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Biomedical subjects

C A McCarty

Publications and source records attributed to C A McCarty.

At least 19 recordsLinked to original sources

Characteristics of progression of early age-related macular degeneration: the cardiovascular health and age-related maculopathy study.

AIMS: To determine the risk of age-related macular degeneration (AMD) progression posed by the presence of each early AMD characteristic. METHODS: A prospective cohort study of 254 participants aged 50 years and older, all with early AMD features at their baseline visit followed for an average of 7 years. Stereoscopic colour fundus photographs were graded for early AMD features using the International Classification System. AMD status was stratified into six exclusive levels along a continuum of disease severity according to drusen type, pigmentary abnormalities, or late AMD. Progression was assessed according to three definitions: a change between or within a severity level, or by side by side grading. RESULTS: The progression rate of early AMD ranged between 3.4 and 4.67% per annum depending upon the definition used. In total, 15 (6%) cases progressed from early AMD to the late complication of AMD. After controlling for age and smoking, cases with soft indistinct drusen at baseline were at a greater risk of progressing from early to late AMD than were cases without this characteristic (OR=3.72, 95%CI 1.20-11.54; P=0.02). CONCLUSION: Our proposed definitions of AMD progression give rates that are consistent with current knowledge of progression and its determinants. Each early AMD characteristic conveys its own risk of progression to an eye, with soft indistinct drusen carrying the greater risk. An international consensus on what defines AMD progression would greatly help the research community when trying to assess the importance of new risk factors and the effectiveness of novel interventions.

Aged↗

Impact of unilateral and bilateral vision loss on quality of life.

AIM: To investigate whether unilateral vision loss reduced any aspects of quality of life in comparison with normal vision and to compare its impact with that of bilateral vision loss. METHODS: This study used cluster stratified random sample of 3271 urban participants recruited between 1992 and 1994 for the Melbourne Visual Impairment Project. All predictors and outcomes were from the 5 year follow up examinations conducted in 1997-9. RESULTS: There were 2530 participants who attended the follow up survey and had measurement of presenting visual acuity. Both unilateral and bilateral vision loss were significantly associated with increased odds of having problems in visual functions including reading the telephone book, newspaper, watching television, and seeing faces. Non-correctable by refraction unilateral vision loss increased the odds of falling when away from home (OR = 2.86, 95% CI 1.16 to 7.08), getting help with chores (OR = 3.09, 95% CI 1.40 to 6.83), and becoming dependent (getting help with meals and chores) (OR = 7.50, 95% CI 1.97 to 28.6). Non-correctable bilateral visual loss was associated with many activities of daily living except falling. CONCLUSIONS: Non-correctable unilateral vision loss was associated with issues of safety and independent living while non-correctable bilateral vision loss was associated with nursing home placement, emotional wellbeing, use of community services, and activities of daily living. Correctable or treatable vision loss should be detected and attended to.

Accidental Falls↗

Awareness of eye diseases in an urban population in southern India.

OBJECTIVE: To assess the level of awareness of eye diseases in the urban population of Hyderabad in southern India. METHODS: A total of 2522 subjects of all ages, who were representative of the Hyderabad population, participated in the population-based Andhra Pradesh Eye Disease Study. Of these subjects, 1859 aged > 15 years responded to a structured questionnaire on cataract, glaucoma, night blindness and diabetic retinopathy to trained field investigators. Having heard of the eye disease in question was defined as "awareness" and having some understanding of the eye disease was defined as "knowledge". FINDINGS: Awareness of cataract (69.8%) and night blindness (60.0%) was moderate but that of diabetic retinopathy (27.0%) was low, while that of glaucoma (2.3%) was very poor. Knowledge of all the eye diseases assessed was poor. Subjects aged > or = 30 years were significantly more aware of all eye diseases assessed except night blindness. Multivariate analysis revealed that women were significantly less aware of night blindness (odds ratio (OR) = 0.78; 95% confidence interval (CI) = 0.63-0.97). Education played a significant role in awareness of these eye diseases. Study subjects of upper socioeconomic status were significantly more aware of night blindness (OR = 2.20; 95% CI = 1.29-3.74) and those belonging to upper and middle socioeconomic strata were significantly more aware of diabetic retinopathy (OR = 2.79; 95% CI = 2.19-3.56). Muslims were significantly more aware of cataract (OR = 2.36; 95% CI = 1.84-3.02) and less aware of night blindness (OR = 0.52; 95% CI = 0.42-0.64). The major source of awareness of the eye diseases was a family member/friend/relative suffering from that eye disease. CONCLUSION: These data suggest that there is a need for health education in this Indian population to increase their level of awareness and knowledge of common eye diseases. Such awareness and knowledge could lead to better understanding and acceptance of the importance of routine eye examinations for the early detection and treatment of eye diseases, thereby reducing visual impairment in this population.

