1,720,991 research outputs found
AGGIORNAMENTI IN PATOLOGIE OCULISTICHE
No full textAggiornamenti ed attualità medico-chirurgiche dal segmento anteriore alla retina
Cilioretinal arteries: incidence in a sample of 1110 patients
No full textThe central retinal artery, supplies retinal vasculature. In some cases, a part of retinal circulation is supplied by a cilioretinal artery. Cilioretinal arteries take rise from a posterior ciliary artey. It was first described by Müller in 1856 and first demonstrated histologically in 1876 by Nettleship, who stated that in sectioning of a human eye, he found “a small artery from the choroid turning round the edge of the disc, and running uninterruptedly for some distance in the retina, where it breaks up into capillaries.” The existence of the cilioretinal arteries is considered congenital. Cilioretinal arteries influence the visual prognosis in case of microvascular and neovascular diseases. In fact, they may reduce the damage due to vascular occlusion and neovascular AMD. On the other hand,studies suggest that cilioretinal arteries increase the risk of diabetic macular oedema
Near-infrared circularly polarized luminescence from chiral Yb(iii)-diketonates
Full text linkWe report a rare example of near infrared circularly polarized luminescence (NIR-CPL) in the 920-1050 nm region associated with the f-f transitions of Yb diketonate complexes bearing chiral ancillary ligands. Developing NIR-CPL emitters may have implications from CPL-based (bio)-assays to chiral optoelectronics
Quantifying the Overall Efficiency of Circularly Polarized Emitters
Full text linkAn increasing number of circularly polarized luminescence (CPL) molecular emitters has been developed in recent years and many of them are intended for applications in which high overall CPL efficiencies are required. In order to have a complete picture of the efficiency of a CPL emitter, dissymmetry factor (glum) is not enough. In the following we propose a new quantity, named CPL brightness (BCPL), which takes into account absorption extinction coefficient and quantum yield along with the glum factor. We calculated BCPL value for more than 180 compounds reported in the literature and we analyse data distribution for the main classes of CPL molecular emitters. This tool can be employed to put into context new CPL active compounds and to direct the choice of molecular systems for specific CPL applications
Ocular hypertension in myopia: analysis of contrast sensitivity
Full text linkPurpose: we evaluated the evolution of contrast sensitivity reduction in patients affected by ocular hypertension and glaucoma, with low to moderate myopia. We also evaluated the relationship between contrast sensitivity and mean deviation of visual field.
Material and methods: 158 patients (316 eyes), aged between 38 and 57 years old, were enrolled and divided into 4 groups: emmetropes, myopes, myopes with ocular hypertension (IOP≥21 ±2 mmHg), myopes with glaucoma. All patients underwent anamnestic and complete eye evaluation, tonometric curves with Goldmann’s applanation tonometer, cup/disc ratio evaluation, gonioscopy by Goldmann’s three-mirrors lens, automated perimetry (Humphrey 30-2 full-threshold test) and contrast sensitivity evaluation by Pelli-Robson charts. A contrast sensitivity under 1,8 Logarithm of the Minimum Angle of Resolution (LogMAR) was considered
abnormal.
Results: contrast sensitivity was reduced in the group of myopes with ocular hypertension (1,788 LogMAR) and in the group of myopes with glaucoma (1,743 LogMAR), while it was preserved in the group of myopes (2,069 LogMAR) and in the group of emmetropes (1,990 LogMAR). We also found a strong correlation between contrast sensitivity reduction and mean deviation of visual fields in myopes with glaucoma (coefficient relation = 0.86) and in myopes with ocular hypertension (coefficient relation = 0.78).
Conclusions: the contrast sensitivity assessment performed by the Pelli-Robson test should be performed in all patients with middle-grade myopia, ocular hypertension and optic disc suspected for glaucoma, as it may be useful in the early diagnosis of the disease.
Introduction Contrast can be defined as the ability of the eye to discriminate differences in luminance between the stimulus and the background.
The sensitivity to contrast is represented by the inverse of the minimal contrast necessary to make an object visible; the lower the
contrast the greater the sensitivity, and the other way around.
Contrast sensitivity is a fundamental aspect of vision together with visual acuity: the latter defines the smallest spatial detail that the subject manages to discriminate under optimal conditions, but it only provides information about the size of the stimulus that the eye is capable to perceive; instead, the evaluation of contrast sensitivity provides information not obtainable with only the measurement of visual acuity, as it establishes the minimum difference in luminance that must be present between the stimulus and its background so that the retina is adequately stimulated to perceive the stimulus itself. The clinical methods of examining contrast sensitivity (lattices,
luminance gradients, variable-contrast optotypic tables and lowcontrast optotypic tables) relate the two parameters on which the
ability to distinctly perceive an object depends, namely the different luminance degree of the two adjacent areas and the spatial frequency,
which is linked to the size of the object.
