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Contact Lenses (contact + lense)
Kinds of Contact Lenses Selected AbstractsAllergic Conjunctivitis and Contact Lenses: Experience with Olopatadine Hydrochloride 0.1% TherapyACTA OPHTHALMOLOGICA, Issue 2000M. Brodsky ABSTRACT. Objective: The efficacy of Patanol®, a topically applied anti-allergic agent, was evaluated in a group of patients with allergic conjunctivitis due to contact lens wear (GROUP I) and a group comprised of seasonal allergic conjunctivitis patients, vernal conjunctivitis patients and atopic keratoconjunctivitis patients (GROUP II). Methods: One drop of Patanol® was administered to each eye twice daily. Signs and symptoms were assessed 7, 14, and 28 days after initiation of drug therapy. Results: Itching/burning, tearing, hyperemia and papillary reaction were reduced to scores of 0/1 (absent/mild) in 85%, 90%, 81% and 62%, respectively, of GROUP I patients at Day 28. The allergic conditions in GROUP II patients also improved with Patanol® treatment. Itching/burning, tearing, hyperemia and papillary reactions were absent/mild in 60%, 76%, 96% and 90%, respectively, of these patients at Day 28. Conclusion: Patanol® treatment effectively and rapidly alleviated the signs and symptoms of allergic conjunctivitis due to contact lens wear as well as vernal conjunctivitis, atopic keratoconjunctivitis and the common seasonal allergic conjunctivitis. Patanol® allowed allergic patients to be more comfortable while permitting them to continue using contact lenses. [source] Contact lenses as a drug delivery device for epidermal growth factor in the treatment of ocular woundsCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 2 2010Clyde L Schultz PhD Background:, This work was conducted to investigate the uptake and release of epidermal growth factor (EGF) from hydrogel contact lenses and to determine whether the released protein would be therapeutically active in a rabbit corneal epithelial defect model of ocular trauma, prior to use in humans. Methods:, The uptake and release of EGF from hydrogel contact lens materials were determined by high-pressure liquid chromatography. Contact lenses composed of vasurfilcon A or lotrafilcon A (containing silicone) were incubated in a source solution containing 0.4 ppm EGF for seven hours. To determine the kinetics of drug uptake into the contact lens matrix, drug concentration in the source solution was measured at zero, one, 60, 240 and 420 minutes. To determine the kinetics of release, loaded contact lenses were immersed in a recipient solution of phosphate-buffered saline. Therapeutic activity in vivo was investigated by placing prepared lenses on the surface of abraded corneas of New Zealand White rabbits, with abraded corneas of contralateral eyes used as controls. Control eyes were treated with contact lenses placed in saline for injection. Wound closure was assessed hourly. Results:, Uptake and release of EGF were demonstrated for vasurfilcon A but not lotrafilcon A contact lens materials. The retention time of EGF released from vasurfilcon A contact lenses was similar to control EGF not exposed to contact lens polymers. The greatest adsorption of EGF into the lens material occurred within approximately 120 minutes, with a flattening of the rate of uptake thereafter. Abraded eyes in rabbits showed a significantly higher overall healing rate for EGF-treated contact lenses compared with control eyes (p < 0.0001). Conclusions:, EGF can be delivered from some but not all hydrogel materials. Lens materials composed of silicone may not be useful for delivering EGF to the eye. EGF-treated contact lenses may be a useful device to facilitate healing of ocular wounds. [source] Equivalences between refractive index and equilibrium water content of conventional and silicone hydrogel soft contact lenses from automated and manual refractometry,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007José M. González-Méijome Abstract Purpose The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. Methods Twelve HEMA-based hydrogels of different hydration and four siloxane-based polymers were assayed. A manual refractometer and a digital refractometer were used. Polynomial models obtained from the sucrose curves of equilibrium water content against refractive index and vice-versa were used either considering the whole range of sucrose concentrations (16,100% equilibrium water content) or a range confined to the equilibrium water content of current soft contact lenses (,20,80% equilibrium water content). Results Values of equilibrium water content measured with the Atago N-2E and those derived from the refractive index measurement with CLR 12,70 by the applications of sucrose-based models displayed a strong linear correlation (r2 = 0.978). The same correlations were obtained when the models are applied to obtain refractive index values from the Atago N-2E and compared with those (values) given by the CLR 12,70 (r2 = 0.978). No significantly different results are obtained between models derived from the whole range of the sucrose solution or the model limited to the normal range of soft contact lens hydration. Conclusions Present results will have implications for future experimental and clinical research regarding normal hydration and dehydration experiments with hydrogel polymers, and particularly in the field of contact lenses. