Myopia (nearsightedness) and hyperopia (farsightedness) are almost equally distributed in the general population but myopia has received the most surgical attention, probably because it produces the greater disability. It also seems more amenable to surgical correction as the widespread successful employment of radial keratotomy bares out. On the other hand, attempts at surgically correcting hyperopia such as hexagonal keratotomy; thermokeratoplasty; hyperopic lamellar keratotomy, and keratophakia have had a less happy experience. Even the more sophisticated technique of laser photoablation is unable to successfully manage hyperopia. It would seem that steepening the cornea is much more difficult than flattening it. Refractive eye surgery is a new subspecialty of ophthalmology only recently come into its own. Considering the tremendous changes in cataract surgery in the past 30 years it is likely that hyperopia will eventually fall to the refractive eye surgeon.
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Graefes Arch Clin Exp Ophthalmol
January 2025
National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, 618# Fengqi East Road, Hangzhou, 310000, Zhejiang, China.
Purpose: To calculate the crystalline lens power and astigmatism, as well as their changes following cycloplegia, in individuals with myopia using swept-source optical coherence tomography (SS-OCT).
Methods: Participants were divided into two groups according to axial length (AL). Crystalline lens parameters, including power, lens thickness (LT), anterior chamber depth (ACD), and astigmatism, were measured with SS-OCT and analysed before and after cycloplegia.
Front Med (Lausanne)
January 2025
Department of Ophthalmology, Emory University, Atlanta, GA, United States.
Objective: Myopia prevalence is increasing at alarming rates, yet the underlying mechanistic causes are not understood. Several studies have employed experimental animal models of myopia and transcriptome profiling to identify genes and pathways contributing to myopia. In this study, we determined the retinal transcriptome changes in response to form deprivation in mouse retinas.
View Article and Find Full Text PDFField-of-view (FOV) and resolution are two critical performance metrics of a near-to-eye display (NED) and are primarily limited by the refractive index (RI) of the waveguide combiner and the number of available pixel counts of the micro display. A high RI material (n = 2.0) is required to transfer an image exceeding a 60 degree full FOV using traditional techniques.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Ophthalmology, Erasmus Medical Centre, Rotterdam, The Netherlands.
This report explores the prevalence of keratoconus in a population-based cohort of adults aged 40 or older according to ten different definitions. All Rotterdam Study participants with reliable Pentacam scans and no prior corneal refractive surgery were cross-sectionally analysed (n = 2660). First, we applied a novel evidence-based definition.
View Article and Find Full Text PDFJ Ophthalmol
January 2025
Optics and Optometry Department, Universidad Complutense de Madrid, Madrid, Spain.
To analyze the refractive accuracy of a novel swept-source optical coherence biometer (SS-OCT), that uses individual refractive indices to measure axial length, in short and long eyes implanted with monofocal intraocular lenses (IOLs). This retrospective comparative study considered eyes with short axial length (AL) (< 22.5 mm) or long AL (> 26 mm) bilaterally implanted with the Acrysof IQ monofocal IOL.
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