Comparing the effects of infrastructure on bicycling injury at intersections and non-intersections using a case-crossover design.

BACKGROUND: This study examined the impact of transportation infrastructure at intersection and non-intersection locations on bicycling injury risk. METHODS: In Vancouver and Toronto, we studied adult cyclists who were injured and treated at a hospital emergency department. A case-crossover design compared the infrastructure of injury and control sites within each injured bicyclist's route. Intersection injury sites (N=210) were compared to randomly selected intersection control sites (N=272). Non-intersection injury sites (N=478) were compared to randomly selected non-intersection control sites (N=801). RESULTS: At intersections, the types of routes meeting and the intersection design influenced safety. Intersections of two local streets (no demarcated traffic lanes) had approximately one-fifth the risk (adjusted OR 0.19, 95% CI 0.05 to 0.66) of intersections of two major streets (more than two traffic lanes). Motor vehicle speeds less than 30 km/h also reduced risk (adjusted OR 0.52, 95% CI 0.29 to 0.92). Traffic circles (small roundabouts) on local streets increased the risk of these otherwise safe intersections (adjusted OR 7.98, 95% CI 1.79 to 35.6). At non-intersection locations, very low risks were found for cycle tracks (bike lanes physically separated from motor vehicle traffic; adjusted OR 0.05, 95% CI 0.01 to 0.59) and local streets with diverters that reduce motor vehicle traffic (adjusted OR 0.04, 95% CI 0.003 to 0.60). Downhill grades increased risks at both intersections and non-intersections. CONCLUSIONS: These results provide guidance for transportation planners and engineers: at local street intersections, traditional stops are safer than traffic circles, and at non-intersections, cycle tracks alongside major streets and traffic diversion from local streets are safer than no bicycle infrastructure.

Evaluating web-based static, animated and interactive maps for injury prevention.

Public health planning can benefit from visual exploration and analysis of geospatial data. Maps and geovisualization tools must be developed with the user-group in mind. User-needs assessment and usability testing are crucial elements in the iterative process of map design and implementation. This study presents the results of a usability test of static, animated and interactive maps of injury rates and socio-demographic determinants of injury by a sample of potential end-users in Toronto, Canada. The results of the user-testing suggest that different map types are useful for different purposes and for satisfying the varying skill level of the individual user. The static maps were deemed to be easy to use and versatile, while the animated maps could be made more useful if animation controls were provided. The split-screen concept of the interactive maps was highlighted as particularly effective for map comparison. Overall, interactive maps were identified as the preferred map type for comparing patterns of injury and related socio-demographic risk factors. Information collected from the user-tests is being used to expand and refine the injury web maps for Toronto, and could inform other public health-related geo-visualization projects.

Correlation between the indiana bleb appearance grading scale and intraocular pressure after phacotrabeculectomy.

PURPOSE: To investigate the relationship between bleb morphology, recorded using the Indiana Bleb Appearance Grading Scale (IBAGS), and intraocular pressure (IOP) after phacotrabeculectomy. METHODS: Two years postphacotrabeculectomy, a single observer compared bleb morphology to the IBAGS standard photographs in 76 eyes of 76 patients. In addition, the presence or absence of microcysts was recorded. IOP was also measured. RESULTS: On multivariate analysis increasing bleb height was associated with a low IOP (P=0.017). An increase in IBAGS height score by 1 U resulted in a reduction in IOP of 2.16 mm Hg (95% confidence interval=0.40-3.92 mm Hg). In this study, there was no association between vascularity, bleb extent or microcysts, and IOP. There were no cases of bleb leak in this series. CONCLUSIONS: Two years postphacotrabeculectomy increased bleb height, as measured by the IBAGS, was associated with a decrease in IOP, with a 1 point increase in IBAGS height score resulting in a decrease of 2.16 mm Hg. We found no association between bleb extent, vascularity, or the presence or absence of conjunctival microcysts. As there were no cases of bleb leak in this study this characteristic could not be evaluated.

Intermediate-term outcome and success of superior versus inferior Ahmed Glaucoma Valve implantation.

