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Paul Mitchell

Publications and source records attributed to Paul Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed2006

Retinal arteriolar emboli and long-term mortality: pooled data analysis from two older populations.

BACKGROUND AND PURPOSE: To assess the relationship between retinal arteriolar emboli and mortality in older people. METHODS: Pooled data from 2 population-based cohort studies. At baseline, the Beaver Dam Eye Study (BDES) examined 4926 persons 43 to 86 years of age (1988 to 1990), and the Blue Mountains Eye Study (BMES) examined 3654 persons 49 to 97 years of age (1992 to 1994). Retinal arteriolar emboli were assessed by grading retinal photographs using standardized methods. Deaths and causes of death were determined from death certificates or Australian National Death Index. Cox regression models were used to estimate mortality hazard ratios (HRs) associated with emboli, adjusting for age, gender, body mass index, hypertension, diabetes, smoking, serum total cholesterol, high-density lipoprotein cholesterol, study site, and past histories of stroke, angina, and acute myocardial infarct. RESULTS: Of 8580 baseline participants, 8384 (98%) had retinal photographs available, and 111 showed retinal arteriolar emboli (BDES n=61; BMES n=50). Over 10 to 12 years, 2506 participants (30%) died, including 344 (4%) from stroke-related and 1315 (16%) from cardiovascular causes. The cumulative mortality rates were higher in participants with than without emboli (all-cause 56% versus 30%; stroke-related 12% versus 4.0%; cardiovascular 30% versus 16%). The increased mortality risk associated with emboli was independent of age, gender, other vascular risk factors, and past histories of stroke or heart disease for all-cause (multivariate-adjusted HR, 1.3; CI, 1.0 to 1.8) and stroke-related mortality (HR, 2.0; CI, 1.1 to 3.8) but not for cardiovascular mortality (HR, 1.2; CI, 0.8 to 1.7). CONCLUSIONS: Our pooled data from 2 older populations suggest that retinal emboli predict a modest increase in all-cause and stroke-related mortality independent of cardiovascular risk factors.

Adult↗
PubMed2006

The association between circulating white blood cell count, triglyceride level and cardiovascular and all-cause mortality: population-based cohort study.

OBJECTIVES: To examine the individual and combined relationship between elevated white blood cell count (WBC), triglyceride level and cardiovascular and all-cause mortality among older Australians. DESIGN: Prospective population-based cohort study. SETTING: Community in Blue Mountains region, Australia. PARTICIPANTS: 2904 individuals, aged 49-84 years, free of cardiovascular disease and cancer at the baseline examination. MAIN OUTCOME MEASURES: Cardiovascular (n=242) and all-cause mortality (n=575). RESULTS: Elevated WBC count and triglyceride level were found to be associated with cardiovascular and all-cause mortality, independent of several important confounders. Multivariable relative risk [RR] (95% confidence interval [CI]) comparing fourth (6.8 x 10(9) cells/L and above) versus first quartile (4.8 x 10(9) cells/L and below) of WBC count was 2.01 (1.40-2.90) for cardiovascular mortality and 1.68 (1.35-2.09) for all-cause mortality. Multivariable RR (95% CI) comparing fourth (1.98 mmol/L and above) versus first quartile (0.95 mmol/L and below) of triglyceride level was 1.58 (1.08-2.30) for cardiovascular mortality and 1.40 (1.11-1.77) for all-cause mortality. Furthermore, a combined exposure to the fourth quartiles of both WBC count and triglyceride level was found to be related to more than three-fold risk of cardiovascular mortality (RR [95% CI]: 3.15 [2.17-4.57], p-interaction=0.01), independent of traditional risk factors. CONCLUSIONS: Elevated WBC count and triglyceride level were associated with cardiovascular and all-cause mortality among older Australians. These data provide new epidemiological evidence regarding cardiovascular risk stratification using simple, inexpensive, and routinely available measures, suggesting that a combined exposure to both high WBC count and triglyceride level is related to more than three-fold risk of cardiovascular mortality, independent of traditional risk factors.

Aged↗
PubMed2006

Temporal trends in the age-specific prevalence of diabetes and diabetic retinopathy in older persons: Population-based survey findings.

