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Epizootics of sudden death in tammar wallabies ( Macropus eugenii) occurred at six research facilities and zoological gardens in New South Wales, Australia, in late 1998 and at one Queensland research facility in March 1999. There were 120 confirmed tammar wallaby deaths during this period; however, population censuses indicated that up to 230 tammar wallabies may have died. The majority of animals died without premonitory signs. A small proportion of wallabies exhibited increased respiratory rate, sat with a lowered head shortly before death or were discovered in lateral recumbency, moribund and with muscle fasciculations. Gross postmortem findings consistently included massive pulmonary congestion, mottled hepatic parenchyma and subcutaneous oedema throughout the hindlimbs and inguinal region. Approximately 30% of the animals examined also had extensive haemorrhage within the fascial planes and skeletal muscle of the hindlimb adductors, inguinal region, ventral thorax, dorsal cervical region and perirenal retroperitoneal area. The tissues of affected animals became autolytic within a short period after death. Bacteriological examination of tissues from 14 animals did not provide any significant findings. Toxicological examination of the gastric and colonic contents of four animals did not reveal evidence of brodifacoume or other rodenticides. Viruses from the Eubenangee serogroup of the Orbivirus genus were isolated from the cerebral cortex of nine, and the myocardium of two, tammar wallabies and the liver and intestine of another tammar wallaby. A similar orbivirus was also isolated from the cerebrospinal fluid of another tammar wallaby that died suddenly. The disease agent appears to be a previously unrecognised orbivirus in the Eubenangee serogroup. This is the first report of epizootics of sudden deaths in tammar wallabies apparently associated with an orbivirus infection. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to investigate universality of access, screening rate, and outcomes from the New South Wales (NSW) Statewide Eyesight Preschooler Screening (StEPS) over the period of 2009 to 2016., Design: Cross-sectional, observational study., Methods: The StEPS program provides vision screening to 4-year-old children residing in NSW and is administered within Local Health Districts (LHDs). Visual acuity (VA) was examined by trained lay and nurse screeners using HOTV logMAR. Children who had VA <6/9-2 were referred to local practitioners while those with VA <6/18 were referred to public hospital pediatric ophthalmic outpatient clinics where available. Activity data were collected by NSW Health and screening rates determined from population projections of 4-year-olds per LHD based on adjusted 2014 Census data. To determine factors impacting screening and referral rates, a random effects panel analysis was undertaken., Results: A total of 719,686 (96.4%) NSW 4-year-old children were offered StEPS vision screening between 2009 and 2016, 84% accepted and 564,825 children (75.6%) were screened. The screening rate increased from 67.3% in 2009 to 74.5% in 2016, with an 80% target reached for 3 consecutive years from 2013 to 2015. Of those screened, 19.2% were referred to an eye health professional or advised to have a vision retest in 12 months. This referral rate remained steady over the period studied, with little variation between metropolitan, and rural and regional LHDs., Conclusions: StEPS is an ideal service model for preschool vision screening providing coverage that is comparable to school-based screening programs and at an age likely to facilitate optimal treatment outcomes., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Asia-Pacific Academy of Ophthalmology. Published by Wolters Kluwer Health, Inc. on behalf of the Asia-Pacific Academy of Ophthalmology.)

