Search results for "ophthalmology"
showing 10 items of 1738 documents
Optical coherence tomography of macular thickness after biaxial vs coaxial microincision clear corneal cataract surgery
2009
PURPOSE To evaluate macular thickness changes after biaxial microincision versus coaxial small incision cataract surgery using optical coherence tomography (OCT). METHODS This prospective, randomized, marked study comprised 70 patients (70 eyes) undergoing biaxial microincision surgery or conventional coaxial phacoemulsification. Patients were evaluated by Stratus OCT preoperatively and 1 day, 4 weeks, and 8 weeks postoperatively. Best-corrected visual acuity (BCVA), phacoemulsification power, and effective phacoemulsification time (EPT) were evaluated. RESULTS In the biaxial group, median foveal thickness changed from 160 microm preoperatively to 168 microm 8 weeks postoperatively (p=0.018…
Incidence of posterior vitreous detachment after cataract surgery
2009
Purpose To report the incidence of posterior vitreous detachment (PVD) after uneventful state-of-the-art small-incision phacoemulsification with implantation of a posterior chamber intraocular lens (PC IOL). Setting Department of Ophthalmology, Ludwigshafen Hospital, Ludwigshafen, Germany. Methods This prospective study evaluated the vitreous status of eyes by biomicroscopic examination, indirect binocular ophthalmoscopy, and B-scan ultrasonography before planned cataract surgery. Patients with the posterior vitreous attached were included for follow-up and examined 1 week, 1 month, and 1 year after uneventful phacoemulsification with PC IOL implantation. The preoperative prevalence and pos…
Visual quality comparison of conventional and Hole-Visian implantable collamer lens at different degrees of decentering
2013
Purpose To compare the visual quality of implantable collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering. Methods An adaptive optics visual simulator (crx1, Imagine Eyes, Orsay, France) was used to simulate the –3, –6 and –12 dioptres (D) conventional and Hole ICLs in three conditions: centred and decentred 0.3 and 0.6 mm. Visual acuity (VA) at high-contrast, medium-contrast and low-contrast and contrast sensitivity (CS) were measured in 15 observers for 3 and 4.5 mm pupils. Results No statistically significant differences in VA and CS were found between conventional and Hole ICLs for any ICL powers and pupil sizes evaluated …
Optical and Visual Simulation of Standard and Modified Spherical Aberration Implantable Collamer Lens Post Myopic LASIK Surgery
2013
To evaluate the visual quality achieved in patients undergoing standard or modified implantable Collamer lens (ICL) to correct residual myopic error after laser-assisted in situ keratomileusis (LASIK) surgery.The adaptive optics visual simulator was used to simulate LASIK surgery of moderate and high myopia with a myopic regression corrected by a standard and modified ICL. Visual acuity (VA) and contrast sensitivity (CS) were measured in 14 subjects at 3- and 4.5-mm pupil. Point spread function and simulated retinal images were calculated.Comparing LASIK plus standard ICL and LASIK plus modified ICL simulations, for moderate myopia, VA improvement was less than 1 line in all VA contrasts an…
Image quality and visual performance in the peripheral visual field following photorefractive keratectomy.
2002
ABSTRACT PURPOSE: A theoretical and experimental study was performed to assess the possible effects of photorefractive keratectomy (PRK) on retinal image quality and thresholds in the peripheral visual field. METHODS: Simple optical calculations suggest that although the quality of the retinal image at the fovea of the postoperative PRK eye may be comparable to that in an emmetropic eye, images in the peripheral field may be markedly worse, since peripheral ray bundles may pass partly through ablated and partly through unablated cornea, giving a simultaneous-vision bifocal effect. This would be expected to create an annular zone of confusion, so that light from two different directions in o…
Effect of phenylephrine on static and dynamic accommodation
2018
Purpose We tested the hypothesis that changes in accommodation after instillation of Phenylephrine Hydrochloride (PHCl) observed in some studies could be caused by changes in optics. Methods We performed two experiments to test the effects of PHCl on static and on dynamic accommodation in 8 and 6 subjects, respectively. Objective wavefront measurements were recorded of the static accommodation response to a stimulus at different distances or dynamic accommodation response to a sinusoidally moving stimulus (between 1 and 3 D of accommodative demand at 0.2 Hz). The responses were characterized using two methods: one that takes into account the mydriatic optical effects on the accommodation pr…
The progression of myopia from its onset at age 8-12 to adulthood and the influence of heredity and external factors on myopic progression. A 23-year…
2013
Purpose To examine myopic progression and factors connected with myopic progression. Methods Myopic schoolchildren, with no previous spectacles, 119 boys and 121 girls, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia with a subsequent 20-year follow-up. Participants' mean age at Baseline was 10.9, ranging from 8.7 to 12.8 years. An ophthalmological examination was carried out annually for 3 years and twice thereafter at ca. 10-year intervals. Additional refraction values were received from prescriptions issued by different ophthalmologists and opticians. Altogether, 1915 refraction values were available. Reading distance and accommodation…
Clinical patterns and electrophysiological findings in retinal pigment epithelium diseases. Does a correlation exist?
1986
At present it is difficult to distinguish those human chorioretinal diseases in which the retinal pigment epithelium (RPE) is the primary site of dysfunction. This difficulty is caused by several factors such as scarcity of biochemical and histological information and a lack of correlation of basic science information available with the clinical body of knowledge. In the present study we examined 134 eyes at early or late stages of hereditary diseases involving the RPE. We tried to distinguish primary RPE involvement by using standard ERG (a- and b-wave) and EOG testing. We conclude that in general primary RPE damage can be better assessed by current electrophysiology in those diseases whic…
The effect of cigar smoking on the lingual microcirculation
2005
The aim of this study was to analyze the lingual microcirculation in vivo and to evaluate the effects on it of cigar smoking, using computerized videocapillaroscopy. Twenty-five healthy nonsmokers and 25 healthy smokers were examined. For each subject we evaluated the visibility, course, tortuosity, and any images characteristic of capillary loops, as well as the possible presence of microhemorrhages, the average caliber of the capillary loops, and the number of capillary loops visible per square millimeter. The investigation of the lingual mucosa revealed capillary loops with a course parallel to the surface. In smokers, capillary loops had a smaller caliber (P < 0.001) and there was a hig…
Flow cytometric analysis of conjunctival epithelium in ocular rosacea and keratoconjunctivitis sicca
2000
Abstract Purpose To investigate by flow cytometry and impression cytology (IC) specimens the inflammatory status of the conjunctival epithelium and goblet cell density in two series of patients with rosacea and dry eye syndrome compared with a population of healthy subjects. Design Nonrandomized, prospective, comparative case series. Participants Twenty-six eyes of 13 patients with rosacea, 26 eyes of 13 patients with dry eye syndrome, and 24 eyes of 12 control subjects were included in this study. Methods IC specimens were collected after clinical examination of the ocular surface and analyzed by flow cytometry, using antibodies directed to human lymphocyte antigen-DR (HLA-DR), intercellul…