Science topic

Astigmatism - Science topic

Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)
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Publications related to Astigmatism (10,000)
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Article
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Background To evaluate the precision of corneal higher-order aberrations measurements after small incision lenticule extraction (SMILE) using the Sirius Scheimpflug-Placido topographer (CSO, Italy). Methods Seventy-five eyes from 75 postoperative subjects were included in this prospective study. Three consecutive corneal aberrometric measurements...
Article
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The purpose of this study was to evaluate corneal irregular astigmatism of patients with granular and lattice corneal dystrophy (GCD and LCD). 70 GCD, 35 LCD, and 81 control eyes were included. Anterior and posterior corneal topographic data obtained from anterior segment optical coherence tomography were expanded into four components via Fourier h...
Article
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In this study, we retrospectively evaluated the deviation from the planned axis of 3 Toric intraocular lenses (TIOL). Included in the study 190 eyes, operated by two surgeons using two different manual marking techniques. The patients were implanted with either AcrySof IQ Toric SN6AT (Alcon) (n = 90), POD FT (PhysIOL) (n = 50), or TECNIS Symfony To...
Article
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Purpose To compare the postoperative visual outcomes of two different preoperative corneal incision schemes in TECNIS toric intraocular lens (IOL) implantation. Methods In this randomized controlled study, patients with preoperative corneal astigmatism greater than 1.0 diopter (D) were included. These patients were grouped according to the differe...
Article
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Purpose: To reach a consensus on the management of progressive school age myopia. Materials and methods: The Myopia Study Group of the Argentine Society of Pediatric Ophthalmology evaluated the available scientific evidence in August and September 2021 to develop a questionnaire on the diagnosis, follow-up, prevention and treatment of myopia in the...
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Introduction: Blepharoptosis or drooping of the eyelid is a common disease entity presenting in oculoplasty department. Depending on its severity it causes visual disturbances as well as cosmetic problems. Appropriate management and timely surgical intervention results in a good outcome. Materials and methods: This is a hospital-based study of a bl...
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Purpose: To study the profile, risk factors, and management outcomes of infantile strabismus at a tertiary eye care center. Methods: We prospectively analyzed the data of infants (children less than 1 year of age) who presented at our institute from August 2018 to December 2019. We excluded infants who did not complete a minimum follow-up of 6 mont...
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Aim To conduct the first systematic review and meta-analysis assessing whether attention-deficit/hyperactivity disorder (ADHD) is associated with disorders of the eye, and/or altered measures of visual function. Method Based on a pre-registered protocol (PROSPERO: CRD42021256352), we searched PubMed, Web of Knowledge/Science, Ovid Medline, Embase...
Article
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To compare visual and refractive outcomes as well as changes in high-order aberrations in patients with 120- versus 140-µm cap thicknesses 12 months after small incision lenticule extraction. Ninety-four patients were randomized to receive small incision lenticule extraction with either a 120-µm cap thickness (n = 47) or a 140-µm cap thickness (n =...
Research
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Background: To evaluate the distribution of A-scan Biometry parameters and Corneal Astigmatism before Cataract Surgery in patients from a Tertiary Eye Care Centre. Methods: Cataract patients were recruited at a Tertiary Eye Care Hospital. Ocular axial length (AL), Lens thickness (LT), keratometry values, anterior chamber depth (ACD) and horizontal...
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Keizo Watanabe Minami Osaka Eye Clinic, Osaka, JapanCorrespondence: Keizo Watanabe, Minami Osaka Eye Clinic, Osaka, Japan, Tel +81 072-453-1750, Email nabedosu@outlook.comPurpose: To assess the refractive accuracy of the intraoperative aberrometer Optiwave Refractive Analysis (ORA) and evaluate factors impacting residual astigmatism in eyes implant...
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We present a methodology that allows to measure the dynamics of polydisperse suspension flows by means of Astigmatism Particle Tracking Velocimetry (APTV). Measurements are successfully performed with tridisperse suspensions flows in a square duct of up to $$\varPhi =9.1\%$$ Φ = 9.1 % particle volume fraction. Using a refractive index matching tech...
Article
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Background Multifocal intraocular lens (IOL) implantation is generally not considered in patients with keratoconus; however, it may provide good optical results in selected patients based on two case reports. Aims To evaluate patient satisfaction and clinical outcomes in this patient population. Methods This is a retrospective single-center, non-...
