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Biomedical subjects

M B Hamill

Publications and source records attributed to M B Hamill.

15 recordsLinked to original sources
PubMed2004

A prospective multicenter clinical trial to evaluate the safety and effectiveness of the implantable miniature telescope.

PURPOSE: To evaluate the safety and preliminary efficacy of a novel visual prosthetic device, the Implantable Miniature Telescope, IMT (by Dr Isaac Lipshitz) (IMT), in a phase I trial in patients with significant bilateral central vision impairment from late-stage age-related macular degeneration (AMD). The IMT is designed to reduce the relative size of the scotoma by rendering enlarged (threefold) central visual field images over the central and peripheral retina. DESIGN: Prospective, multicenter, open-label clinical trial. METHODS: In this prospective, multicenter phase I trial, 14 patients aged 60 or older with bilateral geographic atrophy or disciform scar AMD, cataract, and best-corrected visual acuity (BCVA) between 20/80 and 20/400 had an IMT implanted in one eye. Distance and near BCVA, endothelial cell density, and quality of life, measured as activities of daily life (ADL), were evaluated preoperatively and postoperatively. RESULTS: At 12 months, 10 (77%) of 13 patients gained 2 more lines of either distance or near BCVA, and eight (62%) of 13 patients gained 3 or more lines in either distance or near BCVA. Mean endothelial cell density decreased by 13%. All adverse events resolved without sequelae. ADL scores improved in the majority of patients. CONCLUSION: The results of this phase I trial support further evaluation of the IMT in a larger study population with late-stage AMD. A phase II/III trial is in progress.

Activities of Daily Living↗
PubMed1999

Pediatric cataracts.

There have been major changes over the past 5 to 10 years in our understanding of both the chemical basis for and the surgical treatment of cataract in infants and children. Important questions that remain to be answered include the appropriate power and design selection criteria for intraocular lens implantation, as well as management of the posterior capsule and long-term refractive sequelae. In the past 10 years, there have been radical changes in the management of visually significant cataract in the infant and child. Whereas lens removal, subtotal posterior capsulectomy, vitrectomy, and aphakia were once the standard of care, many physicians now feel that small incisions, phacoemulsification technology, and intraocular lenses (IOLs) are best for these patients. Work is continuing to accumulate a significant body of evidence to evaluate results of these changes in technique and to develop optimal IOL designs and selection criteria for these specialized cataract patients.

Adolescent↗
PubMed1997

Acquired supranuclear ocular motor paresis following cardiovascular surgery.

Acquired supranuclear ocular motor paresis is a rare disorder characterized by impaired saccadic and smooth pursuit eye movements in one or more directions of gaze. Vestibularly induced eye movements, however, are preserved. Six adult patients developed an acquired supranuclear ocular motor paresis following cardiopulmonary bypass surgery. Neuroimaging studies were normal in two patients and were consistent with small vessel ischemia in four patients. The mean cardiopulmonary bypass time was 132.3 min, and mean circulatory arrest time was 38.7 min; these were not outside established norms for this type of surgery. Patients undergoing cardiopulmonary bypass procedures with deep hypothermia are at risk for acquired supranuclear ocular motor paresis, but the development of this syndrome may not be predictable by duration of circulatory arrest or cardiopulmonary bypass times.

Aged↗
PubMed1991

Varicella disciform stromal keratitis.

We treated five patients, aged 26, 4, 6, 13, and 7 years, who developed disciform stromal keratitis one, four, four, eight, and ten weeks, respectively, after the onset of the acute vesicular exanthema. Serologic testing confirmed recent varicella and excluded other infectious causes in two cases. After initial improvement with a topical corticosteroid, three patients developed recurrent corneal inflammation resembling zoster keratitis. These cases and previous reports indicate that varicella-zoster virus is a cause of disciform stromal keratitis that may occur and recur several weeks or months after the primary skin rash has resolved.

Adolescent↗
PubMed1990

The evaluation and management of corneal lacerations.

