BACKGROUND AND OBJECTIVE:This study reports the induced refractive error after 23- and 25-gauge (G) pars plana vitrectomy (PPV). PATIENTS AND METHODS:In this non-randomized retrospective case series, refractive status was assessed with an autokeratorefractometer 1 week or more before and 6 months after surgery. Patients who had suture placement to close ...

BACKGROUND: Eye-tracking technology has been shown to improve trainee performance in the aircraft industry, radiology, and surgery. The ability to track the point-of-regard of a supervisor and reflect this onto a subjects' laparoscopic screen to aid instruction of a simulated task is attractive, in particular when considering the multilingual make ...

Purpose:  The aim was to study the link between refractive error and corneal biomechanical properties. Methods:  Corneal hysteresis and corneal resistance factor were measured using the Ocular Response Analyser in 117 participants. The spherical equivalent refractive error of the participants ranged between -9.00 and +3.00 D. Results:  Corneal hysteresis and corneal ...

To evaluate risk factors for pediatric microbial keratitis and to describe the clinical picture, microbial spectrum, treatment modalities, posttreatment sequelae, and visual outcome in cases with pediatric microbial keratitis. All cases of microbial keratitis that occurred in children 16 years or younger who had an initial examination between January 2000 ...

OBJECTIVE: To investigate the ideal correction of intraocular lens (IOL) power for sulcus implantation. DESIGN: Retrospective, comparative case series. PARTICIPANTS: The records of 679 patients undergoing cataract surgery from June 2007 to June 2008 were reviewed. INTERVENTION: Eyes in this series underwent phacoemulsification and IOL implantation with local anesthesia. Patients ...

Purpose:To study the relationships between refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract.Methods:All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on ...

PURPOSE.: To better understand the functional significance of refractive-error measures obtained using common objective methods in laboratory animals, we compared objective and subjective measures of refractive error in adolescent rhesus monkeys. METHODS.: The subjects were 20 adolescent monkeys. Spherical-equivalent spectacle-plane refractive corrections were measured by retinoscopy and autorefraction while the ...

The present study addresses the suitability of electrodermal lability as an indicator of individual vulnerability to the effects of total sleep deprivation. During two complete circadian cycles, the effects of 48 h of total sleep deprivation on physiological measures (electrodermal activity and body temperature), subjective sleepiness (measured by visual analogue scale ...

Citation information: Guo H, Goncharov A & Dainty C. Intraocular lens implantation position sensitivity as a function of refractive error. Ophthalmic Physiol Opt 2011. doi: 10.1111/j.1475-1313.2011.00888.x ABSTRACT: Purpose:  To quantify the change in ocular aberrations due to intraocular lens (IOL) implantation position errors for pseudo-phakic eyes with different refractive errors. ...

Purpose:To estimate the heritability of peripheral refraction in Chinese children and adolescents.Methods:We examined 72 monozygotic (MZ) twins and 48 dizygotic (DZ) twins aged 8 to 20 years from a population-based twin registry. Temporal and nasal peripheral refraction, each 40 degrees from the visual axis, as well as axial refraction, were ...

PURPOSE:To analyze in vivo structural properties of a case with interface haze that developed after femtosecond laser-assisted LASIK. METHODS:Case report. RESULTS:A 42-year-old man underwent uncomplicated LASIK. Four months after the surgery he developed regression of his refractive error and interface haze in both eyes. Flap thickness was calculated as 73 ...

Our previous study using (123)I-iodo-benzamide single photon emission computed tomography (SPECT) showed a positive relationship in healthy adults between striatal postsynaptic D(2)/D(3) receptor availability and sleep duration in good sleepers. To further investigate the role of dopamine (DA) in the sleep-wake cycle, we explored the correlation between presynaptic dopamine transporter ...

