Search results for "OPTICS"

Optical analysis to predict outcomes after implantation of a double intraocular lens magnification device.

2007

Purpose To analyze the effect of different optical parameters of the eye on the outcomes of implantation of a double intraocular lens (IOL) magnification device in patients with low vision. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods The eye's refraction and magnification before and after surgery were evaluated using a theoretical eye model based on paraxial optics approximation. Four parameters on which refraction and magnification are dependent were evaluated: anterior chamber depth (ACD), axial length (AL), mean keratometry (Km), and the distance between the 2 implanted IOLs. The 4 variables were analyzed separately in the first stage. Next, different combi…

Broad beam transmission data for the shielding of brachytherapy facilities

2008

New Trends in Detectors for Medical Imaging

2010

The improvement of medical imaging instrumentation is based both on the enhancement of the performance of the detectors employed in their construction and on the development of novel techniques and methods that allow full exploitation of the advantages of the new instrumentation.

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…

Biometric characterization of the anterior segment in a Sahrawi pediatric population

2013

Purpose: To examine the biometric characteristics of the anterior segment in a group of Sahrawi children. Methods: A total of 66 children (33 male and 33 female, aged between 8 and 13 years) participated in this prospective, observational study. The non-invasive Pentacam Scheimpflug imaging device was used to measure corneal thickness (CT) (at the thinnest corneal point), mean anterior (Km Ant) and posterior (Km Post) corneal radii, corneal volume (CVol), anterior chamber depth (ACD) and anterior chamber volume (ACVol). The contribution of age and gender to the various parameters was investigated. Results: CT values of the present group of Sahrawi children were 521.70 ± 3.92 m. Boys had thi…

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…

Multi-spectral skin imaging by a consumer photo-camera

2010

The possibilities to perform multi-band spectral imaging by means of a consumer color camera without external filters have been studied. Images at up to 6 spectral bands may be extracted from a single color image after appropriate signal processing. The proposed technique was tested in pilot measurements of in-vivo skin hemoglobin maps and laser-excited autofluorescence images.

High Dynamic Range Spectral Imaging Pipeline For Multispectral Filter Array Cameras

2017

Spectral filter arrays imaging exhibits a strong similarity with color filter arrays. This permits us to embed this technology in practical vision systems with little adaptation of the existing solutions. In this communication, we define an imaging pipeline that permits high dynamic range (HDR)-spectral imaging, which is extended from color filter arrays. We propose an implementation of this pipeline on a prototype sensor and evaluate the quality of our implementation results on real data with objective metrics and visual examples. We demonstrate that we reduce noise, and, in particular we solve the problem of noise generated by the lack of energy balance. Data are provided to the community…

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…

Interocular differences in visual quality due to ocular aberrations and scattering in a patient with post-traumatic anisocoria: A case report

2012

AbstractA 41-year-old patient with visual disturbances after an ocular trauma in right eye three years before was carefully analyzed and discussed. No corneal or intraocular sequelae were present. Only a significant anisocoria could be observed. Right eye (RE) achieved a best spectacle-corrected visual acuity (BSCVA) of 0.05 LogMAR with a refraction of +0.50 sphere and −1.25 cylinder. Left eye (LE) achieved a BSCVA of 0.0 LogMAR with a refraction of +0.75 sphere and −1.00 cylinder. In photopic conditions pupil diameter was 4.96mm for RE and 3.02mm for LE whereas in scotopic conditions, these values were 7.45mm and 6.71mm, respectively. More significant levels of higher-order corneal and ocu…