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Matrix Metalloproteinase-Deactivating Contact Lens for Corneal Melting
摘要： Corneal melting is an uncontrolled, excessive degradation of cellular and extracellular components of the cornea. This potential cause of corneal blindness is caused by excessive expression of zinc-dependent matrix metalloproteinases (MMPs) and has no satisfying cure as of now. Herein, we introduce a novel therapeutic hydrogel which can be made into a contact lens to slow down the progression of corneal melting by deactivating MMPs. The hydrogel backbone is comprised of poly(2-hydroxyetyl methacrylate) (pHEMA), a main material for commercial contact lenses, and dipicolylamine (DPA) which has high affinity and selectivity towards zinc ion. Due to the high affinity towards zinc ions, the DPA-conjugated pHEMA (pDPA-HEMA) hydrogel selectively removes zinc ions from a physiological buffer and deactivates MMP-1, MMP-2 and MMP-9 within 2 hours. pDPA-HEMA hydrogel also effectively prevents degradation of porcine corneas by collagenase A, a zinc-dependent protease, whereas the corneas completely degrades within 15 hours when incubated with pHEMA hydrogel. The presence of pDPA-HEMA hydrogel does not affect the viability of keratocytes and corneal epithelial cells. Unlike the conventional MMP inhibitors (MMPi), the pDPA-HEMA hydrogel minimizes the risk of serious non-specific side effects, and provides a method to slow down the progression of corneal melting and other related ocular diseases.
关键词： dipicolylamine,contact lens,corneal melting,hydrogel,zinc,matrix metalloproteinases
更新于2025-09-23 15:23:52
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Spectroscopy of Oxygen-Sensitive Material for Measuring Contact Lens Oxygen Transmissibility
摘要： Purpose: Oxygen permeability or transmissibility is a crucial parameter for contact lenses to ensure that extended wear will not induce corneal hypoxia. This work tests a new method of using the oxidation of cysteamine, an oxygen-sensitive chemical, to quantify the oxygen transmissibility of current commercial contact lenses and contact lenses loaded with vitamin E. Methods: 3D printing was used to modify eye drop bottles and quartz cuvettes to create systems that allowed insertion of a contact lens in between the cysteamine solution and air. Both systems were exposed to atmospheric conditions where the only path of entry for oxygen was through the contact lens. The entering oxygen reacted with cysteamine, and the rate of cysteamine oxidation was measured using UV-vis spectrophotometry. The rate was then stoichiometrically related to oxygen transmissibility. Results: The eye drop method predicted transmissibility values within 9% of established, commercial values. The cuvette method predicted values within 10% of established values for silicone hydrogel lenses without any correction factor and within 11% for poly-hydroxyethyl-methacrylate lenses after correcting for oxygen entering the system. Incorporation of 20% (w/w) vitamin E into Acuvue? Oasys? lenses did not have a significant impact on the oxygen transmissibility. Conclusions: Both methods presented in this work can reliably measure oxygen transmissibility of contacts lenses or other materials. Further improvements in manufacturing could lead to improved accuracy and reliability, allowing wider use of this method for quantifying the oxygen transport in contact lenses.
关键词： oxidation,oxygen permeability,spectrophotometry,3D printing,contact lens
更新于2025-09-23 15:23:52
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Microscopic analysis of an opacified OFT CRYL? hydrophilic acrylic intraocular lens
摘要： A 51-year-old patient underwent posterior vitrectomy with perfluoropropane gas injection, phacoemulsification, and implantation of an Oft Cryl? hydrophilic acrylic intraocular lens (IOL) because of traumatic retinal detachment and cataract in the right eye. On the first postoperative day, gas was filling the anterior chamber because of patient’s non-compliance in terms of head positioning, and was reabsorbed within one week. Eight months later, the patient returned complaining of a significant decrease in vision. IOL opacification was noticed by slit-lamp examination. The lens was explanted to undergo gross and light microscopic analysis. The lens was also stained with the alizarin red method for calcium identification. Light microscopic analysis confirmed the presence of granular deposits, densely distributed in an overall circular pattern in the central part of the lens optic. The granules stained positive for calcium. This is the first case of the opacification of this type of hydrophilic lens. Surgeons should be aware of this potential postoperative complication, and the use of hydrophilic IOLs should be avoided in procedures involving intracameral gas because of the risk of IOL opacification.
