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Contact Lens (contact + lens)
Terms modified by Contact Lens Selected Abstracts2145: Descemet´s membrane detachment 16 years after PK and 10 months after phacoACTA OPHTHALMOLOGICA, Issue 2010JO FERNANDEZ MENDY Purpose The purpose of this paper is to present an unusual case of DMD and analyze this complication Methods A 57-year-old woman, who had bilateral keratoconus, underwent three penetrating keratoplasties (PK) on her RE in 1981, 1993 and 1995 resulting in ptisis bulbi. In her LE she underwent two PK (1981, 1994) follow by arcuate incisions (1995) and an uneventful phacoemulsification in 2007. 10 months after cataract surgery, she begun with blurred vision, the BCVA was 20/400 and was seen by 3 ophthalmologists who made the diagnosis of endothelial failure and suggested a new PK or a DSAEK. We performed an Optical Coherence Tomography, diagnosing a complete Descemet´s membrane detachment (DMD). An intracameral gas injection of C3F8 at 16% was performed in the operating room, and the patient was instructed to maintain a supine position. After 24 hours VA improved to 20/80 and after 72 hours 20/30 UCVA. A small bubble was present in the anterior chamber for more than 3 weeks. One month later she achieved 20/20 with Contact Lens. During the first year after reattachment it was necessary to change the CL due to an increasing with the rule astigmatism from 3D to 5D. Results Two years after gas injection BSVA is 20/25 because she is no longer using CL, Descemet´s membrane still remains well attached, even thought we realized that there was a trend to steepen the vertical meridian due to the widening of a nasal arcuate incision, that we think was the origin of the DMD. Conclusion DMD is a rare complication of Phacoemulsification, seen immediately after the surgery. So far there has not reported any complete DMD after phaco after PK. We think that it is mandatory to perform a corneal OCT in all cases of PK and stromal edema; it could probably be a DMD. [source] Contact lens induced keratitis associated with contact lens wearACTA OPHTHALMOLOGICA, Issue 5 2001Irene Dejaco-Ruhswurm ABSTRACT. Purpose: To evaluate clinical characteristics, risk factors, management and outcome of contact lens induced keratitis (CLIK) associated with contact lens wear. Methods: The study comprised all consecutive patients presenting with contact lens related presumed microbial keratitis during a 12-month period at our department. Detailed demographic data, type of contact lens, duration of lens wear, wearing schedule and lens hygiene were derived from a self-administered questionnaire. Severity of ulcer, corneal scrapings, treatment and final outcome were evaluated. Results: 27 patients with CLIK, some of which may have been sterile peripheral infiltrates, due to contact lens wear were detected. In the majority of the cases patients had used disposable soft contact lenses (89%) and most of them had a daily wearing schedule (78%). 51.8% patients cleaned their lenses regularly. 6 (22%) applied no disinfection since their lenses were disposable on removal. In 3 of our cases with CLIK, penetrating keratoplasty had to be performed. Conclusion: Disposable contact lenses seem to have been a predisposing factor for contact lens induced keratitis also when used on a daily wear schedule. Insufficient contact lens care products and/or manufacturing characteristics may be responsible for CLIK, which is also observed in otherwise compliant contact lens users. In 3 of our patients with CLIK keratoplasty became necessary, indicating that contact lens induced keratitis may result in severe corneal complications. [source] Contact lens fitting for post-radial-keratotomy residual myopiaCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2003Jeewan S Titiyal MD Abstract Purpose:,To formulate guidelines for contact lens fitting following radial keratotomy and to achieve a relationship between contact lens fitting parameters and refractive and keratometric parameters. Methods:,Thirty-five eyes of 30 patients who had post-radial-keratotomy residual myopia were evaluated for contact lens fitting. The base curve was selected by ,hit and trial' method until a proper fit was achieved, following which an over-refraction was done and final power of the contact lens obtained. Results:,The mean contact lens base curve was 43.04 ± 1.62 D, which was steeper than the postoperative keratometry by 2.35 ± 0.74 D. The base curve and the postoperative keratometry were correlated by regression analysis (r = 0.895, P < 0.001). The mean overall diameter of the contact lenses was 9.64 ± 0.08 mm. The mean contact lens power was 5.81 ± 3.07 D, which was more myopic than the residual myopia by 2.79 ± 1.67 D. Regression analysis showed definite correlation between the contact lens power and postoperative myopia (r = 0.854, P < 0.001). Conclusion:,For correction of post-radial-keratotomy residual myopia, contact lens fitting parameters can be determined by a