394 results match your criteria A-Scan Biometry


Agreement analysis of Lenstar with other four techniques of biometry before cataract surgery.

Int Ophthalmol 2022 May 11. Epub 2022 May 11.

Department of Ophthalmology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, Jiangsu, China.

Purpose: To test whether some biometry measurements provided by the Lenstar LS900 compared well with the AL-Scan, Pentacam rotating Scheimpflug camera, Ultrasound Biomicroscopy (UBM) and Tomey EM-3000.

Methods: Two hundred and one patients having routine cataract surgery had standard preoperative assessment. In this clinical study, the axis length (AL) and lens thickness (LT) were taken by Lenstar LS900 and AL-Scan; anterior chamber depth (ACD) was taken by Lenstar LS900, A-Scan, Pentacam and UBM; central corneal thickness (CCT) was taken by Lenstar LS900, Pentacam and Tomey EM-3000. Read More

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The ocular biometry characteristics of young patients with primary angle-closure glaucoma.

BMC Ophthalmol 2022 Apr 2;22(1):150. Epub 2022 Apr 2.

Eye Center of Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, China.

Background: Although primary angle-closure glaucoma (PACG) mainly occurs in elderly people, diagnosis of PACG in young patients is not uncommon. So far, there is no article specialized on the ocular anatomical characteristics in these patients.In this study, ocular anatomical characteristics in young PACG patients are analyzed. Read More

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Comparison of uveal parameters between acute primary angle-closure eyes and fellow eyes in South Indian population.

Indian J Ophthalmol 2022 Apr;70(4):1232-1238

Department of Biostatistics, Aravind Eye Hospital and Postgraduate Institute of Ohthalmology, Tamil Nadu, India.

Purpose: : To analyze the ocular biometric parameters of eyes with acute primary angle closure (APAC) as compared to fellow eyes.

Methods: : A cross-sectional study was conducted on 27 patients presenting with recent onset APAC to a tertiary eye institute in India. Anterior and posterior ocular biometric parameters were measured simultaneously by anterior segment optical coherence tomography (AS-OCT), A-scan, ultrasound biomicroscopy (UBM), and B-mode ultrasonogram (USG). Read More

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Comparing low-coherence interferometry and A-scan ultrasonography in measuring ocular axial dimensions in young rhesus monkeys.

Exp Eye Res 2022 04 22;217:108937. Epub 2022 Jan 22.

College of Optometry, University of Houston, Houston, TX, USA. Electronic address:

We investigated a commercial low-coherence interferometer (LenStar LS 900 optical biometer) in measuring young rhesus monkey ocular dimensions. Ocular biometry data obtained using a LenStar and an A-scan ultrasound instrument (OPT-scan 1000) from 163 rhesus monkeys during 20-348 days of age were compared by means of coefficients of concordance and 95% limits of agreement. Linear regression was employed to examine and analyze the inter-instrument discrepancies. Read More

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High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye.

Sci Rep 2022 01 19;12(1):992. Epub 2022 Jan 19.

Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.

This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12. Read More

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January 2022

Differences in Axial Length and IOL Power Based on Alternative A-Scan or Fellow-Eye Biometry in Macula-Off Rhegmatogenous Retinal Detachment Eyes.

Ophthalmol Ther 2022 Feb 8;11(1):347-354. Epub 2021 Dec 8.

Department of Ophthalmology and Vision Science, Eye, Ear, Nose and Throat Hospital of Fudan University, 83# Fenyang Road, Xuhui District, Shanghai, 200031, China.

Introduction: This study was performed to observe the potential refractive prediction error based on alternative A-scan ultrasound and fellow-eye biometry for phacovitrectomy in macula-off rhegmatogenous retinal detachment (RRD) eyes.

Methods: Phakic macula-off RRD eyes without axial length (AL) measurements obtained using IOLMaster were included. Vitrectomy without lens extraction was performed for RRD repair. Read More

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February 2022

Comparative analysis of measurements of the anterior segment and the axial length parameters of the eyeball obtained with optical and ultrasound technique.