Adolescent↗

Vision impairment and older drivers: who's driving?

AIM: To establish the association between impaired vision and drivers' decisions to stop driving, voluntarily restrict driving, and motor vehicle accidents. METHODS: Driving related questions were included in a population based study that determined the prevalence and incidence of eye disease. Stratified random cluster samples based on census collector districts were selected from the Melbourne Statistical Division. Eligible participants aged 44 years and over were interviewed and underwent a comprehensive ophthalmic examination. The outcomes of interest were the decision to stop driving, limiting driving in specified conditions, and driving accidents. The associations between these outcomes and the legally prescribed visual acuity (<6/12) for a driver's licence were investigated. RESULTS: The mean age of the 2594/3040 (85%) eligible participants was 62.5 (range 44-101). People with visual acuity less than 6/12 were no more likely to have an accident than those with better vision (chi(2) = 0.175, p>0.9). Older drivers with impaired vision, more so than younger adults, restrict their driving in visually demanding situations (p<0.05). Of the current drivers, 2.6% have vision less than that required to obtain a driver's licence. The risk of having an accident increased with distance driven (OR 2.57, CL 1.63, 4.04 for distance >31 000 km) but not with age. CONCLUSION: There was no greater likelihood of self reported driving accidents for drivers with impaired vision than those with good vision. While many older drivers with impaired vision limit their driving in adverse conditions and some drivers with impaired vision stop driving, there are a significant number of current drivers with impaired vision.

Accidents, Traffic↗

Moderate visual impairment in India: the Andhra Pradesh Eye Disease Study.

AIM: To assess the prevalence and demographic associations of moderate visual impairment in the population of the southern Indian state of Andhra Pradesh. METHODS: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 people of all ages were sampled using a stratified, random, cluster, systematic sampling strategy. The eligible people were invited for interview and detailed dilated eye examination by trained professionals. Moderate visual impairment was defined as presenting distance visual acuity less than 6/18 to 6/60 or equivalent visual field loss in the better eye. RESULTS: Of those sampled, 10,293 (87.3%) people participated in the study. In addition to the previously reported 1.84% prevalence of blindness (presenting distance visual acuity less than 6/60 or central visual field less than 20 degrees in the better eye) in this sample, 1237 people had moderate visual impairment, an adjusted prevalence of 8.09% (95% CI 6.89 to 9.30%). The majority of this moderate visual impairment was caused by refractive error (45.8%) and cataract (39.9%). Increasing age, female sex, decreasing socioeconomic status, and rural area of residence had significantly higher odds of being associated with moderate visual impairment. CONCLUSIONS: These data suggest that there is a significant burden of moderate visual impairment in this population in addition to blindness. Extrapolation of these data to the population of India suggests that there were 82 million people with moderate visual impairment in the year 2000, and this number is likely to be 139 million by the year 2020 if the current trend continues. This impending large burden of moderate visual impairment, the majority of which is due to the relatively easily treatable refractive error and cataract, would have to be taken into account while estimating the eye care needs in India, in addition to dealing with blindness. Specific strategies targeting the elderly population, people with low socioeconomic status, those living in the rural areas, and females would have to be implemented in the long term to reduce moderate visual impairment.