PURPOSE: The superotemporal quadrant is usually the implantation site of choice for glaucoma drainage devices. Inferior placement of glaucoma drainage device is considered technically difficult. The purpose was to determine the success rates, complications, and visual outcome of superior versus inferior Ahmed Glaucoma Valve implantation. PATIENTS AND METHODS: A retrospective review of the records of 83 eyes (77 patients) that underwent Ahmed Glaucoma Valve surgery from 1997 to 2004. Thirty-one eyes had superior insertion (SI) versus 52 eyes with inferior insertion (II). Demographic, preoperative, and postoperative data including intraocular pressure (IOP), visual acuity, and number of medications, and complications were recorded. Success was defined as postoperative IOP between 5 and 21 mm Hg and at least a 20% reduction from baseline IOP. RESULTS: The mean postoperative IOPs at 6 months, 1, 2, 2.5, and 3 years were 13.5+/-3.2 mm Hg versus 12.8+/-3.6 mm Hg (P=0.76), 12.5+/-3.1 mm Hg versus 13.0+/-4.0 mm Hg (P=0.5), 15.7+/-6.2 mm Hg versus 12.6+/-4.7 mm Hg (P=0.06), 13.2+/-3.0 mm Hg versus 12.6+/-3.3 mm Hg (P=0.70), and 14.5+/-3.0 mm Hg versus 13.7+/-5.0 mm Hg (P=0.73) in the SI group versus the II group, respectively. The success rates were similar between the groups over the study period with 87.0% versus 86.5%, 71.5% versus 73.0%, and 71.5% versus 64.6% for SI versus II at 12, 24, and 36 months, respectively. There were more complications in the II group; however, only wound dehiscence and transient diplopia were statistically significant (P=0.04 and 0.001, respectively). The number of glaucoma medications was lower in the SI during the first 3 months but nonsignificant thereafter. CONCLUSIONS: There was no significant difference in IOP control between SI and II over 36 months. II should be considered when there are limitations to SI.

Ahmed glaucoma valve implantation in uveitic glaucoma versus open-angle glaucoma patients.

BACKGROUND: The poor long-term success rate of repeat trabeculectomies in refractory uveitic glaucoma (UG) patients has led to the use of glaucoma drainage devices (GDDs). However, the success and complication rates of GDDs in UG patients utilizing a control group with standard demographic data, design, and surgical technique have never been evaluated. METHODS: Fifteen patients (15 eyes) with chronic uveitis and 53 patients (53 eyes) with uncontrolled open-angle glaucoma (OAG) who underwent Ahmed glaucoma valve (AGV) implantation were included in a retrospective, comparative, case-controlled study. Postoperative intraocular pressure (IOP), number of antiglaucoma medications, visual acuity, and complications were compared. RESULTS: There was a significant difference between the UG versus the OAG group with respect to age only (59.3 years vs 68.4 years, p = 0.006). Regression analysis of the postoperative IOP controlled for age and glaucoma type, and preoperative IOP revealed significantly lower IOP in the UG group at 1 month (p = 0.04; 95% confidence interval [CI] -5.9 to 0.15) and 2 months (p = 0.008; 95% CI -6.0 to 0.97). No significant differences were found at 3, 6, 12, 24, and 30 months. The cumulative success rates at 3 to 30 months for the UG and OAG groups were 80% to 66.6% versus 84.9% to 57% (p = 0.713), respectively. The only complication between the 2 groups that was significantly different was tube removal, which occurred more often in the UG group (p = 0.018). INTERPRETATION: AGV implantation is an effective and safe procedure in the management of UG, similar to primary OAG.

Medical students' attitudes on diversity when applying to Toronto's ophthalmology residency program.

