ARTICLE

Comparison of different methods to calculate the axial length measured by optical biometry

Savini, Giacomo MD; Hoffer, Kenneth J. MD, FACS; Carballo, Laura OD; Taroni, Leonardo MD; Schiano-Lomoriello, Domenico MD

Author Information

From the G.B. Bietti Foundation I.R.C.C.S., Rome, Italy (Savini, Schiano-Lomoriello); Stein Eye Institute, University of California, Los Angeles, California (Hoffer), St. Mary's Eye Center, Santa Monica, California (Dr. Hoffer); Alcon Italia, S.p.A., Milan, Italy (Carballo); University Eye Clinic, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy (Taroni).

Corresponding author: Giacomo Savini, MD, G.B. Bietti Foundation I.R.C.C.S., Via Livenza, 3—00198 Rome, Italy. Email: [email protected].

The contribution of the G.B. Bietti Foundation I.R.C.C.S. was supported by Fondazione Roma and the Italian Ministry of Health.

Disclosures: G. Savini is a consultant to CSO and has received personal fees from Alcon Laboratories, Inc., Johnson & Johnson, Oculus, and Zeiss. K. J. Hoffer licenses the registered trademark name Hoffer to ensure accurate programming of his formulas to Carl Zeiss Meditec (IOLMasters), Haag-Streit (LenStar/EyeStar), Heidelberg Engineering (Anterion), Oculus (Pentacam AXL), Movu (Argos), Nidek (AL-Scan), Optopol (RENO NX), Tomey (OA-2000), Topcon /VisiaImaging (Aladdin), Ziemer (Galilei G6), and all A-scan biometer manufacturers. L. Carballo is an employee of Alcon Laboratories, Inc. Italia. No other disclosures were reported.

First author:Giacomo Savini, MDI.R.C.C.S.—G.B. Bietti Foundation, Rome, Italy

Journal of Cataract & Refractive Surgery 48(6):p 685-689, June 2022. | DOI: 10.1097/j.jcrs.0000000000000821

Purpose:

To compare axial length (AL) measurements in long eyes by 2 swept-source optical coherence tomography (SS-OCT) biometers, one based on the group refractive index (IOLMaster 700, Zeiss) and the other based on sum of segments (Argos, Movu Inc.), and compare these measurements with previously published methods to optimize AL.

Setting:

G.B. Bietti Foundation I.R.C.C.S., Rome, Italy.

Design:

Prospective case series.

Methods:

AL was measured with both optical biometers in patients with myopia (AL > 24.0 mm) and compared with the values obtained with Wang-Koch adjustment, polynomial equations for the Holladay 1 and 2 formulas, and Cooke-modified AL (CMAL).

Results:

In 102 eyes of 55 subjects, a statistically significant difference (P < .0001) was found among the 6 AL values. Posttest revealed that Argos measurements (26.90 ± 1.61 mm) were significantly lower compared with those provided by all methods (P < .001) but CMAL, whereas IOLMaster 700 measurements (27.01 ± 1.65) were higher (P < .001). No difference was found between the 2 Holladay equations. CMAL values did not reveal any difference compared with those of the Argos, but a proportional bias showed that in longer eyes, CMAL provided smaller values (P < .0001, r = −0.7221). AL overestimation by the IOLMaster 700 AL compared with the Argos was higher, the longer the eye was (P < .0001, r = 0.6959, r² = 0.4842).

Conclusions:

The SS-OCT optical biometer based on the group refractive index overestimates AL compared with the device using segmented AL. CMAL provides the measurements closest to those of the device using segmented AL.

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