silicon and Eye-Diseases

Topics: Aluminum; Anterior Eye Segment; Eye Diseases; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Phacoemulsification; Silicon

Topics: Aluminum; Anterior Eye Segment; Eye Diseases; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Phacoemulsification; Silicon

To describe an outbreak of late-onset toxic anterior segment syndrome (TASS) after the implantation of a specific hydrophilic acrylic intraocular lens (IOL).. University Hospitals of Leuven, Belgium.. Retrospective, single-center, observational study.. All eyes undergoing cataract surgery with a monofocal, toric, or enhanced depth-of-focus (EDoF) Synthesis (Cutting Edge) IOL between August 2019 and March 2020 were reviewed. Data were collected on the surgical procedure, postoperative course, time until onset of symptoms, clinical features, and additional treatments. A laboratory surface analysis of all 3 IOL subtypes was performed in the Intermountain Ocular Research Center at the University of Utah, USA. Furthermore, other possible causes of prolonged postoperative inflammation rather than the IOL itself were investigated.. Among the 203 eyes included, 28 TASS cases were identified (13.8%), among which 25 received a monofocal IOL, and 3 received an EDoF IOL. The mean time until onset was 28.9 (±19.9) days. Patients presented with anterior chamber cells (92.9%), deposits on the IOL (57.1%), or fibrinous inflammation (35.7%). 4 eyes (14.3%) underwent a surgical intervention, whereas 24 eyes showed a resolution of inflammation with topical therapy alone. Laboratory analysis showed the presence of both aluminum and silicon particles on the monofocal IOL, silicon particles only on the EDoF IOL, and no particles on the toric IOL surface.. This report describes an outbreak of atypical, late-onset TASS after cataract surgery, possibly correlated with aluminum and silicon contamination of the IOL surfaces.

Topics: Aluminum; Cataract; Eye Diseases; Humans; Inflammation; Lens Implantation, Intraocular; Lenses, Intraocular; Phacoemulsification; Retrospective Studies; Silicon; Visual Acuity

Dysfunction of corneal epithelial stem cells can result in painful and blinding disease of the ocular surface. In such cases, treatment may involve transfer of growth factor and normal adult stem cells to the ocular surface. Our purpose was to develop an implantable scaffold for the delivery of drugs and cells to the ocular surface. We examined the potential of novel composite biomaterials fabricated from electrospun polycaprolactone (PCL) fibres into which nanostructured porous silicon (pSi) microparticles of varying sizes (150-250 μm or <40 μm) had been pressed. The PCL fabric provided a flexible support for mammalian cells, whereas the embedded pSi provided a substantial surface area for efficient delivery of adsorbed drugs and growth factors. Measurements of tensile strength of these composites revealed that the pSi did not strongly influence the mechanical properties of the polymer microfiber component for the Si loadings evaluated. Human lens epithelial cells (SRA01/04) attached to the composite materials, and exhibited enhanced attachment and growth when the materials were coated with foetal bovine serum. To examine the ability of the materials to deliver a small-drug payload, pSi microparticles were loaded with fluorescein diacetate prior to cell attachment. After 6 hours (h), cells exhibited intracellular fluorescence, indicative of transfer of the fluorescein diacetate into viable cells and its subsequent enzymatic conversion to fluorescein. To investigate loading of large-molecule biologics, murine BALB/c 3T3 cells, responsive to epidermal growth factor, insulin and transferrin, were seeded on composite materials. The cells showed significantly more proliferation at 48 h when seeded on composites loaded with these biologics, than on unloaded composites. No cell proliferation was observed on PCL alone, indicating the biologics had loaded into the pSi microparticles. Drug release, measured by ELISA for insulin, indicated a burst followed by a slower, continuous release over six days. When implanted under the rat conjunctiva, the most promising composite material did not cause significant neovascularization but did elicit a macrophage and mild foreign body response. These novel pressed pSi-PCL materials have potential for delivery of both small and large drugs that can be released in active form, and can support the growth of mammalian cells.

