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Yuanling Xia - One of the best experts on this subject based on the ideXlab platform.
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comparison of Lens Thickness measurements using the anterior segment optical coherence tomography and a scan ultrasonography
Investigative Ophthalmology & Visual Science, 2009Co-Authors: Yangfa Zeng, Xing Liu, Yizhi Liu, Chuying Chen, Yuanling XiaAbstract:PURPOSE: To assess Lens Thickness (LT) measurements with anterior segment optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US). METHODS: Enrolled were 66 eyes of 48 phakic elderly volunteers aged > or = 50 years and 56 eyes of 56 young participants aged 18 to 40 years. LT was measured with the internal manual caliper tools in AS-OCT. The A-scan US measurements were based on an average of 10 consecutive automatic measurements. Reproducibility was assessed by three measurements each with AS-OCT and A-scan US independently obtained by two observers who were masked to one another's results. RESULTS: The failure rates of AS-OCT and A-scan US were 9.1% and 7.6%, respectively, in elderly subjects, but no failure was observed in young subjects. The LT values measured by AS-OCT were significantly greater than A-scan US; the paired difference was 0.135 mm in elderly and 0.101 mm in young subjects (P < 0.001). These differences did not correlate with the nuclear cataract grades (r = 0.078, P = 0.558). Intraobserver agreement on AS-OCT (95% limits of agreement [LoA]: -0.049 to +0.045 mm; ICC: 0.999) was better than A-scan US (95%LoA: -0.194 to +0.218 mm; ICC: 0.974). The 95% LoA of interobserver agreement using AS-OCT and A-scan were -0.084 to +0.073 and -0.278 to +0.239 mm, respectively, and the ICCs were 0.996 and 0.960, respectively. CONCLUSIONS: AS-OCT can be used to measure Lens Thickness in most eyes with clear or opacified Lenses. It appears to be an alternative means of measuring Lens Thickness, particularly when a noncontact method is needed.
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Comparison of Lens Thickness measurements using the anterior segment optical coherence tomography and A-scan ultrasonography.
Investigative ophthalmology & visual science, 2008Co-Authors: Yangfa Zeng, Xing Liu, Yizhi Liu, Chuying Chen, Yuanling XiaAbstract:To assess Lens Thickness (LT) measurements with anterior segment optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US). Enrolled were 66 eyes of 48 phakic elderly volunteers aged > or = 50 years and 56 eyes of 56 young participants aged 18 to 40 years. LT was measured with the internal manual caliper tools in AS-OCT. The A-scan US measurements were based on an average of 10 consecutive automatic measurements. Reproducibility was assessed by three measurements each with AS-OCT and A-scan US independently obtained by two observers who were masked to one another's results. The failure rates of AS-OCT and A-scan US were 9.1% and 7.6%, respectively, in elderly subjects, but no failure was observed in young subjects. The LT values measured by AS-OCT were significantly greater than A-scan US; the paired difference was 0.135 mm in elderly and 0.101 mm in young subjects (P < 0.001). These differences did not correlate with the nuclear cataract grades (r = 0.078, P = 0.558). Intraobserver agreement on AS-OCT (95% limits of agreement [LoA]: -0.049 to +0.045 mm; ICC: 0.999) was better than A-scan US (95%LoA: -0.194 to +0.218 mm; ICC: 0.974). The 95% LoA of interobserver agreement using AS-OCT and A-scan were -0.084 to +0.073 and -0.278 to +0.239 mm, respectively, and the ICCs were 0.996 and 0.960, respectively. AS-OCT can be used to measure Lens Thickness in most eyes with clear or opacified Lenses. It appears to be an alternative means of measuring Lens Thickness, particularly when a noncontact method is needed.
Adrian Glasser - One of the best experts on this subject based on the ideXlab platform.