Adolescent↗

Risk factors for age-related maculopathy: the Visual Impairment Project.

OBJECTIVE: To describe the risk factors and associated population attributable risk for age-related maculopathy (ARM) and age-related macular degeneration (AMD) in Australians aged 40 years and older. METHODS: Residents were recruited from 9 randomly selected urban clusters and 4 randomly selected rural clusters in Victoria, Australia. At locally established test sites, the following information was collected: visual acuity, medical and health history, lifetime sunlight exposure, dietary intake, and fundus photographs. Age-related maculopathy and AMD were graded from the fundus photographs using an international classification and grading system. Backwards logistic regression was used to identify the independent risk factors for ARM and AMD. RESULTS: The participation rate was 83% (n = 3271) among the urban residents and 92% (n = 1473) among the rural residents. Gradable fundus photographs of either eye were available for 4345 (92%) of the 4744 participants. There were 656 cases of ARM, giving a weighted prevalence of 15.1% (95% confidence limit [CL], 13.8, 16.4); and there were 30 cases of AMD, giving a weighted prevalence of 0.69% (95% CL, 0.33, 1.03). In multiple logistic regression, the risk factors for AMD were as follows: age (odds ratio [OR], 1.23; 95% CL, 1.17, 1.29), smoked cigarettes for longer than 40 years (OR, 2.39; 95% CL, 1.02, 5.57), and ever taken angiotensin-converting enzyme inhibitors (OR, 3.26; 95% CL, 1.33, 8.01). The magnitude of all of these risk factors was slightly less for ARM, and having ever taken blood cholesterol-lowering medications was also significant (OR, 1.67; 95% CL, 1.12, 2.47; P =.001). CONCLUSION: Smoking is the only modifiable risk factor for ARM and AMD, among the many environmental and systemic factors that were assessed.

Adult↗

Association of demographic, familial, medical, and ocular factors with intraocular pressure.

OBJECTIVE: To describe the distribution and associations of demographic, familial, medical, and ocular factors with intraocular pressure (IOP). METHODS: A cluster stratified random sample of urban and rural residents of Victoria, Australia, aged 40 years and older. Participants completed an interview and underwent a standardized dilated ophthalmic examination including measurement of IOP with an electronic applanation tonometer (Tono-Pen). Glaucoma status (possible, probable, definite) was determined by a consensus panel. The main outcome measure was IOP. RESULTS: The mean age of the 4576 participants was 59 years, 53% were women, 32% were born overseas, and 132 had open-angle glaucoma. Geometric mean (SD) IOP was 14.3 (+/-1.5) mm Hg. The relationship between IOP and nuclear sclerosis, iris color, and family history of glaucoma depended on glaucoma status. In those with glaucoma, family history of glaucoma and country of birth were significantly associated with IOP in multivariate models (model: r(2) = 0.08, P =.01). In the group without glaucoma, place of residence, use of alcohol, iris color, vitamin E intake, and spherical equivalent were associated with IOP (model: r(2) = 0.01, P =.006). CONCLUSION: In participants with glaucoma, genetic factors seem to be stronger predictors of IOP, whereas in those without glaucoma, lifestyle and physiological factors seem to play a greater role.

Adult↗

Cause-specific prevalence of bilateral visual impairment in Victoria, Australia: the Visual Impairment Project.

