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Biomedical subjects

Dana Robaei

Publications and source records attributed to Dana Robaei.

16 recordsLinked to original sources
PubMed2006

Factors associated with a previous diagnosis of strabismus in a population-based sample of 12-year-old Australian children.

PURPOSE: To describe the prevalence of strabismus and factors associated with its diagnosis in a representative sample of older Australian children. DESIGN: Cross-sectional, population-based study. METHODS: A representative stratified random cluster sample of 2353 children (aged 12 years) attending 21 secondary schools in Sydney, Australia was examined in 2004 to 2005 (response 75.3%). Cover testing was performed at near (30 cm) and distance (6 m); cycloplegic autorefraction, visual acuity, and stereoacuity were assessed. Previous strabismus diagnosis was obtained from parental questionnaires. RESULTS: Strabismus was evident in 64 children (2.7%); 21 (33%) had esotropia, 27 (42%) had exotropia, and 16 (25%) had microstrabismus. There were no gender (P = .2) or ethnicity (P = .6) associations. Previous diagnosis by an eye practitioner was noted in 27 (42%). This was related to hyperopia (P = .04), esotropia (P = .001), and amblyopia (P = .001). CONCLUSIONS: Strabismus was relatively infrequent in this Australian childhood sample. Its diagnosis was strongly related to presence of esotropia, hyperopia, and amblyopia.

Child↗
PubMed2006

Refractive error and patterns of spectacle use in 12-year-old Australian children.

PURPOSE: To document the prevalence of visual impairment resulting from refractive error and to describe patterns of spectacle use in a representative sample of 12-year-old Australian school children. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Two thousand three hundred fifty-three predominantly 12-year-old children examined from 2004 through 2005. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity (VA) was measured unaided and with spectacles if worn. Subjective refraction, cycloplegic autorefraction (with cyclopentolate), and detailed dilated fundus examination were performed. MAIN OUTCOME MEASURES: Myopia was defined as spherical equivalent (SE) refraction < or =-0.50 diopters (D), hyperopia as SE refraction > or =2.0 D, and astigmatism as cylinder > or =1.0 D. Uncorrected visual impairment was defined using unaided VA, and presenting visual impairment was defined using spectacle-corrected VA, if worn. Visual impairment was defined as VA <20/40 (<40 logMAR letters) for both better and worse eyes. Spectacle need was defined as uncorrected visual impairment in the better eye, improving by at least 2 lines with refraction, and undercorrection as presenting impairment in the better eye, improving by at least 2 lines with refraction. RESULTS: Uncorrected and presenting visual impairment in at least 1 eye because of refractive error was found in 10.4% and 3.7%, respectively. Spectacle use was reported by 448 children (19.0%); 204 (46.3%) had myopia, 48 (10.9%) had hyperopia, and 96 (21.8%) had astigmatism in at least 1 eye; 38.3% had no significant refractive error in either eye. Eight children were in need of spectacles and 37 children (8.3% of spectacle users) were undercorrected. Nonrefractive spectacle users were more likely to report eyestrain and headache or to have had learning difficulty at school (P<0.0001). CONCLUSIONS: This study documents a relatively low prevalence of undercorrected refractive error in a population of Australian children. Nonrefractive prescription of spectacles is common.

Adolescent↗
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

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

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↗
PubMed2006

Prevalence of eye disorders in young children with eyestrain complaints.

PURPOSE: To determine whether eyestrain symptoms predict eye conditions in 6-year-old children. DESIGN: Cross-sectional population-based study. METHODS: Reports of eyestrain symptoms were sought in parental questionnaires; 1740 children (79% response) underwent eye examinations (visual acuity, cover testing, cycloplegic autorefraction, and fundus examination). RESULTS: Eyestrain information was available for 1448 children; 220 (15.2%) reported eyestrain symptoms, including 60 (3.4%) who reported near work-associated headaches. Most children (82.3%) had a normal eye examination, while refractive errors, amblyopia, and strabismus were found in 15.0%, 3.6%, and 7.3%, respectively. Corresponding rates for children without eyestrain were 9.9%, 1.4%, and 1.8%, respectively. Moreover, 78.7% of children with refractive errors, 68% with amblyopia, and 58% with strabismus reported no eyestrain. CONCLUSIONS: Most children complaining of eyestrain had a normal eye examination; whereas most children with refractive error, amblyopia, or strabismus were free of eyestrain, making this complaint a poor marker of eye conditions in young children.