PURPOSE: To compare the age-specific prevalence of diabetes and diabetic retinopathy (DR) over 6 years. METHODS: The Blue Mountains Eye Study (BMES) examined 3654 residents (82.4% response) aged >49 years in BMES I (1992-1994). Survivors (n = 2335) and newly eligible residents (n = 1174) were examined in BMES II (1997-2000). Diabetes was defined by history or fasting plasma glucose > or =7.0 mmol/L. DR was graded from 6-field retinal photographs using the Airlie House Classification. Age-specific prevalence in 5-year intervals was compared, as samples of each age group were independent. RESULTS: The overall diabetes prevalence increased from 7.8 to 9.9% (p = 0.002) while the age-specific prevalence increased in age groups 60-74 years, over 6 years. A slightly higher prevalence of mild levels of DR (p = 0.018) but lower prevalence of moderate-severe levels of DR (p = 0.049) was evident in BMES II compared to BMES I. Factors significantly associated with DR prevalence were diabetes duration > or =20 years (BMES I, OR 7.6 [2.9-20.5]; BMES II, OR 6.1 [2.5-15.4]) and blood glucose level (BMES I, OR 1.1 [1.0-1.2]; BMES II, OR 1.2 [1.1-1.3] per mmol/L increase). CONCLUSIONS: An increased prevalence of diabetes, but decreased prevalence of severe levels of DR, was documented in two survey samples from the same region over 6 years.

Aged↗
PubMed2006

Factors associated with childhood strabismus: findings from a population-based study.

PURPOSE: To describe strabismus prevalence and associated factors in a representative sample of 6-year-old Australian children. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One thousand seven hundred thirty-nine predominantly 6-year-old children resident in Sydney examined in 2003 and 2004. METHODS: Cover testing was performed at near and distance fixation, and with spectacles if worn. Logarithm of the minimum angle of resolution visual acuity was measured in both eyes before and after pinhole correction, after correcting any cylindrical refraction >0.50 diopters and with spectacles, if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Each child's medical and perinatal histories were sought in a detailed parental questionnaire. MAIN OUTCOME MEASURES: Strabismus was defined as any heterotropia at near or distance fixation, or both, on cover testing. Microstrabismus was defined as a deviation of fewer than 10 prism diopters. RESULTS: Strabismus was diagnosed in 48 children (2.8% of the population), 5 of whom had previously undergone surgical correction; 26 children (54%) had esotropia, 14 (29%) had exotropia, 7 (15%) had microstrabismus, and 1 child had VIth cranial nerve palsy. Prematurity was associated with a 5-fold increase in the risk of esotropia (odds ratio, 5.0; 95% confidence interval, 1.8-14.1). Visual impairment (with presenting correction) was significantly more common in children with (22.9%) than without (1.3%) strabismus (P<0.0001). The presence of strabismus was significantly associated with hyperopia, astigmatism, anisometropia, and amblyopia (P<0.0001). CONCLUSIONS: This report documents the prevalence of strabismus and its relation to other ocular signs and visual impairment in a representative sample of Australian school children. Presence of strabismus was significantly associated with prematurity.

Child↗
PubMed2006

Comparison of age-specific cataract prevalence in two population-based surveys 6 years apart.

BACKGROUND: In this study, we aimed to compare age-specific cortical, nuclear and posterior subcapsular (PSC) cataract prevalence in two surveys 6 years apart. METHODS: The Blue Mountains Eye Study examined 3654 participants (82.4% of those eligible) in cross-section I (1992-4) and 3509 participants (75.1% of survivors and 85.2% of newly eligible) in cross-section II (1997-2000, 66.5% overlap with cross-section I). Cataract was assessed from lens photographs following the Wisconsin Cataract Grading System. Cortical cataract was defined if cortical opacity comprised > or = 5% of lens area. Nuclear cataract was defined if nuclear opacity > or = Wisconsin standard 4. PSC was defined if any present. Any cataract was defined to include persons who had previous cataract surgery. Weighted kappa for inter-grader reliability was 0.82, 0.55 and 0.82 for cortical, nuclear and PSC cataract, respectively. We assessed age-specific prevalence using an interval of 5 years, so that participants within each age group were independent between the two surveys. RESULTS: Age and gender distributions were similar between the two populations. The age-specific prevalence of cortical (23.8% in 1st, 23.7% in 2nd) and PSC cataract (6.3%, 6.0%) was similar. The prevalence of nuclear cataract increased slightly from 18.7% to 23.9%. After age standardization, the similar prevalence of cortical (23.8%, 23.5%) and PSC cataract (6.3%, 5.9%), and the increased prevalence of nuclear cataract (18.7%, 24.2%) remained. CONCLUSION: In two surveys of two population-based samples with similar age and gender distributions, we found a relatively stable cortical and PSC cataract prevalence over a 6-year period. The increased prevalence of nuclear cataract deserves further study.