Expert Rev Med Devices 2021 Dec 3;18(12):1245-1253. Epub 2021 Dec 3.

Chair and Clinical Department of Ophthalmology, Division of Medical Science in Zabrze, Medical University of Silesia, Katowice, Poland.

Purpose: To compare anterior chamber depth (ACD), keratometry (K1, K2), central corneal thickness (CCT), and axial length (AL) measured by four different devices.

Material And Methods: 150 eyes qualified for cataract surgery were included in the study. Four devices: IOL Master 500, OCT CASIA2, Dual Scheimpflug Analyzer Galilei G6, and Quantel Compact Touch ultrasound biometer, were compared. Read More

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December 2021

Ocular Biometry of Primary Angle-Closure Disease in Younger Patients.

Front Med (Lausanne) 2021 3;8:772578. Epub 2021 Nov 3.

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

The purpose of this study was to analyze the ocular biometric parameters of primary angle-closure disease (PACD) in younger patients and compare them with those of elderly patients. This clinic-based, cross-sectional study included 154 eyes of 154 patients with PACD, consisting of 77 eyes of patients aged 40 years or younger and 77 eyes of patients older than 40. The PACD case definition was compatible with the ISGEO definition. Read More

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November 2021

Normative Data of Ocular Biometry, Optical Coherence Tomography, and Electrophysiology Conducted for Cynomolgus Macaque Monkeys.

Transl Vis Sci Technol 2021 11;10(13):14

Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.

Purpose: To present normative data of optical coherence tomography (OCT) parameters, electrophysiological tests, and optical biometry conducted for cynomolgus monkeys.

Methods: Multimodal examinations were performed for 11 adult cynomolgus monkeys (Macaca fascicularis, weighing 2.6-7. Read More

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November 2021

A-scan ultrasound in ophthalmology: A simulation tool.

Med Eng Phys 2021 11 21;97:18-24. Epub 2021 Sep 21.

Department of Electrical and Computer Engineering, Polo II - University of Coimbra, Coimbra 3030-790, Portugal; Centre for Mechanical Engineering, Materials and Processes, University of Coimbra, Coimbra 3030-788, Portugal.

In the present study, we developed a computational tool for simulating the ophthalmological applications of A-scan ultrasound, including cataract characterisation and biometry. A-scan biometry is used to measure the axial length (AL) of the eye before cataract surgery to calculate the refractive power of the intraocular lens to be implanted. Errors in the measurement of the AL lead to post-surgical refractive errors. Read More

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November 2021

Bilateral cataracts extraction by lens aspiration and foldable intraocular lens implantation in a black kite ().

Open Vet J 2021 Jul-Sep;11(3):441-446. Epub 2021 Aug 25.

Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand.

Background: Cataract is a common disease in the lenses of birds. Cataract surgery is the recommended treatment for birds with visual impairment. Nevertheless, reports of the results of cataract surgery in birds are limited. Read More

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December 2021

Ocular Biometry and Intra Ocular Lens Power among Cataract Patients in Rural Eastern Ethiopia.

Ethiop J Health Sci 2021 Jul;31(4):823-830

Associate Professor of Ophthalmology, Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia.

Background: The objective of the study was to report on the main parameters of ocular biometry and Intraocular lens (IOL)power of patients attending a cataract surgical campaign in Eastern Ethiopia.

Methods: The study was a cross-sectional study on 765 eyes which were eligible for cataract surgery during a mass cataract surgical campaign conducted from April 04 to April 10, 2018 at Bisidimo Hospital, Eastern Ethiopia. Ocular biometric parameters were measured by automated keratorefractometer and Sonomed A-Scan (Model 300AP) using contact applanation method. Read More

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Ocular Biometric Risk Factors for Progression of Primary Angle Closure Disease: The Zhongshan Angle Closure Prevention Trial.

