Search results for "Dioptre"
showing 10 items of 86 documents
Astigmatism in infancy and childhood.
2000
ABSTRACT Purpose: To evaluate the prevalence of astigmatism In infancy and childhood In a Spanish population. Methods: A total of 478 children with astigmatism from Valencia Province, Spain were examined. The patients, ranging in age from 2-1 2 years, were classified into groups according to age. Astigmatism error and axis orientation were determined using noncyclopeglc retlnoscopy over each eye. Results: The overall prevalence of astigmatism (5=1.00 diopter of cylinder) decreased In relation to increasing age from 44.3% to 5.2%. The prevalence of against-the-rule astigmatism decreased from 61.5% (at 2 years) to 33.4% (at 12 years), with-the-rule astigmatism increased In prevalence from 23.…
Relationship among Corneal Biomechanics, Refractive Error, and Axial Length
2014
Purpose To evaluate the relationship between different ocular and corneal biomechanical parameters in emmetropic and ametropic healthy white children. Methods This study included 293 eyes of 293 healthy Spanish children (135 boys and 158 girls), ranging in age from 6 to 17 years. Subjects were divided according to the refractive error: control (emmetropia, 99 children), myopia (100 children), and hyperopia (94 children) groups. In all cases, corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer system. Axial length (AL) and mean corneal power were also measured by partial coherence interferometry (IOLMaster), and central corneal thickne…
Toric intraocular lens versus opposite clear corneal incisions to correct astigmatism in eyes having cataract surgery.
2009
To compare toric intraocular lens (IOL) implantation with paired opposite clear corneal incisions (OCCIs) for astigmatism correction in patients having cataract surgery.Ophthalmology Service, Donostia Hospital, San Sebastián, Spain.This randomized prospective clinical study comprised eyes with more than 1.00 diopter (D) of preexisting corneal astigmatism. One group had AcrySof toric IOL implantation and the other, paired 2.75 mm/3.20 mm OCCIs in the steep axis with spherical IOL implantation. Uncorrected (UCVA) and best corrected (BCVA) visual acuity, refraction, corneal and total higher-order aberrations (HOAs), photopic and mesopic contrast sensitivity, and toric IOL axis were measured 3 …
Implantation of a toric poly(methyl methacrylate) intraocular lens to correct high astigmatism
1999
Abstract A 57-year-old man experienced a decrease in visual function because of cataract formation. Corneal astigmatism was 13.4 diopters (D) because he had had a penetrating keratoplasty 27 years before. Cataract surgery was planned, and biometric data for toric intraocular lens (IOL) implantation were collected for the manufacture of a custom IOL. After phacoemulsification, a toric poly(methyl methacrylate) (PMMA) IOL of +19.0 D spherical and +12.0 D cylindrical power was implanted via a sclerocorneal tunnel incision. Three months postoperatively, corneal astigmatism was 14.3 D and best corrected visual acuity (BCVA), 20/25. Postoperative refraction (+1.5 −3.0 × 90) and BCVA remained stab…
Effect of head position on refraction in aphakic and phakic silicone-filled eyes.
1997
BACKGROUND The refraction of the eye is altered significantly after the instillation of silicone oil into the vitreous cavity because of the silicone oil's high refractive index. The degree of the refractive change shows diurnal variation and depends on the patient's head position. PATIENTS AND METHODS To analyze the degree and time course of refractive changes with respect to head position, the authors performed objective refraction in five aphakic and five phakic silicone oil-instilled eyes with attached maculae using an automatic hand-held refractometer. In each patient, 25 measurements were taken at short intervals using a hand-held autorefractometer with the patient in different positi…
Intermediate visual function with different multifocal intraocular lens models
2009
Purpose To compare visual acuity at different distances after bilateral implantation of 1 of 4 multifocal intraocular lenses (IOLs). Setting Fernandez-Vega Ophthalmological Institute, Oviedo, Spain. Methods This study evaluated consecutive patients who had bilateral implantation of a spherical multifocal IOL with a +4.00 diopter (D) addition (add) (AcrySof ReSTOR SN60D3) or an aspheric multifocal IOL with a +4.00 D add (AcrySof ReSTOR SN6AD3), +3.75 D add (Acri.LISA 366D), or +3.00 D add (AcrySof ReSTOR SN6AD1). Six months postoperatively, binocular measurement of corrected distance visual acuity (CDVA) at 4 m, corrected near visual acuity (CNVA) at 40 cm, and corrected intermediate visual …
Visual acuity comparison of 2 models of bifocal aspheric intraocular lenses.
2008
Purpose To compare visual acuity after bilateral implantation of 2 models of multifocal aspheric intraocular lenses (IOLs). Setting Fernandez-Vega Ophthalmological Institute, Oviedo, and University of Valencia, Valencia, Spain. Methods Prospective study of patients who had bilateral implantation of an AcrySof ReSTOR SN6AD3 IOL (Group 1) or an Acri.LISA 366D IOL (Group 2). Six months postoperatively, binocular uncorrected and best corrected distance visual acuity, uncorrected-distance and best distance-corrected near visual acuity, best corrected intermediate visual acuity, and the defocus curve were measured in both IOL groups. Results Group 1 comprised 36 eyes (18 patients) and Group 2, 40…
Optical quality of the eye after lens replacement with a pseudoaccommodating intraocular lens
2007
To examine the optical quality of healthy presbyopic eyes before and after implantation of the pseudoaccommodating AcrySof ReSTOR Natural intraocular lens (IOL) (Alcon Laboratories) by measuring visual acuity and wavefront aberrations.University of Valencia, Fernández-Vega Ophthalmological Institute, Valencia, Spain.Monocular refraction and photopic distance (6 m) and near (0.33 m) visual acuities were determined before and after clear lens extraction with bilateral AcrySof ReSTOR Natural IOL implantation in 30 hyperopic eyes (+0.50 to +4.00 diopters [D]) of presbyopic patients with low astigmatism (or = 1.00 D). Postsurgical binocular visual acuity was measured over a range of effective di…
Refractive Lens Exchange with Foldable Toric Intraocular Lens
2009
To assess visual and refractive outcomes, and rotational stability after refractive lens exchange (RLE) with toric intraocular lens (IOL) implantation to correct ametropia and preexisting astigmatism.Prospective, nonrandomized, observational case series (self-controlled).This prospective, nonrandomized, and self-controlled study included 32 eyes of 19 consecutive patients with more than 1.00 diopter (D) of preexisting corneal astigmatism having RLE with AcrySof Toric IOL implantation (Alcon Laboratories Inc, Fort Worth, Texas, USA). Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refractive sphere, and keratometric and refractive cylinder were recorded preoperatively …
Stereoacuity After Refractive Lens Exchange With AcrySof ReSTOR Intraocular Lens Implantation
2009
Purpose: To evaluate stereoacuity before and after refractive lens exchange (RLE) with AcrySof ReSTOR intraocular lens (IOL) implantation. Methods: Stereoacuity was measured using the Titmus stereotest at 40 cm under photopic conditions (85 cd/m 2 ) before and after RLE with bilateral AcrySof ReSTOR Natural (SN60D3 model) implantation in 30 hyperopic eyes of presbyopes with low astigmatism (⩽1.00 diopter [D]). Stereoacuity measurements after implantation were compared with those found before surgery. Results: Stereoacuity was unchanged after RLE with pseudoaccommodative IOL implantation. In this population of non-cataractous hyperopes with excellent preoperative stereoacuity (46.42±1.36 se…