关键词： Hydrophilic contact lens,Lens implantation,Vitrectomy,Intraocular lens,Capsule opacification
更新于2025-09-23 15:22:29
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Modeling and multiresponse optimization of cutting parameters in SPDT of a rigid contact lens polymer using RSM and desirability function
摘要： Amidst different conventional contact lens manufacturing techniques, single-point diamond turning (SPDT) is one of the recently developed ultra-high precision machining techniques employed in the fabrication of advanced contact lenses due to its capability of producing high optical surfaces of complex shapes and nanometric accuracy. SPDT is regarded as an effective process for the generation of high-quality functional surfaces in optical industries. However, despite advances in the ultra-high precision machining, it is not always easy to achieve a high-quality surface finish with maximum productivity. Machining parameters, namely cutting speed, feed rate, and depth of cut, play the lead role in determining the machine economics and quality of machining. The present study focuses on the determination of the optimum cutting conditions leading to minimum surface roughness as well as electrostatic charge and maximum productivity, in SPDT of the polymethyl methacrylate (PMMA) contact lens polymer using monocrystalline diamond cutting tool. The optimization is based on the response surface methodology (RSM) together with the desirability function approach. In addition, a mathematical model is developed for surface roughness (Ra), electrostatic charge (ESC), and material removal rate (MRR) using RSM regression analysis for a rigid contact lens polymer by the Design-Expert software. RSM allowed the optimization of the cutting conditions for minimal surface roughness, electrostatic charge, and maximal material removal rate which provides an effective knowledge base for process parameters, to make its enhancement of process performance in SPDT of contact lens polymer.
关键词： Electrostatic charge,Response surface methodology,Material removal rate,Surface roughness and optimization,PMMA contact lens polymer,Single-point diamond turning
更新于2025-09-23 15:22:29
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Determination of central corneal clearance in scleral lenses with an optical biometer and agreement with subjective evaluation
摘要： Purpose: To compare three methods to measure center corneal clearance (CCC) during scleral lens wear: subjective (slit lamp), image processed (ImageJ) and with an optic biometer. The optic biometer technique was validated in comparison to an OCT in the first part of the study. Methods: Twenty-two eyes (11 subjects) with healthy corneas were recruited. Three measures of OCT with scleral lens and ten measurements of axial length (AL) with IOLMaster with and without lens were performed. For the second part, 61 eyes (35 subjects) enrolled in a clinical study were selected. Measurements of CCC were done with IOLMaster, SlitLamp and ImageJ. Results: The measurements of CCC indirectly obtained with IOLMaster had a strong correlation with AS-OCT measurements (r = 0.981), showing a mean difference of 122.18 ± 46.05 μm (higher with IOLMaster). Regarding the second part, measurements of CCC were 238.66 ± 95.94 μm, 250.16 ± 124.31 μm and 263.15 ± 90.60 μm, for the IOLMaster, SlitLamp and ImageJ, respectively. The correlations were higher for ImageJ vs Subjective measure (r = 0.891) than for IOL vs Subjective (r = 0.748) and IOL vs ImageJ (r = 0.745). Analysis of differences and correlations between SlitLamp and ImageJ through time showed a mean difference of -32.28 ± 89.95 μm (r = 0.683) and 11.57 ± 32.95 μm (r = 0.940) at V12months. Conclusions: It is possible to measure CCC with IOLMaster, considering AL measured with and without lens and lens thickness. The three methods tested have good correspondence, showing that IOLMaster and ImageJ could be objective techniques to measure CCC. Also, it is possible to improve the agreement of subjective measures when compared to objective measures trough time.
关键词： Clearance,Scleral lens,Contact lens
更新于2025-09-23 15:21:21
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Controlled Release of rAAV Vectors from APMA-Functionalized Contact Lenses for Corneal Gene Therapy
摘要： As an alternative to eye drops and ocular injections for gene therapy, the aim of this work was to design for the first time hydrogel contact lenses that can act as platforms for the controlled delivery of viral vectors (recombinant adeno-associated virus, rAAV) to the eye in an effective way with improved patient compliance. Hydrogels of hydroxyethyl methacrylate (HEMA) with aminopropyl methacrylamide (APMA) (H1: 40, and H2: 80 mM) or without (Hc: 0 mM) were synthesized, sterilized by steam heat (121°C, 20 min), and then tested for gene therapy using rAAV vectors to deliver the genes to the cornea. The hydrogels showed adequate light transparency, oxygen permeability, and swelling for use as contact lenses. Loading of viral vectors (rAAV-lacZ, rAAV-RFP, or rAAV-hIGF-I) was carried out at 4°C to maintain viral vector titer. Release in culture medium was monitored by fluorescence with Cy3-rAAV-lacZ and AAV Titration ELISA. Transduction efficacy was tested through reporter genes lacZ and RFP in human bone marrow derived mesenchymal stem cells (hMSCs). lacZ was detected with X-Gal staining and quantified with Beta-Glo?, and RFP was monitored by fluorescence. The ability of rAAV-hIGF-I-loaded hydrogels to trigger cell proliferation in hMSCs was evaluated by immunohistochemistry. Finally, the ability of rAAV-lacZ-loaded hydrogels to transduce bovine cornea was confirmed through detection with X-Gal staining of β-galactosidase expressed within the tissue.
