Search results for "visual"
showing 10 items of 7386 documents
Light scattering in artificial fog and simulated with light scattering filter.
2009
Disability glare, affecting e.g. road safety at night, may result either from intraocular light scattering or from external conditions such as fog. Measurements were made of light scattering in fog and compared with intraocular straylight data for normal eyes and eyes with simulated cataract. All measurements were made with a direct compensation flicker method. To estimate light scattering levels in fog, straylight measurements were carried in a fog chamber for different densities of fog. Density was characterized by the meteorological term visibility V and ranged from 7 to 25. Test distance for measurements in the fog was constant at 5 m. Cataract eye conditions were simulated by placing a…
Optical and Visual Quality of the Visian Implantable Collamer Lens Using an Adaptive-Optics Visual Simulator
2013
To evaluate visual and optical quality of the implantable collamer lens for different powers and sizes of incision surgery.Prospective study in humans.An adaptive optics visual simulator was used to measure 3 powers of implantable collamer lenses and simulate the implantable collamer lens wavefront aberration's pattern for small- and large-incision surgery. Visual acuity (VA) and contrast sensitivity were measured in 11 observers for 3- and 5-mm pupils. Modulation transfer function, point spread function, and Strehl ratio were calculated.At 3 mm pupil, no statistically significant differences were found between both incision sizes for any implantable collamer lens power, except for -15 diop…
Photobiomodulation therapy reduces postoperative pain after third molar extractions: A randomized clinical trial
2020
Background To assess the efficacy of PBMT on reducing postoperative pain scores in patients submitted to third molar extractions. Material and Methods A randomized controlled trial (ReBEC:RBR-94BCKZ) was designed according to the SPIRIT and followed the CONSORT. Patients were randomly allocated according to control or PBMT groups. PBMT consisted of the application of GaAlAs laser (808nm;50mW) applied in six points (1.23 min;11 J/cm2) after extraction. Pain scores were assessed using the Visual Analogue Scale (VAS) in millimeters evaluated after 6 (T6), 24 (T24), and 48 (T48) hours. The Wilcoxon Mann–Whitney test was used to check for possible associations between VAS scores and treatment gr…
Effect of lingual-based flap design on postoperative pain of impacted mandibular third molar surgery : split-mouth randomized clinical trial
2020
Background The extraction of third molars is one of the most common procedures in oral and maxillofacial surgery clinic. Surgical extraction involves the manipulation of both soft and hard tissues, so the patient usually experiences pain, swelling, and trismus in the immediate post-operative period. Several studies have been conducted using different types of surgical flaps to provide access with the least possible damage of soft tissues. Designing and implementing an optimum flap, which provides easier technique, better visibility, minimal post-operative complications, and best healing, is an aspired goal of every oral surgeon. This study aimed to compare lingual-based four-cornered flap w…
The effect of spherical aberration on visual performance and refractive state for stimuli and tasks typical of night viewing
2018
Purpose: The aim of this work was to examine the impact of Seidel spherical aberration (SA) on optimum refractive state for detecting and discriminating small bright lights on a dark background. Methods: An adaptive-optics system was used to correct ocular aberrations of cyclopleged eyes and then systematically introduce five levels of Seidel SA for a 7-mm diameter pupil: 0, ± 0.18, and ± 0.36 diopters (D) mm−2. For each level of SA, subjects were required to detect one or resolve two points of light (0.54 arc min diameter) on a dark background. Refractive error was measured by adjusting stimulus vergence to minimize detection and resolution thresholds. Two other novel focusing tasks for si…
Interactive effects of avoidant coping and parental hypertension on Rate Pressure Product reactivity in women
2005
Background: Previous research suggests that personality, situational context variables, and genes might interact to potentiate cardiovascular stress responses.Purpose: Our purpose is to examine interactive effects of dispositional avoidant coping and parental hypertension on cardiovascular reactivity to three different laboratory stressors.Method: Participants were 63 healthy female students. Stressors were an evaluated videotaped speech, the cold pressor, and viewing of the speech video. Heart rate and blood pressure were continuously recorded during baselines and tasks.Results: After controlling for age, body mass index, smoking status, reported exercise, alcohol consumption, oral contrac…
Multilayer amniotic membrane transplantation in severe ocular graft versus host disease
2001
To clarify the usefulness of multilayer amniotic membrane transplantation in an unusual case of calcareous corneal degeneration in a patient with graft-versus-host disease.A 20-year-old Caucasian woman had bilateral calcareous corneal degeneration of one year of evolution, secondary to graft-versus-host disease. Treatment for both eyes with topical steroids and antibiotic ointment was not successful. Right eye had a spontaneous corneal perforation, and a three-layer circle amniotic membrane graft was applied to the whole cornea.During a follow-up period of 20 months we observed stability of the corneal epithelium and stroma. The amniotic membrane-covered area showed rapid epithelization, re…
Electrophysiological findings of neuronal ceroid lipofuscinosis in heterozygotes.
1988
Nineteen obligate heterozygotes, 8 individuals at risk of being heterozygote, and 10 patients afflicted with four different forms of neuronal ceroid lipofuscinosis were examined electrophysiologically. The group of obligate heterozygotes was compared to age-matched control groups. Statistically significant differences were found between scotopic b-wave amplitudes, P-ERG amplitudes, and EOG light peaks of the obligate carriers of the juvenile type and the control subjects. The photopic L-ERGs and the latencies of the VEPs were mostly within the normal range. The findings represent the first evidence of functional ophthalmological changes in obligate carriers of neuronal ceroid lipofuscinosis…
Four-phase rhinomanometry: a multicentric retrospective analysis of 36,563 clinical measurements
2015
Rhinomanometry can still be considered as the standard technique for the objective assessment of the ven- tilatory function of the nose. Reliable technical requirements are given by fast digital sensors and modern information technology. However, the xyimaging of the pressure-flow relation typically shows loops as a sign of hysteresis, with the need for resolution of the breath in four phases. The three pillars of 4-phase rhinomanometry (4PR) are the replacement of estimations by measurements, the introduc- tion of parameters related to the subjective sensing of obstruction, and the graphical information regarding the disturbed function of the nasal valve. In a meta-analysis of 36,563 clini…
Influence of optic quality on contrast sensitivity and visual acuity in eyes with a rigid or flexible phakic intraocular lens
2009
Purpose To determine whether the difference in optic quality between 2 types of phakic intraocular lenses (pIOLs) affects visual quality. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods Before implantation of a pIOL for myopia, all eyes had an examination including corrected (CDVA) and uncorrected (UDVA) distance visual acuity testing, corneal endothelial cell count (ECC), and intraocular pressure (IOP) measurement. The postoperative outcomes, determined at least 1 year after surgery, were CDVA; UDVA; contrast sensitivity function under photopic, mesopic, and mesopic with glare conditions; ECC; IOP; keratometry (Scheimpflug photography); and total ocular aberratio…