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Hydrogels: From soft contact lenses and implants to self-assembled nanomaterialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2009Jindrich Kopecek Abstract Hydrogels were the first biomaterials designed for clinical use. Their discovery and applications as soft contact lenses and implants are presented. This early hydrogel research served as a foundation for the expansion of biomedical polymers research into new directions: design of stimuli sensitive hydrogels that abruptly change their properties upon application of an external stimulus (pH, temperature, solvent, electrical field, biorecognition) and hydrogels as carriers for the delivery of drugs, peptides, and proteins. Finally, pathways to self-assembly of block and graft copolymers into hydrogels of precise 3D structures are introduced. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5929,5946, 2009 [source] Perfluorocarbons: Life sciences and biomedical uses Dedicated to the memory of Professor Guy Ourisson, a true RENAISSANCE man.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2007Marie Pierre Krafft Abstract Perfluorocarbons are primarily characterized by outstanding chemical and biological inertness, and intense hydrophobic and lipophobic effects. The latter effects provide a powerful noncovalent, labile binding interaction that can promote selective self- assembly. Perfluoro compounds do not mimic nature, yet they can offer abiotic building blocks for the de novo design of functional biopolymers and alternative solutions to physiologically vital issues. They offer new tags useful for molecular recognition, selective sorting, and templated binding (e.g., selective peptide and nucleic acid pairing). They also stabilize membranes and provide micro- and nanocompartmented fluorous environments. Perfluorocarbons provide inert, apolar carrier fluids for lab-on-a-chip experiments and assays using microfluidic technologies. Low water solubility, combined with high vapor pressure, allows stabilization of injectable microbubbles that serve as contrast agents for diagnostic ultrasound imaging. High gas solubilities are the basis for an abiotic means for intravascular oxygen delivery. Other biomedical applications of fluorocarbons include lung surfactant replacement and ophthalmologic aids. Diverse colloids with fluorocarbon phases and/or shells are being investigated for molecular imaging using ultrasound or magnetic resonance, and for targeted drug delivery. Highly fluorinated polymers provide a range of inert materials (e.g., fluorosilicons, expanded polytetrafluoroethylene) for contact lenses, reconstructive surgery (e.g., vascular grafts), and other devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1185,1198, 2007. [source] Randomised controlled trial of the effects of two rigid gas permeable (RGP) contact lens materials and two surface cleaners on straylight valuesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 5 2009Marten F. Fortuin Abstract Purpose:, In a double-masked randomized controlled crossover study we investigated both the retinal responses to straylight, and the effects of lens cleaners on straylight values, in two different RGP contact lens materials. Methods:, Thirty patients (20,59 years) wearing RGP lenses were refitted with new lenses made of Boston XO material in one eye and made of Comfort O2 (ONSI-56) material in the other eye. Reported wetting angles for the Boston XO material (103°) and for the ONSI-56 material (7.2°) were obtained by sessile drop measurements. After refitting, the study comprised three 5-week trial periods. In Period 1 half of the participants (Group A) wore Boston XO lenses in their right eye and Comfort O2 (ONSI-56) lenses in their left eye, and the other half (Group B) vice versa. In Period 2 Group A wore Comfort O2 (ONSI-56) lenses in their right eye and Boston XO lenses in their left, and Group B vice versa. All participants used Miraflow cleaner during periods 1 and 2. In Period 3, during which all participants used Boston cleaner, Group A wore Boston XO lenses in their right eye and Comfort O2 (ONSI-56) lenses in their left eye and Group B vice versa. Straylight data (log S) were obtained with and without contact lenses using the Oculus C-Quant straylight meter in all three periods. Central corneal thickness (CCT) was measured in the second and third periods. Results:, When not wearing lenses (n = 60 eyes) at the end of the second 5 week trial period straylight was measured twice with averages of 1.07 log S, and the corrected CCT measurements averaged 546 ,m. Straylight values with Comfort O2 (ONSI-56) reached 1.15 log S at the end of both the second (n = 25 eyes) and third periods (n = 23 eyes). Straylight values with Boston XO were 1.17 log S (n = 26 eyes) at the end of the second period, and 1.16 log S (n = 25 