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https://www.readbyqxmd.com/read/28339777/support-system-for-fine-focusing-and-astigmatism-correction-using-an-auditory-signal-in-scanning-electron-microscopy
#1
Eisaku Oho, Kazuhiko Suzuki, Sadao Yamazaki
The current study describes a new support system for fine focusing and near-perfect astigmatism correction for scanning electron microscopy (SEM). The signal-to-noise ratio of a series of SEM images obtained from fast scan rates (TV scan) was adopted as a new metric for evaluating focus. Measured signal-to-noise ratio values were converted to an acoustic signal (sound wave frequency) using digital image processing techniques, enabling the SEM user to evaluate image focus using the auditory modality. Accurate focusing and correcting astigmatism in general-purpose SEM is traditionally time-consuming and difficult...
February 24, 2017: Microscopy
https://www.readbyqxmd.com/read/28328814/clinical-outcomes-of-new-toric-trifocal-diffractive-intraocular-lens-in-patients-with-cataract-and-stable-keratoconus-six-months-follow-up
#2
Doroodgar Farideh, Sanginabadi Azad, Niazi Feizollah, Niazi Sana, Alinia Cyrus, Ghoreishi Mohammad, Baradaran-Rafii Alireza
PURPOSE: To evaluate the clinical results of toric trifocal diffractive intraocular lens in eyes with cataract and mild keratoconus. METHODS: Five keratoconus patients (10 eyes) that had bilateral AT LISA 939 implantation were selected and had followed in 3-time horizons of 1, 3, and 6 months. Patients were 46 to 65 years old age, corneal astigmatism of (2.00 D at 6.75 D) and cataract that all of them needed cataract surgery. The distance, intermediate and near visual acuities, defocus curve, ocular aberrations, contrast sensitivity, were measured as effectiveness criteria...
March 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28326601/quantitative-analysis-of-eyes-and-other-optical-systems-in-linear-optics
#3
William F Harris, Tanya Evans, Radboud D van Gool
PURPOSE: To show that 14-dimensional spaces of augmented point P and angle Q characteristics, matrices obtained from the ray transference, are suitable for quantitative analysis although only the latter define an inner-product space and only on it can one define distances and angles. The paper examines the nature of the spaces and their relationships to other spaces including symmetric dioptric power space. METHODS: The paper makes use of linear optics, a three-dimensional generalization of Gaussian optics...
March 21, 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/28324117/accommodation-responds-to-optical-vergence-and-not-defocus-blur-alone
#4
Antonio J Del Águila-Carrasco, Iván Marín-Franch, Paula Bernal-Molina, José J Esteve-Taboada, Philip B Kruger, Robert Montés-Micó, Norberto López-Gil
Purpose: To determine whether changes in wavefront spherical curvature (optical vergence) are a directional cue for accommodation. Methods: Nine subjects participated in this experiment. The accommodation response to a monochromatic target was measured continuously with a custom-made adaptive optics system while astigmatism and higher-order aberrations were corrected in real time. There were two experimental open-loop conditions: vergence-driven condition, where the deformable mirror provided sinusoidal changes in defocus at the retina between -1 and +1 diopters (D) at 0...
March 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28318725/-comparison-of-refraction-with-or-without-cycloplegia-using-retinomax-%C3%A2-or-plusoptix-%C3%A2-devices
#5
E Bui Quoc, S Guilmin Crepon, S Tinguely, G Lavallee, G Busquet, M Angot, L Vera
PURPOSE: To evaluate the refraction in children measured with Plusoptix(®) without cycloplegia vs. Retinomax(®) apparatus with cycloplegia. PATIENTS AND METHODS: Measure of refraction with Plusoptix(®) in children>1year old referred for systematic vision screening, then measurement after cycloplegia with cyclopentolate by the Retinomax(®) device. RESULTS: Thirty-three children were included, i.e. 66eyes. Mean age was 40.7months (minimum 12; maximum 114)...
March 16, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28318639/enhancement-after-small-incision-lenticule-extraction-incidence-risk-factors-and-outcomes
#6
Yu-Chi Liu, Mohamad Rosman, Jodhbir S Mehta
PURPOSE: To report the incidence, risk factors, and outcomes of enhancement after small-incision lenticule extraction (SMILE). DESIGN: Retrospective cohort study. PARTICIPANTS: Five hundred twenty-four eyes of 307 patients who underwent SMILE at Singapore National Eye Center between February 2012 and March 2016. METHODS: The data collected included patient age at primary SMILE, gender, race, preoperative and postoperative manifest refraction spherical equivalent (MRSE), preoperative and postoperative uncorrected distance visual acuity and corrected distance visual acuity, the occurrence of suction loss during the procedure, and the need for enhancement...