Age Distribution↗
PubMed2006

Associations between elevated intraocular pressure and glaucoma, use of glaucoma medications, and 5-year incident cataract: the Blue Mountains Eye Study.

PURPOSE: To examine incident relationships between elevated intraocular pressure (IOP), open-angle glaucoma (OAG), and use of glaucoma medications with 5-year incident cataract. DESIGN: Population-based cohort study. PARTICIPANTS: The Australian Blue Mountains Eye Study examined 3654 participants > or =50 years old at baseline (82.4% response; 1992-1994); 2335 eligible participants were reexamined after 5 years (75.1% response; 1997-1999). METHODS: A detailed medical and ocular history, including current medications, was taken, and a comprehensive eye examination, including applanation tonometry, automated perimetry, and lens photography, was performed at each examination. The Wisconsin system was used to grade lens photographs in assessing incident nuclear, cortical, and posterior subcapsular cataract (PSC). Data from both eyes were assessed using generalized estimating equation analyses. MAIN OUTCOME MEASURES: Elevated IOP was defined as > or =21 mmHg. Open-angle glaucoma was diagnosed from typical glaucomatous field loss with matching optic disc cupping, without reference to IOP. Subjects without OAG or secondary or angle-closure glaucoma with IOP > 21 mmHg in either eye were classified as having ocular hypertension (OH), as were non-OAG subjects with IOP < 22 mmHg using glaucoma medications. Wisconsin levels 4 to 5 were graded as nuclear cataract, at least 5% lens involvement was graded as cortical cataract, and any PSC defined its presence. RESULTS: The 5-year incidence of nuclear cataract was 23.4% (592/2532), or 23.1% (574/2486) after excluding subjects using glaucoma medication. A marginally significant association was found for elevated IOP or OH at baseline and incident nuclear cataract (odds ratio [OR], 1.93 [95% confidence interval (CI), 0.97-3.89], and OR, 1.83 [95% CI, 0.96-3.48], respectively) in subjects not using glaucoma medications, after multivariate adjustment. Age- and gender-adjusted analyses showed similar but statistically significant associations. The association between elevated IOP or OH and nuclear cataract was significant in multivariate analyses (OR, 2.07 [95% CI, 1.04-3.12], and OR, 1.78 [95% CI, 1.05-3.01], respectively). Use of glaucoma medications was associated with nonsignificantly increased adjusted odds for incident nuclear cataract (OR, 1.90 [95% CI, 0.92-3.92]). No associations, however, were found with incident cortical cataract or PSC. CONCLUSIONS: Elevated IOP may increase the risk of nuclear cataract, but not that of other types. The use of glaucoma medications could magnify this risk.

Aged↗
PubMed2006

Ten-year incidence of retinal emboli in an older population.

BACKGROUND AND PURPOSE: To assess 10-year incidence of retinal emboli and its predictors in an older population. METHODS: Survivors of 3654 Blue Mountains Eye Study participants > or =49 years of age were re-examined 5 and 10 years later. Incident emboli were assessed from retinal photographs. RESULTS: Cumulative 10-year incidence was 2.9% (95% CI, 2.1% to 3.6%) among 2361 at risk. Age was associated with incident emboli (Ptrend=0.0001). After multivariate adjustment, hypertension (odds ratio [OR], 1.8; CI, 1.0 to 3.1), hypercholesterolemia (OR, 1.3; CI, 1.0 to 1.6), overweight (OR, 3.3; CI, 1.6 to 6.9), current smoking (OR, 2.5; CI, 1.1 to 5.9), increasing fibrinogen level (OR per mg/dL, 1.1; CI, 1.0 to 1.2), and retinal vascular signs (arteriovenous nicking OR, 2.0; CI, 1.2 to 3.6; arteriolar wall opacification OR, 2.3; CI, 1.1 to 5.0; retinal vein occlusion OR, 3.2; CI, 1.0 to 9.9) were significantly associated with incident emboli. CONCLUSIONS: The 3% incidence of retinal arteriolar emboli found in this older population is likely to be an underestimate attributable to the transient nature of emboli and differential loss to follow-up. Most cardiovascular risk factors predict retinal embolism.

