Comparison of composite and segmental methods for acquiring optical axial length with swept-source optical coherence tomography

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Abstract

This study compared the optical axial length (AL) obtained by composite and segmental methods using swept-source optical coherence tomography (SS-OCT) devices, and demonstrated its effects on the post-operative refractive errors (RE) one month after cataract surgery. Conventional AL measured with the composite method used the mean refractive index. The segmented-AL method used individual refractive indices for each ocular medium. The composite AL (24.52 ± 2.03 mm) was significantly longer ( P < 0.001) than the segmented AL (24.49 ± 1.97 mm) among a total of 374 eyes of 374 patients. Bland–Altman analysis revealed a negative proportional bias for the differences between composite and segmented ALs. Although there was no significant difference in the RE obtained by the composite and segmental methods (0.42 ± 0.38 D vs 0.41 ± 0.36 D, respectively, P = 0.35), subgroup analysis of extremely long eyes implanted with a low power intraocular lens indicated that predicted RE was significantly smaller with the segmental method (0.45 ± 0.86 D) than that with the composite method (0.80 ± 0.86 D, P < 0.001). Segmented AL with SS-OCT is more accurate than composite AL in eyes with extremely long AL and can improve post-operative hyperopic shifts in such eyes.

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Sources of error in intraocular lens power calculation.

N E Sverker Norrby (2008)

To identify and quantify sources of error in the refractive outcome of cataract surgery. AMO Groningen BV, Groningen, The Netherlands. Means and standard deviations (SDs) of parameters that influence refractive outcomes were taken or derived from the published literature to the extent available. To evaluate their influence on refraction, thick-lens ray tracing that allowed for asphericity was used. The numerical partial derivative of each parameter with respect to spectacle refraction was calculated. The product of the partial derivative and the SD for a parameter equates to its SD, expressed as spectacle diopters, which squared is the variance. The error contribution of a parameter is its variance relative to the sum of the variances of all parameters. Preoperative estimation of postoperative intraocular lens (IOL) position, postoperative refraction determination, and preoperative axial length (AL) measurement were the largest contributors of error (35%, 27%, and 17%, respectively), with a mean absolute error (MAE) of 0.6 diopter (D) for an eye of average dimensions. Pupil size variation in the population accounted for 8% of the error, and variability in IOL power, 1%. Improvement in refractive outcome requires better methods for predicting the postoperative IOL position. Measuring AL by partial coherence interferometry may be of benefit. Autorefraction increases precision in outcome measurement. Reducing these 3 major error sources with means available today reduces the MAE to 0.4 D. Using IOLs that compensate for the spherical aberration of the cornea would eliminate the influence of pupil size. Further improvement would require measuring the asphericity of the anterior surface and radius of the posterior surface of the cornea.

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Comparison of immersion ultrasound biometry and partial coherence interferometry for intraocular lens calculation according to Haigis.

W Haigis, B. Schneider, B Lege … (2000)

The precision of intraocular lens (IOL) calculation is essentially determined by the accuracy of the measurement of axial length. In addition to classical ultrasound biometry, partial coherence interferometry serves as a new optical method for axial length determination. A functional prototype from Carl Zeiss Jena implementing this principle was compared with immersion ultrasound biometry in our laboratory. In 108 patients attending the biometry laboratory for planning of cataract surgery, axial lengths were additionally measured optically. Whereas surgical decisions were based on ultrasound data, we used postoperative refraction measurements to calculate retrospectively what results would have been obtained if optical axial length data had been used for IOL calculation. For the translation of optical to geometrical lengths, five different conversion formulas were used, among them the relation which is built into the Zeiss IOL-Master. IOL calculation was carried out according to Haigis with and without optimization of constants. On the basis of ultrasound immersion data from our Grieshaber Biometric System (GBS), postoperative refraction after implantation of a Rayner IOL type 755 U was predicted correctly within +/- 1 D in 85.7% and within +/- 2 D in 99% of all cases. An analogous result was achieved with optical axial length data after suitable transformation of optical path lengths into geometrical distances. Partial coherence interferometry is a noncontact, user- and patient-friendly method for axial length determination and IOL planning with an accuracy comparable to that of high-precision immersion ultrasound.