Asthenopia↗
PubMed2006

Patterns of eyecare utilization by young Australian children: findings from a population-based study.

OBJECTIVES: To report factors associated with childhood eyecare utilization in a random sample of 1740 Sydney schoolchildren aged 6, examined during 2003-4. METHODS: Information on use of eyecare services, defined as any previous consultation with an ophthalmologist or optometrist, was sought from parents. Children had comprehensive eye examinations, including visual acuity (VA), cover testing, cycloplegic refraction and dilated fundus examination. RESULTS: Prior ophthalmic or optometric assessment was reported by 465 children (29.2%), and was not associated with gender (p = 0.9), parental employment (p = 0.4) or home ownership (p = 0.9). Children of East Asian (odds ratio, OR, 0.7, 95% confidence interval, CI, 0.5-0.9) or other ethnicities (OR 0.7, CI 0.6-1.0) were less likely than European Caucasian children to have been examined. Parent-expressed concern about their child's vision was associated with a 10-fold increased likelihood of previous eye examination (OR 10.2, CI 7.3-14.5). Complaints of eyestrain were associated with a 4-fold increase (OR 4.4, CI 3.2-5.9). Most children with VA < 20/40 in at least one eye (63.1%), amblyopia (80.0%) or strabismus (86.4%) had been assessed. CONCLUSIONS: One third of this childhood sample reported prior examination by an eyecare professional. Given that most children needing vision assessment had been examined and likely effects of parental motivation, this rate seems reasonable and appropriate.

Australia↗
PubMed2005

Numerical confusion errors in ishihara testing: findings from a population-based study.

PURPOSE: To describe the prevalence of numerical confusion errors in Ishihara testing in a representative sample of Australian children. DESIGN: Cross-sectional, population-based study. METHODS: The Sydney Myopia Study examined a representative stratified random cluster sample of 1,741 children (aged 6 years) attending 34 schools in Sydney, Australia (response rate, 78.9%), including color vision tests in 1,735 children. Those with any color vision defects (n = 33; 1.9%; 97% boys) were excluded. Responses for each Ishihara plate were recorded. RESULTS: Numerical confusion errors were made by 75.8% of children with normal color vision; there was no gender difference. Plates 3 and 7 were particularly prone to numerical confusion errors; 48.4% and 40.8%, respectively, of children misread these plates. CONCLUSION: Numerical confusion errors in the Ishihara test were relatively common in children with normal color vision. The frequency of such errors could indicate an inherent deficiency in this commonly used test.

Child↗
PubMed2005

Impact of birth parameters on eye size in a population-based study of 6-year-old Australian children.

PURPOSE: To study the effect of birth parameters, including birth weight, birth length, and birth head circumference on ocular dimensions in 6-year-old children. DESIGN: Cross-sectional study. METHODS: A stratified random cluster sample of 6-year-old Sydney school-students (n = 1765) were participants in this study. Children had ocular dimensions measured with non-contact methods (Zeiss IOLMaster, Zeiss, Meditec-AG, Jena, Germany). Information on birth weight, height, and head circumference was derived from a questionnaire. RESULTS: After adjusting for cluster, age, and gender, children with birth weight <2500 g had mean axial length 22.46 mm (95% confidence interval [CI], 22.20-22.72) and mean corneal radius 7.70 mm (CI 7.61-7.79). This compared with axial length 22.80 mm (CI 22.70-22.90) and mean corneal radius 7.85 mm (CI 7.81-7.89) for children with birth weight > or =4000 g. Axial length and corneal radius were also related to birth length and head circumference. Refraction, however, was unrelated to birth size. CONCLUSION: Birth parameters have a lasting effect on eye size but not on spherical equivalent refraction.

