Search results for "Presbyopia"
showing 10 items of 51 documents
Accuracy of five intraocular lens formulas in eyes with trifocal lens implant.
2020
Accuracy of intraocular lens (IOL) calculation formulas SRK/T, Hoffer Q, Holladay 1, Haigis and Barrett Universal II were compared in prediction of postoperative refraction for multifocal and implants using a single optical biometry device. The authors included 88 refractive lens exchange and cataract surgeries, with AcrySof IQ PanOptix implant (Alcon Laboratories, Inc.). All eyes were divided into three groups based on axial length (AL), group 1: 24.5 mm (6 eyes). The refractive prediction error (RPE) and mean absolute error (MAE) were calculated for 5 different formulas: SRK/T, Hoffer Q, Holladay 1, Haigis and Barrett Universal II. For eyes with the AL between 22 mm and 24.5 mm the greate…
Changes in tear film metrics and ocular signs induced by different types of refractive correction in an aging population
2018
La integridad de la superficie ocular, en otras palabras, su capacidad para responder adecuadamente a los desafíos ambientales, depende de la integración adecuada de la información desde la superficie ocular, la transmisión de la señal creada hacia el cerebro y la generación de una respuesta, que modulará la función secretora así como la inmunidad local de la superficie ocular. Es fácilmente comprensible que cualquier alteración de uno de los tres pasos de este ciclo cerrado pueda desencadenar una respuesta inapropiada y desequilibrar aún más los mecanismos compensatorios que tienen lugar en la superficie ocular. La unidad funcional de la lágrima se puede definir como un conjunto de estruct…
Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and me…
2017
PubMed: 28779882
Objective Amplitude of Accommodation Computed from Optical Quality Metrics Applied to Wavefront Outcomes
2009
Purpose: We studied the accuracy and precision of 32 objective wavefront methods for finding the amplitude of accommodation obtained in 180 eyes. Methods: Ocular accommodation was stimulated with 0.5 D steps in target vergence spanning the full range of accommodation for each subject. Subjective monocular amplitude of accommodation was measured using two clinical methods, using negative lenses and with a custom Badal optometer. Results: Both subjective methods gave similar results. Results obtained from the Badal optometer where used to test the accuracy of the objective methods. All objective methods showed lower amplitude of accommodation that the subjective ones by an amount that varied …
Simulated prototype of posterior chamber phakic intraocular lens for presbyopia correction.
2014
Purpose To evaluate the visual impact of adding different spherical aberration values to an Implantable Collamer Lens phakic intraocular lens (pIOL) to increase the depth of focus using an adaptive optics visual simulator. Setting University of Valencia, Valencia, Spain. Design Experimental study. Methods Wavefront aberrations in −3.00 D and −6.00 diopter (D) pIOLs were measured in vitro. Afterward, different simulated pIOL experimental prototypes were created along with variances in the spherical aberration. An adaptive optics visual simulator was used to simulate vision after the implantation of the different pIOL prototypes from their wavefront aberrations. The corrected distance visual …
Accommodative Functions with Multifocal Contact Lenses: A Pilot Study
2011
PURPOSE: To evaluate accommodative response and facility in presbyopic patients fitted with several types of simultaneous-image multifocal contact lenses (CLs). METHODS: Six presbyopic patients, unadapted wearers of simultaneous-image bifocals, were fitted with the Focus Progressives and the low- and high-addition Pure Vision simultaneous vision multifocal CLs. Each individual wore each of the three types of lenses in successive random order. Accommodative response, accommodative facility, visual acuity, and contrast sensitivity at distance and near were evaluated in all cases. A control group of eight non-presbyopic patients was also studied. RESULTS: The mean age was 28.6 +/- 2.72 and 51.…
Effect of age in the ciliary muscle during accommodation: Sectorial analysis
2017
Abstract Purpose To compare changes in the ciliary muscle area at different sectors between pre-presbyopic and presbyopic eyes during accommodation by means of an anterior segment optical coherence tomographer (OCT). Methods The anterior ciliary muscle area was measured in 20 healthy and phakic pre-presbyopic eyes, whose mean age was 23.3 ± 4.4 years, and in 20 healthy and phakic presbyopic eyes, whose mean age was 46.5 ± 5.2 years. The relative change in the cross-sectional area of the ciliary muscle was measured at the nasal, inferior, and temporal sectors between 0 and −3 D of vergence, in −1 D step. A linear model was used to assess the correlation of each eye parameter with the accommo…
Optical factors influencing the amplitude of accommodation
2017
AbstractThe purpose of this work was to find plausible predictors among optical parameters that may explain the inter-individual differences in subjective amplitude of accommodation not explained by age. An exploratory multivariable regression analysis was carried out retrospectively on a dataset with 180 eyes from 97 subjects (ages ranged from 20 to 58years). Subjective amplitudes of accommodation were recorded with the use of a custom-made Badal system. A commercial aberrometer was used to obtain each eye’s wavefront during the full range of accommodation. The plausible predictors under study were pupil diameter in the unaccommodated eye, its reduction with accommodation; fourth- and six-…
Refractive lens exchange with the Acri. Twin asymmetric diffractive bifocal intraocular lens system
2009
PURPOSE To evaluate efficacy, safety, and predictability after refractive lens exchange (RLE) in patients who had implantation of asymmetric Acri.Twin bifocal diffractive intraocular lenses. METHODS The study comprised 130 eyes of 65 consecutive patients after RLE who had bilateral implantation of the Acri.Twin system. Eyes were divided into myopic and hyperopic groups. Binocular uncorrected distance visual acuity, best-corrected distance visual acuity (BCVA), uncorrected distance near visual acuity, and best distance-corrected near visual acuity (BCNVA) were recorded preoperatively and 6 months after surgery. RESULTS Efficacy indexes were 0.99 for myopic and 0.93 for hyperopic patients at …
Response of the aging eye to first day of modern material contact lens wear
2018
Objectives: To investigate the ocular surface of an aged population wearing a daily disposable contact lens over their first day of wear. Methods: Forty eyes from forty presbyopic subjects were fitted a daily CL (Delefilcon A). Tear osmolarity, tear meniscus area (TMA) and ocular surface aberrations (total higher order root means square (RMS)) were assessed at baseline (t0), at 20 minutes (t1) and after 8 hours (t2) of wear. Fluorescein corneal and conjunctival staining and tear break up time (TBUT) were performed at t0 and t2. Results: No statistically significant changes were found between t0, t1 and t2 for TMA, and between t0 and t2 for fluorescein corneal and conjunctival staining. TBUT…