Search results for "Optica"

Development of a Protocol for CCD Calibration: Application to a Multispectral Imaging System

2005

In this paper we describe in detail a method for calibrating a CCD-based camera. The calibration aims to remove both temporal and systematic noises introduced by the sensor, electronics, and optics after which we can correct the non-linearity of its response. For the non-linearity correction we use a simple and powerful approach consisting on a complementary approach between a polynomial fitting and an LUT based algorithm. The proposed methodology is accurate in the sense that it takes into account individual characteristics of each pixel. In each pixel, systematic noises are measured through acquiring offset images, thermal images, and FlatField images. A rigorous protocol for acquiring th…

2021

Abstract Background As virtual reality (VR) has become more accessible, it has increasingly come into focus for clinical application. Therapy with VR shows potential as an engaging, effective, and economic way to improve cognitive abilities following a stroke. Objectives While application of VR in clinical settings appears promising, its widespread use will crucially depend on acceptance of immersive head mounted display virtual reality (HMD-VR) systems when used in different patient groups. This study aimed to investigate acceptance of HMD-VR in stroke patients compared to a control group of healthy age-matched adults. Methods The attitude towards HMD-VR, as one of the most important predi…

REVIEW OF RETROSPECTIVE DOSIMETRY TECHNIQUES FOR EXTERNAL IONISING RADIATION EXPOSURES

2011

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic re…

Variations of OCT measurements corrected for the magnification effect according to axial length and refractive error in children

2018

Purpose: The aim of this paper was to examine the distribution of macular, retinal nerve fiber layer (RNFL) thickness and optic disc parameters of myopic and hyperopic eyes in comparison with emmetropic control eyes and to investigate their variation according to axial length (AL) and spherical equivalent (SE) in healthy children. Methods: This study included 293 pairs of eyes of 293 children (145 boys and 148 girls), ranging in age from 6 to 17 years. Subjects were divided according to SE in control (emmetropia, 99 children), myopia (100 children) and hyperopia (94 children) groups and according to axial AL in 68 short ([Formula: see text]22.00[Formula: see text]mm, 68), medium (from [For…

Serous Macular Detachment Associated with Dome-Shaped Macula and Tilted Disc

2011

Introduction: An entirely new type of staphyloma has been recently described as dome-shaped macula (DSM). It is characterized by an abnormal convex macular contour within the concavity of a posterior staphyloma. We found DSM associated with serous macular detachment (SMD) and tilted disc in two consecutive cases. Case Reports: Case 1: A 37-year-old female presented to our department because of sudden onset blurred vision in her right eye (OD). The best-corrected visual acuity (BCVA) was 0.5 in both eyes. Funduscopy evidenced bilateral tilted disc associated with posterior staphyloma. Optical coherence tomography (OCT) demonstrated a DSM with SMD in her OD. After 15 months of follow-up, BCVA…

Autofluorescence imaging for recurrence detection in skin cancer postoperative scars

2020

This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non-melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check-ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to r…

Intravitreal dexamethasone implant for cystoid macular edema and inflammation after scleral buckling

2015

Purpose Cystoid macular edema may occur following scleral buckling and therefore deteriorate the visual outcome. Inflammation may be the major causative factor in the development of postoperative cystoid macular edema. This case demonstrates the effectiveness of a dexamethasone implant as a treatment after the onset of choroidal inflammation and cystoid macular edema 6 months following scleral buckling and having visual acuity restored. Methods A 59-year-old phakic woman treated with scleral buckling for macula-off retinal detachment presented 2 months after surgery with cystoid macular edema with choroidal inflammation. Optical coherence tomography and fluorescein angiography were performe…

Electrochemical detection and screening of bladder cancer recurrence using direct electrochemical analysis of urine: A non-invasive tool for diagnosis

2018

Although detection of urothelial cell carcinoma (or bladder cancer, BC) can be performed via cytological, molecular and genetic marker tests on urine, cystoscopy, an invasive technique, still remains as the gold methodology in clinical practice. It is presented a non-invasive method for detecting BC recurrence consisting of a direct electrochemical test in urine combining voltammetric data at gold and glassy carbon electrodes. The diagnosis is based on the ratio between characteristic voltammetric features recorded for tryptophan, serotonin and melatonin and other related metabolites. The method was tested by means of a clinical trial with 30 patients diagnosed of bladder cancer and a two c…

Beals–Hecht syndrome and choroidal neovascularization

2010

PURPOSE To describe a case of choroidal neovascularization (CNV) in a female diagnosed with Beals-Hecht syndrome. METHODS A retrospective, interventional case is described in a 26-year-old female complaining of metamorphopsia and visual loss in her left eye (counting fingers). The fluorescein angiogram and the optical coherence tomography supported the diagnosis of CNV. Intravitreal ranibizumab was administered. RESULTS After the third intravitreal ranibizumab, her visual acuity improved to 0.8 and the morphology of the macular area was restored. CONCLUSIONS To our knowledge this is the first report of CNV in Beals-Hecht syndrome treated with ranibizumab. Self-monitoring by periodically per…

Automated macular choroidal thickness measurement by swept-source optical coherence tomography in pseudoxanthoma elasticum

2016

Introduction Pseudoxanthoma elasticum (PXE) typically involves elastic fibers in blood vessels and Bruch membrane. Our purpose was to analyze retinal and choroidal macular thickness in patients with angioid streaks due PXE compared with a control group. Methods Best-corrected visual acuity (BCVA), axial length (AL), and macular swept-source optical coherence tomography were obtained. Automated segmentations of the retina and the choroid were used to obtain the corresponding thickness values. An age, gender and AL matched control group was used to compare the thickness values. Results Twelve eyes of 6 patients were included. The mean BCVA was 0.68 ± 0.29 versus 1.0 in controls (p < 0.001). T…