Novel antibacterial ocular prostheses: Proof of concept and physico-chemical characterization.

Discouraging bacterial colonization of ocular biomaterials and implants is a significant challenge in ophthalmology as infections often lead to the need for secondary surgery, with associated risks and additional stress to patients. In this work we demonstrate for the first time the feasibility of an innovative antibacterial ocular prosthesis produced by depositing a silver nanocluster/silica composite layer on the poly(methyl methacrylate) implant surface via radio-frequency sputtering. Tape test performed according to relevant ASTM standard provided a preliminary evidence of the mechanical stability and good adhesion of the coating to the substrate (absence of macroscopic damage after tape removal). Coating integrity was maintained after prolonged soaking in aqueous medium (1 month). The antibacterial effect of the coating, associated to silver ion release upon contact with aqueous fluid, was confirmed by the in vitro formation of a 5-mm inhibition halo test against Staphylococcus aureus that is one of the most common bacteria involved in ocular infections. The approach proposed in the present study for facing implant-related ocular infections can have a significant impact in the field of ophthalmic biomaterials, suggesting a valuable alternative to the administration of antibiotics that may become ineffective due to bacterial resistance.

Biomaterials for orbital implants and ocular prostheses: overview and future prospects.

The removal of an eye is one of the most difficult and dramatic decisions that a surgeon must consider in case of severe trauma or life-threatening diseases to the patient. The philosophy behind the design of orbital implants has evolved significantly over the last 60 years, and the use of ever more appropriate biomaterials has successfully reduced the complication rate and improved the patient's clinical outcomes and satisfaction. This review provides a comprehensive picture of the main advances that have been made in the development of innovative biomaterials for orbital implants and ocular prostheses. Specifically, the advantages, limitations and performance of the existing devices are examined and critically compared, and the potential of new, smart and suitable biomaterials are described and discussed in detail to outline a forecast for future research directions.

Cogan syndrome: confocal microscopy assessment of corneal damage.

PURPOSE: To perform in vivo assessment of corneal alterations in patients with Cogan syndrome (CS) and to correlate these findings with prior histopathologic descriptions. METHODS: Four consecutive patients (8 eyes) presenting with typical CS underwent confocal microscopy examination. At the moment of evaluation, ocular inflammation was quiescent in all the patients. The images were studied singularly, and then compared to those obtained from 5 healthy controls. Statistical analysis was performed with Student t test. RESULTS: All the cases showed multiple brightly reflective deposits in the stroma with moderate reflectivity of the surrounding stromal tissue. The outer corneal layers and the endothelium were spared. In 3/4 of the patients, the nerve fibers of the subepithelial plexus were thin and poorly reflective, with interruptions and lack of the typical branching pattern. No cells different from keratocytes could be detected in either case or control eyes. Corneal vascularization was present in one case. In CS-affected eyes, corneal thickness was 552+/-62 microm on average, and endothelial cell count was 2466+/-288 cells/mm(2). Statistical significance was not reached compared to the control group. CONCLUSIONS: Confocal microscopy was able to provide detailed images of corneal alterations in CS. This confirmed the interstitial nature of the keratitis and showed an excellent accordance with prior histopathologic findings. The absence of inflammatory cell infiltration may be explained by the prolonged control of ocular inflammation in our patients, which may also have limited stimuli for corneal neovascularization.