Search results for " OPT"
showing 10 items of 13620 documents
Comparison of Macular Thickness in Patients with Keratoconus and Control Subjects Using the Cirrus HD-OCT
2014
Purpose.The aim of the present study was to compare macular thickness in patients with keratoconus (KC) with macular thickness in healthy subjects.Subjects and Methods.Twenty-six patients with KC and 52 control subjects were included. The macular structure was evaluated using a Zeiss Cirrus HD-OCT. The scan pattern used was 512 × 128, which covers an area of approximately 6 × 6 mm of the retina. The cube volume was assessed as well as macular thickness in each of the 9 sectors defined by the software.Results.The mean signal strength was significantly lower in the KC group (mean 8.4, range 6–10) compared with the control group (mean 9.7, range 7–10),P<0.0001(unpairedt-test). There were no…
In vivo ultrasound real-time motion of the cervical spine during intubation under manual in-line stabilization: a comparison of intubation methods
2007
Background and objectiveIn emergency trauma situations, manual in-line stabilization of the cervical spine is recommended to reduce cervical spine movement during intubation. The aim of this study was to compare the effect of manual in-line stabilization during different intubation techniques on three-dimensional cervical spine movements and times to intubation.MethodsForty-eight subjects without any history of trauma, inflammatory or degenerative disorder of the cervical spine were randomly grouped, regardless of gender or age. All underwent elective surgery under general anaesthesia. Under manual in-line stabilization, laryngeal intubation with Macintosh laryngoscope, intubating laryngeal…
Subjective Satisfaction in Long-term Orthokeratology Patients
2013
Purpose: To AU3 evaluate the subjective satisfaction in visual stability, night vision complains, and light distortion phenomena, and also the number of hours and days per week of lens wear, in patients with myopia undergoing orthokeratology (OK) treatment for at least 1 year. Methods: A visual analog scale (VAS) questionnaire containing 18 items was administered to 44 patients, 29 women and 15 men (mean age, 24.39 6 9.11 years), with a baseline spherical equivalent refractive error of 22.40 6 0.94 diopters and astigmatism up to 20.5 diopters. Average treatment period by the time of data collection was 19 6 7 months. Patients rated their satisfaction with the correction, with complaints of …
Light distortion of soft multifocal contact lenses with different pupil size and shape
2020
Purpose: To study the light distortion effects of soft multifocal contact lenses and the influence of different pupil size and shape.Methods: A total of 14 eyes of 7 healthy contact lens users (mean age 28.6 +/- 8.5 years) were recruited. The "Light Disturbance Analyser" device was employed for light characterization. The selected lenses were the monthly disposable "Biofinity multifocal" (CooperVision, CA, USA), both centre-distance and centre-near designs (addition power + 2.50 D). Two circular pupils of 3 mm and 5 mm of diameter, and an elliptical shape (3 horizontal and 5 vertical mm) were used. Metrics such as the light distortion index (LDI), best-fit circle radius and its irregularity…
A clinical longitudinal study 323 porcelain laminate veneers. Period of study from 3 to 11 years
2009
Objective: The objective of this study was to evaluate the clinical results of 323 porcelain laminate veneers over a period of 3 to 11 years. Material and Methods: This study included 70 patients, aged between 18 and 74 years. Of the 323 total veneers, 124 were of a simple design and 199 were of a functional design. The condition of the soft tissues and hygiene, in addition to the condition of the abutment teeth, the restorations and patient satisfaction were all clinically examined. In carrying out the statistical analysis, a descriptive approach was taken in analyzing the data. The Kaplan Meier method was used for statistically analyzing the survival rates of the porcelain laminate veneer…
Accommodative stimulus-response curves to low-pass filtered natural images
2018
To assess how the monocular steady-state accommodative stimulus-response curve is modified when viewing low-pass filtered natural images. Eighteen adult subjects participated in the study. The accommodative stimulus-response curve was objectively assessed by means of a Hartmann-Shack wavefront sensor. Measurements were taken at different accommodative demands. Target images were low-pass filtered versions of a natural image that were obtained applying different digital spatial filters that limited the spatial frequency content of the natural image. Cutoff spatial frequencies were set at 30, 21, and 15 cycles per degree (cy/deg). Mean data obtained for each target were fitted to linear model…
Effect of luminance on photopic visual acuity in the presence of laser speckle
1988
Visual acuity in coherent and incoherent light has been determined by using square-wave gratings of 100% contrast. Luminance was varied from 3 to 400 cd/m2. Coherent illumination resulted in a 40% loss of visual acuity. This is probably due to the masking effect of coherent spatial noise (speckle). However, the most interesting finding is the change in shape of the photopic visual-acuity-luminance function. With coherent illumination, the function is vertically displaced and of a different gradient. An increase in luminance produces a decrease in visual acuity. This indicates that the masking effect of the speckle is dependent on luminance. Two observers were used, and similar results were …
An Emerging Method to Assess Tear Film Spread and Dynamics as Possible Tear Film Homeostasis Markers
2021
This study aims to assess the performance of an analysis method to measure in vivo the movement speed of tear film particles post-blink as a measure of tear film spreading. Ocular surface parameter...
Relationship between foot eversion and thermographic foot skin temperature after running.
2017
The main instruments to assess foot eversion have some limitations (especially for field applications), and therefore it is necessary to explore new methods. The objective was to determine the relationship between foot eversion and skin temperature asymmetry of the foot sole (difference between medial and lateral side), using infrared thermography. Twenty-two runners performed a running test lasting 30 min. Skin temperature of the feet soles was measured by infrared thermography before and after running. Foot eversion during running was measured by kinematic analysis. Immediately after running, weak negative correlations were observed between thermal symmetry of the rearfoot and eversion at…
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…