PURPOSE: To study the cause-specific prevalence of eye diseases causing bilateral visual impairment in Australian adults. DESIGN: Two-site, population-based cross-sectional study. PARTICIPANTS: Participants were aged 40 years and older and resident in their homes at the time of recruitment for the study. The study was conducted during 1992 through 1996. METHODS: The study uses a cluster stratified random sample of 4744 participants from two cohorts, urban, and rural Victoria. Participants completed a standardized interview and eye examination, including presenting and best-corrected visual acuity, visual fields, and dilated ocular examination. The major cause of vision loss was identified for all participants found to be visually impaired. Population-based prevalence estimates are weighted to reflect the age and gender distribution of the two cohorts in Victoria. MAIN OUTCOME MEASURES: Visual impairment was defined by four levels of severity on the basis of best-corrected visual acuity or visual field: <6/18 > or =6/60 and/or <20 degrees > or =10 degrees radius field, moderate vision impairment; severe vision impairment, <6/60 > or =3/60 and/or <10 degrees > or =5 degrees radius field; and profound vision impairment <3/60 and/or <5 degrees radius field. In addition, less-than-legal driving vision, <6/12 > or =6/18, and/or homonymous hemianopia were defined as mild vision impairment. In Australia, legal blindness includes severe and profound vision impairment. RESULTS: The population-weighted prevalence of diseases causing less-than-legal driving or worse impairment in the better eye was 42.48/1000 (95% confidence interval [CI], 30.11, 54.86). Uncorrected refractive error was the most frequent cause of bilateral vision impairment, 24.68/1000 (95% CI, 16.12, 33.25), followed by age-related macular degeneration (AMD), 3.86/1000 (95% CI, 2.17, 5.55); other retinal diseases, 2.91/1000 (95% CI, 0.74, 5.08); other disorders, 2.80/1000 (95% CI, 1.17, 4.43); cataract, 2.57/1000 (95% CI, 1.38, 3.76); glaucoma, 2.32/1000 (95% CI, 0.72, 3.92); neuro-ophthalmic disorders, 1.80/1000 (95% CI, 0, 4.11); and diabetic retinopathy, 1.53/1000 (95% CI, 0.71, 2.36). The prevalence of legal blindness was 5.30/1000 (95% CI, 3.24, 7.36). Although not significantly different, the causes of legal blindness were uncorrected refractive errors, AMD, glaucoma, other retinal conditions, and other diseases. CONCLUSIONS: Significant reduction of visual impairment may be attained with the application of current knowledge in refractive errors, diabetes mellitus, cataract, and glaucoma. Although easily preventable, uncorrected refractive error remains a major cause of vision impairment.

Adult↗

Prevalence and predictors of open-angle glaucoma: results from the visual impairment project.

PURPOSE: To determine the prevalence and investigate predictors of open-angle glaucoma in Victoria, Australia. DESIGN: Two-site, population-based cross-sectional study. PARTICIPANTS: Permanent residents aged 40 years and older at recruitment from 1992 through 1996. METHODS: A cluster-stratified random sample of 4744 participants from two cohorts, urban and rural, participated. Participants completed a standardized interview regarding demographic, lifestyle, and medical characteristics and a dilated eye examination including measurement of intraocular pressure, visual fields, cup-to-disc ratios, and paired stereo photography of the optic discs. A consensus panel of six ophthalmologists determined glaucoma diagnosis. MAIN OUTCOME MEASURE: Diagnosis of glaucoma (possible, probable, definite). RESULTS: The prevalence of possible glaucoma cases was 1.2% (95% confidence interval [CI], 0.60, 1.7), of probable cases was 0.70% (95% CI, 0.39, 1.0), and of definite cases was 1.8% (95% CI, 1.4, 2.2). There was a significant increase in glaucoma prevalence with age across all definitions, but there was no difference in age-standardized rates between genders. A total of 60% of probable and definite glaucoma cases were undiagnosed before this study. Adjusted for age, the strongest risk factor for glaucoma was a positive family history of glaucoma (odds ratio, 3.1; 95% CI, 1.6, 5.3). Glaucoma patients who had not attended an eye care provider in the last 2 years were eight times (95% CI, 3.2, 20.4) more likely to have undiagnosed disease. CONCLUSIONS: These results support the importance of the genetic or familial basis of many glaucoma cases and highlight the need to develop appropriate techniques to screen for undiagnosed disease.