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Purpose To compare the vector analysis, visual, and refractive outcomes after myopic astigmatic correction using SMILE between the right and left eyes. Methods This is a retrospective study including 41 right and 40 left eyes that underwent SMILE for correction of myopic astigmatism greater than 0.75 diopters (D) with a follow-up of at least 3 mon...
Article
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Dear Editor, As we are all aware that Keratoconus is a non-inflammatory, bilateral, progressive ectatic corneal disorder that causes central thinning and myopic astigmatism. It reduces the quality of vision and impacts the day‑to‑day activities of patients.[1] Prompt diagnosis and meticulous management are needed to improve the quality of life of t...
Preprint
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In a $\Lambda$CDM universe, most galaxies evolve by mergers and accretions, leaving faint and/or diffuse structures, such as tidal streams and stellar halos. Although these structures are a good indicator of galaxies' recent mass assembly history, they have the disadvantage of being difficult to observe due to their low surface brightness (LSB). To...
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Purpose: To examine whether sociodemographic, and ocular factors relate to optical coherence tomography (OCT)-derived foveal curvature (FC) in healthy individuals. Methods: We developed a deep learning model to quantify OCT-derived FC from 63,939 participants (age range, 39-70 years). Associations of FC with sociodemographic, and ocular factors...
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To compare the agreement of ocular biometric parameters measured by IOLMaster 500 and IOLMaster 700. This is a prospective study. IOLMaster 500 and IOLMaster 700 were used to measure the axial eye length (AL), corneal flat keratometry (Kf), corneal steep keratometry (Ks), mean keratometry (Km), corneal astigmatism(CA), J0, J45, anterior chamber dep...
Article
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Purpose To compare the visual outcomes of digital and slit-beam manual marking for toric intraocular lenses (IOL) in cataract surgery. Setting Single-center, Beijing Tongren Hospital, China. Design Retrospective study. Methods All patients with cataracts and regular corneal astigmatism greater than 0.75 diopters (D) underwent cataract surgery an...
Article
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Purpose To evaluate the clinical results of primary topography-guided femtosecond laser-assisted in situ keratomileusis (TG-FS-LASIK) using the Pentacam-measured anterior corneal astigmatism axis (ACA) or manifest refractive astigmatism axis (MRA). Methods In this prospective cohort study, all eyes were treated with primary TG-FS-LASIK using the m...
Article
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Background and Objective: This study aims to investigate the prevalence of systemic and ophthalmic manifestations in different refractive groups in children and young adults with Down syndrome (DS). Materials and Methods: The study was a population-based, cross-sectional study that included 141 Caucasian children and young adults with DS. They were...
Article
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O ceratocone é uma doença progressiva que se manifesta como uma elevação semelhante a um cone da cór­nea central ou paracentral inferior e é associada a uma re­dução irregular da espessura do estroma. Há uma diminuição gradual da acuidade visual devido à assimetria da córnea, ao astigmatismo irregular e a um aumento das aberrações ópticas, o que pr...
Article
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Visual rehabilitation after a keratoplasty is often compromised due to high amounts of residual astigmatism. Femtosecond laser-assisted astigmatic keratotomy (FLAK) is gaining popularity in decreasing this astigmatism. Though one set of two incisions suffices in most cases, sometimes the treatment proves insufficient and additional treatment is req...
Article
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The motor development of the child, especially motor coordination, is important for performing purposeful activities. The aim of this study was to determine the impact of individual educational and rehabilitation treatment on motor coordination in students with visual impairment. The sample included one student, male, aged 9 years, with a diagnosis...
Article
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We examined the refractive characteristics and related factors of amblyopia in pediatric patients with limbal dermoids undergoing lamellar keratoscleroplasty. Forty-one children (mean age: 56.15 ± 22.47 months) were enrolled. Cycloplegic refraction, corneal topography, and anterior segment photography were performed. The corneal topographic and dis...
Article
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The current investigation evaluates the efficiency of the trifocal toric Liberty 677MTY intraocular lens (IOL) in correcting preoperative corneal astigmatism in cataract patients demanding spectacle independence. The retrospective evaluation included 28 eyes of 15 patients with preoperative corneal astigmatism of at least 1.0 Dioptre (D). All patie...
Article
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To evaluate the changes in anterior chamber dimensions including horizontal anterior chamber diameter (HACD), anterior chamber depth (ACD), and iridocorneal angle (ICA) following small incision lenticule extraction (SMILE) using Scheimpflug-Placido disk tomographer (Sirius). Methods The records of the 73 eyes of 47 patients who received SMILE for...