March 15, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28317667/small-incision-lenticule-extraction-in-a-patient-with-congenital-nystagmus
#7
Bu Ki Kim, Su Joung Mun, Dae Gyu Lee, Hyun Tae Choi, Young Taek Chung
We report a case of a 23-year-old woman with congenital nystagmus who had small-incision lenticule extraction (SMILE) procedure to correct refractive errors. The manifest refraction was -5.50 -1.75 × 180 in the right eye, -5.0 -2.50 × 180 in the left eye, and the patient presented with horizontal pendular nystagmus with an amplitude range of 5 to 10 degrees. Uneventful simultaneous bilateral small-incision lenticule extraction was performed. Six months postoperatively, the uncorrected distance visual acuity was 20/18 with -0...
January 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/28316192/-effect-of-optical-zone-diameter-on-corneal-biomechanical-properties-after-small-incision-lenticule-extraction
#8
P H Wei, Y Wang, H Li, R Dou, L Y Li, W Zhao, J M Zhang
Objective: To investigate the effect of optical zone diameter on corneal biomechanical properties after small incision lenticule extraction (SMILE). Methods: In this prospective case-control study, 62 eyes of 42 patients with myopia and myopic astigmatism that had undergone SMILE procedure were divided into 2 groups according to the optical zone (OZ) diameter: group A, 31 eyes of 19 patients, OZ= 6.5 mm; group B, 31eyes of 23 patients, OZ=6.0 mm. These patients were examined for corneal hysteresis (CH) and corneal resistance factor (CRF) with the Ocular Response Analyzer (ORA) preoperatively and at 1 week, 1 month and 3 months postoperatively; at the same time, the central corneal thickness-corrected indices of DifCH and DifCRF were calculated...
March 11, 2017: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
https://www.readbyqxmd.com/read/28301857/structural-and-functional-characterization-of-benign-fleck-retina-using-multimodal-imaging
#9
Srividya Neriyanuri, Chetan Rao, Rajiv Raman
PURPOSE: To report structural and functional features in a case series of benign fleck retina using multimodal imaging. METHODS: Four cases with benign fleck retina underwent complete ophthalmic examination that included detailed history, visual acuity, and refractive error testing, FM-100 hue test, dilated fundus evaluation, full field electroretinogram, fundus photography with autofluorescence, fundus fluorescein angiography, and swept-source optical coherence tomography...
April 2017: Retinal Cases & Brief Reports
https://www.readbyqxmd.com/read/28300736/the-melaka-hospital-cataract-complications-study-analysis-of-12-992-eyes
#10
Thanigasalam Thevi, Zin Maizura, Adinegara Lutfi Abas
INTRODUCTION: As in all surgeries, complications during cataract surgery are unavoidable and cause distress to the surgeon and the patient. This study was conducted to know the factors contributing to complications in our settings, to be able to counsel patients about complications and outcomes and to reduce litigations. MATERIALS AND METHODS: The secondary data analysis was conducted using the National Eye Database from 2007 to 2014. Demographic features, ocular comorbidities, technique of surgery, grade of surgeons, types of intraoperative complications, and reasons for not obtaining good visual acuity following intraoperative complications were studied...
January 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28300735/comparison-of-femtosecond-laser-assisted-descemetic-and-predescemetic-lamellar-keratoplasty-for-keratoconus
#11
Yan Lu, Ana Beatriz Diniz Grisolia, Yi-Rui Ge, Chun-Yan Xue, Qian Cao, Li-Ping Yang, Zhen-Ping Huang
PURPOSE: The purpose of this study is to compare the outcomes following femtosecond laser-assisted deep anterior lamellar keratoplasty (DALK) with 75% of stromal dissection (predescemetic group) and femtosecond laser-assisted DALK using big-bubble technique with total stromal resection (descemetic group) for the treatment of keratoconus. SUBJECTS AND METHODS: Twenty eyes of 17 patients with keratoconus were studied. There were 10 eyes of 9 patients in predescemetic group and 10 eyes of 8 patients in descemetic group...
January 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28298709/prevalence-of-corneal-astigmatism-in-an-nhs-cataract-surgery-practice-in-northern-ireland
#12
David S Curragh, Patrick Hassett
PURPOSE: Post-operative corneal astigmatism following cataract surgery can leave the patient with visual impairment. Correcting it at the time of surgery with a toric intraocular lens (TIOL) can give patients a better final visual outcome. The purpose was to determine the prevalence of corneal astigmatism in a cataract population and assess the demand for TIOL. METHODS: Keratometric data was collected and analyzed for all patients who attended for routine cataract surgery under the care of a single surgeon based in Altnagelvin Area Hospital, Northern Ireland (NI)...
January 2017: Ulster Medical Journal
https://www.readbyqxmd.com/read/28293434/visual-motor-and-perceptual-task-performance-in-astigmatic-students
#13
Erin M Harvey, J Daniel Twelker, Joseph M Miller, Tina K Leonard-Green, Kathleen M Mohan, Amy L Davis, Irene Campus
Purpose. To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. Methods. Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D) or bilateral astigmatism group (right and left eye ≥ 1.00 D) based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI) and Visual Perception (VMIp)...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28292778/small-incision-guarded-hydroaspiration-of-iris-lesions
#14
Arun D Singh
AIM: To describe the technique and results of a minimally invasive surgical technique for resection of small iris lesions. METHODS: Consecutive case series of 22 patients with localised, small iris lesions that were resected using the described surgical technique that composed of multiple, small corneal incisions created to allow for internal iris resection with 23-gauge horizontal vitrectomy scissors, followed by guarded tumour aspiration through a clear plastic tubing (diameter 3...
