Search results for "Genetic Structures"
showing 10 items of 2107 documents
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-…
Gly114Asp mutation of rhodopsin in autosomal dominant retinitis pigmentosa
1995
Two autosomal dominant retinitis pigmentosa families of different origin were screened for rhodopsin mutations using the method of single strand conformation polymorphism and direct sequencing. We found a CGG-CAG substitution in codon 114 of rhodopsin in both families. This change predicted the replacement of a glycine by an aspartic acid and suggested that this change is the cause of the disease in these families.
Dependence of Perceived Purity of a Chromatic Stimulus on Saturation Adaptation
2012
Background and Objective. The purpose of sensory adaptation of the visual system is to adjust sensitivity of the photoreceptors to optimize the dynamic range of response of the visual system. It has been shown in numerous research papers that chromatic adaptation influences both color appearance and color discrimination. However, there are almost no studies in which the influence of chromatic adaptation on perceived purity has been investigated. Therefore, the aim of this study was to investigate how chromatic adaptation to stimuli with certain saturation influences perceived purity of test stimuli with the same hue but different saturation. Material and Methods. As the stimuli were modulat…
Mutational screening of the USH2A gene in Spanish USH patients reveals 23 novel pathogenic mutations
2011
Abstract Background Usher Syndrome type II (USH2) is an autosomal recessive disorder, characterized by moderate to severe hearing impairment and retinitis pigmentosa (RP). Among the three genes implicated, mutations in the USH2A gene account for 74-90% of the USH2 cases. Methods To identify the genetic cause of the disease and determine the frequency of USH2A mutations in a cohort of 88 unrelated USH Spanish patients, we carried out a mutation screening of the 72 coding exons of this gene by direct sequencing. Moreover, we performed functional minigene studies for those changes that were predicted to affect splicing. Results As a result, a total of 144 DNA sequence variants were identified.…
Comparison of short-term light disturbance, optical and visual performance outcomes between a myopia control contact lens and a single-vision contact…
2020
Purpose To compare the optical and visual performance of a dual-focus (DF) contact lens used for myopia control with a single-vision (SV) contact lens of the same material. Methods A randomised, double-masked crossover study. Twenty-eight healthy, myopic volunteers between 18 and 32 years of age (23.49 +/- 4.07 years) participated in this study. The sensory dominant eye for distance vision was determined. Refraction, best-corrected visual acuity (VA) and aberrations for 3 mm and 5 mm pupil diameters were quantified without a contact lens in situ. Subjects were fitted with two contact lens designs: DF and SV, both made of omafilcon A material. The Quality of Vision (QoV) questionnaire, over-…
The hippocampus is required for short-term topographical memory in humans.
2007
The hippocampus plays a crucial role within the neural systems for long-term memory, but little if any role in the short-term retention of some types of stimuli. Nonetheless, the hippocampus may be specialized for allocentric topographical processing, which impacts on short-term memory or even perception. To investigate this we developed performance-matched tests of perception (match-to-sample) and short-term memory (2 s delayed-match-to-sample) for the topography and for the nonspatial aspects of visual scenes. Four patients with focal hippocampal damage and one with more extensive damage, including right parahippocampal gyrus, were tested. All five patients showed impaired topographical m…