Biometry↗
PubMed2005

Accuracy of the Lang II stereotest in screening for binocular disorders in 6-year-old children.

PURPOSE: To assess the accuracy of the Lang II stereotest in screening for strabismus, amblyopia, and anisometropia in 6-year-old children. DESIGN: Cross-sectional population-based study. METHODS: The Sydney Myopia Study examined 1765 6-year-old children (78.9% of eligible) who were identified by random cluster sampling of 34 schools in Sydney, Australia. Sensitivity and specificity of the Lang II stereotest was determined by best stereoacuity. Cycloplegic autorefraction, assessment of visual acuity, and ocular motility were conducted. RESULTS: Test sensitivity ranged from 21.4% for anisometropia (> or =1.0 diopter) to 31.3% for amblyopia. The detection rate for new cases of amblyopia ranged from 20% to 40%; the detection rate for new cases of strabismus was 30%. Specificity was >98% in all three conditions. Children with false-negative results included newly diagnosed cases of strabismus (14 of 25 children) or amblyopia (5 of 12 children). CONCLUSION: The Lang II stereotest, when used alone, has very limited value as a screening test of binocular dysfunction.

Amblyopia↗
PubMed2005

Patterns of spectacle use in young Australian school children: findings from a population-based study.

PURPOSE: To describe the patterns of spectacle use in a population-based sample of Australian Year 1 school children (mostly aged 6 years). METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction, and using spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Visual impairment was defined as visual acuity <40 logMAR letters (ie, <20/40 Snellen equivalent). Myopia was defined as spherical equivalent (SE) refraction < or = -0.50 diopters (D), and hyperopia as SE refraction > or = +2.0D, deemed significant when > or = +3.0D. Astigmatism was defined as cylinder > or =1.0D and anisometropia as SE refraction difference between the two eyes at least 1.0D. RESULTS: One thousand seven hundred forty predominantly 6-year-old school children were examined during 2003 to 2004. Spectacle use was documented in 77 children (4.4% of sample). Uncorrected visual impairment was found in the worse eye of 71 children (4.1%) and refractive error accounted for the majority (69.0%). Astigmatism was the most common refractive error causing visual impairment, accounting for 46.5%. Hyperopia, with or without astigmatism, was the most frequent reason for spectacle use, documented in 40.3%. Spectacle use in the absence of significant refractive error, amblyogenic risk factors, or visual impairment was noted in 26 children (33.8% of spectacle wearers). The prescription of spectacles could have benefited a further 26 children (1.5% of sample), mostly for correction of astigmatism. CONCLUSION: This study documents a significant disparity between spectacle use and need. Astigmatism was the most common cause of visual impairment due to refractive error.

Child↗
PubMed2005

Visual acuity and the causes of visual loss in a population-based sample of 6-year-old Australian children.

PURPOSE: To describe the distribution of visual acuity and causes of visual loss in a representative sample of Australian schoolchildren. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One thousand seven hundred thirty-eight predominantly 6-year old children examined during 2003 to 2004. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction and with spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. MAIN OUTCOME MEASURES: Visual impairment was defined as any (visual acuity <20/40; <40 letters) or severe (visual acuity < or =20/200; 0-5 letters) for both better and worse eyes. Myopia was defined as spherical equivalent (SE) refraction < or =-0.50 diopters (D), and hyperopia as SE refraction > or =+2.0 D, deemed significant when > or =+3.0 D. Astigmatism was defined as cylinder > or =1.0 D and anisometropia as SE refraction difference between eyes at least 1.0 D. Amblyopia was defined as corrected visual acuity <0.3 logMAR units (<20/40; <40 letters) in the affected eye not attributable to any underlying structural abnormality of the eye or visual pathway, together with a 2-logMAR line difference between the eyes and presence of an amblyogenic risk factor. RESULTS: The mean visual acuity of this sample was 20/25 (49.3 letters). Uncorrected visual impairment was found in the better eye of 23 children (1.3%) and in the worse eye of 71 children (4.1%). The prevalence was higher in girls than boys and among children of lower socioeconomic status. Refractive error was the most frequent cause, accounting for 69.0%, followed by amblyopia (22.5%). Astigmatism was the principle refractive error causing visual impairment and was frequently uncorrected. Presenting visual impairment (using current glasses if worn) was found in the better and worse eyes of 15 children (0.9%) and 54 children (2.8%), respectively. This was mainly due to under corrected or uncorrected refractive error. CONCLUSIONS: This study has documented a relatively low prevalence of visual impairment in a population of Australian children. Uncorrected astigmatism and amblyopia were the most frequent causes.