The measurement of contrast sensitivity becomes valuable in the diagnosis and follow up of some important eye conditions such as
glaucoma. Studies show that contrast sensitivity can be related to data obtained with the visual perimetry, especially with the perimetric
damage of the central area and of the optic nerve head
Cilioretinal artery distribution influences retinal microvascular pattern and blood flow. An in vivo OCT angiographhyb study
No full textThe retina is most often vascularized only by branches of the central retinal artery; in some cases (34.2% of individuals), one or more arteries stemming from posterior ciliary artery, vascularize the retina to a variable extent. These vessels are called cilioretinal arteries. Almost no information about the differences of microvasculature deriving from the retinal and the cilioretinal arteries is available.
OCT-Angiography (OCT-A) makes it possible to visualize in vivo retinal vascular flow.
Thus, we have studied the microvascular networks stemming from retinal and cilioretinal arteries by means of OCT-A both in basal conditions and during in valsalva maneuver
Peribulbar anesthesia in sclero-retinal surgery: two quadrants vs single injection
No full textPurpose. To evaluate the advantage of peribulbar anesthesia in two quadrants (infero-temporal and upper nasal) vs single injection tedchnique (infero-temporal) for scleral rhegmatogenous detachment surgery (RRD). Patiets and methods. 57 patients, aged between 33 and 75 years (57.01 + - 8.68), waiting for retinal detachment surgery, were randomized in two gruops: a group S (29 patients), with single quadrant injection technique and a group C (28 patients) with two quadrants injection. Patients in Group S were injected in two quadrants with a 10 ml mixture containing Mepivacaine 2% 5ml and Ropivacaine 0.75% 5ml, with hyaluronidase 10UI/ml. Patients in group C were injected with the same mixture in one quadrant. Number of additional injections, during surgery, in two groups, were reported. Pain was tested with VAS (Verbal Analogue Scale 0-10) after regional block, when muscles were insulated, during scleral buckling positioning, when conjunctive was closed and 6, 12, 24 hours after surgery. Results. The need for a second peribulbar injection of anesthetic occurred in 9 patients of group C (32.14%); further injection was necessary in 1 patient (3.57%) of group S during scleral buckling (VAS=7), statistically significant p<0.05). Postoperative VAS 6-12-24 hours after surgery was not significant. Conclusions. The peribulbar anesthesia may be proposed in scleral surgery of retinal detachment; the injection in two quadrants secured solid and satisfectory anesthesia, increasing the outcome of retinal surgery in loco-regional anesthesia
Local anesthetic infiltration vs. nervous blocks in face’s skin lesions: what’s new
Full text linkSkin tumors are the most common type of cancer. They are localized throughout the body, more frequently in those regions chronically exposed to sun, like face, scalp and neck, compromising aesthetic appearance. The optimization of day hospital surgical procedures is mandatory, to avoid erroneous indications, insufficient intra operative comfort and prolonged recovery. New guidelines should be discussed and shared. Patients were divided in two groups: i. Group A of 50 patients, 21 male and 29 female, age 65 ±9, ASA I – III (10/19/21), weight 68±11 kg, height 160±8, with anesthetic Local Infiltration (LI); ii. Group B of 50 patients, 16 male, 34 female, age 68 ±10, ASA I – III (9/22/19), weight 64 ± 9 kg, height 158 ±11, with nerve block (NB). The purpose of our study is to evaluate the analgesia level, compliance and complication rate after LI or selective NB with alkalinised mepivacaine cloridrate 2%, Guardant®. Demographic data, ASA physical stauts, size of lesions, surgery, anesthesia durations and volume of LA injected were analyzed. Fisher’s exact test and Student’s t test were used; P ≤ 0.05 was considered statistically significant. No differences in age (65 ± 9 vs 68 ± 10 years), weight (68 ± 11 vs 64 ± 9), height (160 ± 8 vs 158 ± 11 cm), size of lesion (23 ± 11 vs 25 ± 14 mm), duration of surgery (47 ± 18 vs 51 ± 23 minutes) were detected in two groups (p > 0.05). Both anesthetic techniques ensured good analgesia, but only nerve’s blocks were be able to determine satisfactory intra operative patient’s comfort, a bloodless wound and weak risk for nervous lesions and toxic reaction to local anesthetic
Farmaci per via topica e anestesia generale in Oftalmochirugia Pediatrica: manifestazioni Cliniche da interazioni Farmacologiche
No full text- …
