376 results match your criteria A-Scan Biometry


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 Jun 7. 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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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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February 2021

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

Health Technol Assess 2021 Feb;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 May 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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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 2020 Apr 8:1120672120914536. 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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Biometry characteristics in congenital cataract patients before surgery in a tertiary eye care centre in Nepal.

Saudi J Ophthalmol 2019 Oct-Dec;33(4):342-346. Epub 2019 Jul 17.

Sagarmatha Choudhary Eye Hospital, Lahan - 3, Siraha, Nepal.

Purpose: To evaluate the anterior segment biometry characteristics in congenital cataract patients before undergoing surgery in a tertiary eye care centre.

Methods: We retrospectively reviewed the charts of congenital cataract patients aged less than 15 years who had undergone the congenital cataract surgery from Jan-Dec, 2015. 451 eyes of 351 patients were reviewed. Read More

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Impact of Different Scan Bodies and Scan Strategies on the Accuracy of Digital Implant Impressions Assessed with an Intraoral Scanner: An In Vitro Study.

J Prosthodont 2020 Apr 16;29(4):309-314. Epub 2019 Dec 16.

Department of Prosthodontics, University Hospital Erlangen, Glueckstraße 11, Erlangen, 91054, Germany.

Purpose: Sufficient data are not currently available on how the various geometries of scan bodies and different scan strategies affect the quality of digital impressions of implants. The purpose of this study was to present new data on these two topics and give clinicians a basis for decision making.

Materials And Methods: A titanium master model containing three Nobelreplace Select™ implants (Nobelbiocare Services AG, Zurich, Switzerland) was digitized using an ATOS industrial noncontact scanner. Read More

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The Effects of High Lighting on the Development of Form-Deprivation Myopia in Guinea Pigs.

Invest Ophthalmol Vis Sci 2019 10;60(13):4319-4327

Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China.

Purpose: To investigate the effects of high ambient lighting on refraction and ocular biometry in guinea pig models of form-deprivation myopia (FDM).

Methods: Forty 3-week-old guinea pigs were randomly assigned to groups exposed to either high light (HL, 10,000 lux) or normal light (NL, 500 lux) with normal vision or form deprivation. Throughout the 10-week rearing period, animals were exposed to high light or normal light for 12 hours with a 12-hour light/dark cycle. Read More

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October 2019

Frankel 2 appliance versus the Modified Twin Block appliance for Phase 1 treatment of Class II division 1 malocclusion in children and adolescents: .

Angle Orthod 2020 03 15;90(2):202-208. Epub 2019 Oct 15.

Objective: To compare Phase 1 treatment, using the Frankel 2 (FR2) or the modified Twin Block (MTB), for Class II division 1 malocclusion in children and adolescents with respect to: treatment duration, number of appliance breakages, occlusal outcome, and patient and parent perspectives.

Materials And Methods: Sixty participants with a Class II division 1 malocclusion were randomly assigned to either the FR2 or MTB appliance in a two-armed parallel randomized clinical trial with an allocation ratio of 1 to 1. Time to achieve a Class I incisor relationship was the primary outcome. Read More

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Cataract Surgery Practices in the Republic of Korea: A Survey of the Korean Society of Cataract and Refractive Surgery 2018.

Korean J Ophthalmol 2019 Oct;33(5):451-457

Department of Ophthalmology, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.

Purpose: To describe current cataract surgery practice patterns and changing trends among Korean ophthalmologists.

Methods: A survey of members of the Korean Society of Cataract and Refractive Surgery was performed in July 2018. One hundred and two (12. Read More

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October 2019

The Effect of an Asymmetric Energy Window on Bone Scintigraphy Image Quality.

J Nucl Med Technol 2020 Mar 11;48(1):46-50. Epub 2019 Oct 11.

Nuclear Medicine Department, Royal United Hospitals Bath, Combe Park, Avon, United Kingdom; and

Bone scintigraphy is one of the most common nuclear medicine tests. Previous work investigated the effectiveness of an asymmetric window (ASW) for planar bone scintigraphy using simulation and phantom data. Phantom studies concluded that the ASW improved both the resolution and the contrast-to-noise ratio when imaging objects with high scatter. Read More

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Effect of Visibility of the Ciliary Body Processes on Ocular Biometric Parameters in Patients with Primary Angle Closure.