Corneal lacerations represent a significant portion of ocular trauma. Effective management of this type of injury involves a thorough evaluation to assess the severity of the injury and the development of a logical management plan. Minor corneal trauma may be handled on an out-patient basis with the use of contact lenses and tissue adhesives. Severe injuries generally require admission and surgical intervention. Utilizing kerato-refractive principles and new suture techniques, post-operative astigmatism can be minimized at the time of primary closure.

Contact Lenses↗
PubMed1989

Bacterial keratitis after radial keratotomy.

The authors identified nine patients with culture-proven keratitis after radial keratotomy (RK). Three patients became infected in the immediate post-operative period, and six patients had delayed-onset keratitis. Gram-negative rods were the predominant pathogens in late-onset keratitis (4 of 6 infections). Gram-positive cocci were implicated in all three postoperative infections. The inferior corneal quadrants were involved in seven of nine patients. Two episodes of late-onset keratitis were associated with contact lens wear. Five of these patients had transverse incisions or greater than eight radial cuts. All six patients regained visual acuity of 20/40 or better. Two additional cases of early-onset and six cases of late-onset keratitis with many features similar to these cases have been reported previously.

Adult↗
PubMed1988

Fungal keratitis in contact lens wearers.

In a retrospective review from 1972 through 1987 of patients with microbial keratitis, fungal infection occurred in four (4%) of 90 cosmetic or aphakic contact lens wearers and in four (27%) of 15 patients using a therapeutic soft contact lens. Predisposing factors included improper lens care by the refractive lens wearers and a chronic epithelial defect with topical corticosteroid use among the therapeutic lens wearers. The responsible organisms in the refractive lens group were Fusarium solani (two patients) and Cephalosporium and Paecilomyces (one patient each), and in the therapeutic lens group Candida (three patients) and Aspergillus (one patient). Filamentous fungi were more likely to be associated with cosmetic or aphakic lens wear, whereas yeasts were more frequently found with therapeutic lens use.

Adult↗
PubMed1984

Experimental evaluation of chlorhexidine gluconate for ocular antisepsis.

Chlorhexidine gluconate is a bisguanide germicide currently available with 70% isopropanol (Hibistat, Hibitane) or a detergent (Hibiclens, Hibiscrub) for preoperative skin preparation. As these solvents are toxic to the cornea, we investigated the safety and efficacy of aqueous chlorhexidine solutions for ophthalmic use. Chlorhexidine in Tris-glycine buffer was evaluated for retardation of epithelial regeneration after experimental corneal abrasion in rabbits. Irrigant concentrations of 2.0 and 4.0% chlorhexidine significantly slowed the healing rate (0.546 and 0.076 mm/h, respectively) compared with saline controls (0.938 mm/h). Irrigant concentrations of less than or equal to 1% did not statistically delay healing (P greater than 0.4). In a separate group of animals, the right conjunctivae of pigmented rabbits were inoculated with Staphylococcus epidermidis (approximately 10(7) organisms per eye) and irrigated with 40 microliters of aqueous chlorhexidine in concentrations of 0.1, 0.5, and 1.0%; the left eyes were irrigated with saline or left untreated. Quantitative conjunctival cultures were obtained, and the total number of organisms recovered per eye was calculated. All chlorhexidine-treated eyes showed significant reduction in organisms compared with either untreated or saline-irrigated control eyes (P less than 0.001). In vitro antimicrobial susceptibility testing demonstrated chlorhexidine in concentrations of 0.1 to 4% to be highly active against a variety of gram-positive and gram-negative bacterial pathogens by disk diffusion and broth diffusion assays. Topical aqueous chlorhexidine may be an alternate agent for preoperative conjunctival antisepsis.

Animals↗
PubMedDate not supplied

Post-traumatic subgaleal hematoma with subperiosteal orbital extension.

Delayed, progressive proptosis is rare following mild head trauma. We describe a case of subperiosteal orbital extension of a subgaleal hematoma and review ten cases from the literature of solitary subperiosteal hematoma and one of subgaleal hematoma with orbital extension. A patient profile, mode of clinical presentation, management options, and an algorithm for management are presented.

Child↗