关键词： controlled release,gene therapy,corneal diseases,rAAV vectors,therapeutic contact lens
更新于2025-09-23 15:19:57
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Outcomes of Flap Lift Laser In Situ Keratomileusis Enhancements in a Large Patient Population
摘要： Purpose: To compare the incidence of corneal epithelial ingrowth (EIG) and the visual outcomes of enhancement with laser in situ keratomileusis (LASIK) by ?ap lift when a bandage soft contact lens (CL) was ?tted after the procedure and when it was not. Methods: This is a multicenter, retrospective, interventional case series in which all patients who underwent LASIK enhancement from January 2005 to January 2015 were included consecutively. Patients were grouped depending on whether a bandage CL was ?tted after re-treatment by ?ap lift (group 1) or not (group 2). Results: A total of 16,702 eyes from 12,485 patients were included. There were statistically signi?cant differences between the groups regarding corrected distance visual acuity (better in group 1) and safety index (better in group 2) although these were not clinically relevant. The incidence of EIG was 0.58% in group 1 and 0.55% in group 2 although, again, the difference was not statistically different. Conclusions: We found no relevant differences in LASIK enhancement between patients who received a bandage CL and those who did not regarding the incidence of EIG and visual outcomes.
关键词： LASIK re-treatment,corneal epithelial ingrowth,bandage contact lens,laser in situ keratomileusis,LASIK
更新于2025-09-12 10:27:22
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Realisation and assessment of a low-cost LED device for contact lens disinfection by visible violet light
摘要： This study presents a device for efficient, low-cost and eye-friendly overnight disinfection of contact lenses by visible violet light as an alternative to disinfection with biocide-containing solutions. Bacterial solutions with one Pseudomonas and one Staphylococcus strain each were irradiated for up to 8 h in commercial transparent contact lens cases by the presented light-emitting diode (LED) device. Samples were taken at different intervals and distributed on agar plates. The surviving bacteria were determined by counting of colony-forming units and compared to the specific requirements of the stand-alone test for contact lens disinfection of the hygiene standard ISO 14729. The concentration of both microorganisms was reduced by three orders of magnitude after less than 4 h of irradiation. The LED current and intensity have not yet been at maximum and could be further increased if necessary for other microorganisms. The presented device fulfils the requirement of the stand-alone test of the contact lens hygienic standard ISO 14729 for the tested Pseudomonas and Staphylococcus strains. According to literature data, the inactivation of Serratia marcescens, Candida albicans and Fusarium solani seems also possible, but may require increased LED current and intensity.
关键词： Staphylococcus,LED device,contact lens,visible light,photoinactivation,Pseudomonas,disinfection
更新于2025-09-12 10:27:22
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Customized Silicone Hydrogel Lens-A Case Study
摘要： We report a case in which customized contact lens were fitted in eyes of a high hypermetropic patient. Initially patient was using a readily available contact lens but complained about not compatible with those lens. In slit lamp examination over the old contact lens revealed those lenses were too loose fit and was folding when patient blinked. The symptoms resolved after custom made silicon hydrogel lens were given to the patient. These findings indicate that customized contact lens can help in certain high refractive error patient where ready stock contact lens may not be helpful.
关键词： Silicone hydrogel,Customized contact lens,Contact lens
更新于2025-09-10 09:29:36
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Functional Vision with X Chrome Lenses
摘要： Purpose: To implement x chrome lens in children Methods: A pilot, cross sectional study was performed in the tertiary eye centre during the period of 1 year. Functional vision like Visual Acuity, Contrast Sensitivity, Stereopsis and color vision of 10 existing x chrome soft contact lenses users were analyzed with and without lenses. Results: Visual functions were compared statistically using paired t test with SPSS 20 software. Negligible change observed in visual acuity and contrast sensitivity with p value of 0.015 and 0.010 respectively. No change is observed in stereopsis. Ishihara shows normal color vision with x chrome lenses while D-15 test shows reduction in severity of color vision deficiency. Conclusions: If X chrome color contact lenses are implemented during child’s learning period, it will eliminate many of the academic challenges that are faced with color coded learning and teaching materials and improve their quality for many recreational activities.
关键词： Pediatrics,Color vision,X chrome contact lens
更新于2025-09-10 09:29:36