eyes) at the end of the third period. Conclusions:, Existing RGP lens wearers refitted with new lenses with different contact angles, made of Boston XO and Comfort O2 (ONSI-56) showed, over three 5 week periods, relatively small increases in straylight, which were functionally comparable, irrespective of the type of lens material or lens cleaner used. At every visit, straylight values and CCTs returned to baseline levels after RGP lens removal, confirming that the straylight fluctuations were mainly due to scattering from the RGP lenses; or tear film interaction; or a combination of both. [source] Technical Note: Effect of contact lenses on measurement of the accommodation microfluctuationsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008Mhairi Day Abstract Aim:, Dynamic measurement of accommodation in subjects with myopia usually involves recording through soft contact lenses (CLs) to correct the refractive error. Conversely, dynamic accommodation measurement in emmetropic control subjects is generally undertaken without any corrective lenses. The aim of this experiment was to determine whether CL correction affects the measurement of accommodation microfluctuations using infrared refractometry, and whether this needs to be considered in studies which attempt to compare accommodation responses between the two groups. Methods:, Ten young emmetropic subjects viewed a high contrast Maltese cross target monocularly using the right eye at a target vergence of 0 D. The subjects viewed the target under two conditions: with CL condition and without CL condition, where the subjects viewed the target with the eye only. Accommodation responses of the right eye were recorded continuously for 2 min at a sampling rate of 52 Hz using the Shin-Nippon SRW-5000 autorefractor. Results:, No significant difference (two-tailed paired t -test, t9 = ,1.499, p = 0.168) was found in mean accommodation response between the with CL (mean ± S.D. = ,0.02 ± 0.24 D) and without CL conditions (mean ± S.D. = +0.01 ± 0.25 D). No significant (two-tailed paired t -test, t9 = 0.151, p = 0.883) difference in the magnitude of the accommodation microfluctuations was found between the with CL (mean ± S.D. = 0.162 ± 0.04 D) and without CL condition (mean ± S.D. = 0.169 ± 0.04 D). Power spectrum analysis revealed no differences in the characteristics of the microfluctuations waveform between the two conditions. A control experiment carried out on a subgroup of five subjects using a negative (,3 D) CL demonstrated that there was no significant effect of the dioptric power of the CL on the magnitude of the accommodation microfluctuations (anova: F3,15 = 0.254, p = 0.782). Conclusion:, Thin soft CLs do not affect the magnitude or frequency characteristics of accommodation microfluctuations when measured using the Shin-Nippon SRW-5000. [source] Microbial contamination of contact lenses and lens care accessories of soft contact lens wearers (university students) in Hong KongOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2007M. S. Yung Abstract Purpose:, This study aimed to examine the rates of microbial contamination, and identify contaminants associated with contact lenses and lens care accessories used by a group of young contact lens wearers. Methods:, Collected contact lenses, lens cases, and lens care solutions were studied by bacterial culture. Contamination rates of these samples were recorded and compared with those reported in previous studies. Results:, Of the samples tested, 9% of lens extracts, 34% of case extracts and 11% of solution samples were contaminated with ocular pathogenic microorganisms. Serratia spp., Staphylococcus aureus and coagulase-negative staphylococci were the most common microorganisms isolated. Lens cases were the most frequently contaminated item. Lens cases also yielded the widest range of bacterial isolates. Contact lenses used by occasional wearers were associated with a higher contamination rate. Using either saline or multipurpose solution to rinse lenses before use appeared to be effective in reducing incidence of contamination. Conclusion:, Our findings demonstrate that contact lenses and lens care accessories are not well maintained by contact lens wearers. Regular reviews and reinforcement of lens care procedures for the usage and care of contact lenses and lens care accessories is therefore important and essential. [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 prospects for super-acuity: limits to visual performance after correction of monochromatic ocular aberrationOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2003W. N. Charman Abstract It has recently been suggested that correction of the monochromatic aberration of the eye could lead to substantial improvements in visual acuity and contrast sensitivity function. After consideration of the best-corrected visual acuity of normal eyes, the optical and neural limits to visual performance are reviewed. It is concluded that, even if current problems with the accuracy of the suggested techniques of aberration correction, through corneal excimer laser ablation or customised contact