Refractive errors

PURPOSE: This study evaluates the accuracy of modern intraocular lens (IOL) calculation formulas using axial length (AL) data obtained by ultrasound biometry (UBM) compared to the third-generation SRK/T calculator. MATERIAL AND METHODS: The study included 230 patients (267 eyes) with severe lens opacities that prevented optical biometry, who underwent phacoemulsification (PE) with IOL implantation. IOL power calculation according to the SRK/T formula was based on AL and anterior chamber depth obtained by UBM (Tomey Biometer Al-100) and keratometry on the Topcon KR 8800 autorefractometer...

PURPOSE: This study aimed to evaluate the accuracy of 12 intraocular lens (IOL) power calculation formulae for eyes that have undergone both radial keratotomy (RK) and laser assisted in situ keratomileusis (LASIK) surgery to determine the efficacy of various IOL calculations for this unique patient group. Currently, research on this surgical topic is limited. METHODS: In this retrospective study, 11 eyes from 7 individuals with a history of RK and LASIK who underwent cataract surgery at Hoopes Vision were analyzed...

BACKGROUND: Scoliosis is one of the most common surgical disorders of the pediatric spine. Refractive errors are commonly associated with vision impairment worldwide. However, it is currently unclear whether refractive error correlates directly with the development of scoliosis. METHODS: A cross-sectional study was performed in 2023, and a stratified cluster sampling technique was employed among school-aged students in Nantong City, China. Univariate and multivariate logistic regression analyses were used to investigate specific correlations between scoliosis and related parameters; various types of refractive errors were also included in the study...

PURPOSE: To investigate refractive, visual, and safety outcomes of cataract surgery performed after scleral buckling (SB) for retinal detachment (RD). PATIENTS AND METHODS: A chart review at an academic medical center identified eyes with history of SB followed by subsequent cataract extraction between 2010 and 2022. Eyes with less than 3 weeks follow-up, silicone oil at time of biometry measurement, previous cornea surgery, or co-existing pathology impacting refractive outcomes were excluded...

INTRODUCTION: The aim of this work is to compare 20 intraocular lens (IOL) power calculation formulas in medium-long eyes (24.50-25.99 mm) in terms of root mean square absolute error (RMSAE), median absolute error (MedAE), and percentage of eyes with prediction error (PE) within ± 0.50 D. METHODS: The data of patients who underwent uneventful phacoemulsification between January 2017 and September 2023 were reviewed. Pre-surgery IOL power was calculated using Holladay1, SRK/T, Hoffer Q, Holladay 2, and Haigis...

The aim of this study was to pharmacologically induce accommodative paralysis and evaluate its effects on the bioelectrical activity of the muscular system. The study included two participant groups: those with myopia and those with normal vision (emmetropes). Electromyographic assessments were performed using the Noraxon Ultium DTS 8-K MR 3 myo Muscle Master Edition system. The muscles analyzed in this study were the temporalis, masseter, sternocleidomastoid, trapezius, abdominal muscles, biceps brachii, and the external oblique muscles of the abdomen...

OBJECTIVE: To investigate the feasibility of optical coherence tomography (OCT)-based digital image correlation (DIC) analysis and to identify the experimental parameters for measurements of polymerization shrinkage. METHODS: Class I cavities were prepared on bovine incisors and filled with Filtek Z350XT Flowable (Z350F). One OCT image of the polymerized restoration was processed to generate virtually displaced images. In addition, the tooth specimen was physically moved under OCT scanning...

BACKGROUND/AIMS: To investigate whether compensating retinal nerve fibre layer (RNFL) thickness measurements for demographic and anatomical ocular factors can strengthen the structure-function relationship in patients with glaucoma. METHODS: 600 eyes from 412 patients with glaucoma (mean deviation of the visual field (MD VF) -6.53±5.55 dB) were included in this cross-sectional study. Participants underwent standard automated perimetry and spectral-domain optical coherence tomography imaging (Cirrus; Carl Zeiss Meditec)...

PURPOSE: To assess the prevalence of ocular morbidities and associated factors among hearing-impaired (HI) students at the Embangweni School for the Deaf in Mzimba, Malawi. METHODS: This was an institutional cross-sectional study of HI students at Embangweni School for the Deaf. A series of optometric and audiometric tests was performed, and the results were exported to the Statistical Package for Social Science for statistical analysis (SPSS) version 25. Pearson's chi-square test was used to assess correlations and associations between variables...

OBJECTIVE: To assess the association between ethnicity and self-reported refractive errors (REs) among Peruvian children aged 7-11 years. MATERIALS AND METHODS: We conducted a cross-sectional study incorporating a secondary data analysis of 2017-2021 data from the Peruvian Demographic and Health Survey (DHS). REs and ethnicity were obtained from focal child's mother's report. Four outcomes were assessed: hyperopia, myopia, astigmatism and any RE. We included potential confounders, such as age, sex, wealth index, area of residence, region of origin, frequency of watching TV and watching screens at less than 30 cm distance...

