The measurement of ocular axial length in normal human eyes based on an improved <scp>Twyman‐Green</scp> interferometer

Wang, Cheng; Huangfu, Shengnan; Zhou, Qi; Li, Yanrui; Xiang, Huazhong; Chen, Ming‐Hui; Zheng, Gang; Zhao, Jie; Zhang, Dawei

doi:10.1002/jbio.202100021

Cited by 5 publications

(2 citation statements)

References 35 publications

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“…The coefficient of variance (CoV) can be used to express the precision and repeatability of a measurement, where lower CoV values indicate higher accuracy. This metric has previously been used to report the quality of a measurements obtained with different biometers, including the IOLMaster and Pentacam [ 15 , 16 , 17 , 18 ]. In 2017, Ruiz-Mesa et al compared a Scheimpflug/PCI-based system with an optical low-coherence reflectometry (OLCR) device.…”

Section: Discussionmentioning

confidence: 99%

Development and Verification of an Adjustment Factor for Determining the Axial Length Using Optical Biometry in Silicone Oil-Filled Eyes

et al. 2022

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The aim of this prospective clinical study was to establish and verify an adaptation for axial length (AL) measurement in silicone oil (SO)-filled pseudophakic eyes with a Scheimpflug and partial coherence interferometry (PCI)-based biometer. The AL was measured with a Pentacam AXL (OCULUS Optikgeräte GmbH, Wetzler, Germany) and IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany). The coefficients of variation (CoV) and the mean systematic difference (95% confidence interval (CI)) between the devices were calculated. After implementing a setting for measuring AL in tamponaded eyes with a Pentacam based on data of 29 eyes, another 12 eyes were examined for verification. The mean AL obtained with the Pentacam was 25.53 ± 1.94 mm (range: 21.70 to 30.76 mm), and with IOLMaster, 24.73 ± 1.97 mm (ranged 20.84 to 29.92 mm), resulting in a mean offset of 0.80 ± 0.08 mm (95% CI: 0.77, 0.83 mm), p < 0.001. The AL values of both devices showed a strong linear correlation (r = 0.999). Verification data confirmed good agreement, with a statistically and clinically non-significant mean difference of 0.02 ± 0.04 (95% CI: −0.01, 0.05) mm, p = 0.134. We implemented a specific adaptation for obtaining reliable AL values in SO-filled eyes with the Pentacam AXL.

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Section: Discussionmentioning

confidence: 99%

Development and Verification of an Adjustment Factor for Determining the Axial Length Using Optical Biometry in Silicone Oil-Filled Eyes

et al. 2022

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“…Commercial and research TD optical biometers include various types of ODLs. The majority employ bulky mechanically scanning components, such as retroreflectors mounted on a linear translation stage actuated by a stepper motor with leadscrew [ 13 , 20 ], as the Zeiss IOL Master 500 [ 21 ]. Others employ a 25-30 mm rotating cube [ 22 , 23 ], as the Haag-Streit Lenstar LS 900 [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Long-range frequency-domain optical delay line based on a spinning tilted mirror for low-cost ocular biometry

Urizar,

Gambra,

de Castro

et al. 2023

Biomed. Opt. Express

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Optical biometers are routinely used to measure intraocular distances in ophthalmic applications such as cataract surgery planning or myopia monitoring. However, due to their high cost and reduced transportability, access to them for screening and surgical planning is still limited in low-resource and remote settings. To increase patients’ access to optical biometry we propose a novel low-cost frequency-domain optical delay line (FD-ODL) based on an inexpensive stepper motor spinning a tilted mirror, for integration into a time-domain (TD)-biometer, amenable to a compact footprint. In the proposed FD-ODL, the axial scan range and the A-scan rate are decoupled from one another, as the former only depends on the spinning mirror tilt angle, while the A-scan rate only depends on the motor shaft rotational speed. We characterized the scanning performance and specifications for two spinning mirror tilt angles, and compared them to those of the standard, more expensive FD-ODL implementation, employing a galvanometric scanner for group delay generation. A prototype of the low-cost FD-ODL with a 1.5 deg tilt angle, resulting in an axial scan range of 6.61 mm and an A-scan rate of 10 Hz was experimentally implemented and integrated in a dual sample beam optical low-coherence reflectometry (OLCR) setup with a detour unit to replicate the measurement window around the anterior segment and the retina. The intraocular distances of a model eye were measured with the proposed low-cost biometer and found to be in good agreement with those acquired by a custom swept-source optical coherence tomography (SS-OCT) system and two commercial biometers, validating our novel design.

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Modelling, experimental validation and analysis of a multiple stage PC-PMF Sagnac loop interferometer with spectral shape versatility using an optimized fitting algorithm

Pizzaia

Martins

Rocha

et al. 2023

Optical Fiber Technology

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The measurement of ocular axial length in normal human eyes based on an improved Twyman‐Green interferometer

Cited by 5 publications

References 35 publications

Development and Verification of an Adjustment Factor for Determining the Axial Length Using Optical Biometry in Silicone Oil-Filled Eyes

Development and Verification of an Adjustment Factor for Determining the Axial Length Using Optical Biometry in Silicone Oil-Filled Eyes

Long-range frequency-domain optical delay line based on a spinning tilted mirror for low-cost ocular biometry

Modelling, experimental validation and analysis of a multiple stage PC-PMF Sagnac loop interferometer with spectral shape versatility using an optimized fitting algorithm

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