Jpn J Ophthalmol 2019 Nov 14;63(6):467-473. Epub 2019 Sep 14.

Department of Ophthalmology, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand.

Purpose: To evaluate the differences in ocular biometric parameters between eyes with primary angle closure (PAC) with and without visible ciliary body processes (CBP) (PAC+CBP and PAC-CBP) and normal open-angle controls.

Study Design: Cross-sectional study.

Methods: Eyes with PAC and normal open-angle controls underwent detailed ocular examinations and gonioscopy to determine the visibility of the CBP. Read More

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November 2019

A feasibility study of pulmonary nodule detection by ultralow-dose CT with adaptive statistical iterative reconstruction-V technique.

Eur J Radiol 2019 Oct 7;119:108652. Epub 2019 Sep 7.

Department of Radiology, Peking University Third Hospital, Beijing, China. Electronic address:

Purpose: To evaluate the clinical value of ultralow-dose CT (ULDCT) with adaptive statistical iterative reconstruction-V (ASiR-V) in the detection of pulmonary nodules in a Chinese population.

Method: One hundred eighty-eight patients (16.41 ≤ BMI ≤ 29. Read More

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October 2019

Accuracy of Intraocular Lens Power Calculation in Eyes Filled with Silicone Oil.

Semin Ophthalmol 2019 1;34(5):392-397. Epub 2019 Jul 1.

b Department of Ophthalmology, University of Warmia and Mazury , Olsztyn , Poland.

Silicone oil (SO) is used mainly when managing complex retinal detachments, commonly with proliferative vitreoretinopathy, as well as a hemostatic agent in proliferative diabetic retinopathy. Combined lens exchange and pars plana vitrectomy remains preferred by many surgeons; however, sequential surgery might be advantageous to minimize the postoperative anterior chamber inflammatory response, particularly in proliferative diabetic retinopathy or retinal detachment. The aim of the study was to evaluate the optimal method of intraocular lens (IOL) calculation in eyes filled with SO. Read More

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[Distribution of corneal thickness in the Tunisian population: Study by anterior segment optical coherence tomography].

J Fr Ophtalmol 2019 Oct 1;42(8):874-879. Epub 2019 Jun 1.

Faculté de médecine de Tunis, université Tunis El Manar, hôpital Habib Thameur, 3, rue A. Ben Ayed, 1089 Tunis, Tunisie.

Goals: To describe the distribution of the central corneal thickness (CCT) in the Tunisian population.

Methods: A prospective descriptive study was performed in 201 right eyes of 201 randomly selected healthy Tunisian subjects without glaucoma. We measured the spherical error by autorefraction, the axial length using A-scan ultrasound biometry and the central corneal thickness using anterior segment optical coherence tomography (DRI TRITON OCT). Read More

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October 2019

Improved Refractive Outcomes of Small-Incision Extracapsular Cataract Surgery after Implementation of a Biometry Training Course.

Middle East Afr J Ophthalmol 2019 Jan-Mar;26(1):17-22

Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand.

Purpose: To determine whether a biometry training course could improve refractive outcomes of patients undergoing manual small-incision extracapsular cataract surgery (SICS).

Materials And Methods: This was a prospective, interventional, cohort study at the Pacific Eye Institute, Fiji. SICS refractive outcomes were evaluated before and after a structured biometry teaching course. Read More

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Early Changes of Ocular Biological Parameters in Rhesus Monkeys After Scleral Cross-linking With Riboflavin/Ultraviolet-A.

J Refract Surg 2019 May;35(5):333-339

Purpose: To evaluate the ocular biological parameter difference between scleral corneal cross-linking (CXL) and control eyes in rhesus monkeys by using a rebound tonometer, A-scan ultrasonography, retinoscopy, optical coherence tomography, and electroretinography (ERG).

Methods: Six rhesus monkeys were used in this study, with ages ranging from 3 to 3.5 years. Read More

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Strain-Dependent Differences in Sensitivity to Myopia-Inducing Stimuli in Guinea Pigs and Role of Choroid.

