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Biomedical subjects

Grant R Snibson

Publications and source records attributed to Grant R Snibson.

5 recordsLinked to original sources
PubMed2005

Microbial keratitis predisposing factors and morbidity.

PURPOSE: To examine predisposing factors, treatment costs, and visual outcome of microbial keratitis in an ophthalmic casualty and inpatient population. DESIGN: Retrospective medical records review. PARTICIPANTS: Fifteen- to 64-year-olds with microbial keratitis treated at the Royal Victorian Eye and Ear Hospital between May 2001 and April 2003 (n = 291). METHODS: Risk factors were identified from patient files. Demographic, clinical, and microbiological data; severity; outpatient visits; hospital bed days; and vision loss were examined. MAIN OUTCOME MEASURES: Cost to treat (Australian dollars), vision loss, and factors influencing these outcomes. RESULTS: Ocular trauma (106/291 [36.4%]) and contact lens (CL) wear (98/291 [33.7%]) were the most commonly identified predisposing factors; 18 (6.1%) had multiple predisposing factors; 17 (5.8%), ocular surface disease; 20 (6.9%), herpetic eye disease; 4 (1.4%), systemic associations; 5 (1.7%), other; and 23 (7.9%), unknown cause. Of trauma cases, 90.6% involved males, compared with 44% to 57% for other groups (P<0.001). Contact lens wearers were younger than the other groups--mean age 30 years, compared with 40 to 47 years (P<0.01). Gram-negative organisms were isolated more frequently in CL wearers than trauma cases (18.7% vs. 6.5%, P = 0.01). The number of outpatient visits was 4+/-1 (median +/- interquartile range), and 19.6% (57/291) were hospitalized for 5+/-2 days. Hospital resource use and vision loss were similar for predisposing factors but differed by causative microorganism. Eighty-eight percent of cases were scraped: acanthamoeba keratitis was the most expensive to treat, followed by fungal and herpetic keratitis and, lastly, culture-proven bacterial keratitis or culture-negative cases (P<0.0001). After treatment, 21.7% exhibited >2 lines of vision loss, and 1.6% of cases had > or =10 lines of vision loss. Vision loss was associated with clinical severity (P = 0.005). CONCLUSIONS: Ocular trauma and CL wear are the major predisposing factors for microbial keratitis in this age range. These cases require significant hospital resources during treatment, and the keratitis may result in loss of vision.

Acanthamoeba Keratitis↗
PubMed2004

Amniotic membrane grafting in the surgical management of primary pterygium.

BACKGROUND: To evaluate the efficacy of amniotic membrane transplantation in primary pterygium surgery. METHODS: Patients presenting to the outpatient clinic of the Royal Victorian Eye and Ear Hospital with primary pterygium requiring surgical management were included in this study. The pterygia were excised to bare sclera and the conjunctival defects were closed with amniotic membrane grafts. The primary outcome was pterygium recurrence. RESULTS: Twenty-eight pterygia of 26 patients were included. Twenty-three patients (88%, 25 eyes) completed 12 months follow up. By 12 months postoperatively 16 of these eyes (64%) had developed corneal recurrence and a further two had developed a limbal recurrence (9%). Five required repeat surgery during the 12 month follow-up period. No association was found between pterygium recurrence and pterygium size (P = 0.33), amniotic membrane graft dimension (P = 0.12), patient age (P = 0.53) or patient sex (P = 0.63). CONCLUSION: Amniotic membrane grafting for primary pterygium was associated with an unacceptably high recurrence rate in this population.

Adult↗
PubMed2003

AlphaCor cases: comparative outcomes.

PURPOSE: To describe clinical outcomes after a novel type of corneal surgery, implantation of an artificial cornea, AlphaCor , and to evaluate outcomes in comparison with alternative keratoprostheses and high-risk grafts. METHODS: Case reports and data from a noncontrolled clinical trial and a literature review. RESULTS: The probability of AlphaCor retention to 1 year is 80%. Postoperative best corrected visual acuity ranges from Perception Light to 20/30. The most significant complications are stromal melts and optic depositions, for both of which the main risk factors have been identified. Complications can be managed without loss of the eye. CONCLUSION: Results from the clinical trial period have helped to determine the indications and risk factors for AlphaCor surgery and to refine surgical techniques. Continued monitoring of outcomes as the series increases will allow a more accurate determination of comparative outcomes. The series provides preliminary evidence that AlphaCor may have a lower incidence of complications than traditional keratoprostheses and may prove to be preferable to a donor graft in high-risk cases.

Aged↗
PubMed2002

Outcomes of implantation of an artificial cornea, AlphaCor: effects of prior ocular herpes simplex infection.

PURPOSE: To review outcomes of AlphaCor artificial cornea implantation in patients with and without a history of ocular herpes simplex virus (HSV) and to determine whether herpetic eye disease is an indication for AlphaCor surgery. METHODS: Outcomes of the initial 40 implantations were reviewed and stratified by the presence of a history of ocular disease caused by HSV. Outcomes measures (complications, visual acuity gained) were compared. RESULTS: Eight of the 40 AlphaCor implantations (20%) were in patients with a history of ocular HSV. Six of these eight patients (75%) developed melt-related complications after AlphaCor insertion. Half of the affected patients required removal of the AlphaCor and replacement with a donor corneal graft to restore ocular integrity. In comparison, only six of the 32 (18.8%) patients without HSV developed a melt after AlphaCor insertion. Patients with HSV with devices in situ exhibited a mean loss of 0.3 line of best-corrected visual acuity compared with the preoperative visual acuity, whereas patients without HSV exhibited a mean gain of 1.4 lines of best-corrected visual acuity. CONCLUSIONS: The extensive lamellar corneal surgery involved in AlphaCor implantation may precipitate reactivation of latent HSV such that reactivation and resultant inflammation reduce device biointegration and facilitate melting of corneal stromal tissue anterior to the device. Although there may be some benefit from systemic antiviral medication, the current series is not large enough to demonstrate such a benefit, and melting can occur despite medication. The statistically significant difference in outcomes between recipients of AlphaCor with and without HSV is evidence that a history of HSV should be an exclusion factor for AlphaCor surgery.

Artificial Organs↗