regression formula using keratometric and refractive values. [source] Diffusion and Monod kinetics to determine in vivo human corneal oxygen-consumption rate during soft contact-lens wearJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Mahendra Chhabra Abstract The rate of oxygen consumption is an important parameter to assess the physiology of the human cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment. Therefore, estimation of in vivo corneal oxygen-consumption rate is essential for gauging adequate oxygen supply to the cornea. Phosphorescence quenching of a dye coated on the posterior of a soft contact lens provides a powerful technique to measure tear-film oxygen tension (Harvitt and Bonanno, Invest Ophthalmol Vis Sci 1996;37:1026,1036; Bonanno et al., Invest Ophthalmol Vis Sci 2002;43:371,376). Unfortunately, previous work in establishing oxygen-consumption kinetics from transient postlens tear-film oxygen tensions relies on the simplistic assumption of a constant corneal-consumption rate. A more realistic model of corneal metabolism is needed to obtain reliable oxygen-consumption kinetics. Here, physiologically relevant nonlinear Monod kinetics is adopted for describing the local oxygen-consumption rate, thus avoiding aphysical negative oxygen tensions in the cornea. We incorporate Monod kinetics in an unsteady-state reactive-diffusion model for the cornea contact-lens system to determine tear-film oxygen tension as a function of time when changing from closed-eye to open-eye condition. The model was fit to available experimental data of in vivo human postlens tear-film oxygen tension to determine the corneal oxygen-consumption rate. Reliance on corneal oxygen diffusivity and solubility data obtained from rabbits is no longer requisite. Excellent agreement is obtained between the proposed model and experiment. We calculate the spatial-averaged in vivo human maximum corneal oxygen-consumption rate as Q = 1.05 × 10,4 mL/(cm3 s). The calculated Monod constant is Km = 2.2 mmHg. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Spectral optical coherence tomography: a new imaging technique in contact lens practiceOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2006omiej J. Ka Abstract Purpose:, Spectral optical coherence tomography (SOCT) is a new non-invasive, non-contact, high-resolution technique, which provides cross-sectional images of objects that weakly absorb and scatter light. The aim of this article is to demonstrate the application of SOCT to imaging of eyes fitted with contact lenses. Methods:, Nine eyes of six different subjects fitted with various contact lenses have been examined with a slit-lamp and a prototype SOCT instrument. Results:, Our SOCT system provides high-resolution (4,6 ,m longitudinal, 10 ,m transversal) tomograms composed of 3000,5000 A-scans with acquisition time of 100,250 ms. The quality of the images is adequate for detailed evaluation of contact lens fit. Design, shape and lens edge position were assessed, and complications of contact lens wear could be visualized. Thickness of the lens, corneal epithelium and stroma as well as the space between the lens and the eye surface have been measured. Conclusions:, SOCT allows high-resolution, cross-sectional visualization of the eye fitted with a contact lens. The ability to carry out a detailed evaluation of the fitting relationship between the lens and the ocular surface might be useful in research and optometric practice. SOCT can also be helpful in diagnosis, evaluation and documentation of contact lens complications. [source] Vasovagal syncope evoked by needle phobia when inserting a contact lens,OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2005Tatsuya Mimura Abstract Purpose:, To report a patient who fell unconscious because of vasovagal syncope evoked by needle phobia when he tried to wear contact lenses. Case reports:, A 16-year-old healthy boy had sometimes experienced dizziness when looking at the tips of pens. When he put his finger and the lens close to his eye to insert a soft contact lens, he felt sick and dizzy and fell unconscious. Conclusion:, Our experience suggests that patients with needle phobia may develop vasovagal syncope by concentrating on a fingertip when inserting a contact lens. We need to be aware of unconsciousness because of phobia when trying to insert contact lenses. [source] The effect of perceived length on visuomotor localizationOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2001Nick Fogt Summary Purpose: The purpose of this experiment was to study visuomotor localization in the presence of either a horizontal array of equally spaced dots or a thin horizontal line. Methods: Pointing behavior was used to assess directional localization. In experiment 1, subjects were made myopic using a contact lens and then corrected with a spectacle lens. Subjects were tested in the presence and absence of a regularly spaced, horizontal array of dots with and without the contact lens/spectacle