Adult↗

Control-related beliefs and depressive symptoms in clinic-referred children and adolescents: developmental differences and model specificity.

The contingency-competence-control (CCC) model links contingency and competence beliefs to perceived control and, in turn, to depression. However, a developmental perspective suggests that noncontingency may be too abstract a concept to be directly tied to depression before adolescence. We tested the CCC model and this developmental notion, using structural equation modeling, with 360 clinic-referred 8- to 17-year-olds. The CCC model fit the data well for the full sample accounting for 46% of the variance in depression. Separate analyses by age group placed perceived contingency in the best-fit model for adolescents (ages 12-17 years) but not for children (8-11 years). This suggests that abstract cause-effect concepts may have more direct affective impact after the cognitive changes of adolescence (e.g., formal operations) than before. Finally, the CCC model accounted for much more variance in depression than conduct problems, suggesting diagnostic specificity.

Adolescent↗

Costs of mobile screening for diabetic retinopathy: a practical framework for rural populations.

Australia's rural and remote residents experience considerably higher hospitalisation and death rates due to diabetes than their metropolitan counterparts. There is clearly a need for improved diabetes care services in these areas and interventions that target conditions associated with diabetes will yield beneficial results for the community. All people with diabetes are at risk for diabetic retinopathy, which can cause vision loss and blindness. Although vision loss and blindness due to diabetes is nearly 100% preventable through regular eye examinations, 35% of Victoria's rural population with diabetes do not have their eyes examined on a regular basis. A pilot, mobile screening program for the early detection of diabetic eye disease was conducted in rural Victoria and proved to be a successful model of adjunct eye care for people with diabetes. Actual costs from the pilot screening were applied to a permanent model for rural eye care. At A$41 per participant, costs for mobile screening were competitive with Medicare rebate costs for eye examinations. The model addresses barriers of accessibility and availability, targets a portion of the rural population with diabetes that is not otherwise having eye examinations, and is cost-saving to the Government.

Cost Savings↗

Management of diabetic retinopathy by general practitioners in Victoria.

PURPOSE: To compare the self-reported management of diabetic retinopathy by general practitioners to the National Health and Medical Research Council of Australia (NHMRC) Guidelines for the Management of Diabetic Retinopathy. METHODS: In 1994, a stratified (by urban/rural practice location) sample of 500 general practitioners in Victoria was surveyed in regard to their management of diabetic retinopathy. Following the release of the NHMRC Guidelines for the Management of Diabetic Retinopathy in 1997, these same general practitioners were sent a two-page questionnaire related to their management of diabetic retinopathy. RESULTS: Completed questionnaires were received from 228 general practitioners (59% of original participants). Only 37% (79/216) of the general practitioners reported that they had received a copy of the guidelines. Of the general practitioners who had received the guidelines, 18% (14/79) said that they had not read them at all, while 65% (51/79) had read them partially and 18% (14/79) had read them in their entirety. At follow up, less than half (98/214) of general practitioners reported examining 50% or more of their patients for diabetic retinopathy, compared with 104/214 at baseline. General practitioners who had read the guidelines were more likely to report that not being sure what to do when changes were detected was a minor barrier or was not a barrier to them performing dilated ophthalmoscopy (93% vs 83%, chi2(1) = 3.67, P = 0.055). Nearly all of the general practitioners reported that they refer their patients with diabetes to an ophthalmologist or optometrist at least every 2 years as recommended. Seventy-six per cent (170/224) of the general practitioners felt that 70% or more of their patients complied with their instructions to visit an ophthalmologist or optometrist. CONCLUSION: The NHMRC guidelines for diabetic retinopathy appear to have had a positive effect on some of the attitudes of general practitioners who have read them, but more effort is needed to disseminate the guidelines to all general practitioners and to increase their uptake.

Diabetic Retinopathy↗