyes (32.43%), Alcon SA60AT (Alcon Laboratories Inc.) in 12
eyes (12.63%), Alcon SN60WF (Alcon Laboratories Inc.) in 11 eyes
(11.58%), and Alcon Clareon (Alcon Laboratories Inc.) in 3 eyes
Submitted: April 4, 2020 | Final revision submitted: June 21, 2020 | Accepted: June 24, 2020
From the Department of Ophthalmology, University of P ´ ecs Medical School, P ´ ecs, Hungary.
Corresponding author: Eszter Szalai, MD, PhD, Department of Ophthalmology, University of P ´ ecs Medical School, R ´ akóczi u. 2, 7623 P ´ ecs, Hungary.
Email: szalai.eszter@pte.hu.
1138
Copyright © 2020 Published by Wolters Kluwer on behalf of ASCRS and ESCRS
Published by Wolters Kluwer Health, Inc.
0886-3350/$ - see frontmatter
https://doi.org/10.1097/j.jcrs.0000000000000329
Copyright © 2020 Published by Wolters Kluwer on behalf of ASCRS and ESCRS. Unauthorized reproduction of this article is prohibited.