Child↗
PubMed2005

Distribution of ocular biometric parameters and refraction in a population-based study of Australian children.

PURPOSE: To study the distribution of spherical equivalent refraction and ocular biometric parameters in a young Australian population. METHODS: Noncontact methods were used to examine ocular dimensions and cycloplegic autorefraction in a stratified random cluster sample of year 1 Sydney school students (n = 1765), mean age 6.7 years (range, 5.5-8.4 years). Repeated measures of axial length, anterior chamber depth, and greatest and least corneal radius of curvature (CR1, CR2, respectively) were taken in each eye. Refraction was measured as the spherical equivalent. RESULTS: Mean spherical equivalent refraction in right eyes was +1.26 +/- 0.03 D (SEM; range, -4.88 to +8.58). The distribution was peaked (kurtosis 14.4) and slightly skewed to the right (skewness, 1.7). Prevalence of myopia, defined as spherical equivalent refraction < or = -0.5 D, was 1.43% (95% CI, 0.94-2.18) in the overall population. Axial length, anterior chamber depth, and corneal radii of curvature were normally distributed. The mean axial length in right eyes was 22.61 +/- 0.02 mm (SEM; range, 19.64-25.35). The mean anterior chamber depth was 3.34 +/- 0.01 mm (SEM; range, 2.14-4.06). Mean CR1 was 7.85 +/- 0.01 mm (SEM) and mean CR2 was 7.71 +/- 0.01 mm (SEM). The distribution of axial length/mean corneal radius ratio was peaked (leptokurtic) with a mean of 2.906. Mean axial length was longer, anterior chambers were deeper, and corneas were flatter in the boys. CONCLUSIONS: A peaked (leptokurtic) distribution of spherical equivalent refraction was present in this predominantly hyperopic 6-year-old population. The results also showed that ocular biometric measures were normally distributed, with statistically significant gender differences found in measurements.

Adolescent↗
PubMed2005

Effect of stature and other anthropometric parameters on eye size and refraction in a population-based study of Australian children.

PURPOSE: To determine the effect of anthropometric parameters on refraction and ocular biometry. METHODS: Noncontact methods were used to examine ocular dimensions and cycloplegic refraction in a stratified random cluster sample of year-1 Sydney school students (mean age, 6 years; n = 1765). Height, body weight, and waist circumference were measured according to a standardized protocol. Body mass index (BMI) was subsequently calculated. The percentage of body fat was measured with leg-leg bioelectrical impedance analysis. Associations between parameters were analyzed by multiple linear regression. RESULTS: After adjustment for age in weeks, height was found to be strongly associated with axial length and corneal radius. Children in the 1st quintile for height had axial length of 22.39 +/- 0.04 mm compared with 22.76 +/- 0.04 mm in children in the 5th quintile. Other anthropometric parameters were not associated with axial length or corneal radius. Height was not associated with anterior chamber depth after adjustment for weight. Increases in weight, BMI, and waist circumference were associated with a deeper anterior chamber after adjustment for height. No associations were found between the measured anthropometric parameters and refraction or axial length-corneal radius ratio. CONCLUSIONS: This study found a strong association between height and axial length and corneal radius, but not spherical equivalent refraction. The findings may demonstrate the effectiveness of emmetropization in the presence of normal physiological influences.

Anterior Chamber↗