Search results for " Lens"
showing 10 items of 510 documents
Change in pupil size after implantation of an iris-fixated toric phakic intraocular lens
2005
Purpose To evaluate the changes in pupil size after implantation of an iris-supported toric phakic intraocular lens (TPIOL) for correction of myopia and hyperopia with astigmatism. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Twenty-two myopic eyes and 9 hyperopic eyes were included in the study. The mean age of the 2 groups was 34 years and 40 years, respectively. The scotopic pupil size was measured with a handheld infrared pupillometer (Colvard, Oasis Medical) before and 6 months after implantation of the TPIOL. All examinations were performed under scotopic conditions after 2 minutes of dark adaptation with the fellow eye covered. Intraindi…
Effect of trypan blue on the elasticity of the human anterior lens capsule.
2007
Purpose To evaluate the effect of trypan blue (VisionBlue) staining on the elastic properties of the human anterior lens capsule. Setting Center for Vision Science, Ruhr University Eye Hospital, Bochum, Germany. Methods Nineteen anterior capsules were obtained from 19 human eyes at the time of cataract operation. Two same-size strips were prepared from each capsule; 1 was exposed to trypan blue staining for 10 seconds, and the other was a control. The elasticity measurements were performed on both specimens using a modified rheometer. Results The mean age of the patients was 75.3 years ± 13.3 (SD) (range 35 to 89 years). Sixty-three measurements of 19 suitable specimen pairs were performed.…
Tear film stability over a myopia control contact lens compared to a monofocal design
2021
Background: To compare the short-term effect of two contact lenses on pre-lens tear film stability and comfort: dual-focus contact lens (MiSight) and a monofocal contact lens (Proclear 1-day).Methods: This randomised, double-masked, crossover study was performed in twenty-eight healthy, myopic volunteers aged between 18 and 32 years (23.5 +/- 4.1 years). Only one randomly chosen eye was assessed. Distance vision and refraction were evaluated at baseline. Each contact lens type (monofocal and dual-focus) was randomly fitted, always in both eyes. A visual analogue scale between 0 and 10 was used to assess general comfort, physical comfort, and visual comfort. Tear Film Surface Quality (TFSQ) …
Optical and Visual Quality of the Visian Implantable Collamer Lens Using an Adaptive-Optics Visual Simulator
2013
To evaluate visual and optical quality of the implantable collamer lens for different powers and sizes of incision surgery.Prospective study in humans.An adaptive optics visual simulator was used to measure 3 powers of implantable collamer lenses and simulate the implantable collamer lens wavefront aberration's pattern for small- and large-incision surgery. Visual acuity (VA) and contrast sensitivity were measured in 11 observers for 3- and 5-mm pupils. Modulation transfer function, point spread function, and Strehl ratio were calculated.At 3 mm pupil, no statistically significant differences were found between both incision sizes for any implantable collamer lens power, except for -15 diop…
Influence of optic quality on contrast sensitivity and visual acuity in eyes with a rigid or flexible phakic intraocular lens
2009
Purpose To determine whether the difference in optic quality between 2 types of phakic intraocular lenses (pIOLs) affects visual quality. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods Before implantation of a pIOL for myopia, all eyes had an examination including corrected (CDVA) and uncorrected (UDVA) distance visual acuity testing, corneal endothelial cell count (ECC), and intraocular pressure (IOP) measurement. The postoperative outcomes, determined at least 1 year after surgery, were CDVA; UDVA; contrast sensitivity function under photopic, mesopic, and mesopic with glare conditions; ECC; IOP; keratometry (Scheimpflug photography); and total ocular aberratio…
Fixed Mydriatic Pupil Associated with an Intraocular Pressure Rise as a Complication of the Implant of a Phakic Refractive Lens (PRL)
2013
We describe a case report of a patient that was implanted with a posterior chamber phakic intraocular lens (Phakic Refractive Lens, PRL) for the correction of moderate myopia and who developed postoperatively a fixed mydriasis compatible with an Urrets-Zavalia Syndrome (UZS). Specifically, a sudden acute increase of IOP in the left eye was observed in the immediate postoperative period. After IOP stabilization, the refractive result was good, but a fixed and mydriatic pupil appeared. This condition led the patient to experience visual discomfort, halos, and glare associated with high levels of higher-order aberrations in spite of the good visual result. A tinted-contact lens was fitted in o…
Impact of the line of sight on toric phakic intraocular lenses for hyperopia
2003
We present a hyperopic patient with a decentered line of sight in whom the residual refractive error after toric phakic intraocular lens (TP IOL) implantation was improved by displacement and individualized treatment. A 35-year-old woman presented with asthenopic complaints 2 months after bilateral TP IOL implantation and IOL rotation 4 weeks later. Examination revealed the line of sight to be nasally and inferiorly decentered in relation to the center of the pupil. A more nasal reenclavation of the TP IOL decreased the coma, and the uncorrected visual acuity was 20/20. We conclude that line of sight should be measured before TP IOL implantation, especially in hyperopic eyes.
Differences in Corneal Anatomy in a Pair of Monozygotic Twins Due to Continuous Contact Lens Wear
2003
Purpose To study the differences in the corneal anatomy in a pair of 31-year-old monozygotic female twins, one of whom has been a contact lens wearer for the past 15 years and the other is a nonwearer. Methods We analyzed the corneal thickness and the corneal endothelial cell density of the monozygotic twins and of two age-matched control groups, one made up of non-contact lens wearers (35 eyes of 35 patients; mean age, 29.32 +/- 2.83 years) and the other made up of soft contact lens wearers (30 eyes of 30 patients; mean age, 33.08 +/- 3.72 years; mean duration of contact lens use, 10.62 +/- 4.32 years). Five corneal thickness measurements were carried out with the Orbscan Topography System…
Simulating Images Seen by Patients with Inhomogeneous Sensitivity Losses
2012
PURPOSE We aim to simulate how colored images are perceived by subjects with local achromatic and chromatic contrast sensitivity losses in the visual field (VF). METHODS The spatiochromatic corresponding pair algorithm, introduced in a previous article (J Opt Soc Am (A) 2004;21:176-186), has been implemented with a linear model of the visual system. Spatial information is processed separately by the chromatic and achromatic mechanisms by means of a multiscale model, with sensors selective to frequency, orientation, and spatial position, whose mechanism-dependent relative weights change with the spatial location of the image. These weights have been obtained from perimetric data from a patie…
Lens-vault analysis and its correlation with other biometric parameters using swept-source OCT
2021
Purpose To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT). Methods We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ± 12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance. Results Mean LV wa…