combination. In experiment 2, subjects wore the contact lens/spectacle in all cases. Some subjects were tested in the presence and then in the absence of a regularly spaced, horizontal array of dots while the order of conditions was reversed for other subjects. In experiments 3 and 4, subjects were tested without the contact lens/spectacle combination. In experiment 3, subjects were tested in the absence and then in the presence of a regularly spaced, horizontal arrays of dots. In experiment 4, subjects were tested in the absence and then in the presence of a thin horizontal line. Results: In experiment 1, in the absence of the array of dots, subjects undershot targets with the contact lens/spectacle combination. When the array was present, pointing with the contact lens/spectacle combination was accurate. In experiment 2, subjects undershot targets in the absence of the array of dots if this condition was performed first. If the array was present in the initial condition, the pointing undershoot in the second condition (array absent) was reduced. In all cases, the pointing undershoot was reduced in the presence of the array. In experiments 3 and 4, a pointing overshoot was found in the presence of an array of dots or a thin line. Conclusions: It is concluded that extraretinal eye position information is not the primary determinant of visuomotor localization in the presence of a horizontal contour. The overshoot produced by a horizontal contour may be related to a length illusion brought about by spatial filtering in the visual system or inaccurate distance judgments. [source] Spoliation of a rigid gas permeable contact lens by sodium chloride: A free volume microprobe studyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2009M. V. Deepa Urs Abstract The interaction of one of the major inorganic ions present in tears, viz., sodium chloride (NaCl), with a rigid gas permeable contact lens, poly(Fluorosilicone acrylate) (FP92) has been investigated using Positron Annihilation Lifetime Spectroscopy (PLS) and refrac-tive index measurement. We monitored the changes in its free volume size and number density in the presence of NaCl solute trans-ported through diffusion. Based on PLS results, we propose that the adhesion of sodium chloride salt to the fluorine and methacrylate sites of FP92 results in zones of excess salt concentration. The changes in refractive index of the contact lens material due to the salt adhesion, correlates well with the changes in free volume of the material. Presence of sodium chloride perturbs the free volume of the lens material and hence its polarizability (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] 1231: How to identify retinal tears?ACTA OPHTHALMOLOGICA, Issue 2010JP BERROD Purpose Locating the retinal tear(s) in rhegmatogenous retinal detachment witout PVR is the first step of a successful treatment. The purpose of the course is to present the different techniques and rules to examine the retina in order to detect and locate all the tears. Methods We emphasised the 3 Lincoff's rules that permit concentration of the efforts to a small area of the periphery to identify the breaks. More than one break is present in 50% of eyes. Hence, there is a need to inspect the rest of the fundus including areas of attached retina. Results In the evaluation, one needs to stress the importance of good binocular indirect ophthalmoscopy with scleral depression or direct ophthalmocopy with slitlamp and 3 mirror contact lens. Vitrectomy can be indicated in certain cases of failure to detect breaks. In the presence of severe PVR the surgery would involve thorough cleaning of the entire retina, hence it may not be so important to identify all breaks preoperatively. Conclusion A minimal rate of postoperative failure for rhegmatogenous retinal detachment can only be achieved if a maximal preoperative search for the retinal breaks has been performed. [source] 2141: Fitting of challenging corneas with a special design of rigid gas permeable (RGP) lensACTA OPHTHALMOLOGICA, Issue 2010W ABOU SAMRA Purpose To study the safety and efficacy of a new design of RGP lens namely Rose K irregular cornea (IC) in management of corneas with high degree of irregular astigmatism. Methods The study was made in 66 eyes of 40 patients with irregular astigmatism. The selection criterion was to obtain a sample population with irregular astigmatism that was unlikely to be corrected with spectacles or conventional contact lens. A complete ophthalmologic exploration which included topography was made. All eyes were fitted with Rose K IC after measuring precisely lens parameters according to a special trial set of this design.Refraction, visual acuity before and after fitting,maximum wearing time, contact lens related problems and patient satisfaction were analyzed. Results The studied eyes included eyes with high degree of irregular astigmatism due to keratoconus in 42 eyes (63.6%),corneal injuries in 6 eyes (9.1%), PMD in 12 eyes (18.2%), and post Lasik