Outcomes of scleral buckle removal with and without concurrent prophylactic laser retinopexy.

OBJECTIVE: To present the outcomes of scleral buckle (SB) removal with and without concurrent prophylactic laser retinopexy. DESIGN: Retrospective, interventional case series. PARTICIPANTS: Eighty-seven eyes of 87 patients who had SB removal after primary rhegmatogenous retinal detachment repair. METHODS: All patients who had SB removal after primary rhegmatogenous retinal detachment repair from both Wills Eye Institute and University of Alberta from 2000 to 2011 were identified. All patients had a minimum of 6 months of follow-up. RESULTS: Eighty-seven patients met the study criteria. Primary indications for SB removal were extrusion (76%, n = 66), diplopia (8%, n = 7), infection (6%, n = 5), a combination of extrusion and infection (6%, n = 5), and others (5%, n = 4). Only 3 of 87 eyes (3.4%) developed a recurrent retinal detachment after SB removal. Only 1 eye (2.2%) from the group that received laser retinopexy (n = 45) at the time of SB removal had a retinal redetachment, whereas 2 eyes (4.2%) in the group that did not receive laser (n = 42) had a recurrent retinal detachment (p = 0.61). CONCLUSIONS: The overall rate of recurrent retinal detachment after SB removal was low. No significant difference in recurrent retinal detachment was found between the eyes that received prophylactic laser retinopexy compared with those that did not at the time of SB removal.

The 1-year incidence of rhegmatogenous retinal detachment post 23-gauge pars plana vitrectomy.

OBJECTIVE: The purpose of this study was to evaluate the 1-year incidence of retinal tear or retinal detachment following 23-gauge pars plana vitrectomy (PPV) for epiretinal membrane (ERM), macular hole (MH), or vitreomacular traction (VMT). METHODS: A retrospective chart review of all patients who underwent 23-gauge PPV for ERM, MH, or VMT between January 1, 2007, and December 31, 2007, was performed. Inclusion criteria included age greater than 50 years and absence of other significant ocular pathology. Exclusion criteria included confounding retinal pathology, laser treatment at the time of surgery, previous laser treatment of the retina, or previous PPV. RESULTS: A total of 272 eyes of 268 patients were eligible for inclusion: 159 eyes (58%) had the diagnosis of ERM; 108 (40%) had MH; and 5 (2%) had VMT. The average patient age was 70 years. Of the patients, 15 required additional surgery related to persistent macular pathology within 1 year (5 with ERM, 10 with MH). The incidence of retinal detachment after surgery was 1.1% (3 eyes of 3 patients). The mean time duration prior to development of retinal detachment was 159 days (range, 19 to 333 days). CONCLUSIONS: The 1-year incidence of rhegmatogenous retinal detachment post 23-gauge vitrectomy for repair of macular pathology without prophylactic laser of sclerotomy sites is approximately 1%.

Chaos game representation of human pallidal spike trains.

Many studies have demonstrated the presence of scale invariance and long-range correlation in animal and human neuronal spike trains. The methodologies to extract the fractal or scale-invariant properties, however, do not address the issue as to the existence within the train of fine temporal structures embedded in the global fractal organisation. The present study addresses this question in human spike trains by the chaos game representation (CGR) approach, a graphical analysis with which specific temporal sequences reveal themselves as geometric structures in the graphical representation. The neuronal spike train data were obtained from patients whilst undergoing pallidotomy. Using this approach, we observed highly structured regions in the representation, indicating the presence of specific preferred sequences of interspike intervals within the train. Furthermore, we observed that for a given spike train, the higher the magnitude of its scaling exponent, the more pronounced the geometric patterns in the representation and, hence, higher probability of occurrence of specific subsequences. Given its ability to detect and specify in detail the preferred sequences of interspike intervals, we believe that CGR is a useful adjunct to the existing set of methodologies for spike train analysis.

Efficacy of Routine Notification and Request on reducing corneal transplantation wait times in Canada.

OBJECTIVE: To determine whether the implementation of Routine Notification and Request (RNR) has been effective in increasing the amount of donor corneal tissue available and reducing wait times for corneal transplant (CT) surgeries. DESIGN: Survey of the CT surgeons and eye banks in Canada. PARTICIPANTS: CT surgeons and representatives of the 10 eye banks in Canada. METHODS: Voluntary, anonymous questionnaires were distributed between May 1 and September 30, 2006. RESULTS: Following the implementation of RNR, 3 eye banks had an increase in the amount of corneal tissue available: Manitoba, 81% (from 42 tissues in 2004 to 76 tissues in 2006); Ontario, 25% (from 1304 tissues in 2005 to 1626 tissues in 2006); New Brunswick, 129% (from 86 tissues in 2005 to 197 tissues in 2006). British Columbia, where RNR was implemented in 1999, had a 6% increase (from 766 in 2005 to 812 in 2006). There has been a significant decrease in wait times from the time of diagnosis by CT surgeons to the time of surgery in British Columbia (from 48+/-18 weeks in 2004 to 39+/-20 weeks in 2006), Manitoba (from 82+/-56 weeks in 2004 to 32+/-23 weeks in 2006), Ontario (from 82+/-56 weeks in 2004 to 31+/-34 weeks in 2006), and Nova Scotia (from 44+/-12 weeks in 2004 to 32+/-28 weeks in 2006). CONCLUSIONS: RNR has been effective in increasing corneal tissue availability and decreasing wait times in provinces where it has been implemented. We recommend similar legislative changes to be considered in those provinces where corneal tissue shortage is delaying the availability of CT surgery.