lenses, can be overcome, changes in monochromatic ocular aberration over time, the continuing presence of chromatic aberration, errors of focus associated with lags and leads in accommodation, and other factors, are likely to result in only minor improvements in the high-contrast acuity performance of most normal eyes being produced by attempted aberration control. Significant gains in contrast sensitivity might, however, be achievable, particularly under mesopic and scotopic conditions when the pupil is large, provided that correct focus can be maintained. In the immediate future, reduction of the high levels of aberration that are currently found in eyes that have undergone refractive surgery and in some abnormal eyes should bring useful benefits. [source] The ChromaGen contact lens system: colour vision test results and subjective responsesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2001Helen A. Swarbrick Summary The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D-15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2-week lens-wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced Ishihara error rates(p<0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors(p<0.005) on the D-15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour-related tasks, but are not indicated as an aid for CVD in occupations with colour vision-related restrictions. [source] Economical Advantages of Low-Pressure Plasma Polymerization CoatingPLASMA PROCESSES AND POLYMERS, Issue 6 2005Hirotsugu Yasuda Abstract Summary: Low-pressure plasma polymerization coating, as described in this paper, is an ultimately green process that uses a minimum amount of substances and produces a minimum amount of effluent and hence does not require an environmental remediation process. The super-green aspect of the processing entirely changes the equation for the viability of the process in industrial applications. The main hampering factors for the low-pressure processes are 1) psychological fear of vacuum processes, 2) relatively high initial equipment costs, and 3) a lack of adequate cost estimate for the entire process. In many cases, the first two factors are enough for planners to shy away from this promising technology. However, when one examines the overall cost of processing as a whole, the cost of initial equipment often is not the decisive factor. Such cases are presented in the nano-film coating applied in corrosion protection of aluminum alloys, steel, and surface-state modification of contact lenses. The benefits of environmental friendliness, non-hazardous processing and superior performance of products that can be achieved only by low-pressure plasma polymerization coatings are more than enough to compensate the initial cost of the equipment. For nanofilm (20 nm) coatings, the most expensive annual operation cost is for wastewater treatment, which is much more than the initial cost of vacuum plasma polymerization reactor. [source] New silicone hydrogels based on interpenetrating polymer networks comprising polysiloxane and poly(vinyl alcohol) networksPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2009V. N. Pavlyuchenko Abstract A method for the synthesis of a new silicone hydrogel as a biphase material for soft contact lenses is considered. The method is based on the synthesis of sequential interpenetrating polymer networks (IPN) and includes the following stages: (1) cross-linked silicone synthesis by the reaction of vinyl- and hydride-containing oligosiloxanes; (2) silicone network saturation with vinyl acetate and cross-linking monomer followed by UV-initiated polymerization to form an IPN comprising the silicone and cross-linked poly(vinyl acetate) (PVAc) network; (3) PVAc network alcoholysis with methanol to obtain silicone hydrogels comprising the silicone and cross-linked poly(vinyl alcohol) (PVAl). A study of hydrophilic, optical, mechanical, and structural features of the silicone hydrogels showed that optical transparency is achieved for materials with the highest density of silicone network cross-linking where the size of IPN structural units does not exceed 100,nm. The water content in hydrophilic networks of silicone hydrogel is found to be below the values typical of cross-linked PVAl, leading to non-additivity of IPN mechanical properties. Indeed, the elasticity moduli (E) of the hydrophilic and silicone networks are 0.4,0.7 and 0.7,1.8,MPa, respectively, whereas for some IPN this value reaches 3.0,MPa. The optimal parameters of synthesis providing the reduction of E to 0.8,1.6,MPa without deterioration of the required performance characteristics (optical transparency 90,92%, water content 20,39,wt%) are determined. Copyright © 2009 John Wiley & Sons, Ltd. [source] Biosynthetic corneas , evaluation in humansACTA OPHTHALMOLOGICA, Issue 2009P FAGERHOLM Collagen-based biosynthetic corneas, designed to mimic the extracellular matrix of the corneal stroma have been developed and extensively evaluated in animal models over the last 7 years. Human recombinant collagen type III (RHC III) was crosslinked with water-soluble carbodiimides and fabricated into optically transparent corneal substitutes for transplantation. Following study approval of the Medical Product Agency, Sweden and the Human Ethics Committee, University of Linköping, Sweden, a Phase I study was initiated. 