Adult↗
PubMed2006

Association between circulating white blood cell count and cancer mortality: a population-based cohort study.

BACKGROUND: Inflammatory processes are implicated in the development and progression of cancer. However, it is not clear whether systemic markers of inflammation predict cancer. We examined the prospective relationship between circulating white blood cell (WBC) count and cancer mortality. METHODS: Population-based cohort study of 3189 individuals, aged 49 to 84 years and free of cancer at the baseline examination (January 1, 1992, to December 31, 1994), in the Blue Mountains region, west of Sydney, Australia. The main outcome of interest was all cancer mortality ascertained from vital status as of December 31, 2001. RESULTS: Higher WBC count was found to be associated with all cancer mortality. In proportional hazards models adjusting for age, sex, education, body mass index, hematocrit level, alcohol consumption, physical inactivity, smoking, weekly aspirin use, diabetes mellitus or fasting hyperglycemia status, and fasting glucose levels, the multivariable relative risk of all cancer mortality comparing quartile 4 of WBC count ( > or = 7400 cells/microL) with quartile 1 (< or = 5300 cells/microL) was 1.73 (95% confidence interval [CI], 1.18-2.55). In subgroup analyses, the relative risk of cancer mortality comparing quartile 4 of WBC count with quartile 1 was higher among those with diabetes or fasting hyperglycemia (3.03 [95% CI, 1.01-9.15]) than among those with normoglycemia (1.68 [95% CI, 1.12-2.52]). Also, the relative risk of cancer mortality associated with joint exposure to quartile 4 of WBC count and aspirin nonuse was 2.42 (95% CI, 1.46-4.01) compared with their absence. CONCLUSION: These data provide new epidemiological evidence of an association between circulating WBC count, a widely available marker of inflammation, and subsequent cancer mortality.

Aged↗
PubMed2006

Association between vision and hearing impairments and their combined effects on quality of life.

OBJECTIVES: To assess associations between age-related vision and hearing impairments and whether combined sensory losses magnify effects on health-related quality of life. METHODS: Seventy-five percent of survivors (n = 2334) were reexamined at Blue Mountains Eye Study 5-year examinations and 86.3% (2015) attended hearing assessments. Visual impairment was defined as visual acuity less than 20/40 (better eye), and hearing impairment as average pure-tone air conduction threshold greater than 25 dB (500-4000 Hz, better ear). RESULTS: Persons with visual impairment, compared with those without visual impairment, had lower mean audiometric thresholds across all frequencies (P< or =.05). For each 1-line (5-letter) reduction in best-corrected visual acuity and presenting visual acuity, hearing loss prevalence increased by 18% and 13%, respectively. Cataract and age-related maculopathy were also associated with hearing loss (respectively, multivariate-adjusted odds ratio, 1.3 and 1.6; 95% confidence interval, 1.0-1.7 and 1.1-3.1). The association between age-related maculopathy and hearing loss was stronger at younger ages (<70 years). Combined impairments were associated with poorer health-related quality of life than were single impairments (multivariate-adjusted 36-Item Short-Form Health Survey mean physical and mental component scores; Ptrend = .001 and <.001, respectively). CONCLUSIONS: Older persons with visual impairment were also more likely to have hearing loss in this study, which suggests that these sensory impairments could share common risk factors or biologic aging markers. Combined sensory impairments also cumulatively affect health-related quality of life.

Aged↗
PubMed2006

Ten-year incidence of retinal vein occlusion in an older population: the Blue Mountains Eye Study.

