Search results for " Excimer"

Comparison of Intraocular Pressure During Corneal Flap Preparation Between a Femtosecond Laser and a Mechanical Microkeratome in Porcine Eyes

2011

To compare the increase in intraocular pressure (IOP) during corneal flap preparation in porcine eyes when using a femtosecond laser or a mechanical microkeratome.The present study was conducted at a university hospital and a private clinic.The vitreous IOP was directly measured with a cannula through the optic nerve in 24 porcine globes (n = 12 for each device). In the first procedure (worst-case procedure), the eye interface was lowered against the globe until abortion of the docking maneuver when using the IntraLase femtosecond laser (Abbott Medical Optics, Santa Ana, CA) or the suction ring was pressed very firmly against the globe when using the Amadeus microkeratome (Ziemer Ophthalmic…

Corneal thickness differences between type 2 diabetes and non-diabetes subjects during preoperative laser surgery examination

2016

Aims To evaluate the differences in corneal thickness between type 2 diabetes subjects with HbA1c under 7.0% and non-diabetes subjects during their preoperative laser surgery examinations. Methods The mean of five consecutive corneal thickness measurements at the central and mid-peripheral cornea was obtained by means of noncontact scanning-slit corneal topography (Orbscan Topography System II; Orbscan, Inc., Salt Lake City, UT, USA) in 35 myopic non-insulin dependent type 2 diabetes subjects (17 males and 18 females) and 48 healthy myopic controls (23 males and 25 females). Results The corneal thickness values at the central and mid-peripheral cornea were significantly higher in the diabet…

Femtosecond laser for residual refractive error correction after refractive lens exchange with multifocal intraocular lens implantation.

2008

Purpose To assess visual and refractive outcomes of femtosecond laser for residual refractive error correction after refractive lens exchange (RLE) with multifocal intraocular lens (IOL) implantation. Design Prospective, nonrandomized, masked observational case series (self-controlled). Methods Fifty-three eyes of 31 consecutive patients were submitted to femtosecond laser surgery after RLE with multifocal IOL implantation. Patients showed an average manifest refractive error (D) of M , 0.200 ± 0.490; J 0 , −0.051 ± 0.532; and J 45 , −0.007 ± 0.371. Visual acuity (VA) was measured at distance and near vision before and six months after the surgery. Results At six months after surgery, mean …

Incisional Keratotomy to Toric Intraocular Lenses: An Overview of the Correction of Astigmatism in Cataract and Refractive Surgery

2003

Optical and visual performance of diffractive intraocular lens implantation after myopic laser in situ keratomileusis

2008

To evaluate the optical and visual quality in eyes with diffractive intraocular lenses (IOLs) after myopic laser in situ keratomileusis (LASIK).Fernández-Vega Ophthalmological Institute, Oviedo, Spain.The best corrected visual acuity (BCVA [distance]) at 12.5%, 25.0%, and 100% contrasts under photopic and mesopic conditions; best distance-corrected near acuity; corneal total higher-order aberrations (HOAs); and optical quality by modulation transfer function (MTF) were measured after myopic LASIK in eyes with a spherical AcrySof ReSTOR SN60D3 IOL or an aspheric Acri.LISA 366D IOL and phakic eyes (control).Under photopic conditions at 100% contrast, the BCVA was 0.1 logMAR or better in all g…

Visual quality after diffractive intraocular lens implantation in eyes with previous hyperopic laser in situ keratomileusis

2010

To evaluate distance, intermediate, and near visual quality in eyes with diffractive intraocular lens (IOL) implantation after previous hyperopic laser in situ keratomileusis (LASIK).Fernández-Vega Ophthalmological Institute, Oviedo, Spain.Cohort study.Corrected distance visual acuity (CDVA) at 12.5%, 25.0%, and 100% contrast levels under photopic and mesopic conditions; uncorrected (UNVA) and distance-corrected (DCNVA) near visual acuity, defocus curves, and corneal higher-order aberrations (HOAs) were measured in eyes that had AcrySof Restor SN60D3 spherical IOL implantation (study group) and in phakic eyes (control group) after hyperopic LASIK.Under photopic conditions at 100% contrast, …

Toward the understanding of DNA fluorescence: The singlet excimer of cytosine

2006

By using the multiconfigurational second-order perturbation method CASPT2, including corrections for the basis set superposition error, the lowest-singlet excited state of the face-to-face π-stacked cytosine homodimer is revealed to be bound by about half an eV, being the source of an emissive feature consistent with the observed redshifted fluorescence. Gloria.Olaso@uv.es Daniel.Roca@uv.es Luis.Serrano@uv.es Manuela.Merchan@uv.es

Ultraviolet-induced paramagnetic centers and absorption changes in singlemode Ge-doped optical fibers

2009

We investigated the laser-energy-density dependence of absorption changes and paramagnetic centers induced by a cw Ar+ laser operating at 5.1 eV, in both unloaded and H-2-loaded single mode Ge-doped optical fibers. The induced absorption is measured in the blue and near ultraviolet spectral range by using the 3.1 eV photoluminescence, ascribed to Ge lone pair center (GLPC), as an in situ probe source. We find that the Ge (1) center (GeO4-) is induced upon UV exposure by electron trapping on GeO4 precursors, where the free electrons are most likely produced by ionization of GLPC. Ge (1) is responsible of optical transmission loss of the fiber in the investigated range. Hydrogen loading stron…

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…

Irregularity of the posterior corneal surface during applanation using a curved femtosecond laser interface and microkeratome cutting head.

2012

PURPOSE: To evaluate the irregularity of the posterior corneal surface and intrastromal dissection during the preparation of donor tissue for Descemet stripping automated endothelial keratoplasty (DSAEK) using a curved interface femtosecond laser and microkeratome. METHODS: Sixteen human donor corneas unsuitable for transplantation were divided into two groups: a femtosecond (FS) laser group (n=7) using the VisuMax femtosecond laser (Carl Zeiss Meditec) and a microkeratome group (n=9) using the Amadeus II microkeratome (Ziemer Ophthalmic Group). The corneas were fixed on artificial anterior chambers. Horizontal cross-sections were obtained using spectral-domain optical coherence tomography…