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Lens diameter and Thickness as a function of age and pharmacologically stimulated accommodation in rhesus monkeys
Experimental eye research, 2008Co-Authors: Mark Wendt, Mary Ann Croft, Jared P. Mcdonald, Paul L. Kaufman, Adrian GlasserAbstract:Uncertainty exists regarding accommodative and age changes in Lens diameter and Thickness in humans and monkeys. In this study, unaccommodated and accommodated refraction, Lens diameter, and Lens Thickness were measured in rhesus monkeys across a range of ages. Iridectomized eyes were studied in 33 anesthetized monkeys aged 4-23 years. Refraction was measured using a Hartinger coincidence refractometer and Lens Thickness was measured with A-scan ultrasound. Lens diameters were measured with image analysis from slit-lamp images captured via a video camera while a saline filled, plano perfusion Lens was placed on the cornea. Accommodation was pharmacologically stimulated with 2% pilocarpine via the perfusion Lens in 21 of the monkeys and Lens diameters were measured until a stable minimum was achieved. Refraction and Lens Thickness were measured again after the eye was accommodated. Unaccommodated Lens Thickness increased linearly with age by 0.029 mm/year while unaccommodated Lens diameter showed no systematic change with age. Accommodative amplitude decreased by 0.462 D/year in response to pilocarpine. The accommodative increase in Lens Thickness decreased with age by 0.022 mm/year. The accommodative decrease in Lens diameter declined linearly with age by 0.021 mm/year. Rhesus monkeys undergo the expected presbyopic changes including increasing Lens Thickness and a decreasing ability of the Lens to undergo changes in Thickness and diameter with accommodation, however without an age-related change in unaccommodated Lens diameter. As in humans, the age-related decrease in accommodative amplitude in rhesus monkeys cannot be attributed to an age-related increase in Lens diameter.
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Comparisons between Pharmacologically and Edinger-Westphal–Stimulated Accommodation in Rhesus Monkeys
Investigative ophthalmology & visual science, 2005Co-Authors: Lisa A. Ostrin, Adrian GlasserAbstract:Accommodation results in increased Lens Thickness and Lens surface curvatures. Previous studies suggest that Lens biometric accommodative changes are different with pharmacological and voluntary accommodation. In this study, refractive and biometric changes during Edinger-Westphal (EW) and pharmacologically stimulated accommodation in rhesus monkeys were compared. Accommodation was stimulated by an indwelling permanent electrode in the EW nucleus of the midbrain in one eye each of four rhesus monkeys. Dynamic refractive changes were measured with infrared photorefraction, and Lens biometric changes were measured with high-resolution, continuous A-scan ultrasonography for increasing stimulus current amplitudes, including supramaximal current amplitudes. Accommodation was then stimulated pharmacologically and biometry was measured continuously for 30 minutes. During EW-stimulated accommodation, Lens surfaces move linearly with refraction, with an increase in Lens Thickness of 0.06 mm/D, an anterior movement of the anterior Lens surface of 0.04 mm/D, and a posterior movement of the posterior Lens surface of 0.02 mm/D. Peak velocity of accommodation (diopters per second) and Lens Thickness (in millimeters per second) increased with supramaximal stimulus currents, but without further increase in amplitude or total Lens Thickness. After carbachol stimulation, there was initially an anterior movement of the anterior Lens surface and a posterior movement of the posterior Lens surface; but by 30 minutes, there was an overall anterior shift of the Lens. Ocular biometric changes differ with EW and pharmacological stimulation of accommodation. Pharmacological stimulation results in a greater increase in Lens Thickness, an overall forward movement of the Lens and a greater change in dioptric power.
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Dynamic accommodative changes in rhesus monkey eyes assessed with A-scan ultrasound biometry.
Optometry and vision science : official publication of the American Academy of Optometry, 2003Co-Authors: Abhiram S. Vilupuru, Adrian GlasserAbstract:Prior studies in humans measured time constants of biometric accommodative changes as a function of amplitude, and prior studies in monkeys used slit lamp videography to analyze dynamic lenticular accommodative movements. Neither of these studies related biometric changes to refractive changes. We wished to develop and test methodology to begin to test the hypothesis that ocular biometric changes are well correlated with accommodative refractive changes in rhesus monkeys. Methodology is described to dynamically measure biometric accommodative changes with A-scan ultrasonography. Lens Thickness, anterior chamber depth, and anterior segment length (anterior chamber depth plus Lens Thickness) were measured dynamically during Edinger-Westphal-stimulated accommodation in two eyes of one rhesus monkey. In addition, dynamic accommodative refractive changes were measured with infrared photorefraction. Functions were fit to the accommodative and disaccommodative responses to obtain time constants. Derivatives of these functions allow peak velocities to be determined for each amplitude. Dynamic changes in Lens Thickness and anterior chamber depth measured with A-scan biometry were compared with dynamic measures of accommodation using infrared photorefraction. Lens Thickness and anterior segment length increase and anterior chamber depth decreases during accommodation. The biometric changes are well correlated with the accommodative optical changes. Peak velocities of accommodative changes in Lens Thickness and anterior chamber depth increase with amplitude and peak velocities for disaccommodation were higher than those for accommodation. Dynamic A-scan provides a method for dynamic analysis of the accommodative biometric changes during Edinger-Westphal-stimulated accommodation in monkeys, although the measurement resolution of this approach is limited.