Purpose: It is accepted practice to use a spherical equivalent power as an alternative contact lens correction for those patients with lower amounts of astigmatism, allowing for an easier fit, but the blur caused by one diopter of uncorrected astigmatism can reduce acuity of 6/6 to that of about 6/8. ...

The aim of the study is to retrospectively determine the pattern of refractive errors seen in the eye clinic of Aminu Kano Teaching Hospital, Kano-Nigeria from January to December, 2008. The clinic refraction register was used to retrieve the case folders of all patients refracted during the review period. Information ...

OBJECTIVE: To evaluate the risk of primary acute angle closure (AAC), changes in intraocular pressure (IOP), and associated risk factors after pupil dilation in Asian subjects with narrow angles (primary angle-closure suspects [PACS]). DESIGN: Prospective clinical study. PARTICIPANTS: A total of 471 subjects aged more than 50 years with narrow ...

Purpose:To investigate age-related trends in refractive, corneal and internal astigmatism, and to assess the association between internal astigmatism and lens opacity in an elderly Chinese population.Methods:A population-based study was conducted among 1,360 inhabitants aged ≥65 years in Taipei, Taiwan. Participants underwent measurements of refraction, corneal dioptric power and slit lamp ...

To compare the accuracy of intraocular lens (IOL) power calculation formulas in eyes with primary angle closure glaucoma (ACG). This retrospective study compared the refractive outcomes of 63 eyes with primary ACG with the results of 93 eyes with normal open angles undergoing uneventful cataract surgery. Anterior segment biometry including ...

PURPOSE.: To obtain an accurate algorithm for calculating the keratometric index that minimizes the errors in the calculation of corneal power assuming only a single corneal surface in the range of corneal curvatures of the normal population. METHODS.: Corneal power was calculated by using the classical keratometric index and also ...

Total ocular higher order aberrations and corneal topography of myopic, emmetropic and hyperopic eyes of 675 adolescents (16.9±0.7years) were measured after cycloplegia using COAS aberrometer and Medmont videokeratoscope. Corneal higher order aberrations were computed from the corneal topography maps and lenticular (internal) higher order aberrations derived by subtraction of corneal ...

PURPOSE: To compare the macular choroidal thickness in 2 types of early dry-type myopic maculopathy. DESIGN: Prospective, observational, comparative study. METHODS: Patients with a refractive error of less than -8 diopters were included and were classified into 2 groups. Group 1 consisted of 24 eyes with a tessellated fundus, and ...

Aim : Eye morbidities with or without symptoms delineate a significant morbidity among adolescent schoolgirls in India. The study was undertaken to assess the extent of visual impairment and ocular morbidity to identify influencing factors and the impact on scholastic performance. Materials and Methods : A population-based cross-sectional study was ...

PURPOSE: To describe a new method of alignment of toric intraocular lenses (IOLs) and evaluation of their rotation errors using anterior segment optical coherence tomography (AS-OCT). METHODS: Twenty-nine eyes of 22 patients who had cataract extraction and implantation of an acrylic toric IOL were included. The new AS-OCT method was ...

PURPOSE.: To assess epidemiological aspects of refractive errors in school-age children in Burkina Faso (west-central Africa). METHODS.: A total of 315 school children (ranging from 6 to 16 years of age and belonging to different ethnic groups) taken at random from two urban schools in eastern Burkina Faso were examined ...

Purpose: To compare the effects of the 4-haptic angulated (FA) intraocular lens (IOL) with the 2-haptic non-angulated (TNA) IOL vis-a-vis post-operative refractive error following phacovitrectomy with gas tamponade. Methods: A prospective study was conducted on 40 eyes of 40 patients who underwent phacovitrectomy with gas tamponade for repair of macular ...

Purpose. To analyze by means of a vectorial method the corneal astigmatic changes occurring after crosslinking (CXL) in keratoconic eyes and to determine the relationship between these changes and the final clinical outcome. Methods. A total of 16 eyes of 12 patients with the diagnosis of mild to moderate keratoconus ...

