Search results for "Refractive"
showing 10 items of 559 documents
Optical quality of the diabetic eye: a review
2014
Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each of ocular component have been described in detail during the past decades. Due to these abnormalities, the diabetic patient undergoes a degradation of the retinal image by an increase of higher ocular aberrations and ocular scattering coming from mainly tear film, cornea, and crystalline lens. This review aims to provide an overview of current knowledge about the effects of diabetes mellitus in these optical phenomena and its consequence on the visual quality of the diabetic patient.
Brimonidine versus dapiprazole: Influence on pupil size at various illumination levels.
2005
To evaluate the influence of dapiprazole versus brimonidine on pupil size at various illumination levels.Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.In randomized prospective study, 19 healthy volunteers received 2 ophthalmic solutions, dapiprazole and brimonidine, 1 in each eye, for intraindividual comparison. Before and after application, pupil diameter was measured using an infrared binocular pupillometer at 3 illumination levels (0.03, 0.82, and 6.4 lux).Only slight pupil dilation was observed under scotopic conditions after application of both agents. After 20 minutes, the median reduction in pupil width was 1.4 mm for brimonidine and 0.9 mm for dapiprazo…
Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clini…
2012
Purpose: To analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes. Methods: Prospective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75 D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in v…
The "sandwich technique" for iris-fixated phakic intraocular lens implantation.
2006
ABSTRACT PURPOSE: To describe a new technique of implantation of the Artisan/Verisyse phakic intraocular lens (PIOL). METHODS: After PIOL insertion into the anterior chamber, a bolus of a high viscosity ophthalmic viseosurgical device (OVD) is placed over the optic, separating it widely from the endothelium. RESULTS: The technique decreases the chance of endothelial damage during enclavation. CONCLUSIONS: A bolus of a high viscosity OVD placed on the anterior surface of the Artisan/Verisyse PIOL may make enclavation safer. [J Refract Surg. 2006;22:96-98.]
Artiflex Toric Phakic Intraocular Lens Implantation in Congenital Nystagmus
2011
Case: A 44-year-old woman with congenital nystagmus and myopic astigmatism in both eyes who was submitted to phakic intraocular lens (pIOL) implantation. Methods: Full ophthalmologic examination including refractive status, corrected (CDVA) and uncorrected (UCVA) monocular and binocular visual acuities, ocular motility, slit-lamp evaluation, tonometry and fundoscopy before and after implantation of toric pIOLs (Artiflex; Ophtec BV, The Netherlands) in both eyes. Results: Preoperative logMAR CDVA were 0.699 and 0.420 in the right and left eye, respectively. Three months after surgery, logMAR UCVA were 0.398 and 0.182, reaching binocular logMAR UCVA of 0.132. There were no changes in nystagmu…
Role of the tear film in the optical quality of the human eye.
2007
This paper reviews recent studies of the role of the tear film in the optical quality of the eye. Recent investigations focus on the dynamics of the tear film after a blink and its important role in the optical quality of the eye. The results in this review were used in an attempt to understand the optical and visual impact of tear-film breakup in normal eyes and dry eyes. It was noted that patients with dry-eye syndrome have large optical aberrations compared with those in normal eyes, which may be the cause of blurry vision associated with the syndrome. In addition, instillation of artificial tears reduces optical aberrations and thus improves the optical quality of vision in these patien…
Measurement of the soliton number in guiding media through continuum generation.
2020
No general approach is available yet to measure directly the ratio between chromatic dispersion and the nonlinear coefficient, and hence the soliton number for a given optical pulse, in an arbitrary guiding medium. Here we solve this problem using continuum generation. We experimentally demonstrate our method in polarization-maintaining and single-mode fibers with positive and negative chromatic dispersion. Our technique also offers new opportunities to determine the chromatic dispersion of guiding media over a broad spectral range while pumping at a fixed wavelength. (C) 2020 Optical Society of America
Mechanical and optical properties of as-grown and thermally annealed titanium dioxide from titanium tetrachloride and water by atomic layer deposition
2021
Funding Information: This work was carried out within the MECHALD project funded by Business Finland (Tekes) and is linked to the Finnish Centers of Excellence in Atomic Layer Deposition (ref. 251220) and Nuclear and Accelerator Based Physics (refs. 213503 and 251353) of the Academy of Finland. Funding Information: This work was carried out within the MECHALD project funded by Business Finland (Tekes) and is linked to the Finnish Centers of Excellence in Atomic Layer Deposition (ref. 251220 ) and Nuclear and Accelerator Based Physics (refs. 213503 and 251353 ) of the Academy of Finland. Publisher Copyright: © 2021 The use of thin-films made by atomic layer deposition (ALD) is increasing in …
Long-transient conoscopic pattern technique
1999
0038-1098; Recent results on laser induced anisotropy in terbium gallium garnet are extended to the dynamic regime. We observed that the characteristic conoscopic pattern formation time presents a quadratic dependence on the beam size. The observed pattern intensity is accounted for by a simple analytical formula. The transient refractive index change due to thermal stress in the terbium gallium garnet is determined. (C) 1999 Elsevier Science Ltd. All rights reserved.
Refractive index sensing by a silicon metasurface
2022
The availability of smart materials represents a key enabling milestone for the realization of smart sensors. In this research field, optical sensing has gained a lot of attention in various applications ranging from basic physics to chemistry and biology. Here, we exploit the non-invasive nature of light to achieve an innovative sensor based on all-optical dielectric nano-resonators arranged in a periodic fashion. The proposed sensor can measure refractive index changes up to 10(-6).