Giacomo Savini - One of the best experts on this subject based on the ideXlab platform.
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agreement between Lens Thickness measurements by ultrasound immersion biometry and optical biometry
Journal of Cataract and Refractive Surgery, 2018Co-Authors: Giacomo Savini, Kenneth J Hoffer, Domenico SchianolomorielloAbstract:Purpose To compare Lens Thickness measurements provided by immersion ultrasound (US) biometry and optical biometry. Setting IRCCS-Fondazione Bietti, Rome, Italy. Design Evaluation of diagnostic technology. Methods Immersion US biometry and optical biometry were performed in a consecutive series of eyes having cataract surgery. Three optical biometers (OA-2000, Aladdin, and Galilei G6) were used. To assess how the differences in Lens Thickness measurements influenced intraocular Lens (IOL) power calculation, the Lens Thickness values were entered into the Olsen formula. Results Eighty-eight eyes were analyzed. Ultrasound immersion biometry yielded significantly higher Lens Thickness values than all of the optical biometers (P Conclusions Lens Thickness measurements by immersion US biometry and optical biometry cannot be considered interchangeable. Minor, but still significant, differences between the 3 optical biometers tested were also found.
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Agreement between Lens Thickness measurements by ultrasound immersion biometry and optical biometry.
Journal of cataract and refractive surgery, 2018Co-Authors: Giacomo Savini, Kenneth J Hoffer, Domenico Schiano-lomorielloAbstract:To compare Lens Thickness measurements provided by immersion ultrasound (US) biometry and optical biometry. IRCCS-Fondazione Bietti, Rome, Italy. Evaluation of diagnostic technology. Immersion US biometry and optical biometry were performed in a consecutive series of eyes having cataract surgery. Three optical biometers (OA-2000, Aladdin, and Galilei G6) were used. To assess how the differences in Lens Thickness measurements influenced intraocular Lens (IOL) power calculation, the Lens Thickness values were entered into the Olsen formula. Eighty-eight eyes were analyzed. Ultrasound immersion biometry yielded significantly higher Lens Thickness values than all of the optical biometers (P < .0001). The mean difference ranged between 0.29 mm and 0.43 mm. Although the differences between the 3 optical biometers were smaller, they were still statistically significant (P < .001). With respect to the immersion US biometry, Lens Thickness measurements using the optical biometric measurements would have resulted in the selection of a lower IOL power in between 43.2% and 62.5% of eyes, depending on the optical biometer. Comparison of the measurements of the 3 optical biometers showed that a different IOL power would have been selected in between 9.1% and 19.3% of eyes. Lens Thickness measurements by immersion US biometry and optical biometry cannot be considered interchangeable. Minor, but still significant, differences between the 3 optical biometers tested were also found. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
Yangfa Zeng - One of the best experts on this subject based on the ideXlab platform.
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Correlation between Lens Thickness and central anterior chamber depth.
Eye science, 2012Co-Authors: Yangfa Zeng, Xing Liu, Tao Wang, Yimin Zhong, Jingjing HuangAbstract:To investigate gender differences in Lens Thickness (LT) and central anterior chamber depth (ACD) in normal subjects, and to assess age associated changes in these measures. The anterior chamber depth (ACD), and Lens Thickness (LT), of 150 normal subjects (150 eyes) was measured by anterior segment optical coherence tomography (AS- OCT). Gender differences were assessed by independent t-test, and correlation analysis was used to examine the effect of age. The mean values of ACD and LT were 0.69±0.32 mm and 4.85±0.43 mm, respectively. Women had a significantly lower Mean ACD as compared to men (2.56±0.33mm vs 2.85±0.29 mm; P﹤0.05). No statistically significant difference was found in LT between male and female subjects (P＞0.05). Correlation analysis findings suggest that LT increases with age (r =0.83, P﹤0.05), and that ACD decreases with age (r=- 0.57, P﹤0.05). After controlling for LT, no significant correlation was observed between age and ACD (P＞0.05). The ACD of female subjects was, on average, shallower than that of their male counterparts. Aging was associated with increasing LT, and the observed narrowing of ACD with age, might be partially mediated by the increasing LT.