10 patients who were scheduled for corneal grafting were enrolled into the study. Nine had keratoconus and one had a deep scar following Pseudomonas keratitis. A central 6 mm diameter deep lamellar button was excised and was replaced by a 6.25 mm diameter 500 µm thick construct. Six overlying sutures were used to anchor the graft. Topical 0.1% dexametasone and chloramphenicol was used for the first 1 month postoperatively. The sutures were removed after 5-7 weeks. The patients were followed clinically and evaluated for UCVA, BSCVA and VA with contact lenses. Corneal touch sensitivity (Cochet-Bonnet) and tear production (Schirmer ) were tested. Photography, OCT (Visante), topography (Orbscan II) and in vivo confocal microscopy (Heidelberg) was documented. After 3 months all patients had stably epithelialized and implants were anchored by recipient keratocyte ingrowth. The mean BSCVA at 6 months (20/133) improved slightly at 12 months (20/90). The mean BCLCVA was 20/50 at 12 months and was notably better in younger patients (mean of 20/40 in the 5 youngest). One patient had BCLVA of 20/20 at 12 months. The mean central corneal thickness was stable between 3 and 12 months at about 400µm. The mean 5min Schirmer values were 20 ± 10mm in operated eyes and 17 ± 8 mm in fellow eyes. At 12 months the mean touch sensitivity was 25mm in operated eyes and 60mm in fellow eyes, which was the same as in penetrating grafts. In-vivo confocal microscopy revealed the ingrowth of corneal nerves at the subbasal epithelium. We have shown for the first time that bioengineered collagen-based corneal substitutes are fully compatible and promote regeneration of corneal cells. The 18 months follow-up results will be presented aswell. [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] 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] Allergic Conjunctivitis and Contact Lenses: Experience with Olopatadine Hydrochloride 0.1% TherapyACTA OPHTHALMOLOGICA, Issue 2000M. Brodsky ABSTRACT. Objective: The efficacy of Patanol®, a topically applied anti-allergic agent, was evaluated in a group of patients with allergic conjunctivitis due to contact lens wear (GROUP I) and a group comprised of seasonal allergic conjunctivitis patients, vernal conjunctivitis patients and atopic keratoconjunctivitis patients (GROUP II). Methods: One drop of Patanol® was administered to each eye twice daily. Signs and symptoms were assessed 7, 14, and 28 days after initiation of drug therapy. Results: Itching/burning, tearing, hyperemia and papillary reaction were reduced to scores of 0/1 (absent/mild) in 85%, 90%, 81% and 62%, respectively, of GROUP I patients at Day 28. The allergic conditions in GROUP II patients also improved with Patanol® treatment. Itching/burning, tearing, hyperemia and papillary reactions were absent/mild in 60%, 76%, 96% and 90%, respectively, of these patients at Day 28. Conclusion: Patanol® treatment effectively and rapidly alleviated the signs and symptoms of allergic conjunctivitis due to contact lens wear as well as vernal conjunctivitis, atopic keratoconjunctivitis and the common seasonal allergic conjunctivitis. Patanol® allowed allergic patients to be more comfortable while permitting them to continue using contact lenses. [source] The desperate last gasps of rigid contact lensesCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 4 2005Nathan Efron PhD DSc FAAO No abstract is available for this article. [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] Serotype and adhesion of Pseudomonas aeruginosa isolated from contact lens wearersCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2001Sophy J Thuruthyil PhD ABSTRACT The purpose of the present study was to correlate the serotypes of Pseudomonas aeruginosa to the bacterial adhesion to contact lenses and human corneal epithelial cells. Twenty-three strains isolated from contact lens wearers were used for the study. The bacterial serotypes were examined with a P. aeruginosa antisera kit. The attachment of bacteria on contact lenses or human corneal epithelial cells was determined by counting the number of adhered bacteria after incubation of the bacteria with contact lenses or corneal epithelial cells. The 23 ocular isolates belonged to seven serotypes. Strains of serotypes I, G and E were the three dominant serogroups and were more adhesive to contact lenses compared with other groups of the bacteria. The bacterial serotypes and the clinical sequelae were not strongly related. These results indicate that the surface characteristics of bacterial serotypes are related to the bacterial adhesion to the surface, but the pathogenesis of the bacteria may result from multiple factors. [source] Contact lenses as a drug delivery device for epidermal growth factor in the treatment of ocular woundsCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 2 2010Clyde L Schultz PhD Background:, This work