OBJECTIVE: This randomised clinical trial assessed the impact on symptoms, tear film dynamics and ocular surface integrity of daily disposable silicone-hydrogel contact lenses (CLs) over a month, paying special attention to lid wiper epitheliopathy (LWE) and its implications for CL discomfort. METHODS: Neophyte CL wearers (n = 44, 21.09 ± 5.00 years old) were randomly assigned to either the experimental (n = 24) or control group (n = 20)...

A significant contributor to blindness and visual impairment globally is uncorrected refractive error. To plan effective interventions, eye care professionals must promptly identify people at a high risk of acquiring myopia, and monitor disease progress. Artificial intelligence (AI) and machine learning (ML) have enormous potential to improve diagnosis and treatment. This systematic review explores the current state of ML and AI applications in the diagnoses and treatment of refractory errors in optometry. A systematic review and meta-analysis of studies evaluating the diagnostic performance of AI-based tools in PubMed was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines...

PURPOSE: To understand the ocular biometric parameters characteristics and refractive errors in 3-to 6-year-old preschool children in Chengdu, China, and to investigate the prevalence of refractive errors. METHOD: A school-based cross-sectional study was conducted in Chengdu from 2020 to2022 with a total of 666 kindergartens. All children were measured by non-cycloplegic autorefraction and uncorrected visual acuity (UCVA) and ocular biometric parameters. Finally, univariate linear regression models were used to analyze the relationship between ocular biometric parameters and refraction...

BACKGROUND: Schoolteachers who have knowledge on eye diseases can detect early children with eye disorders and refer them promptly to an eye specialist. The aim of this study is to assess the effectiveness of teachers in a vision screening program for primary school children in Abakaliki. METHODS: This descriptive cross-sectional study was conducted among 20 randomly selected primary schoolteachers in Abakaliki to screen for vision abnormalities and detect eye problems among 350 children from 5 schools...

BACKGROUND: Non-traumatic ectopia lentis is a rare ocular disorder usually associated with syndromes like Marfans's syndrome, Weil-Marchesani and Homocystinuria. Ectopia lentis can lead to profound visual loss from refractive errors, glaucoma as well as retinal detachment if left unattended. AIM: The aim of this study was to describe the clinical profile of patients with non-traumatic ectopia lentis in a paediatric ophthalmology clinic in Ibadan, Nigeria. METHODS: The clinical records of children ≤16 years diagnosed with non- traumatic ectopia lentis at the Paediatric Ophthalmology Clinic, University College Hospital Ibadan, from May 1, 2015 to Dec 31, 2019 were retrospectively reviewed...

PURPOSE: To assess whether the use of measured posterior corneal astigmatism (PCA) values improves the prediction accuracy of toric intraocular lens power formulas, compared to predicted PCA values, when the orientation of the steep axis of PCA is non-vertical. DESIGN: Retrospective observational cohort study METHODS: 418 eyes of 344 patients were included in the study. Prediction errors (PE) for postoperative refractive astigmatism at 4 weeks postoperatively were determined using vector analysis and compared for the following toric intraocular lens power formulas: Barrett Toric with predicted posterior corneal astigmatism (PPCA); Barrett Toric with measured posterior corneal astigmatism (MPCA); EVO Toric PPCA; EVO Toric MPCA; Holladay I with Abulafia-Koch regression...

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively...

PURPOSE OF REVIEW: Pediatric refractive surgery has been growing at a steady pace since its introduction in the early 1980 s. This article will review common laser refractive surgeries performed on pediatric patients along with controversies regarding the practice. RECENT FINDINGS: Pediatric refractive surgery is reserved for a small population of children who fail amblyopic treatment due to high anisometropic refractive errors. Publications over the years have treated these children with various types of laser refractive surgery...

PURPOSE: To evaluate the predictive accuracy of modern intraocular lens (IOL) formulas and axial length (AL) adjusted traditional IOL formulas, including Wang-Koch and Cooke-modified AL (CMAL) method, in long eyes with plate-haptic IOLs, and to compare refractive prediction error variances with C-loop IOLs. DESIGN: Retrospective consecutive case series study. METHODS: Data from 391 eyes with Zeiss 509M and 302 eyes with Alcon SN6CWS implants in highly myopic patients, following cataract surgery from January 2019 to November 2023, were collected...

PURPOSE: To evaluate the visual outcomes and perioperative complications for cataract surgery in eyes with axial length (AL) > 33.0 mm. DESIGN: Prospective clinical cohort study. METHODS: One hundred and twenty-two eyes with moderate high myopia (26.0 mm ≤ AL<28.0 mm, control group), and 118 eyes with extreme high myopia (AL > 33.0 mm, EHM group) were followed up after cataract surgery (one week and one year post-op). Myopic maculopathy grading according to ATN system, best-corrected visual acuity (BCVA), and complications were compared...