BACKGROUND: Affirmative action is a controversial admissions policy practised by universities in the United States and other countries around the world. It is currently not used at the University of Toronto ophthalmology residency program. A survey was conducted to determine the opinions of applicants as to the role that affirmative action and quotas should play during the admissions process and to determine the current ethnic breakdown of the applicants to ophthalmology. METHODS: A survey of 14 questions was sent out to all 72 medical students applying for a residency position in our program. The response rate was 58%. The students were asked to agree or disagree on a 5-point Likert scale with statements related to ethnicity, gender, and whether affirmative action policies exist or should exist for certain groups. RESULTS: The majority of the respondents (26/42, 62%) considered themselves an ethnic minority, and 57% (24/42) considered themselves a visible minority. Most (32/42) felt that the sex of the applicant should not play a role in the selection process. Only 24% (10/42) supported affirmative action, and only 12% (5/42) supported quotas for minority applicants. INTERPRETATION: The majority of survey respondents in this study did not support affirmative action or quotas at the University of Toronto ophthalmology program. The applicants to this program represent a diverse group of individuals from a multitude of ethnic, cultural, and racial backgrounds, and, in their average opinion, affirmative action policies would not benefit our admissions program.

Prospective randomized comparison of one- versus two-site Phacotrabeculectomy two-year results.

PURPOSE: Previous studies have failed to find a significant difference in intraocular pressure (IOP) between one- and two-site phacotrabeculectomy. A possible explanation has been relatively small samples and short follow-up. We prospectively observed 80 patients for 2 years randomized to one- versus two-site phacotrabeculectomy with the primary outcome measure being IOP. DESIGN: Prospective randomized controlled study. PARTICIPANTS: Eighty eyes were randomized and 79 underwent phacotrabeculectomy; 76 completed 24 months' follow-up. METHODS: Eligible patients scheduled for phacotrabeculectomy were randomized to one- or two-site phacotrabeculectomy after giving informed consent. A sample size of 54 was calculated to detect a difference of 2 mmHg between the groups with a power of 80%. Data recorded included demographics, visual acuity, IOP, endothelial cell counts, glaucoma medications, phacoemulsification settings, iris manipulation, suture lysis, needling, and complications. Follow-up data were obtained at 3, 6, 12, and 24 months. MAIN OUTCOME MEASURE: Mean IOP at 24 months. RESULTS: There were no significant differences between the groups preoperatively. Mean IOPs were 17.6 versus 17.6, 12.6 versus 12.5, 13.1 versus 11.7, 13.1 versus 12.7, and 12.5 versus 12.9 mmHg for one- versus two-site at baseline and 3, 6, 12, and 24 months. There was a significant lowering of IOP compared with baseline at all time points (P<0.05). There was no significant difference in mean IOP between the groups at any time. The mean number of glaucoma medications decreased from 3.0 in each group to 0.2 and 0.4 for one- and two-site, respectively, at 24 months (P = 0.20). At 3 and 12 months, the endothelial counts (cells/mm(2)) were significantly lower in the two-site group: 2333 versus 2207 (P = 0.17), 2239 versus 1938 (P = 0.01), 2180 versus 1934 (P = 0.04), and 2147 versus 1947 (P = 0.08) at baseline and 3, 12, and 24 months, respectively. The surgical time was significantly longer for two-site (48.1+/-7.8 minutes) compared with one-site (39.2+/-6.4 minutes; P<0.001). CONCLUSION: At 2 years after phacotrabeculectomy, there was no statistically significant difference in IOP between groups. Corneal endothelial cell counts were significantly lower in the two-site group at 3 and 12 months. Two-site surgery took significantly more time.

Effect of medical therapy on glaucoma filtration surgery rates in Ontario.

OBJECTIVE: To analyze trends of glaucoma filtration surgery in Ontario. METHODS: From April 1, 1992, through March 31, 2004, correlations were examined between the annual rates of trabeculectomies in Ontario, the use of glaucoma medications, and the numbers of practicing ophthalmologists and optometrists. RESULTS: The number of trabeculectomies per 1000 persons at risk for primary open-angle glaucoma increased from 33.5 in 1992 to 46.2 in 1996 (37.7% increase; 6.6% increase per year) and then steadily decreased to 38.2 in 2004 (17.0% decrease; 2.7% decrease per year). The number of glaucoma medications dispensed in Ontario increased from 766 000 in 1992 to 1 466 543 in 2004 (91.5% increase; 10.5% annual increase). The increase in dispensed prostaglandin analogues strongly correlated (P<.001; 95% confidence interval, -0.87 to -0.41) with the decreasing number of trabeculectomies. The decreasing number of ophthalmologists positively correlated (r = 0.87) with the filtration surgery rate after 1997. CONCLUSIONS: The number of trabeculectomies has decreased substantially in Ontario coinciding with the introduction of medications for the treatment of glaucoma in December 1996. This decrease in trabeculectomies highly correlated with the introduction of prostaglandin analogues (P<.001) and the decreasing number of ophthalmologists from 1997 through 2004.