Ophthalmology 2022 03 8;129(3):267-275. Epub 2021 Oct 8.

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China.

Purpose: To assess baseline ocular biometric risk factors for progression from primary angle closure suspect (PACS) to primary angle closure (PAC) or acute angle closure (AAC).

Design: Prospective, observational study.

Participants: Six hundred forty-three mainland Chinese with untreated PACS. Read More

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Application and repeatability of ocular biometric measures for gaze position calibration in children.

Ophthalmic Physiol Opt 2021 09 11;41(5):1144-1151. Epub 2021 Aug 11.

Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana.

Purpose: The purpose of this study was to investigate the utility of two ocular biometric measurements to obtain Hirschberg ratios (HRs) in a binocularly normal paediatric population, and to assess the repeatability of this approach.

Methods: Ocular biometry data from 80 participants (aged 5 to 14 years) was obtained using the KM-1 LED manual keratometer and the Tomey Biometer AL-100 A-scan. HRs were calculated from corneal curvature and anterior chamber depth measurements in the horizontal and vertical meridians of each eye using a regression equation based on a geometric optics model. Read More

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September 2021

Diagnostic performance of cerebroplacental and umbilicocerebral ratio in appropriate for gestational age and late growth restricted fetuses attempting vaginal delivery: a multicenter, retrospective study.

J Matern Fetal Neonatal Med 2021 Jun 8:1-7. Epub 2021 Jun 8.

Fetal Medicine Unit, Maternal and Child Health and Development Network, Department of Obstetrics and Gynecology, University Hospital 12 de Octubre, Complutense University of Madrid, Madrid, Spain.

Background: Cerebroplacental Doppler studies have been advocated to predict the risk of adverse perinatal outcome (APO) irrespective of fetal weight.

Objective: To report the diagnostic performance of cerebroplacental (CPR) and umbilicocerebral (UCR) ratios in predicting APO in appropriate for gestational age (AGA) fetuses and in those affected by late fetal growth restriction (FGR) attempting vaginal delivery.

Study Design: Multicenter, retrospective, nested case-control study between 1 January 2017 and January 2020 involving five referral centers in Italy and Spain. Read More

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Extended measuring depth dual-wavelength Fourier domain optical coherence tomography.

Biomed Tech (Berl) 2021 Dec 7;66(6):557-562. Epub 2021 Jun 7.

Stiftungslabor für Grundlagen-forschung, Universitäts-Augenklinik Tübingen, Tübingen, Germany.

In this work an enhanced wide range dual band spectral domain optical coherence tomography technique (SD-OCT) is presented to increase the depth and accuracy of the measurement of optical A-scan biometry. The setup uses a Michelson interferometer with two wide-spectrum Superluminescent Diodes (SLD). The emissions of the SLDs are filtered by a long-pass filter (900 nm) in front of the reference mirror. Read More

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December 2021

The Heritability of Primary Angle Closure Anatomic Traits and Predictors of Angle Closure in South Indian Siblings.

Am J Ophthalmol 2021 10 13;230:188-199. Epub 2021 May 13.

Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA. Electronic address:

Purpose: To estimate the heritability of ocular biometric and anterior chamber morphologic parameters and to determine predictors of angle closure concordance in South Indian probands with angle closure and their siblings DESIGN: Prospective observational cohort study METHODS: Subjects received a standardized ophthalmic examination, A-scan ultrasonography, pachymetry, and anterior segment optical coherence tomography (ASOCT) imaging. Heritability was calculated using residual correlation coefficients adjusted for age, sex, and home setting. Concordant sibling pairs were defined as both proband and sibling with angle closure. Read More

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October 2021

A-scan biometry, phacoemulsification, and foldable intraocular lens implantation in a young orangutan ().

Open Vet J 2021 Jan-Mar;11(1):121-127. Epub 2021 Feb 13.

Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand.

Background: Cataracts are the major cause of visual impairment in animals which can be curable by surgical treatment. Phacoemulsification is the standard technique for cataract treatment that is applied to almost all species with a high success rate.

