Search results for "Ophthalmology"

Characterization of the effect of intracorneal ring segment in corneal ectasia after laser refractive surgery

2018

Purpose: To evaluate the visual, refractive, topographic, pachymetric, and biomechanical outcomes after intracorneal ring segment implantation in corneas with post-LASIK ectasia. Methods: Retrospective longitudinal study enrolling 26 eyes of 22 patients with post-LASIK ectasia and undergoing intracorneal ring segment implantation (KeraRing®, Mediphacos) using a 60-kHz femtosecond laser (IntraLase®, IntraLase Corp.) for corneal tunnelization. Visual, refractive, anterior, and posterior corneal topographic (Pentacam HR, Oculus), pachymetric, and corneal biomechanical changes (Ocular response Analyzer, Reichert) were evaluated during a 12-month follow-up. Vector analysis of astigmatic changes …

Results of an Adaptive Surgical Approach for Managing Late Onset Hypotony After Trabeculectomy With Mitomycin C.

2018

OBJECTIVES The objective of this study is to investigate the results of an adaptive approach of bleb revision surgery for late onset hypotony after trabeculectomy with mitomycin C because of bleb leakage and/or scleral melting. METHODS A total of 29 eyes of 27 patients, aged 63.8±11.7 years with hypotony maculopathy [intraocular pressure (IOP), ≤6 mm Hg] because of late onset bleb leakage and/or scleral melting after trabeculectomy with mitomycin C in which minimally invasive transconjunctival suturing of the scleral flap was impossible were enrolled in this retrospective interventional case series. External bleb leakage was seen in 16 eyes, 11 eyes suffered from scleral melting. Because of…

Endothelial study of iris-claw phakic lens: four year follow-up.

1998

Abstract Purpose: To study quantitative and morphometric endothelial changes in phakic eyes implanted with the Worst iris-claw lens to correct high myopia. Setting: Department of Ophthalmology, University Hospital “La Fe”, Valencia, Spain. Material and Methods: This retrospective study involved 111 phakic eyes (73 patients) implanted with the Worst iris-claw lens. Noncontact specular microscopy and computer-assisted analysis was performed preoperatively and 6 months and 1, 2, 3, and 4 years postoperatively. Results: The mean cell loss was 3.85% at 6 months, 6.59% at 1 year, 9.22% at 2 years, 11.68% at 3 years, and 13.42% at 4 years. At 2 years, the hexagonality and coefficient variation in …

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 …

Structure-function relationship between FDF, FDT, SAP, and scanning laser ophthalmoscopy in glaucoma patients.

2012

Purpose Flicker defined form perimetry (FDF) and frequency doubling technology perimetry (FDT) are alleged to detect glaucoma at an earlier stage than standard automated perimetry (SAP). It is the purpose of this study to investigate the structure-function relationship between FDF, FDT, SAP, and confocal scanning laser ophthalmoscopy (cSLO) in patients with glaucoma. Methods Seventy-six patients with glaucoma were included in the study. Patients were tested with SAP, Matrix-FDT, FDF perimetry, and cSLO. Structure-function relationships between global and sectoral cSLO parameters and global and sectoral mean sensitivity (MS) of SAP, Matrix-FDT, and FDF were calculated using Spearman's rank c…

Flicker Defined Form Perimetry in Glaucoma Suspects with Normal Achromatic Visual Fields

2014

To evaluate if repeated flicker-defined form (FDF) perimetry can detect visual field (VF) defects in glaucoma suspects with normal findings in achromatic standard automated perimetry (SAP).Patients with optic nerve heads (ONHs) or retinal nerve fiber layer (RNFL) findings clinically suspicious for glaucoma and normal SAP were enrolled. Patients underwent VF testing with FDF perimetry (Heidelberg Edge Perimetry, HEP) at two consecutive visits (HEP I and HEP II) and confocal scanning laser ophthalmoscopy with the Heidelberg Retina Tomograph (HRT). Abnormal HEP was defined by cluster-point analysis (CPA) and by the HEP specific glaucoma hemi-field test (GHT). Results were compared with an age-…

Testing the egocentric mirror-rotation hypothesis.

2011

AbstractAlthough observers know about the law of reflection, their intuitive understanding of spatial locations in mirrors is often erroneous. Hecht et al. (2005) proposed a two-stage mirror-rotation hypothesis to explain these misconceptions. The hypothesis involves an egocentric bias to the effect that observers behave as if the mirror surface were rotated by about 2° to be more orthogonal than is the case. We test four variants of the hypothesis, which differ depending on whether the virtual world, the mirror, or both are taken to be rotated. We devised an experimental setup that allowed us to distinguish between these variants. Our results confirm that the virtual world — and only the v…

Prevalence of visual problems in a rural population of Kenya

2012

Intravitreal foscarnet for cytomegalovirus retinitis in a patient with acquired immunodeficiency syndrome.

1992

We treated a patient who had acquired immunodeficiency syndrome and cytomegalovirus retinitis of the left eye. After anesthetic had been topically administered, the patient received intravitreal injections of 1,200 micrograms of foscarnet. Plasma and vitreous foscarnet levels were measured by high-performance liquid chromatography. Systemic absorption of the drug was not evident. Elimination half-life from the vitreous after one injection was 54.0 hours. Vitreous levels remained above the mean 50% inhibition value for cytomegalovirus for approximately 56 hours and above the mean inhibition value for human immunodeficiency virus for approximately 241 hours. The patient's visual acuity improv…

Temporal expectation and spectral expectation operate in distinct fashion on neuronal populations

2013

The formation of temporal expectation (i.e., the prediction of ‘when’) is of prime importance to sensory processing. It can modulate sensory processing at early processing stages probably via the entrainment of low-frequency neuronal oscillations in the brain. However, sensory predictions involve not only temporal expectation but also spectral expectation (i.e., the prediction of ‘what’). Here we investigated how temporal expectation may interrelate with spectral expectation by explicitly setting up temporal expectation and spectral expectation in a target detection task. We found that temporal expectation and spectral expectation interacted on reaction time (RT). RT was shorter when target…