ectasia in 6 eyes (9.1%). After fitting of the eyes with the RGP lens, there was a significant improvement in the visual acuity (VA)in all fitted eyes. The mean VA improved from 0.16±0.25 to 0.85± 0.13(p<0.001).Study of spherical and astigmatic errors showed also a highly significant improvement. The mean spherical error was -4.6 ± 2.4 and improved to 0.50 ± 0.20 after final fitting (p<0.001). The mean astigmatic error of studied eyes was -6.2 ± 2.3 while after fitting was -0.75±0.32(p<0.001).Statistical analysis of the subjective responses indicated a strong acceptance of the lens by all subjects. Conclusion Rose K IC proved to be effective in correcting high degree of corneal astigmatism caused by a variable number of challenging corneal conditions with high visual performance and good patient comfortability. [source] An antibiotic releasing contact lensACTA OPHTHALMOLOGICA, Issue 2009J CIOLINO Purpose To characterize a drug-eluting contact lens designed to release ciprofloxacin to the eye in a controlled manner for an extended period of time. Methods Thin fiilms, containing ciprofloxacin or fluorescein encapsulated in PLGA (Poly[lactic-co-glycolic acid]), were coating by pHEMA (poly[hydroxyethyl methacrylate]) by ultraviolet light polymerization, creating prototype contact lenses. The films were characterized by scanning electron microscopy. Release studies were conducted in phosphate buffered saline at 37°C with continuous shaking. Ciprofloxacin eluted from the contact lens was studied in an antimicrobial assay to verify antimicrobial effectiveness. Results Ciprofloxacin and fluorescein were released from the contact lenses in a controlled manner, demonstrating zero-order release kinetics under infinite sink conditions for over 4 weeks. The rate of drug release was controlled by modifying either the ratio of drug to PLGA or the molecular weight of the PLGA employed. Both the PLGA and the pHEMA affected release kinetics. Ciprofloxacin released from the contact lenses inhibited ciprofloxacin-sensitive Staphylococcus aureus at all time-points tested. Conclusion A thin drug-PLGA film coated with pHEMA could potentially be used to create contact lenses which can serve as a platform for ocular delivery of antibiotics and other medications, with widespread therapeutic applications. [source] Scanning beyond the limits of standard OCT: OCT scans of the peripheral retina and the anterior chamber angle with a slitlamp integtrated FD-OCT systemACTA OPHTHALMOLOGICA, Issue 2009M STEHOUWER Purpose Exploring the quality of OCT images of the peripheral retina and anterior chamber angle made through a 3-mirror contactlens and a new FD-OCT device integrated into a slit lamp. Methods Patients with peripheral lesions (n=10) and glaucoma (n=10), seen in the outpatient clinic of the Academic Medical Center, were scanned with a Fourier Domain OCT integrated into a common Topcon slitlamp (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A-scans per second, up to 1024 A-scans per b-scan). For posterior segment scans a fast Z-tracking system in the reference arm compensates for the dynamic character (movements of patient, handheld lens, slitlamp) of the examination. Scans of peripheral lesions, and the anterior chamber angle were made with a 3-mirror lens, while simultaneously the lesions were observed with the slitlamp. Results Scans of the peripheral retina obtained with a 3-mirror lens with the FD-OCT integrated into the slitlamp were of reasonably good quality and lesions, like peripheral laser scars, could be clearly identified. Compared to stand alone OCT systems, the integrated OCT system reached more peripheral lesions. The anterior chamber angle scanned through a 3-mirror lens enabled scans of the angle structures. Conclusion It is possible to scan the peripheral retina and anterior chamber angle through a 3-mirror contact lens with the slitlamp with integrated OCT. These scans could be of clinical interest in patients with pathology in the peripheral retina pathology or the anterior chamber angle. [source] Wireless contact lens sensor for intraocular pressure monitoring: assessment on enucleated pig eyesACTA OPHTHALMOLOGICA, Issue 4 2009Matteo Leonardi Abstract. Purpose:, Assessment on enucleated pig eyes of a novel and minimally invasive method for the continuous monitoring of intraocular pressure (IOP), based on a novel wireless contact lens sensor (CLS). Methods:, The wireless CLS is a disposable silicone soft contact lens with a sensor embedded in it, allowing the wireless measurement of changes in corneal curvature induced by IOP variations. A CLS was adapted and tested on enucleated pig eyes. To demonstrate the measurement principle of the device, the enucleated pig eye was cannulated, allowing precise control of IOP. The CLS signal was then compared to the imposed IOP. Results:, First, the IOP of enucleated pig eyes was changed between 11 and 14 mmHg, simulating ocular pulsation. Then, IOP was changed with static steps of 1 mmHg between 20 