Hitting home: a survey of housing conditions of homes used for long-term care in Ontario.

A telephone survey of a random sample of 811 long-term home care clients from three geographically distinct regions in Ontario was conducted to illuminate the living and working conditions in households receiving long-term care services. The median age of clients was 77 years and 75 percent were female. The majority had not completed high school. Almost half were widowed, had income levels of dollar 20,000 (Canadian) or less, and lived alone. Approximately one-third needed help with most basic activities of daily living. The vast majority could not bathe or dress themselves. More than three-quarters needed help with preparing meals, housekeeping, and shopping. Few clients could perform yardwork and home repairs. Many clients' homes required major and minor repairs, were not suitable in size, were not affordable, and lacked important household amenities. More than 30 percent required modifications to enable clients to live and be cared for comfortably and safely, and half the clients had not completed these because of exorbitant costs. Overall, many clients were living in homes less than optimal for domestic life and long-term care provision. These results highlight significant gaps in care provision and a need to link housing to health and social service policies.

Laser trabeculoplasty trends with the introduction of new medical treatments and selective laser trabeculoplasty.

PURPOSE: To correlate trends of laser trabeculoplasties (LTPs) with the introduction of medical therapies for glaucoma and to assess whether these trends changed after the introduction of selective laser trabeculoplasty (SLT) in 2001. METHODS: A retrospective analysis of LTP numbers, filtration surgeries, glaucoma medications dispensed, and population distribution by age in Ontario, Canada, between April 1992 and March 2005. RESULTS: The number of LTP per 1,000 persons estimated to have primary open angle glaucoma (POAG) increased from 138.05 in 1992 to a maximum of 149.23 in 1996 (8.1% increase, 1.96% annual increase) and then steadily decreased to 70.65 in 2001 (47.3% decrease, 14% annual decrease). From 2001 to 2004, the LTP rate increased to 162.54 (230% increase, 32% annual increase). The number of filtration surgeries per 1,000 persons estimated to have POAG steadily decreased from 1996 to 2004 by 21.42% (2.4% annual decrease). The number of glaucoma medications dispensed in Ontario increased from 1992 to 2004 by 91.5% (10.5% annual increase). There were no significant correlations between the LTP rates and the new glaucoma medications rates (r=-0.35 to 0.09; P=0.34 to 0.82) or filtration surgeries rates (r=0.007; P=0.98). CONCLUSIONS: There was a substantial reduction in the number of LTP between 1997 and 2001 coinciding, but not correlated with the introduction of medications for the treatment of glaucoma. Between 2002 and 2004 the LTP rates increased, coinciding with the introduction of SLT.

Unsafe driving in North American automobile commercials.

BACKGROUND: Motor-vehicle crashes (MVCs) are a leading cause of death of young Americans and Canadians. Aggressive driving and driving at high speed are frequently cited as contributing to crashes. Consumer and safety associations have raised concern that driving behaviour portrayed in automobile commercials may influence consumer-driving behaviour. However, the prevalence of aggressive driving in automobile commercials has not been systematically evaluated. OBJECTIVES: To identify the prevalence and types of unsafe driving that are portrayed in United States and Canadian televised automobile commercials as well as the use of safety promotion and disclaimers. DESIGN: All English language automobile and truck commercials (>or=30 seconds in length), airing nationally on major broadcast and cable networks in either the United States or Canada during January or July between 1998 and 2002 were assessed by three independent raters for the presence and type of unsafe driving activity, presence of safety promotion and the use of written disclaimers in each commercial. RESULTS: Of 250 total commercials, 113 (45 per cent) contained an unsafe driving sequence as determined by at least two of three raters. Unanimous agreement as to the presence of an unsafe driving sequence was found in 63 (25 per cent) commercials. Aggressive driving accounted for 85 per cent of the unsafe driving sequences, including 56 per cent with speed violations. Safety promotion was present in 30 (12 per cent) commercials. Of 141 commercials in which the gender /sex of the driver was shown, 115 (81 per cent) displayed a male driver. CONCLUSION: Unsafe driving is prevalent in North American automobile commercials. Given the extent to which MVCs are a public health and economic concern, this finding seems in conflict with responsible advertising. The degree to which the portrayal of driving in automobile commercials affects consumer-driving behaviour should be an area of further investigation.

