Refractive errors

Purpose: To evaluate the difference between planned and measured central ablation depth (CAD) and compare the first and second operated eye in simultaneous bilateral myopic alcohol-assisted PRK. Methods: A retrospective review of patients was performed. Demographic and preoperative data was abstracted. Intraoperative assessment included environmental data, laser-planned algorithm of ablation (L-CAD), and optical coherence pachymetry (OCP) measurements. The true stromal ablation depth (O-CAD) was calculated by subtracting the immediate post-ablation OCP measurement from the OCP measurement before laser ablation...

This paper investigates non-invasive techniques for annular two-phase flow analysis, focusing on liquid film characterization to understand the interfacial phenomena that are crucial for heat and mass transfer. Limited methods allow the study of the temporal and spatial evolution of liquid film, such as Planar Laser-Induced Fluorescence (PLIF). However, this method possesses optical challenges, leading to the need for improved techniques to mitigate refraction and reflection, such as Refractive Index Matching (RIM)...

OBJECTIVES: To evaluate the 10-year visual, refractive, and tomographic outcomes of epithelium-off accelerated corneal collagen cross-linking (ACCL) in paediatric patients with progressive keratoconus (KC) and to compare the stages in terms of re-progression. METHODS: Patients under 18 years of age with progressive KC who underwent ACCL between 2010 and 2012 and completed at least 10 years of follow-up were included in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, and corneal tomography parameters were evaluated preoperatively and at 1, 5, and 10 years postoperatively...

BACKGROUND: Myopia is becoming a huge burden on the world's public health systems. The purpose of this study was to explore the effect of brimonidine in the treatment of form-deprivation myopia (FDM) and the relationship between intraocular pressure (IOP) and myopia development. METHODS: Monocular form deprivation myopia (FDM) was induced in three-week-old pigmented male guinea pigs. They were treated with 3 different methods of brimonidine administration (eye drops, and subconjunctival or intravitreal injections)...

AIMS: The aim of this study was to analyse the effective lens position (ELP) in patients with Marfan syndrome (MFS) and ectopia lentis (EL). METHODS: Patients with MFS undergoing lens removal and primary intraocular lens (IOL) implantation were enrolled in the study. The back-calculated ELP was obtained with the vergence formula and compared with the theoretical ELPs. The back-calculated ELP and ELP error were evaluated among demographic and biometric parameters, including axial length (AL), corneal curvature radius (CCR) and white-to-white (WTW)...

BACKGROUND/OBJECTIVES: The See4School programme in Scotland is a pre-school vision screening initiative delivered by orthoptists on a national scale. The primary objective of any vision screening programme is to identify amblyopia, given the common understanding that this condition is unlikely to be detected either at home or through conventional healthcare channels. The target condition is not bilateral visual impairment, as it is believed that most children will be identified within the first year of life either through observations at home or as part of the diagnosis of another related disorder...

PURPOSE: Studies report conflicting findings regarding choroidal thickness changes in response to myopic defocus in humans. This study aimed to investigate the choroidal response to myopic defocus in children and adults using automated analysis. METHODS: Participants (N = 46) were distance-corrected in both eyes and viewed a movie on a screen for 10 minutes. Two optical coherence tomography (OCT) radial scans were collected for each eye, then +3 diopters was added to one eye...

INTRODUCTION: Corneal characteristics are unique to each eye and can vary among different levels of refractive errors. However, minimal data are available in the literature on corneal characteristics in myopic Malay school children including the difference between the low myopic group and the moderate myopic group. Therefore, this study aims to determine the corneal characteristics of myopic Malay school children and their associations with axial length. METHODS: A total of eighty-four data samples were extracted from forty-two myopic Malay school children...

PURPOSE: To explore the association between the cause of amblyopia and pre-treatment contrast sensitivity, stereoacuity, fixation and nystagmus. DESIGN: Retrospective cohort study. METHODS: A retrospective review was conducted for 3408 patients with amblyopia who had not yet started amblyopia treatment utilizing a large amblyopia patient database maintained at Zhongshan Ophthalmic Centre. Six amblyogenic factor subtypes were identified: anisometropia, isoametropia, strabismus, anisometropia and strabismus, monocular visual deprivation, and binocular visual deprivation amblyopia...

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality...