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comparison of Lens Thickness measurements using the anterior segment optical coherence tomography and a scan ultrasonography
Investigative Ophthalmology & Visual Science, 2009Co-Authors: Yangfa Zeng, Xing Liu, Yizhi Liu, Chuying Chen, Yuanling XiaAbstract:PURPOSE: To assess Lens Thickness (LT) measurements with anterior segment optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US). METHODS: Enrolled were 66 eyes of 48 phakic elderly volunteers aged > or = 50 years and 56 eyes of 56 young participants aged 18 to 40 years. LT was measured with the internal manual caliper tools in AS-OCT. The A-scan US measurements were based on an average of 10 consecutive automatic measurements. Reproducibility was assessed by three measurements each with AS-OCT and A-scan US independently obtained by two observers who were masked to one another's results. RESULTS: The failure rates of AS-OCT and A-scan US were 9.1% and 7.6%, respectively, in elderly subjects, but no failure was observed in young subjects. The LT values measured by AS-OCT were significantly greater than A-scan US; the paired difference was 0.135 mm in elderly and 0.101 mm in young subjects (P < 0.001). These differences did not correlate with the nuclear cataract grades (r = 0.078, P = 0.558). Intraobserver agreement on AS-OCT (95% limits of agreement [LoA]: -0.049 to +0.045 mm; ICC: 0.999) was better than A-scan US (95%LoA: -0.194 to +0.218 mm; ICC: 0.974). The 95% LoA of interobserver agreement using AS-OCT and A-scan were -0.084 to +0.073 and -0.278 to +0.239 mm, respectively, and the ICCs were 0.996 and 0.960, respectively. CONCLUSIONS: AS-OCT can be used to measure Lens Thickness in most eyes with clear or opacified Lenses. It appears to be an alternative means of measuring Lens Thickness, particularly when a noncontact method is needed.
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Comparison of Lens Thickness measurements using the anterior segment optical coherence tomography and A-scan ultrasonography.
Investigative ophthalmology & visual science, 2008Co-Authors: Yangfa Zeng, Xing Liu, Yizhi Liu, Chuying Chen, Yuanling XiaAbstract:To assess Lens Thickness (LT) measurements with anterior segment optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US). Enrolled were 66 eyes of 48 phakic elderly volunteers aged > or = 50 years and 56 eyes of 56 young participants aged 18 to 40 years. LT was measured with the internal manual caliper tools in AS-OCT. The A-scan US measurements were based on an average of 10 consecutive automatic measurements. Reproducibility was assessed by three measurements each with AS-OCT and A-scan US independently obtained by two observers who were masked to one another's results. The failure rates of AS-OCT and A-scan US were 9.1% and 7.6%, respectively, in elderly subjects, but no failure was observed in young subjects. The LT values measured by AS-OCT were significantly greater than A-scan US; the paired difference was 0.135 mm in elderly and 0.101 mm in young subjects (P < 0.001). These differences did not correlate with the nuclear cataract grades (r = 0.078, P = 0.558). Intraobserver agreement on AS-OCT (95% limits of agreement [LoA]: -0.049 to +0.045 mm; ICC: 0.999) was better than A-scan US (95%LoA: -0.194 to +0.218 mm; ICC: 0.974). The 95% LoA of interobserver agreement using AS-OCT and A-scan were -0.084 to +0.073 and -0.278 to +0.239 mm, respectively, and the ICCs were 0.996 and 0.960, respectively. AS-OCT can be used to measure Lens Thickness in most eyes with clear or opacified Lenses. It appears to be an alternative means of measuring Lens Thickness, particularly when a noncontact method is needed.
Domenico Schianolomoriello - One of the best experts on this subject based on the ideXlab platform.
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agreement between Lens Thickness measurements by ultrasound immersion biometry and optical biometry
Journal of Cataract and Refractive Surgery, 2018Co-Authors: Giacomo Savini, Kenneth J Hoffer, Domenico SchianolomorielloAbstract:Purpose To compare Lens Thickness measurements provided by immersion ultrasound (US) biometry and optical biometry. Setting IRCCS-Fondazione Bietti, Rome, Italy. Design Evaluation of diagnostic technology. Methods Immersion US biometry and optical biometry were performed in a consecutive series of eyes having cataract surgery. Three optical biometers (OA-2000, Aladdin, and Galilei G6) were used. To assess how the differences in Lens Thickness measurements influenced intraocular Lens (IOL) power calculation, the Lens Thickness values were entered into the Olsen formula. Results Eighty-eight eyes were analyzed. Ultrasound immersion biometry yielded significantly higher Lens Thickness values than all of the optical biometers (P Conclusions Lens Thickness measurements by immersion US biometry and optical biometry cannot be considered interchangeable. Minor, but still significant, differences between the 3 optical biometers tested were also found.