Case Description: A 2-year-old intact female orangutan () was presented for the study having bilateral opacity of the lenses, for 2 weeks. Read More

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October 2021

Comparison of A-Scan ultrasonography and the Lenstar optical biometer in Guinea pig eyes.

Exp Eye Res 2021 06 20;207:108578. Epub 2021 Apr 20.

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China. Electronic address:

Objective: To compare the biometric parameters provided by A-scan ultrasonography and the Lenstar optical biometer in guinea pig eyes, including anterior segment depth (ASD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL), and differences of them between treated form deprivation (FD) eyes and untreated fellow eyes after 4 weeks of FD.

Methods: Three-week-old guinea pigs (N = 41) were subjected to biometric measurements before monocular FD (baseline) and after a 4-week FD. Statistical analyses including within-subject standard deviation (SD), coefficient of variation (CV), and intraclass correlation coefficient (ICC), used to evaluate repeatability for both the A-scan ultrasonography and the Lenstar individually, and correlation and Bland-Altman analyses were used to assess agreement between the two methods. Read More

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Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis.

Health Technol Assess 2021 02;25(15):1-190

The Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Background: Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

Objectives: We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. Read More

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February 2021

Preoperative measurements for cataract surgery: a comparison of ultrasound and optical biometric devices.

Int Ophthalmol 2021 Apr 28;41(4):1521-1530. Epub 2021 Jan 28.

Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada.

Purpose: To evaluate differences in preoperative measurements and refractive outcomes between ultrasound and optical biometry when using the Barrett Universal II intraocular lens (IOL) power formula.

Methods: In this consecutive case series, cataract extraction and IOL implantation cases from two surgical centers in Toronto, Canada, were recruited between January 2015 and July 2017. Differences between ultrasound (applanation or immersion A-scan) and optical biometry (IOLMaster 500) were compared for axial length (AL), anterior chamber depth and refractive outcomes. Read More

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Influence of measurement differences of anterior chamber depth and axial length on lens thickness evaluation in cataract patients: a comparison of two tests.

BMC Ophthalmol 2020 Dec 7;20(1):481. Epub 2020 Dec 7.

Department of Ophthalmology, the First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China.

Background: The purpose of this study was to investigate the agreement of lens thickness (LT) measurements made by contact A-scan ultrasonography and Lenstar LS900 as well as the influence of anterior chamber depth (ACD) and axial length (AL) measurement differences on LT measurement in cataract patients in the two techniques.

Methods: 1247 cataract patients (1247 eyes) participated in this retrospective cross-sectional study. Ocular biometric measurements were performed with Lenstar LS900 and A-scan ultrasonography respectively, and the measured results of AL, ACD and LT were compared using Pearson correlation coefficients (r) and Bland-Altman analyses. Read More

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December 2020

The Development of Ocular Biometric Parameters in Premature Infants without Retinopathy of Prematurity.

Curr Eye Res 2021 05 16;46(5):746-750. Epub 2020 Nov 16.

Department of Ophthalmology, Northwest Women's and Children's Hospital, Xi 'An, China.

Purpose: The aim of this study was to investigate the developmental tendencies and distribution of ocular biometric parameters in premature infants without retinopathy of prematurity (ROP). Axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and vitreous length (VL) were measured, and their relationships with birth weight (BW) and postmenstrual age (PMA) were analyzed during their earliest weeks of life.

Methods: This cross-sectional cohort study included 633 premature infants. Read More

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Added Value of Digital over Analog PET/CT: More Significant as Image Field of View and Body Mass Index Increase.

J Nucl Med Technol 2020 Dec 4;48(4):354-360. Epub 2020 Sep 4.

Division of Nuclear Medicine, Department of Radiology, Saint Louis University, St. Louis, Missouri; and.