BACKGROUND: Huntington disease (HD) is a genetic, neurodegenerative disorder characterized by chorea, behavioral co-morbidities, cognitive deficits, and eye movement abnormalities. We sought to evaluate whether reflexive and voluntary orienting prove useful as biomarkers of disease severity in HD. METHODS: Eleven HD subjects were evaluated with the motor subscale of the ...

AimTo determine variations in eye volume, surface area, and shape with refractive error in young children using a three-dimensional (3D) magnetic resonance imaging (MRI) model.MethodsA subset of Singaporean Chinese boys enrolled in the population-based Strabismus, Amblyopia, and Refractive Error in Singapore (STARS) study underwent MRI using a 3-Tesla whole body ...

PURPOSE: To describe progressive tilting of the optic nerve head (ONH) and development/enlargement of parapapillary atrophy (PPA) observed in children with incipient myopia and to investigate factors associated with such changes. DESIGN: Retrospective, observational study. PARTICIPANTS: This study included 118 eyes of 118 Korean children who were assessed by serial ...

BACKGROUND: Laser-assisted in situ keratomileusis (LASIK) has undergone several evolutions since it was first approved by the U.S. Food and Drug Administration. Currently, excimer lasers are approved by the U.S. Food and Drug Administration to treat refractive errors with a standard ablation profile, a wavefront-optimized ablation profile, or a wavefront-guided ...

To determine the surgically induced refractive and keratometric effects of intrastromal corneal ring segments (ICRS). St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. Case series. Keratoconic patients had implantation of 2 vertically aligned 0.3 mm Intacs ICRS with the incision site at 90 degrees. Principal outcome measures ...

Intraocular lens (IOL) formulas based on aphakic refraction alone have been proposed as an alternative to biometry-based formulas. The purpose of this study was to determine the relative accuracy of these simplified formulas. Records of patients who received secondary in-the-bag (IOL) implants and for whom aphakic refraction was obtainable were ...

PurposeTo compare the degree of tilt and decentration of an intraocular lens (IOL), refractive status, and prediction error between eyes that underwent trans-scleral suturing of the IOL within the capsular bag (in-the-bag scleral suturing) and eyes that underwent scleral suturing outside of the bag (out-of-the-bag scleral suturing) because of severe ...

Purpose:To experimentally examine the effect of corneal modulus on Goldmann Applanation Tonometry (GAT) and Tonopen measurements of intraocular pressure (IOP) in a canine eye model.Methods:Twenty-one canine globes were recovered from healthy animals. IOP was controlled at 10, 15, 20, 30, and 40 mmHg and measured by GAT and Tonopen following ...

To investigate the relationship between insufficient sleep and poor attention in Korean adolescents, adjusting for potential confounding factors of depressed mood and habitual snoring. School-based cross-sectional study. Eight high schools in 3 cities in the Republic of Korea. A sample of 2638 urban high school students (42.2% male and 57.8% ...

To evaluate fluid dynamics and fluid shear stress on the retinal wall in a model eye after vitrectomy and gas tamponade in relation to saccadic eye movements and sudden head movements and to correlate the results with gas fill fraction (GF). Methods. Analyses was undertaken using high-resolution computational fluid dynamic ...

Purpose:The study of the peripheral refractive error is of growing interest as degradation of the retinal image quality in the periphery is known to affect central refractive error development and ocular shape in animal models. The purpose of this study was to measure relative peripheral refraction (RPR) across the horizontal, ...

In a temporal difference learning approach of classical conditioning, a theoretical error signal shifts from outcome deliverance to the onset of the conditioned stimulus. Omission of an expected outcome results in a negative prediction error signal, which is the initial step towards successful extinction and may therefore be relevant for ...

To evaluate changes in anterior corneal optical density and the refractive index after photorefractive keratectomy (PRK) using a rotating Scheimpflug system. Department of Ophthalmology, University Federico II, Naples, Italy. Comparative case series. Anterior corneal optical density was evaluated with a rotating Scheimpflug system at baseline and 3 months and 12 ...

Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Deficits in balance and postural control have long been associated with falls risk in elderly adults. The gold standard for quantitative assessment of human balance in a clinical setting is the force plate which is highly ...

PURPOSE. The purpose of this study was to determine whether visual signals from the fovea contribute to the changes in the pattern of peripheral refractions associated with form deprivation myopia in monkeys. METHODS. Monocular form-deprivation was produced in 18 rhesus monkeys by securing diffusers in front of their treated eyes ...

PURPOSE:: To assess the frequency and severity of segmentation errors in spectral-domain optical coherence tomography, and present an appropriate scan protocol for measuring macular thickness. METHODS:: In this study we examined 40 eyes of healthy subjects, 45 eyes with retinal pathology and 31 eyes with subretinal pathology. Patients were prospectively ...

Citation information: Tian Y, Tarrant J & Wildsoet CF. Optical and biometric characteristics of anisomyopia in human adults. Ophthalmic Physiol Opt 2011. doi: 10.1111/j.1475-1313.2011.00858.x ABSTRACT: Purpose:  To investigate the role of higher order optical aberrations and thus retinal image degradation in the development of myopia, through the characterization of anisomyopia ...

PurposeTo evaluate the impact of reducing B-scan frame-sampling density on retinal thickness measurements using spectral domain optical coherence tomography (SD-OCT) in eyes with diabetic macular edema (DME).MethodsWe retrospectively collected OCT data for 64 eyes of 43 patients undergoing imaging for DME using the Cirrus HD-OCT 512 × 128 macular cube ...

BACKGROUND: Sleep deprivation affects surgical performance and has the potential to endanger patient safety. Pharmacological stimulants may counter this consequence of long working hours. This study aimed to investigate whether commonly available stimulants can counter the effects of fatigue on technical and neurocognitive skill. METHODS: This was a single-blind crossover ...

OBJECTIVE: To define theoretical correction factors for second-eye intraocular lens (IOL) power adjustment based on first eye refractive prediction error (PE). DESIGN: Database study. PARTICIPANTS: We included 2129 patients who underwent bilateral sequential phacoemulsification cataract surgery with the same IOL model. METHODS: Retrospectively calculated PEs (Hoffer Q, Holladay 1, SRK/T) ...

PURPOSE.: To observe and analyze corneal asphericity and its related factors in Chinese subjects. METHODS.: The corneal asphericity of 1052 right eyes from a Chinese population was determined using the Wavelight-ALLEGRO Topographer. The corneal asphericity coefficient Q describes the rate of curvature variation of the cornea from its center to ...

Aim: To study accommodation in relation to different refractive errors, amblyopia and to measure the anatomical changes in the accommodating eye Materials and methods: We studied the amplitude of accommodation (AA) in 150 patients in the age group 11 ± 30 years which included emmetropes, myopes, hypermetropes and hypermetropic amblyopes ...

To determine the normal ultrasonographic thickness of the iris and ciliary body. This prospective 35-MHz ultrasonographic study included 80 normal eyes of 40 healthy volunteers. The images were obtained at the 12-, 3-, 6-, and 9-o'clock radial meridians, measured at three locations along the radial length of the iris and ...

Aim: To evaluate the safety and efficacy of laser in-situ keratomileusis (LASIK) in eyes with residual/induced refractive error following radial keratotomy (RK). Design: Retrospective study. Materials and Methods: A retrospective analysis of data of 18 eyes of 10 patients, who had undergone LASIK for refractive error following RK, was performed. ...

To illustrate and develop a method for estimating crystalline lens decentration as a function of accommodative response using changes in wavefront error and show the method and limitations using previously published data (2004) from 2 iridectomized monkey eyes so that clinicians understand how spherical aberration can induce coma, in particular ...