Search results for "Lens implantation"
showing 10 items of 140 documents
Modulation transfer function: Rigid versus foldable phakic intraocular lenses
2008
Purpose To study in a standard eye model the changes in modulation transfer function (MTF) of a monofocal intraocular lens (IOL) when a phakic IOL (pIOL) is placed in the anterior chamber, compare the MTFs of the rigid Artisan pIOL and foldable Artiflex pIOL, and evaluate the temporal evolution of the MTF of the foldable pIOL after the mechanical stress the pIOL undergoes when injected. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods The MTF values of the IOLs were calculated from the cross-line spread function recorded with the Opal Vector System. The measurements were taken using an eye model following the British and EN-ISO standards with 2.0 mm, 3.0 mm, 4.0 mm…
The posterior chamber phakic refractive lens (PRL): a review
2012
Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient’s accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on…
Implantable collamer lens and femtosecond laser for myopia: comparison using an adaptive optics visual simulator.
2014
Purpose: To compare optical and visual quality of implantable collamer lens (ICL) implantation and femtosecond laser in situ keratomileusis (F-LASIK) for myopia. Methods: The CRX1 adaptive optics visual simulator (Imagine Eyes, Orsay, France) was used to simulate the wavefront aberration pattern after the two surgical procedures for -3-diopter (D) and -6-D myopia. Visual acuity at different contrasts and contrast sensitivities at 10, 20, and 25 cycles/degree (cpd) were measured for 3-mm and 5-mm pupils. The modulation transfer function (MTF) and point spread function (PSF) were calculated for 5-mm pupils. Results: F-LASIK MTF was worse than ICL MTF, which was close to diffraction-limited MT…
Myopic astigmatism correction: comparison of a Toric Implantable Collamer Lens and a bioptics technique by an adaptive optics visual simulator.
2013
Purpose To compare the optical and visual quality of a simulated Toric Implantable Collamer Lens (TICL) and a bioptics technique to treat high myopic astigmatism. Methods An adaptive optics visual simulator was used to simulate the vision after TICL implantation and a bioptics procedure from the wavefront aberration pattern for moderate and high-myopic astigmatism. Visual acuity (VA) at different contrasts and contrast sensitivity (CS) at 10, 20 and 25 cycles degree−1 were measured for 3 and 5-mm pupils. Modulation Transfer Function (MTF) and Point Spread Function (PSF) were calculated for a 5-mm pupil. Results At a 3-mm pupil we only found statistically significant differences in VA betwee…
Optical Characterization Method for Tilted or Decentered Intraocular Lenses
2016
Purpose To test and validate a method for measuring the optical quality and optical power of monofocal intraocular lenses (IOLs) in the presence of a tilt or a decentration as well as its optical power. Methods The experimental system consists of an artificial eye (wet-cell) and a commercial aberrometer with a Shack-Hartmann sensor. Optical image quality parameters such as point spread function (PSF), modulation transfer function (MTF), and the simulations of the retinal image of an extended object are computed from the in vitro wavefront data of an IOL. Repeatability and reproducibility of the system are tested. Mathematical and ray-tracing simulations are used to ascertain the precision a…
Surgical management of acute angle-closure glaucoma after toric implantable contact lens implantation
2006
A case of pupillary block after implantation of an implantable contact lens (ICL) is reported, and surgical management and prevention are discussed. In a myopic patient, the best corrected visual acuity in the right eye was 20/50 with -15.50 -3.00 x 175. After uneventful implantation of an ICL, painful acute glaucoma developed with an intraocular pressure beyond measurable values. Apparent anterior vaulting of the ICL suggested a sizing problem. In a situation of a mid-wide dilated pupil, immediate explantation of the ICL was performed. Then, using a preoperative iris photography as guidance, an anterior chamber iris-claw toric phakic intraocular lens was implanted. On postoperative examina…
Intraocular lens centration and stability: efficacy of current technique and technology
2008
Purpose of review The manuscript presents a review of recently published studies analyzing different methodologies to assess centration and stability of intraocular lenses after implantation. Recent findings Considering that there is no current gold standard for centration and stability of intraocular lenses after implantation, we have summarized the different techniques used clinically for intraocular lenses centration and stability estimation. We have described the use of Scheimpflug imaging, the anterior segment optical coherence tomography and photography analysis used for lens position estimation. Techniques used to assess lens rotation are based on image analysis on digital retroillum…
Analysis of the possible benefits of aspheric intraocular lenses: review of the literature.
2008
We reviewed recently published studies that analyzed the visual and optical quality in eyes with different spherical and aspheric intraocular lenses (IOLs). Recent studies focused on visual quality metrics, such as visual acuity and contrast sensitivity, under photopic and mesopic lighting conditions and optical metrics, such as wavefront aberrations, especially spherical aberration. The results in this review were used in an attempt to understand whether there is a visual and/or optical benefit of implanting aspheric IOLs over implanting spherical IOLs.
Subjective photic phenomena with refractive multifocal and monofocal intraocular lenses. results of a multicenter questionnaire.
2001
Abstract Purpose To compare the incidence and severity of photic phenomena after the implantation of the Array® (Allergan) refractive multifocal intraocular lens (MIOL) and a monofocal IOL. Setting Multicenter study at Kiel, Mainz, Karlsruhe, and Bremerhaven, Germany. Methods The study comprised 231 randomly selected patients from 4 study centers. The patients had had uneventful phacoemulsification with implantation of a refractive MIOL (n = 138) or a monofocal IOL (n = 93). By questionnaire, patients were asked whether they experienced light sensations postoperatively (light streaks, halos, flare, flashes, or glare) that had not been noticed preoperatively. Additional questions evaluated w…
Endothelial cells loss to the hyperopic pacients during phacoemulsification
2018
Introduction The phacoemulsification cataract surgery is the most frequently performed surgery and it generally improves vision in over 90% of the patients. Hyperopic patients are a challenge during phacoemulsification especially because of their short eyeball and shallow anterior chamber. A shallow anterior chamber is associated with overall reduction of the safe zone, which may lead to difficulty in creating the corneal incisions, harder capsulorhexis performing, or endothelial complications. Purpose The aim of the study was to present the endothelial cells loss after the phacoemulsification procedure in the hyperopic patients. Material and methods A number of 1775 patients operated in th…