OBJECTIVE: To assess the 10-year incidence of retinal vein occlusion (RVO) and its predictors in an older population. METHODS: The Blue Mountains Eye Study examined 3654 residents aged 49 years and older (82.4% response) from 1992 to 1994, reexamined 2335 residents (75.1% of survivors) from 1997 to 1999, and reexamined 1952 residents (75.6% of survivors) from 2002 to 2004. Incident RVO was assessed from stereoscopic retinal photographs. Kaplan-Meier cumulative 10-year incidence was calculated. RESULTS: After excluding 47 residents with RVO at baseline and 171 residents with no photographs at either follow-up examination, 2346 residents were considered at risk of developing RVO. The cumulative 10-year incidence of RVO was 1.6%. Age was significantly associated with the incidence of RVO (P = .03, Mantel-Haenszel chi(2) test for trend). Factors predicting the incidence of RVO included mean arterial blood pressure (age-adjusted odds ratio [OR], 1.41 per 10-mm Hg increase), ocular perfusion pressure (OR, 1.71 per 10-mm Hg increase), obesity (OR, 2.16), and presence of retinal arteriolar wall signs (focal narrowing: OR, 3.37; arteriovenous nicking: OR, 4.09; and opacification: OR, 4.89). CONCLUSIONS: Older age (> or =70 years), increasing mean arterial blood pressure, and atherosclerotic retinal vessel signs were significant predictors of incident RVO.

Aged↗
PubMed2006

The impact of modest prematurity on visual function at age 6 years: findings from a population-based study.

OBJECTIVE: To determine the effects of modest low birth weight and prematurity on visual function of children predominantly aged 6 years. METHODS: Children with a birth weight of 1500 to 2499 g were considered exposed to a modest low birth weight (n = 82) and were compared with children with a birth weight of 2500 g or more (n = 1386). Exposure to modest prematurity, 32 to 36 weeks' gestation (n = 115), was similarly analyzed and compared with birth at term, 37 or more weeks' gestation (n = 1446). Logarithm of the minimum angle of resolution visual acuity was measured in both eyes. Cycloplegic autorefraction (cyclopentolate), cover testing, and dilated fundus examinations were performed. RESULTS: A modest low birth weight increased the risk of amblyopia (relative risk [RR], 5.1; 95% confidence interval [CI], 2.2-12.0), strabismus (RR, 3.7; 95% CI, 1.5-9.1), and anisometropia (RR, 3.7; 95% CI, 1.2-11.1), together with an increased risk of uncorrected visual acuity in the lowest quartile (RR, 1.7; 95% CI, 1.3-2.2). Modest prematurity increased the risk of amblyopia (RR, 4.5; 95% CI, 1.9-10.6), strabismus (RR, 2.6; 95% CI, 1.1-6.0), and uncorrected visual acuity in the lowest quartile (RR, 1.5; 95% CI, 1.1-2.0). CONCLUSION: Modest degrees of low birth weight and prematurity may be associated with increased ophthalmic morbidity at age 6 years.

Amblyopia↗
PubMed2006

Causes and associations of amblyopia in a population-based sample of 6-year-old Australian children.

OBJECTIVES: To describe the prevalence of amblyopia and associated factors in a representative sample of 6-year-old Australian children. METHODS: Logarithm of minimum angle of resolution visual acuity (VA) was measured in both eyes before and after pinhole correction, correcting cylindrical refractive components greater than 0.50 diopter (D), and with spectacles (if worn) in a population-based sample of 1741 schoolchildren. Retinal pathological abnormalities were excluded based on photographs. Amblyopia was defined using various best-available corrected VA measures in the absence of significant organic pathological abnormalities. RESULTS: Using the criteria of corrected VA less than 20/40 and at least a 2-line difference between eyes, amblyopia was diagnosed in 13 children (0.7%). The inclusion of children with amblyopia who had been successfully treated (n = 19) increased the amblyopia prevalence to 1.8%. Strabismus or strabismus surgery history was present in 37.5% of the children with amblyopia, anisometropia in 34.4%, both conditions in 18.8%, and isoametropia in 6.3%. Mean corrected VA in amblyopic eyes was 37.7 logarithm of minimum angle of resolution letters (Snellen VA equivalent < 20/40), ranging from 0 to 48 logarithm of minimum angle of resolution letters (Snellen VA equivalent < 20/200-20/25). Most amblyopic eyes (58.7%) were significantly hyperopic (spherical equivalent > or = +3.00 D); 8.7% were myopic. CONCLUSIONS: A relatively low prevalence of amblyopia in a sample of 6-year-old children is documented. The majority of these children had already been diagnosed and treated for this condition.

Amblyopia↗
PubMed2006

Dietary fatty acids and the 5-year incidence of age-related maculopathy.