Topics: Animals; Biocompatible Materials; Cattle; Cell Proliferation; Cells, Cultured; Conjunctiva; Disease Models, Animal; Drug Combinations; Drug Delivery Systems; Eye Diseases; Humans; Materials Testing; Mice; Mice, Inbred BALB C; Polyesters; Porosity; Rats; Rats, Sprague-Dawley; Silicon; Tensile Strength

Topics: Angiogenesis Inhibitors; Aptamers, Nucleotide; Choroidal Neovascularization; Eye Diseases; Eye Foreign Bodies; Humans; Injections; Mass Spectrometry; Silicon; Silicone Oils; Ultrasonography; Vascular Endothelial Growth Factor A; Vitreous Body

To describe the association between calcification of older and newer designs of silicone intraocular lenses (IOLs) and asteroid hyalosis.. Case series with clinicopathologic correlation.. Sixteen silicone IOLs explanted because of decreased visual acuity associated with opacifying deposits on the posterior optic surface.. All 16 lenses underwent gross and light microscopic analyses. Selected lenses underwent alizarin red staining or scanning electron microscopy coupled with energy dispersive x-ray spectroscopy for elemental composition. Clinical data in each case were obtained by a questionnaire sent to the explanting surgeons. Clinical data in relation to 111 hydrophilic acrylic lenses explanted because of calcification also were assessed for comparison.. Deposit morphologic features and location were evaluated under gross and light microscopy. The calcified nature of the deposits was assessed by histochemical staining and surface analyses. Clinical data obtained included age at IOL implantation, gender, implantation and explantation dates, as well as history of neodymium:yttrium-aluminum-garnet laser treatment. The presence of asteroid hyalosis in the affected eye was investigated for the explanted silicone and hydrophilic acrylic lenses.. The 16 lenses were of 8 designs manufactured from different silicone materials, which were explanted 9.21+/-3.66 years after implantation. Neodymium:yttrium-aluminum-garnet laser applications performed in 12 cases partially removed deposits from the lens, followed by a gradual increase in their density after the procedures. The presence of asteroid hyalosis was confirmed in 13 cases; no notes regarding this condition were found in patient charts in the other 3 cases. The deposits were only on the posterior optic surface of the silicone lenses and were composed of calcium and phosphate. A history of asteroid hyalosis was not found in relation to any of the 111 cases of postoperative calcification of hydrophilic acrylic lenses.. Including this current series, there are 22 cases of calcification of silicone lenses involving 8 designs manufactured from different silicone materials described in the literature. The presence of asteroid hyalosis was confirmed in 86.4% of cases. These findings may be added to the list of pros and cons surgeons consider when selecting or recommending an IOL.

Topics: Acrylic Resins; Aged; Aged, 80 and over; Calcinosis; Calcium; Device Removal; Eye Diseases; Female; Humans; Lenses, Intraocular; Male; Microscopy, Electron, Scanning; Middle Aged; Phosphates; Prosthesis Design; Prosthesis Failure; Silicon; Silicone Elastomers; Sodium; Spectrometry, X-Ray Emission; Surveys and Questionnaires; Visual Acuity; Vitreous Body

Energy-dispersive x-ray analysis (EDXA) was used to study nine intraocular lenses from one manufacturer. Residual polishing compound was found on two of three dry-sterilized lenses from a "hot lot" associated with a high incidence of sterile hypopyon. Similar material was not present on normal lenses. This polishing compound was apparently fused to the lens surface, preventing its removal by ultrasonic cleaning. In addition, three wet-sterilized lenses were found to be covered with small crystals containing barium. These crystals apparently resulted from leaching of the glass storage vial by the caustic storage fluid. It is suggested that some cases of sterile hypopyon following intraocular lens surgery may be caused by residual polishing compound present on the lens surface.

Topics: Anterior Chamber; Barium; Eye Diseases; Humans; Lenses, Intraocular; Microscopy, Electron, Scanning; Quality Control; Silicon; X-Rays

Topics: Astigmatism; Eye Diseases; Female; Follow-Up Studies; Functional Laterality; Humans; Male; Middle Aged; Myopia; Retinal Detachment; Sclera; Sex Factors; Silicon

Topics: Animals; Anterior Chamber; Eye Diseases; Granuloma; Rabbits; Salicylates; Silicon; Silicon Dioxide