Invest Ophthalmol Vis Sci 2019 03;60(4):1226-1233

Berkeley Myopia Research Group, Vision Science Program and School of Optometry, University of California, Berkeley, California, United States.

Purpose: To investigate differences in sensitivity to myopia-inducing stimuli of two strains of pigmented guinea pigs.

Methods: Eleven-day-old animals (New Zealand [NZ], n = 24 and Elm Hill strains [EH], n = 26) wore either a +2 or -2 diopter (D) lens over one eye and a plano lens over the fellow eye for 5 days; other 10-day-old EH (n = 9) and 7-day-old NZ (n = 9) animals were monocularly form-deprived (FD) for 28 days. Choroidal thickness and axial length were measured using A-scan ultrasonography at baseline and after 1 and 5 days for optical defocus treatments, and at baseline and after 28 days for the FD treatment. Read More

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[Usefulness of contralateral oriented fixation in ocular axial length measurement by ultrasound A-scan: A prospective study of 50 eyes].

J Fr Ophtalmol 2019 Apr 21;42(4):e193-e194. Epub 2019 Mar 21.

Service d'Ophtalmologie, Hôpital militaire d'instruction Med-V, Rabat, Maroc.

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Accuracy of swept-source optical coherence tomography based biometry for intraocular lens power calculation: a retrospective cross-sectional study.

BMC Ophthalmol 2019 Jan 24;19(1):30. Epub 2019 Jan 24.

Catholic Institute for Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

Background: To evaluate the accuracy of biometric measurements by a swept-source optical coherence tomography (SS-OCT) based biometry for intraocular lens (IOL) power calculation.

Methods: This retrospective observational study enrolled 431 patients undergoing cataract surgery. The charts were reviewed to investigate the failure rate of axial length (AL) measurement of the SS-OCT biometer, partial coherence interferometry (PCI), and A-scan ultrasonography (US) according to cataract type and severity. Read More

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January 2019

The Association Between Retinopathy of Prematurity and Ocular Growth.

Invest Ophthalmol Vis Sci 2019 01;60(1):98-106

Department of Ophthalmology, Medical School, University of Thessaly, Larissa, Greece.

Purpose: The purpose of this study was to prospectively investigate the association between retinopathy of prematurity (ROP) and ocular growth in premature infants during the earliest weeks of life.

Methods: Premature infants in the national ROP screening program were recruited and examined at 1- or 2-week intervals between 30 and 38 weeks of postmenstrual age. One hundred infants with gestational age (GA) between 24 and 35 weeks (30. Read More

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January 2019

Matching the LenStar optical biometer to A-Scan ultrasonography for use in small animal eyes with application to tree shrews.

Exp Eye Res 2019 03 27;180:250-259. Epub 2018 Dec 27.

Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, AL, USA. Electronic address:

We describe an analysis strategy to obtain ultrasonography-matched axial dimensions of small animal eyes using the LenStar biometer. The LenStar optical low-coherence reflectometer is an attractive device for animal research due to its high precision, non-invasiveness, and the ability to measure the axial dimensions of cornea, anterior chamber, lens, vitreous chamber, and axial length. However, this optical biometer was designed for clinical applications in human eyes and its internal analysis provides inaccurate values when used on small eyes due to species-dependent differences in refractive indices and relative axial dimensions. Read More

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Effects of the Tyrosinase-Dependent Dopaminergic System on Refractive Error Development in Guinea Pigs.

Invest Ophthalmol Vis Sci 2018 09;59(11):4631-4638

School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Ophthalmology, and Vision Science, Wenzhou, Zhejiang, China.

Purpose: To determine if myopia in albino guinea pigs is linked to altered ocular dopamine (DA) levels in both the retinal and uveal dopaminergic systems.

Methods: Retina and retinal pigment epithelium (RPE)/choroid were dissected from eyes of 2-week-old albino myopic (AM) and pigmented hyperopic (PH) guinea pigs. The levels of DA, dihydroxy-phenyl acetic acid (DOPAC), and homovanillic acid (HVA) were determined. Read More

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September 2018