Article
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Background: Chalazion may affect visual acuity. This study aimed to evaluate refractive status of chalazia and effect of different sites, sizes, and numbers of chalazion on astigmatism. Methods: Three hundred ninety-eight patients aged 0.5-6 years were divided into the chalazion group (491 eyes) and the control group (305 eyes). Chalazia were cl...
Preprint
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For decades, manufacturers have attempted to reduce or eliminate the optical aberrations that appear on the progressive addition lens' surfaces during manufacturing. Besides every effort made, some of these distortions are inevitable given how lenses are fabricated, where in fact, astigmatism appears on the surface and cannot be entirely removed or...
Article
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Purpose: There has been little research on myopia management options for patients with astigmatism. This study quantified changes in peripheral refraction induced by toric orthokeratology (TOK) and soft toric multifocal (STM) contact lenses. Methods: Thirty adults with refractive error of plano to -5.00 D (sphere) and -1.25 to -3.50 D (cylinder)...
Article
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Background Refractive errors are relatively common all around the world. In particular, early onset myopia is associated with a significant burden in later life. Little is known about refractive errors in preschool children. The aim of this study was to assess the prevalence of spectacle wear, visual acuity and refractive errors in young Dutch chil...
Article
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Background Opaque bubble layer (OBL), which generates from photo-disruptive procedures on the cornea, has been a common phenomenon during femtosecond laser-assisted refractive surgeries and it would potentially impact eye tracking and flap lifting. And we have observed that an updated flap-making pattern could form less OBL clinically than the trad...
Article
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Purpose: To compare the total corneal astigmatism (TCA) measured by IOLMaster 700 and Pentacam and to investigate the consistency of corneal keratometry (CK) measured by IOLMaster and Pentacam. Methods: Cataract patients were retrospectively enrolled in March and April, 2021. Retrospective analysis was performed on those patients with binocular...
Article
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Purpose/Aim Detecting keratoconus (KC) progression helps determine the surgical indication for corneal cross-linking (CXL). This retrospective observational study aimed to examine changes in keratometric indices and corneal thickness in patients with KC who used rigid gas-permeable (RGP) contact lenses. Materials and methods This study involved 31...
Article
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Purpose To evaluate the clinical outcomes of sutureless capsular bag and intraocular lens (IOL) fixation with flattened, flanged intrascleral fixation technique in patients with large zonular dialysis. Methods Fifty-five eyes of 51 patients who underwent flattened flanged intrascleral capsular bag and IOL fixation and optic capture for traumatic c...
Article
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Purpose To determine the two-year results of small incision lenticule extraction (SMILE) for correcting post-keratoplasty myopia and myopic astigmatism. Methods In this case-series study, 10 eyes of 10 patients with a 6- to 10-year history of successful deep lamellar keratoplasty (DALK) underwent SMILE using the VisuMax laser platform. Ophthalmolo...
Article
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Purpose To compare the choroidal thickness (CT) and retinal vascular caliber in the differentiation of patients who have keratoconus (KC) from those of astigmatic and normal patients. Methods This was a prospective, cross-sectional study. A total of 72 patients who had KC, 70 who had astigmatism, and 83 healthy control subjects were enrolled in th...
Article
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Background There are limited systematic reviews on the prevalence of uncorrected refractive errors in children. We aimed to summarize the prevalence and causes of pediatric uncorrected refractive error (URE) from studies in the Global Burden of Disease (GBD) sub-regions. Methods The pooled analysis used the individual participant data (ages less t...
Article
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Background: The objective of this study was to determine the causes and distribution of vision impairment and refractive error among children in Zimbabwe. Methods: A hospital-based retrospective cross-sectional study was conducted among children (3-16) who attended the Eye Institute, Harare, Zimbabwe, from January 2010 to December 2020. Patients...
Article
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Purpose Accurate intraocular lens (IOL) calculation in subjects with irregular astigmatism is challenging. This study evaluated the accuracy of using Scheimpflug-derived central 2-mm equivalent keratometry reading (EKR) values for IOL calculation in irregular astigmatism. Methods This retrospective study included subjects (31 eyes of 30 patients)...
Article
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Purpose: The aim of the study is to evaluate the effect of limbal autograft location on corneal astigmatism in inferior and superior conjunctival autografted pterygium surgery. Methods: Patients were divided into 2 groups as diagnosed with primary pterygium and planned to receive surgical treatment. Pterygium surgery was performed on 25 patients...
