Search results for "Cornea"
showing 10 items of 404 documents
Corneal Biomechanics, Retinal Nerve Fiber Layer, and Optic Disc in Children
2014
Purpose. To evaluate the possible associations between corneal biomechanical parameters, optic disc morphology, and retinal nerve fiber layer (RNFL) thickness in healthy white Spanish children. Methods. This cross-sectional study included 100 myopic children and 99 emmetropic children as a control group, ranging in age from 6 to 17 years. The Ocular Response Analyzer was used to measure corneal hysteresis (CH) and corneal resistance factor. The optic disc morphology and RNFL thickness were assessed using posterior segment optical coherence tomography (Cirrus HD-OCT). The axial length was measured using an IOLMaster, whereas the central corneal thickness was measured by anterior segment opti…
Intravitreal Docosahexaenoic Acid in a Rabbit Model: Preclinical Safety Assessment
2014
PurposeThe purpose of the present study was to evaluate the retinal toxicity of a single dose of intravitreal docosahexaenoic acid (DHA) in rabbit eyes over a short-term period.MethodsSixteen New Zealand albino rabbits were selected for this pre-clinical study. Six concentrations of DHA (Brudy Laboratories, Barcelona, Spain) were prepared: 10 mg/50 µl, 5 mg/50 µl, 2'5 mg/50 µl, 50 µg/50 µl, 25 µg/50 µl, and 5 µg/50 µl. Each concentration was injected intravitreally in the right eye of two rabbits. As a control, the vehicle solution was injected in one eye of four animals. Retinal safety was studied by slit-lamp examination, and electroretinography. All the rabbits were euthanized one week a…
Retroespalhamento luminoso das córneas de pacientes com diabete melito dependente e não dependente de insulina: estudo piloto
2017
ABSTRACT Purpose: To compare central corneal backscatter obtained from Scheimpflug images between patients with insulin-dependent and non-insulin-dependent diabetes mellitus (IDDM and NIDDM, respectively) and healthy controls. Methods: Seven patients with IDDM (7 eyes), eleven patients with NIDDM (11 eyes), and sixteen healthy subjects (16 eyes) were included in this pilot study. Scheimpflug imaging system (Pentacam, Oculus Inc., Germany) was used to obtain optical sections of the cornea. Seven meridians were analyzed for each eye, oriented from 70° to 110°. Optical density values for the central 3-mm and 5-mm zones of the cornea were obtained by image analysis using external software. Resu…
Contrast sensitivity loss in the peripheral visual field following laser in situ keratomileusis.
2007
We report a case of contrast sensitivity loss in the peripheral visual field following laser in situ keratomileusis (LASIK). A 50-year-old white man was referred to us for differences in visual perception in the peripheral field between the right eye, which had had LASIK, and the left eye, which was emmetropic. Linear meridional static perimetry was carried out in the 0- to 180-degree meridian using a Goldmann perimeter to assess the peripheral perimetric thresholds. There was a statistically significantly marked increased threshold in contrast sensitivity in the nasal and temporal fields from 40 degrees of eccentricity in the LASIK eye compared with that in the emmetropic eye. Eyes treated…
Perioperative pupil size in low-energy femtosecond laser-assisted cataract surgery
2020
Purpose To assess potential changes in pupil size during femtosecond laser-assisted cataract surgery (FLACS) using a low-energy laser system. Methods The pupil sizes of eyes undergoing FLACS were measured using the Ziemer LDV Z8 by extracting images from the laser software after each of the following steps: application of suction, lens fragmentation, and capsulotomy. Furthermore, the pupil diameters were measured based on preoperative surgical microscope images and after releasing the suction. Paired t-test and the two one-sided tests (TOST) procedure were used for statistical analyses. The horizontal and vertical pupil diameters were compared in each of the steps with preoperative values.…
Anisometropia of spherical equivalent and astigmatism among myopes: a 23-year follow-up study of prevalence and changes from childhood to adulthood.
2017
Purpose To study anisometropia of spherical equivalent and astigmatism from the onset of myopia at school age to adulthood. Methods A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Examinations with subjective cyclopedic refraction were repeated 3 years later (follow-up 1) for 238 subjects and thereafter at the mean ages of 23.2 (follow-up 2) and 33.9 years (follow-up 3) for 178 and 134 subjects. After exclusions, the 102 subjects who attended all three follow-ups were included in the analyses. Corneal refractive power and astigmatism and anterior cha…
Corneal thickness in children with growth hormone deficiency: The effect of GH treatment.
2014
Abstract OBJECTIVE: The eye represents a target site for GH action, although few data are available in patients with GH deficiency (GHD). Our aim was to evaluate central corneal thickness (CCT) and intraocular pressure (IOP) values in GHD children to assess the role played by GHD or GH treatment on these parameters. DESIGN: In 74 prepubertal GHD children (51M, 23F, aged 10.4±2.4years) we measured CCT and IOP before and after 12months of treatment. A baseline evaluation was also made in 50 healthy children matched for age, gender and body mass index. The study outcome considered CCT and IOP during treatment and their correlations with biochemical and auxological data. RESULTS: No difference …
Topical allopurinol or corticosteroids and acetylcysteine in the early treatment of experimental corneal alkali burns: a pilot study.
2002
PURPOSE. To investigate the effect of topical allopurinol on experimental corneal burns and to compare this to established treatment modalities such as topical prednisolone and acetylcysteine. METHODS. Twenty Wistar rats were randomly assigned to four groups (n=5 each). The groups were controls (normal saline), allopurinol 0.4% eye drops, prednisolone acetate 1% eye drops and acetylcysteine 8% eyedrops. Corneal burn was induced using a 3 mm paper disc soaked in 1N NaOH for 60 seconds. Drops were instilled 6 times per day. In addition, one drop/day ofloxacine was given to prevent secondary infections. Eyes were enucleated 50 hours later and fixed in 4.5% formaldehyde. Three histological leve…
The Effect of Anesthetic Eye Drop Instillation on the Distribution of Corneal Thickness
2012
PURPOSE To address the effect of topical instillation of oxybuprocaine on the relative distribution of corneal thickness (CT) in young healthy subjects. METHODS Prospective study involving 30 eyes of 30 emmetropic subjects (24 ± 3 years). Corneal thickness measurements were carried out before and 3 minutes after the instillation of oxybuprocaine 4% using slit-scanning corneal topography (Orbscan topography system II). No acoustic correction factor was applied. The mean of 5 consecutive Orbscan measurements was obtained at the center and 3 mm from the visual axis in the temporal, superior, nasal, and inferior hemimeridians. RESULTS No significant mean differences were found at any corneal lo…
Anterior Segment Biometry and Their Correlation with Corneal Biomechanics in Caucasian Children.
2018
Purpose: To assess the relationship between the corneal biomechanical parameters and the anterior segment parameters in Caucasian children. Methods: This study included 293 eyes from 293 healthy children aged between 6 and 17 years. Corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer, axial length (AL) with IOLMaster and the anterior segment with Pentacam. Anterior segment parameters obtained were the following: central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and mean anterior and posterior keratometry. Two multiple linear regression models were constructed to assess th…