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Evaluation and comparison of the new swept source OCT-based IOLMaster 700 with the IOLMaster 500

Ahmet Akman, Leyla Asena, Sirel Gür Güngör (2015)

Purpose To compare the measurements and failure rates obtained with a new swept source optical coherence tomography (OCT)-based biometry to IOLMaster 500. Setting Eye Clinic, Baskent University Faculty of Medicine, Ankara, Turkey. Design Observational cross-sectional study and evaluation of a new diagnostic technology. Methods 188 eyes of 101 subjects were included in the study. Measurements of axial length (AL), anterior chamber depth (ACD), corneal power (K1 and K2) and the measurement failure rate with the new Zeiss IOLMaster 700 were compared with those obtained with the IOLMaster 500. The results were evaluated using Bland–Altman analyses. The differences between both methods were assessed using the paired samples t test, and their correlation was evaluated by intraclass correlation coefficient (ICC). Results The mean age was 68.32±12.71 years and the male/female ratio was 29/72. The agreements between two devices were outstanding regarding AL (ICC=1.0), ACD (ICC=0.920), K1 (ICC=0.992) and K2 (ICC=0.989) values. IOLMaster 700 was able to measure ACD AL, K1 and K2 in all eyes within high-quality SD limits of the manufacturer. IOLMaster 500 was able to measure ACD in 175 eyes, whereas measurements were not possible in the remaining 13 eyes. AL measurements were not possible for 17 eyes with IOLMaster 500. Nine of these eyes had posterior subcapsular cataracts and eight had dense nuclear cataracts. Conclusions Although the agreement between the two devices was excellent, the IOLMaster 700 was more effective in obtaining biometric measurements in eyes with posterior subcapsular and dense nuclear cataracts.

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Author and article information

Contributors

Naoyuki Maeda: nmaeda@ophthal.med.osaka-u.ac.jp

Journal

Journal ID (nlm-ta): Sci Rep

Journal ID (iso-abbrev): Sci Rep

Title: Scientific Reports

Publisher: Nature Publishing Group UK (London )

ISSN (Electronic): 2045-2322

Publication date (Electronic): 11 March 2020

Publication date PMC-release: 11 March 2020

Publication date Collection: 2020

Volume: 10

Electronic Location Identifier: 4474

Affiliations

[1 ]ISNI 0000 0004 0373 3971, GRID grid.136593.b, Department of Ophthalmology, Osaka University Graduate School of Medicine, ; Osaka, Japan

[2 ]GRID grid.416239.b, Department of Ophthalmology, National Hospital Organization, Tokyo Medical Center, ; Tokyo, Japan

[3 ]ISNI 0000 0001 2181 7878, GRID grid.47840.3f, School of Optometry and Vision Science, University of California Berkeley, ; California, 94720 USA

[4 ]Laboratorio de Lente Verde, Chiba, Japan

[5 ]ISNI 0000 0004 0373 3971, GRID grid.136593.b, Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, ; Osaka, Japan

Article

Publisher ID: 61391

DOI: 10.1038/s41598-020-61391-7

PMC ID: 7066125

PubMed ID: 32161358

SO-VID: 04b9059b-a320-424d-be40-3e2730d8286e

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Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

History

Date received : 25 November 2019

Date accepted : 4 February 2020

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ScienceOpen disciplines: Uncategorized

Keywords: outcomes research,lens diseases,optical metrology,imaging and sensing

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ScienceOpen disciplines: Uncategorized

Keywords: outcomes research, lens diseases, optical metrology, imaging and sensing

Comparison of composite and segmental methods for acquiring optical axial length with swept-source optical coherence tomography

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Most cited references 31

Sources of error in intraocular lens power calculation.

Comparison of immersion ultrasound biometry and partial coherence interferometry for intraocular lens calculation according to Haigis.

Evaluation and comparison of the new swept source OCT-based IOLMaster 700 with the IOLMaster 500

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