March 14, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28291554/implantation-of-posterior-chamber-phakic-intraocular-lens-for-myopia-and-hyperopia%C3%A2-%C3%A2-long-term-clinical-outcomes
#15
H Kocová, E Vlková, L Michalcová, O Motyka
PURPOSE: To evaluate long-term refractive outcomes of implantable collamer lens (ICL) implantation and late postoperative complications. METHODS: We assessed outcomes of patients who underwent ICL implantation (type ICM V4 for myopia, ICH V3 for hyperopia, TICM V4 for astigmatism) in our department between 1998 and 2013. It comprised 62 eyes (40 myopic and 22 hyperopic). The average follow-up period was 10.5 years. We evaluated: uncorrected and best-corrected visual acuity (UCVA and BCVA), spherical equivalent (SE), ICL vault, endothelial cell density and late postoperative complications...
March 11, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28290963/longitudinal-outcomes-of-u-s-air-force-pilot-applicants-with-waivered-astigmatism
#16
David E Andrus, Jared T Haynes, Steven T Wright
BACKGROUND: Current U.S. Air Force medical standards allow applicants to enter pilot training with up to 1.50 D of astigmatism. However, waivers are considered for individuals with up to 3.00 D of astigmatism. Although typically a benign finding, higher levels of astigmatism may be progressive and can be associated with corneal ectasia (e.g., keratoconus or pellucid marginal degeneration) leading to reduced visual acuity with spectacles and/or soft contact lenses. The goal of this study was to evaluate the long-term outcomes of pilot applicants waivered into training with astigmatism exceeding the aeromedical standard...
March 2017: Military Medicine
https://www.readbyqxmd.com/read/28289951/distribution-of-the-anterior-posterior-and-total-corneal-astigmatism-in-healthy-eyes
#17
Sepehr Feizi, Mohammad Naderan, Vahid Ownagh, Fatemeh Sadeghpour
PURPOSE: To evaluate the magnitude and axis orientation of the anterior, posterior, and total corneal astigmatism in normal healthy eyes of an Iranian population. METHODS: In a prospective cross-sectional study, ophthalmic and anterior segment parameters of 153 healthy eyes of 153 subjects were evaluated by Galilei dual Scheimpflug analyzer. The magnitude and axis orientation [with-the-rule (WTR), against-the-rule (ATR), and oblique] of the anterior, posterior, and total corneal astigmatism measurements (ACA, PCA, and TCA) were compared according to the age, sex, and other ophthalmic parameters...
March 13, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28289879/-predictability-of-residual-astigmatism-after-implantation-of-posterior-chamber-toric-lenses
#18
D Mies, T Klink, W Eisenbarth, L M Meyer
BACKGROUND: The objective of the study was to examine the predictability of residual astigmatism after cataract surgery and implantation of the posterior chamber aspheric toric lens TECNIS® ZCT, Abott Medical Optic (Ettlingen, Deutschland). MATERIAL AND METHODS: The retrospective study included a total of 88 patient eyes undergoing a cataract operation with a toric lens implantation between March 2014 and October 2015. The inclusion criteria were a regular astigmatism of at least 0...
March 13, 2017: Der Ophthalmologe: Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
https://www.readbyqxmd.com/read/28285388/effect-of-iris-registration-on-visual-outcome-in-wavefront-guided-lasek-for-myopic-astigmatism
#19
Jong Joo Lee, Mee Kum Kim, Won Ryang Wee
PURPOSE: This study aimed to investigate the effect of iris registration (IR) on visual outcomes in wavefront-guided LASEK for myopic astigmatism. METHODS: The retrospective chart review was performed for wavefront-guided LASEK using VISX Star S4 in patients with myopic astigmatism (cylinder ≥ 1.00 diopter[D]). Eyes were divided into IR group (LASEK with IR at the time of surgery) and Non-IR group (LASEK without IR system + failed-IR engagement during LASEK)...
March 11, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28281302/compensation-of-corneal-oblique-astigmatism-by-internal-optics-a-theoretical-analysis
#20
Tao Liu, Larry N Thibos
PURPOSE: Oblique astigmatism is a prominent optical aberration of peripheral vision caused by oblique incidence of rays striking the refracting surfaces of the cornea and crystalline lens. We inquired whether oblique astigmatism from these two sources should be expected, theoretically, to have the same or opposite signs across the visual field at various states of accommodation. METHODS: Oblique astigmatism was computed across the central visual field for a rotationally-symmetric schematic-eye using optical design software...
March 9, 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
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