was conducted to investigate the uptake and release of epidermal growth factor (EGF) from hydrogel contact lenses and to determine whether the released protein would be therapeutically active in a rabbit corneal epithelial defect model of ocular trauma, prior to use in humans. Methods:, The uptake and release of EGF from hydrogel contact lens materials were determined by high-pressure liquid chromatography. Contact lenses composed of vasurfilcon A or lotrafilcon A (containing silicone) were incubated in a source solution containing 0.4 ppm EGF for seven hours. To determine the kinetics of drug uptake into the contact lens matrix, drug concentration in the source solution was measured at zero, one, 60, 240 and 420 minutes. To determine the kinetics of release, loaded contact lenses were immersed in a recipient solution of phosphate-buffered saline. Therapeutic activity in vivo was investigated by placing prepared lenses on the surface of abraded corneas of New Zealand White rabbits, with abraded corneas of contralateral eyes used as controls. Control eyes were treated with contact lenses placed in saline for injection. Wound closure was assessed hourly. Results:, Uptake and release of EGF were demonstrated for vasurfilcon A but not lotrafilcon A contact lens materials. The retention time of EGF released from vasurfilcon A contact lenses was similar to control EGF not exposed to contact lens polymers. The greatest adsorption of EGF into the lens material occurred within approximately 120 minutes, with a flattening of the rate of uptake thereafter. Abraded eyes in rabbits showed a significantly higher overall healing rate for EGF-treated contact lenses compared with control eyes (p < 0.0001). Conclusions:, EGF can be delivered from some but not all hydrogel materials. Lens materials composed of silicone may not be useful for delivering EGF to the eye. EGF-treated contact lenses may be a useful device to facilitate healing of ocular wounds. [source] Contact lens management of infantile aphakiaCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 1 2010Richard G Lindsay BScOptom MBA FAAO (DipCL) FCLSA FVCO The visual outcomes for infants 18 months or younger with cataracts have improved dramatically over the past couple of decades. Earlier detection of infantile cataract and prompt surgical removal,with subsequent visual rehabilitation with contact lenses,mean that these patients now have a much better visual prognosis. Advances in contact lens technology have led to a significantly higher success rate with contact lenses and this has been a major factor in improving the visual outcomes for aphakic infants. This review outlines the contact lens management of infantile cataract, including a detailed analysis of the various contact lens options available and a discussion regarding the important factors that can cause issues with contact lens wear and affect the overall visual rehabilitation of the infant. [source] Bifocal soft contact lenses as a possible myopia control treatment: a case report involving identical twinsCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 4 2008Thomas A Aller OD Background:, Several studies have suggested that bifocal and progressive spectacles can reduce progression of myopia in esophoric children. This study compared myopic progression with bifocal (BSCL) and single vision soft contact lenses (SVSCL) in identical twins with near point esophoria. Methods:, Two 12-year-old myopic girls were randomly assigned to wear either BSCL or SVSCL for one year using a double-masked design. Both twins then wore BSCLs for another year. Ocular measurements included cycloplegic and manifest refractions, corneal curvature and axial length. Distance and near phorias were measured through distance corrections and near associated phorias, with both types of contact lenses. Results:, Through their SVSCLs, both children exhibited near associated esophorias, which were neutralised by the BSCLs. The child wearing SVSCLs over the first year showed significant myopic progression, increasing -1.19 D (binocular average), while the child wearing BSCLs showed no progression (+0.13 D). The latter child showed limited progression (-0.28 D) over the second year, while switching from SVSCLs to BSCLs arrested progression in the other child (+0.44 D after one year). Axial length data were consistent with the refractive findings; the child exhibiting more myopia at the end of the first 12 months of the study had longer eyes (by 0.64 mm) than her sister, although their corneas also had steepened more (by 0.44 D compared to 0.18 D). The children showed similar, small increases in eye size over the second year when both wore BSCLs (binocular averages: 0.05, 0.09 mm, respectively). Conclusion:, The apparent inhibitory effect of BSCLs on myopic progression reported in this twin study argues for further study of their efficacy as a control treatment for myopes with near esophoria. [source] Do contact lenses shape up?CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2006Leo G Carney DSc PhD MScOptom No abstract is available for this article. [source] | |||||||||||||