PURPOSE: To determine the changes in keratometry measurements and refraction in patients having the thermo-mechanical periorbital skin treatment, Tixel®, to treat dry eye disease (DED). METHODS: A multi-centre, prospective, non-masked study was conducted. DED patients were recruited in 3 international centres and were evaluated in 5 visits separated by an interval of 2 weeks except for the last visit which took place after 18 weeks from visit 1. The same clinical examination was performed at all visits: OSDI questionnaire, tear stability, keratometry, best corrected visual acuity and refraction...

PURPOSE: To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. METHODS: In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters...

PURPOSE: To investigate the efficacy of incorporating Generative Adversarial Network (GAN) and synthetic images in enhancing the performance of a convolutional neural network (CNN) for automated estimation of Implantable Collamer Lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). METHODS: This study was a retrospective evaluation using synthetic data and real patient images in a deep learning framework. Synthetic ICL AS-OCT scans were generated using GANs and a secondary image editing algorithm, creating approximately 100,000 synthetic images...

PURPOSE: To investigate the effect of age on visual outcomes after the bilateral implantation of trifocal intraocular lenses (IOLs). METHODS: A total of 290 patients (580 eyes) who underwent bilateral implantation of a trifocal IOL were enrolled in this retrospective case-control study. Patients were divided into five age groups: 45 to 49, 50 to 54, 55 to 59, 60 to 64, and 65 years and older. Postoperative monocular uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively), uncorrected near visual acuity (UNVA), binocular distance-corrected defocus curve, spectacle dependence for near and distance vision, and patient satisfaction scores were compared among the five groups...

PURPOSE: Myopic marmosets are known to exhibit significant inner retinal thinning compared to age-matched controls. The purpose of this study was to assess inner retinal activity in marmosets with lens-induced myopia compared to age-matched controls and evaluate its relationship with induced changes in refractive state and eye growth. METHODS: Cycloplegic refractive error (Rx), vitreous chamber depth (VCD), and photopic full-field electroretinogram were measured in 14 marmosets treated binocularly with negative contact lenses compared to 9 untreated controls at different stages throughout the experimental period (from 74 to 369 days of age)...

This observational study aimed to evaluate the use of a single portable device to assess the non-invasive tear break-up time (NITBUT), tear meniscus height (TMH), and lipid layer patterns (LLP) in young females with refractive errors (REs). The study was conducted at the College of Applied Medical Science (Female campus), Riyadh, Saudi Arabia between January 5, 2021 to May 15, 2021. Forty young females, with mean age of 23.0± 4.3 years with REs (-2.53 ± 2.05 D) and 40 females, mean age 23.8± 4...

INTRODUCTION: BRPF1 gene on 3p26-p25 encodes a protein involved in epigenetic regulation, through interaction with histone H3 lysine acetyltransferases KAT6A and KAT6B of the MYST family. Heterozygous pathogenic variants in BRPF1 gene are associated with Intellectual Developmental Disorder with Dysmorphic Facies and Ptosis (IDDDFP), characterized by global developmental delay, intellectual disability, language delay, and dysmorphic facial features. The reported ocular involvement includes strabismus, amblyopia, and refraction errors...

A 4-month-old girl was referred for evaluation of an anterior chamber cyst in the left eye. Examination under anesthesia (EUA) revealed a large iris stromal cyst in the anterior chamber involving the angle and the pupillary border, with touch of the corneal endothelium and anterior lens capsule. Intraocular pressure was normal. There was no anisometropic refractive error by retinoscopy. Close observation with amblyopia management was recommended as the pupil was only partially occluded by the cyst, and there was a clear red reflex around the cyst...

Deviations in corneal endothelium morphology and thickness may indicate corneal abnormalities and could be associated with myopia development. This study aimed to evaluate corneal endothelial cell morphology and central corneal thickness in young individuals with myopia. A prospective study was conducted at Al-Neelain University Eye Hospital between January 2019 and January 2020, including 160 patients with myopia (320 eyes). Data was gathered through clinical assessment of visual acuity, refractive error, and corneal endothelial cells...

PURPOSE: Refractive error is a major cause of visual impairment in children and its early detection can prevent ocular morbidity such as amblyopia and strabismus. Brückner test is a comprehensive test which can be easily administered in children using a direct ophthalmoscope. We aimed to determine refractive error in children by analysis of the red reflex using modified Brückner test. PATIENTS AND METHODS: This prospective observational study was conducted on 683 undilated eyes of 683 children aged four to 10 years...