Search results for "Optical"
showing 10 items of 7671 documents
Design and Baseline Characteristics of the HELP Study: An Extended and Long-Term Observation of Pathological Myopia in Caucasians.
2017
<b><i>Purpose:</i></b> To assess the natural disease progression of high myopia in Caucasians considered at risk for the development of myopic choroidal neovascularization (mCNV). <b><i>Methods:</i></b> Subjects were recruited in 25 clinical sites between June 2014 and June 2016. Main inclusion criteria included axial length of ≥26 mm, best-corrected visual acuity ≥0.05 decimal equivalent and presence of at least one out of five predefined morphological disease risk criteria. These were (1) subfoveal choroidal thinning &#x3c; 50 µm, (2) enhanced choroidal curvature length &#x3e; 6,300 µm, (3) lacquer cracks, (4) patchy atrophy &#x3…
Intravitreal clindamycin and dexamethasone for zone 1 toxoplasmic retinochoroiditis at twenty-four months.
2009
Purpose To report the anatomic and functional outcomes of intravitreal clindamycin and dexamethasone for the treatment of zone 1 toxoplasmic retinochoroiditis (TRC). Patients had 1 or more of the following indications for local therapy: intolerance to oral medication, contraindication to oral medication because of pregnancy, lack of response despite oral antimicrobial treatment, or treatment with concomitant oral and local therapy to avoid or limit foveal or optic disc involvement. Design Noncomparative, retrospective, multicentric interventional case series. Participants We reviewed the medical records of 12 consecutive patients (eyes) with posterior pole (zone 1) TRC who were treated week…
Bilateral maculopathy after exposure to a laser pointer: Optical coherence tomography angiography findings.
2018
Abstract Case report A 36-year-old man went to the emergency department the day after exposure to a laser pointer. Funduscopy revealed dispersed macular pigment alterations, and optical coherence tomography showed a disruption of the retinal layers. The visual acuity was counting fingers in both eyes. Nine months later, optical coherence tomography angiography showed a rarefaction in the choriocapillaris vascular flow in the area of the laser injuries. Discussion The retinal layer mainly damaged by the laser injury was the retinal pigment epithelium. However, it is suggested that the laser injury could involve tissues beyond the retinal pigment epithelium, since a rarefaction of the chorioc…
Optical coherence tomography-based retinal vessel analysis for the evaluation of hypertensive vasculopathy
2013
Purpose Evaluation of retinal vessels in cardiovascular disease traditionally relies upon funduscopy, but more recently digital photo analysis has expanded the spectrum. As spectral domain optical coherence tomography (OCT) allows an in-vivo assessment of retinal tissue and its vessels on a histological scale, our study aimed at using this tool for the analysis of the retinal vasculature. Methods Circumferential peripapillary OCT scans (3DOCT-2000; Topcon Inc., Tokyo, Japan), with centration on the optic nerve head, were taken from 20 eyes (20 participants) with normal blood pressure and 20 eyes (20 participants) with arterial hypertension above 120 mmHg (mean blood pressure). The diameter …
Evaluating tear clearance rate with optical coherence tomography
2017
Purpose: To assess the early-phase of tear clearance rate (TCR) with anterior segment optical coherence tomography (OCT) and to determine the association between TCR and other clinical measures of the tear film in a group of young subjects with different levels of tear film quality. Methods: TCR was classified as the percentage decrease of the inferior tear meniscus height 30s after instillation of 5uL 0.9% saline solution. Fifty subjects (32F and 18M) aged (mean +/- standard deviation) 25.5 +/- 4.3 years volunteered for the study. It consisted of a review of medical history, Ocular Surface Disease Index (OSDI) questionnaire, tear film osmolarity measurements, slit lamp examination and TCR …
Optical coherence tomography of chorioretinal and choroidal folds
2007
. Purpose: To report the optical coherence tomography (OCT) findings in cases of chorioretinal and choroidal folds. Methods: Eight subjects with folds of the fundus of the eye were examined with fundus photography, fluorescein angiography, B-scan ultrasonography and Stratus OCT. Results: Two types patterns were found on OCT. Five cases showed undulating retinal as well as retinal pigment epithelial lines of normal thickness; these were defined as chorioretinal folds. The posterior vitreous surface often adhered to the crests of the folds only. Three cases exhibited a wavy appearance of the retinal pigment epithelium and a flat retinal surface; these were classified as choroidal folds. Co…
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…
Imaging photoplethysmography for clinical assessment of cutaneous microcirculation at two different depths
2016
The feasibility of bispectral imaging photoplethysmography (iPPG) system for clinical assessment of cutaneous microcirculation at two different depths is proposed. The iPPG system has been developed and evaluated for in vivo conditions during various tests: (1) topical application of vasodilatory liniment on the skin, (2) skin local heating, (3) arterial occlusion, and (4) regional anesthesia. The device has been validated by the measurements of a laser Doppler imager (LDI) as a reference. The hardware comprises four bispectral light sources (530 and 810 nm) for uniform illumination of skin, video camera, and the control unit for triggering of the system. The PPG signals were calculated and…
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…
Visual Acuity in Simple Myopic Astigmatism: Influence of Cylinder Axis
2006
Purpose. The relationship between astigmatic refractive errors and their associated visual acuity has been studied in recent years in the context of refractive power space. The influence of the axis of astigmatism remains a matter of controversy. Our goal in this study is to provide additional experimental evidence to clarify this subject. The influence of the simulated axis orientation was compared with other factors that affect visual acuity such as the particular design of the test and the differences between eyes. Methods. Simple myopic astigmatism from 0 to 3.00 D, in steps of 0.25 D, and with five different axes between 0° and 90°, were simulated on four healthy eyes of young observer…