OBJECTIVE: To assess longitudinal associations between dietary fat and incident age-related maculopathy (ARM) in an older, population-based, historical cohort. METHODS: A total of 3654 persons, 49 years or older, participated in the Blue Mountains Eye Study (1992-1994); 2335 (75.1% of survivors) were reexamined after 5 years (1997-1999). Dietary data were collected from 2895 people (79%) at baseline by means of a semiquantitative food frequency questionnaire to calculate dietary fat intakes. Presence of ARM was graded from retinal photographs (Wisconsin ARM Grading System). Logistic regression adjusted for age, sex, vitamin C intake, and smoking. RESULTS: Participants with the highest vs lowest quintiles of n-3 polyunsaturated fat intake had lower risk of incident early ARM (odds ratio [95% confidence interval], 0.41 [0.22-0.75). A 40% reduction of incident early ARM was associated with fish consumption at least once a week (odds ratio [95% confidence interval], 0.58 [0.37-0.90]), whereas fish consumption at least 3 times per week could reduce the incidence of late ARM (odds ratio [95% confidence interval], 0.25 [0.06-1.00]). We found no association between incident ARM and butter, margarine, or nut consumption. CONCLUSIONS: A regular diet high in n-3 polyunsaturated fat, especially from fish, suggests protection against early and late ARM in this older Australian cohort. Our study could not confirm deleterious effects of higher polyunsaturated fat intakes reported by other clinic-based studies.

Aged↗
PubMed2006

Hypermetropia is not associated with hypertension: the Blue Mountains Eye Study.

PURPOSE: An association between hypermetropia and hypertension was recently reported. We sought to verify this finding in the Blue Mountains Eye Study cohort (n = 3654; ages 49 to 97 years). DESIGN: Cohort study. METHODS: We defined hypermetropia as mean spheric equivalent refraction (SER) > 1.00 diopter, myopia as mean SER < -1.00 diopters, and emmetropia as mean SER < or = 1.00 diopters and > or = -1.00 diopters, inclusive. We used the 2003 World Health Organization/International Society of Hypertension guidelines to define severe hypertension as grade 2 or higher. RESULTS: Of 1290 people who were at risk of the development of hypertension, 378 people developed incident severe hypertension after five years. The multivariate-adjusted relative risk of incident hypertension in persons with hypermetropia compared with those with emmetropia was 1.06 (95% CI, 0.89 to 1.26); the relative risk in persons with myopia was 1.22 (95% CI, 0.96 to 1.56). CONCLUSION: Neither hypermetropia nor myopia was associated with incident hypertension in this older population.

Aged↗
PubMed2006

Correctable and non-correctable visual impairment in a population-based sample of 12-year-old Australian children.

PURPOSE: To document the prevalence of correctable and non-correctable visual impairment in a representative sample of Australian children, predominantly age 12 years. DESIGN: Population-based cross-sectional study. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes unaided, with spectacles if worn, and after subjective refraction if required, in 2353 children, examined during 2004 to 2005. Cycloplegic autorefraction (using cyclopentolate) and dilated fundus examination were performed. Using a cut-off of 0.3 logMAR units (<20/40), presenting visual impairment was defined using unaided visual acuity if spectacles were not worn or with usual correction if spectacles were worn. Impairment not eliminated by refraction was considered non-correctable; any difference between this and presenting impairment was defined as correctable impairment. Myopia was defined as spherical equivalent refraction (SER) < or =-0.50 diopters (D), hyperopia as SER > or =+2.0 diopters, anisometropia as SER difference > or =1.00 diopters, and astigmatism as cylinder > or =1.0 diopters. Amblyopia was defined as corrected visual acuity <0.3 logMAR not attributable to an underlying structural eye or visual pathway abnormality. RESULTS: Visual impairment was found in the worse eye of 117 children (5.0%) and comprised correctable (82%) and non-correctable impairment (18%). Correctable impairment was due to myopia in 67 (69.8%), hyperopia in 11 (11.5%) and astigmatism in 32 subjects (33.3%). Causes of non-correctable impairment were: amblyopia 66.7%, congenital glaucoma 9.5%, optic nerve hypoplasia 9.5%, congenital nystagmus 4.8%, and cortical blindness 4.8%. CONCLUSIONS: Visual impairment had a relatively low prevalence in this older childhood population, a large proportion of which was correctable by refraction alone.

Adolescent↗