The digital PET/CT scanner with digital photon-counting technique promises a shorter scan time, improved small-lesion detectability, and reduced radiation dose for the PET and CT portions of the exam while improving image quality. In this single-institution retrospective review study, 84 participants who had undergone PET/CT on both analog and digital scanners were analyzed. The aim was to evaluate the impact of image field of view (FOV) and body mass index (BMI) on the digital compared with the analog PET/CT scanners. Read More

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December 2020

Ocular Biometric Determinants of Anterior Chamber Angle Width in Chinese Americans: The Chinese American Eye Study.

Am J Ophthalmol 2020 12 28;220:19-26. Epub 2020 Jul 28.

Southern California Eye Institute, CHA Hollywood Presbyterian Medical Center, Los Angeles, California, USA.

Purpose: We sought to investigate anatomic mechanisms of angle narrowing by assessing ocular biometric determinants of anterior chamber angle width.

Design: Population-based cross-sectional study.

Methods: Subjects ≥50 years of age from the Chinese American Eye Study underwent a comprehensive ocular examination, including anterior segment optical coherence tomography imaging and ultrasound A-scan. Read More

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December 2020

Anterior Chamber Angle, Intraocular Pressure, and Globe Biometric Parameters in the Children with β-Thalassemia Major.

J Curr Glaucoma Pract 2020 Jan-Apr;14(1):30-36

Ophthalmology Department, Al-Azher University, Faculty of Medicine, Cairo, Egypt.

Background: To evaluate the intraocular pressure (IOP), anterior chamber angle (ACA), and globe biometric parameters in β-thalassemia major children and the correlations of these changes.

Materials And Methods: Eighty-four eyes were included (42 eyes of thalassemia patients and 42 eyes of control). All participates underwent head circumference and height measurements, full ophthalmic examination, anterior segment optical coherence tomography (AS-OCT), and A-scan biometry. Read More

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Comparison of 13 formulas for IOL power calculation with measurements from partial coherence interferometry.

Br J Ophthalmol 2021 04 10;105(4):484-489. Epub 2020 Jun 10.

Eye Clinic of Genoa, Policlinico San Martino, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI), University of Genoa, Genoa, Italy.

Background/aims: To compare the accuracy of 13 formulas for intraocular lens (IOL) power calculation in cataract surgery.

Methods: In this retrospective interventional case series, optical biometry measurements were entered into these formulas: Barrett Universal II (BUII) with and without anterior chamber depth (ACD) as a predictor, EVO 2.0 with and without ACD as a predictor, Haigis, Hoffer Q, Holladay 1, Holladay 2AL, Kane, Næser 2, Pearl-DGS, RBF 2. Read More

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How often do we incidentally find a fetal abnormality at the routine third-trimester growth scan? A population-based study.

Am J Obstet Gynecol 2020 12 3;223(6):919.e1-919.e13. Epub 2020 Jun 3.

Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom. Electronic address:

Background: Third-trimester scans are increasingly used to try to prevent adverse outcomes associated with abnormalities of fetal growth. Unexpected fetal malformations detected at third-trimester growth scans are rarely reported.

Objective: To determine the incidence and type of fetal malformations detected in women attending a routine third-trimester growth scan. Read More

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December 2020

Evaluation of biometric parameters in phacomorphic glaucoma and mature cataracts.

Eur J Ophthalmol 2021 May 8;31(3):1101-1106. Epub 2020 Apr 8.

University of Health Sciences, Ulucanlar Eye Education and Research Hospital, Ankara, Turkey.

Purpose: The aims of this study were to compare the biometric parameters and axial lengths of eyes with phacomorphic glaucoma and mature cataract and to identify differences that might predispose to development of phacomorphic glaucoma.

Methods: Three hundred forty-two patients were enrolled in this retrospective study. The eyes were divided into four groups-Group (G)1: phacomorphic glaucoma ( = 29), G2: mature cataract ( = 313), G3: contralateral phacomorphic glaucoma ( = 29), and G4: contralateral mature cataract ( = 313). Read More

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