The influence of dental insurance on institutionalized older adults in ranking their oral health status.

To assess whether dental insurance influences how institutionalized older adults ages 65 and older rank their oral health status, a census survey was designed for residents of Durham's (Canada) Municipal Homes for the Aged. The odds ratio (OR) and the Cochran & Mantel-Haenszel's OR were used to estimate the crude and adjusted effect of dental insurance on oral health status, respectively. Overall, 64 percent participated in the interview. Oral health status was ranked as "good," "very good" or "excellent" by 57 percent of the participants. This ranking was clearly unrelated to the residents having dental insurance, as only 28 percent had dental coverage. Significant effect modifiers included age, dental status and whether the participant had visited the dentist within the last year. Dental insurance positively influenced how dentate participants ranked their oral health status (OR = 2.26; 95 percent CI = 1.19; 4.28). In edentulous participants, age and visiting the dentist within the last year modified the effect of dental insurance on oral health status. Having dental insurance reduced the odds of reporting "good," "very good" or "excellent" oral health (OR = 0.20; 95 percent CI = 0.08; 0.49) among the participants ages 85 and older who did not visit the dentist within the last year; however, the opposite was true for their younger counterparts who visited the dentist within the last year (OR = 7.20; 95 percent CI = 1.08; 47.96). In this population, therefore, dental insurance was associated with higher oral health status rank among the dentate, but its effect on the edentulous population depended on age and the pattern of visiting the dentist.

Urban/rural variation in children's bicycle-related injuries.

The objective of this study was to examine bicycle-related injury rates for children living in urban and rural areas. Data on all Canadian children hospitalised because of bicycling-related injuries (1994-1998) were obtained from the Canadian Institute for Health Information (CIHI). Injured children were classified as residing in urban, mixed urban, mixed rural or rural areas. Incidence rates for bicycle-related head injuries and other bicycle-related injuries were calculated. Logistic regression was used to estimate the odds of head injury, controlling for age, sex, socio-economic status (SES), collision with a motor vehicle, and the presence of provincial helmet legislation. In total, 9367 children were hospitalised for a bicycling-related injury over the 4-year-study period. Of these, 21% occurred in rural areas, 18% in mixed rural, 17% in mixed urban, while the remaining 44% occurred in urban areas. The average annual incidence rate for bicycle-related head injuries in children was 18.49 per 100000 for children living in rural areas compared with 10.93 per 100000 for those living in urban areas, 15.49 for children in mixed urban areas and 17.38 for children living in mixed rural areas. This variation may be explained by differences in bicycling exposure, helmet use, hospital admission criteria, or road environments across geographic areas.

Side impact crashes--factors affecting incidence and severity: review of the literature.

Many traffic crashes are side impact collisions resulting in significant death and injury. A review was conducted of the evidence of driver, road, and vehicle characteristics affecting either the risk of occurrence or the severity of injury in such crashes for papers published from 1996 to early 2003. For drivers, evidence was found of increased crash risk or injury severity only for age and age-related medical conditions (e.g., dementia). Traffic roundabouts and other traffic control devices--stop signs, traffic lights, and so on--had mixed results; traffic controls were better than no controls, but their effectiveness varied with circumstance. Most vehicle characteristics have had little or no effect on crash occurrence. Antilock braking systems (ABS) in the striking vehicle had been anticipated to reduce the risk of crashes, but so far have demonstrated little effect. The primary emphasis in vehicle design has been on protective devices to reduce the severity of injury. Disparity in the size of the two vehicles, especially when the struck vehicle is smaller and lighter, is almost a consistent risk factor for occupant injury. The occupants of light trucks, however, when struck by passengers cars on the opposite side, were at higher risk of injury. Wearing seat belts had a consistently protective effect; airbags did not, but there were few studies, and no field studies, of lateral airbags found. Of all the characteristics examined, vehicle design, including occupant restraints, is the most easily modified in the short term, although road design, traffic control, and the monitoring of older drivers may also prove effective in reducing side impact crashes in the longer term.