Article
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In this paper, we investigate theoretically the properties of a vortex cosine-hyperbolic-Gaussian beam (vChGB) propagating in uniaxial crystals orthogonal to the optical axis. Analytical expressions for the vChGB propagating through a uniaxial crystal orthogonal to the optical axis are derived. From the obtained formulas the evolution properties of...
Article
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Background Overall ocular magnification (OOM) and meridional ocular magnification (MOM) with consequent image distortions have been widely ignored in modern cataract surgery. The purpose of this study was to investigate OOM and MOM in a general situation with an astigmatic refracting surface. Methods From a large dataset containing biometric measu...
Article
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Purpose Albinism is known to disrupt emmetropisation in animal models. However, it is not clear if the same effect is seen in humans. This study aimed to investigate the refractive profile in individuals diagnosed with ocular albinism (OA) and oculocutaneous albinism (OCA) based on a large dataset. Methods Required data from 618 individuals (61% m...
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PurposeThis study aims to investigate the characteristics, potential risk factors and associated severity of keratoconus on the east coast of China.Methods In this case–control study, patients diagnosed with keratoconus were invited to fill in the online electronic questionnaire designed with the help of the App named WenJuanXing. Several questions...
Article
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Objectives To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step transepithelial PRK for myopia and myopic astigmatism. Methods A prospective randomized study. The study enrolled 100 eyes of 50 patients with mild to moderate myopia or myop...
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Purpose: This study aimed to evaluate the associations of GJD2 (rs634990, rs524952) and RASGRF1 (rs8027411, rs4778879, rs28412916) gene polymorphisms with refractive errors. Methods: The study included 373 subjects with refractive errors (48 myopia, 239 myopia with astigmatism, 14 hyperopia, and 72 hyperopia with astigmatism patients) and 104 op...
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Introduction: Trial rigid lens fitting is considered the best approach to determine whether the correction of residual defocus and irregular astigmatism might improve the visual acuity in patients with corneal disorders including keratoconus. This study aimed to analyze the correlation between hybrid lenses and pinhole visual acuity (VA). Methods...
Article
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Purpose To introduce a modified procedure of ICL implantation, to summarize the perioperative problems and their corresponding treatment after myopia correction with Implantable Collamer Lens (ICL), and to compare the difference of complications between the no-hole ICL and hole ICL. Methods We searched all articles on ICL-related perioperative pro...
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Objective To assess the long-term refractive status, visual outcome, astigmatism, and the change in biometric optic components in older adolescents up to age 17 years with threshold retinopathy of prematurity (ROP) treated with diode laser. Methods A retrospective, longitudinal study in which cycloplegic refraction, keratometry, and the biometric...
Article
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Dichoptic therapy is a promising method for improving vision in pediatric and adult patients with amblyopia. However, a systematic understanding about changes in specific visual functions and substantial variation of effect among patients is lacking. Utilizing a novel stereoscopic augmented-reality based training program, 24 pediatric and 18 adult...
Article
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During the COVID-19 pandemic, the Hong Kong Government enforced a “school from home” policy between February and September 2020. This cross-sectional epidemiological study was conducted to investigate the prevalence of astigmatism and visual habits after the home confinement period. Vision screenings were conducted at three local government-funded...
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Purpose This systematic review aims to compare corneal astigmatism correction in cataract surgery through corneal relaxing incision, manually and femtosecond laser assisted. Methods The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We used PubMed, Scopus,...
Article
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Background: Optical coherence tomography (OCT) is a modern, non-invasive technique for examining the posterior segment of the eye in vivo. The quality of images is crucial for the diagnostic process. Despite good image quality and high signal strength, we still obtain images with less relevant diagnostic data, especially in relation to RNFL and GC...
Article
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Introduction A pterygium is a wing-shaped fibrovascular conjunctival development in the cornea. It changes depending on where you are. It's one of the most common types of ocular surface disease. The prevalence of pterygium varies between 0.7 and 31 percent. (1) The actual pathophysiology of this damage is complicated, and it is still unknown. A nu...
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Objective: To investigate the clinical study of acupoint massage combined with recombinant bovine basic fibroblast growth factor (rbFGF) ophthalmic gel combined with limbal stem cell transplantation on visual quality, corneal refraction, and aesthetic outcome in patients with pterygium. Methods: Sixty patients with pterygium treated in People's...