and 30 mmHg to assess the reproducibility and linearity of the CLS. In both cases, measurements from the CLS and IOP showed very good correlation. A calibration graph shows that the CLS is capable of monitoring the IOP of each individual eye with a reproducibility of ± 0.2 mmHg (95% confidence interval). Conclusion:, The wireless CLS shows a good functionality to monitor the IOP on enucleated pig eyes. The device is placed in the same way as a soft disposable contact lens. This device would allow a minimally invasive and continuous monitoring of IOP over prolonged periods of up to 24 hr, regardless of patient activity, thus opening up new diagnostic and therapeutic methods to manage glaucoma. [source] Aberration controll with contact lensesACTA OPHTHALMOLOGICA, Issue 2007A LINDSKOOG PETTERSSON Purpose: To investigate and compare the reduction in ocular aberrations with standard hydrogel contact lenses (i.e., lenses not designed to control aberrations) and with aberration controlled hydrogel and silicon-hydrogel contact lenses. Methods: The aberrations with and without contact lenses were measured in 42 subjects between 20 and 37 years of age using a Zywave wave front sensor (B&L). 22 subjects were fitted a standard contact lens and an aberration controlled hydrogel lens. The remaining 20 subjects were fitted aberration controlled silicon-hydrogel lenses Results: With the standard lens the aberrations were controlled (i.e., close to zero) with a 4.0 mm pupil. Whereas, with both the aberration control lenses the residual spherical aberrations became negative. The reduction in aberrations differed significantly (p<0.05) between all lenses. Conclusions: Since aberration controlled contact lenses in many subjects overcorrect the spherical aberrations when the pupil size is normal (~4.0 mm) we suggest measuring wave front aberrations in each patient both with and without contact lenses in order to achieve the desired effect. [source] Contact lens induced keratitis associated with contact lens wearACTA OPHTHALMOLOGICA, Issue 5 2001Irene Dejaco-Ruhswurm ABSTRACT. Purpose: To evaluate clinical characteristics, risk factors, management and outcome of contact lens induced keratitis (CLIK) associated with contact lens wear. Methods: The study comprised all consecutive patients presenting with contact lens related presumed microbial keratitis during a 12-month period at our department. Detailed demographic data, type of contact lens, duration of lens wear, wearing schedule and lens hygiene were derived from a self-administered questionnaire. Severity of ulcer, corneal scrapings, treatment and final outcome were evaluated. Results: 27 patients with CLIK, some of which may have been sterile peripheral infiltrates, due to contact lens wear were detected. In the majority of the cases patients had used disposable soft contact lenses (89%) and most of them had a daily wearing schedule (78%). 51.8% patients cleaned their lenses regularly. 6 (22%) applied no disinfection since their lenses were disposable on removal. In 3 of our cases with CLIK, penetrating keratoplasty had to be performed. Conclusion: Disposable contact lenses seem to have been a predisposing factor for contact lens induced keratitis also when used on a daily wear schedule. Insufficient contact lens care products and/or manufacturing characteristics may be responsible for CLIK, which is also observed in otherwise compliant contact lens users. In 3 of our patients with CLIK keratoplasty became necessary, indicating that contact lens induced keratitis may result in severe corneal complications. [source] Contact lens fitting for post-radial-keratotomy residual myopiaCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2003Jeewan S Titiyal MD Abstract Purpose:,To formulate guidelines for contact lens fitting following radial keratotomy and to achieve a relationship between contact lens fitting parameters and refractive and keratometric parameters. Methods:,Thirty-five eyes of 30 patients who had post-radial-keratotomy residual myopia were evaluated for contact lens fitting. The base curve was selected by ,hit and trial' method until a proper fit was achieved, following which an over-refraction was done and final power of the contact lens obtained. Results:,The mean contact lens base curve was 43.04 ± 1.62 D, which was steeper than the postoperative keratometry by 2.35 ± 0.74 D. The base curve and the postoperative keratometry were correlated by regression analysis (r = 0.895, P < 0.001). The mean overall diameter of the contact lenses was 9.64 ± 0.08 mm. The mean contact lens power was 5.81 ± 3.07 D, which was more myopic than the residual myopia by 2.79 ± 1.67 D. Regression analysis showed definite correlation between the contact lens power and postoperative myopia (r = 0.854, P < 0.001). Conclusion:,For correction of post-radial-keratotomy residual myopia, contact lens fitting parameters can be determined by a regression formula using keratometric and refractive values. [source] | ||||||||||