Repeated use of transscleral cyclophotocoagulation laser G-probes.

PURPOSE: To evaluate the energy transmission of transscleral cyclophotocoagulation laser G-probes after repeated use. METHODS: In this prospective study, eight new laser probes were each used for 30 transscleral cyclophotocoagulation (TSCPC) sessions in cadaver human eyes with the laser settings of 2000 mW power, 2000 milliseconds duration, and 18 shots. The laser power output was measured using a laser energy output meter before and after each TSCPC session, after swabbing the laser probe tip with alcohol, and finally after thorough cleaning by flushing 70% alcohol inside the plastic footplate tip and swabbing with alcohol the fiberoptic tip. Laser probes were inspected for deterioration. Statistical analysis was done using Analysis of Covariance (ANCOVA). RESULTS: The laser power output increased on average by 1.99 +/- 0.18 mW after each cycle (P < 0.01, 95% confidence interval: 1.63-2.35 mW, ANCOVA). No deterioration of the probes was found after 30 TSCPC and sterilization cycles. Laser energy output increased on average 6% (P < 0.01) from the baseline to the first TSCPC cycle. Probe number one broke during the tenth cycle and accordingly data was recorded for this probe until that cycle. CONCLUSION: G-probes not only remain fully functional after repeated use and sterilization with 70% alcohol but also slightly increase in energy output.

Impact of mandatory helmet legislation on bicycle-related head injuries in children: a population-based study.

OBJECTIVE: Childhood bicycle-related head injuries can be prevented through the use of helmets. Although helmet legislation has proved to be a successful strategy for the adoption of helmets, its effect on the rates of head injury is uncertain. In Canada, 4 provinces have such legislation. The objective of this study was to measure the impact of helmet legislation on bicycle-related head injuries in Canadian children. METHODS: Routinely collected data from the Canadian Institute for Health Information identified all Canadian children (5-19 years) who were hospitalized for bicycling-related injuries from 1994-1998. Children were categorized as head or other injury on the basis of International Classification of Diseases, Ninth Revision, codes. Rates of head injuries and other injuries were compared over time in provinces that adopted legislation and those that did not. RESULTS: Of the 9650 children who were hospitalized because of a bicycle-related injury, 3426 sustained injuries to the head and face and the remaining 6224 had other injuries. The bicycle-related head injury rate declined significantly (45% reduction) in provinces where legislation had been adopted compared with provinces and territories that did not adopt legislation (27% reduction). CONCLUSION: This country-wide study compared rates of head injury in regions with and without mandatory helmet legislation. Comparing head injuries with other non-head-injured children controlled for potential differences in children's cycling habits. The strong protective association between helmet legislation and head injuries supports the adoption of helmet legislation as an effective tool in the prevention of childhood bicycle-related head injuries.

The effect of dental insurance on the ranking of dental treatment needs in older residents of Durham Region's homes for the aged.

The effect of dental insurance on the ranking of dental needs in older adults has not been reported previously. We examined this effect using data obtained from a cross-sectional survey of older adults living in homes for the aged in Durham Region, Ontario. History of dental insurance was obtained during interviews. Dental needs, assessed during clinical examinations, were ranked from no need to urgent need according to the guideline of the American Dental Association. The associations between the rank of dental needs, dental insurance and other factors were analyzed with the Kruskal Wallis test, chi-square test, analysis of variance and multiple logistic regression. Of the 252 participants, 80 (31.7%) had been insured continuously since 1974, 69 (27.4%) had no need for dental treatment and 59 (23.4%) needed urgent dental care. More of the continuously insured than the uninsured residents were dentate (46/80 [57.5%] vs. 75/172 [43.6%], p = 0.04). Ranking of the need for care was not significantly influenced by dental insurance; need of any kind was explained by being dentate (odds ratio 12.3, 95% confidence interval 5.6 27.3).