Purpose: To provide population-based normative visual acuity (VA) by age, in children participating in the Sydney Paediatric Eye Disease Study aged 6 to <72 months., Methods: Monocular VA was measured using the Amblyopia Treatment Study (ATS HOTV) protocol (24 to <72 months). Some children were also tested using linear ETDRS or HOTV logMAR VA charts (30 to <72 months). If unable to perform recognition acuity, the Teller Acuity Cards II (TAC II) was performed (6 to <42 months). Children with significant refractive error or ocular disease were excluded., Results: Improvement in VA with age was shown on all three vision tests (all p < 0.0001). Mean VA using ATS HOTV (n = 836) was 0.13 logMAR (6/8) at <36 months, which improved to -0.01 (6/6) at 66 to <72 months. Mean ETDRS/HOTV (n = 399) VA was 0.26 logMAR (6/11) at <36 months, which improved to 0.1 (6/7.5) at 66 to <72 months. Mean monocular TAC II (n = 442) was 5.7 cycles/degree (0.72 logMAR) at 6 to <9 months and improved to 12.4 cycles/degree (0.38 logMAR) at age 30 to <33 months. Associations with ATS HOTV VA included prematurity (p = 0.027) and socio economic status (SES) factors such as home ownership (p = 0.039) and employment of one (p = 0.019) or both parents (p = 0.003)., Conclusions: VA norms in children improved with age and were different according to the VA test used. Low SES was associated with poorer VA, supporting the need for test specific VA norms to be established for different populations. The ATS HOTV appears to be the best test to use for vision screening due to its lower false positive referral rate., (© 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To determine the prevalence, incidence, and change in refractive errors for Australian schoolchildren and examine the impact of ethnicity and sex., Design: Population-based cohort study., Participants: The Sydney Adolescent Vascular and Eye Study, a 5- to 6-year follow-up of the Sydney Myopia Study, examined 2760 children in 2 age cohorts, 12 and 17 years. Longitudinal data were available for 870 and 1202 children in the younger and older cohorts, respectively., Methods: Children completed a comprehensive examination, including cycloplegic autorefraction (cyclopentolate 1%; Canon RK-F1). Myopia was defined as ≤-0.50 diopters (D) and hyperopia as ≥+2.00 D right eye spherical equivalent refraction., Main Outcome Measures: Baseline and follow-up refraction., Results: Prevalence of myopia increased between baseline and follow-up for both the younger (1.4%-14.4%; P<0.0001) and older cohorts (13.0%-29.6%; P<0.0001). The annual incidence of myopia was 2.2% in the younger cohort and 4.1% in the older. Children of East Asian ethnicity had a higher annual incidence of myopia (younger 6.9%, older 7.3%) than European Caucasian children (younger 1.3%, older 2.9%; all P<0.0001). The prevalence of myopia in European Caucasian children almost doubled between the older (4.4%; 95% confidence interval [CI], 3.0-5.8) and younger samples (8.6%; 95% CI, 6.7-10.6) when both were aged 12 years. Children with ametropia at baseline were more likely to have a significant shift in refraction (hyperopia: odds ratio [OR], 3.4 [95% CI, 1.2-9.8]; myopia: OR, 6.3 [95% CI, 3.7-10.8]) compared with children with no refractive error. There was no significant difference in myopia progression between children of European Caucasian and East Asian ethnicity (P = 0.7)., Conclusions: In Sydney, myopia prevalence (14.4%, 29.6%) and incidence (2.2%, 4.1%) was low for both age cohorts, compared with other locations. However, in European Caucasian children at age 12, the significantly higher prevalence of myopia in the younger sample suggests a rise in prevalence, consistent with international trends. Progression of myopia was similar for children of East Asian and European Caucasian ethnicity, but lower than reported in children of East Asian ethnicity in East Asia, suggesting that environmental differences may have some impact on progression., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To examine the patterns of myopigenic activity (high near work, low time outdoors) in children growing up in Sydney, Australia, by age, ethnicity and gender., Methods: The Sydney Adolescent Vascular and Eye Study (SAVES) re-examined children from the two age cohorts (6 and 12 years at baseline) from the Sydney Myopia Study (SMS). At 5-6 year follow-up, 863 in the younger cohort and 1196 in the older cohort had complete refraction data. Cycloplegic autorefraction (cyclopentolate 1%; Canon RK-F1) was measured at baseline and follow-up. Children who became myopic (≤-0.50 dioptres spherical equivalent refraction) were those classified as non-myopic at baseline and myopic at follow-up. A detailed questionnaire was administered to measure weekly activities, including time spent outdoors and near work at both baseline and follow-up examination., Results: Overall, 128 (14.8%) children in the younger cohort and 210 (17.6%) in the older cohort became myopic. At follow-up, for both cohorts, children had significantly reduced the amount of time spent outdoors (younger cohort, p = 0.001, older cohort, p < 0.0001) and increased near work time (younger cohort, p < 0.0001, older cohort, p = 0.006). Children of East Asian ethnicity spent significantly less time outdoors by more than 7 h per week (both cohorts at baseline and follow-up, all p < 0.0001) and more time in near work activities by close to 3 h compared to European Caucasian children at all ages examined (both cohorts at baseline and follow-up all, p < 0.03). The average pattern of activity for girls differed from that of boys in a similar way (both cohorts at baseline and follow-up all, p < 0.0001). The two independent samples of 12 year-old children provided by follow-up in the younger cohort and baseline in the older cohort gave very similar answers to the questionnaire, with significant differences only evident for computer use (p = 0.001) and books read (p < 0.0001)., Conclusions: Answers to the activity questionnaire were very similar in the two cohorts of 12 year-olds, suggesting that the questionnaire gives reproducible answers. However, further work is required for validation. Children's pattern of activities become more myopigenic with age, and differed by gender and by ethnicity at all ages, with girls having a more myopigenic activity pattern than boys, and children of East Asian ancestry having a more myopigenic activity pattern than European Caucasian children., (Ophthalmic & Physiological Optics © 2013 The College of Optometrists.)

Aim: To establish the range of normal stereoacuity thresholds and evaluate the diagnostic reliability of stereoacuity tests in preschool-aged children., Methods: 1606 children, aged 24-72 months, had detailed eye examinations and stereoacuity testing. Lang-Stereotest II (LangII) was attempted on all children, Stereo Smile Stereoacuity II Test (SSST) was conducted on children aged < 30 months and on older children who could not complete the Randot Preschool Stereoacuity Test (RPST). The RPST was conducted on children aged ≥ 30 months and on some younger children who passed both the LangII and SSST., Results: Modes for the age groups 24-47 months and 48-72 months were: 200 arcsec for both age groups with the LangII test; 120 arcsec and 60 arcsec, respectively, with the SSST; 100 arcsec and 60 arcsec, respectively, with the RPST. Age-adjusted areas under the curve for detecting amblyopia, strabismus and anisometropia were: for the LangII test, 0.72, 0.68 and 0.60, respectively; for the SSST, 0.73, 0.80 and 0.57, respectively; for the RPST, 0.92, 0.82 and 0.73, respectively., Conclusions: Normative data for the LangII, RPST and SSST stereoacuity tests were determined for children aged 24-72 months. Sensitivity and specificity at individual disparity levels for detecting anisometropia, amblyopia and strabismus were also determined for RPST and SSST. Using area under age-adjusted receiver operating curves, the RPST was found to be the most reliable in detecting ocular conditions compared with the LangII and SSST tests.

Purpose: To compare refraction and ocular biometry in European Caucasian children aged 6 to 7 years and 12 to 13 years, living in Sydney, Australia, and Northern Ireland., Methods: All children had a comprehensive eye examination, including cycloplegic (cyclopentolate 1%) autorefraction and ocular biometry. Hyperopia was defined as a right spherical equivalent refraction (SER) of ≥+2.00 diopters (D), myopia as ≤-0.50 D, and astigmatism as a cylindrical error of ≥1.00 D., Results: The mean SER was similar at age 6 to 7 years (P = 0.9); however, at 12 to 13 years, children in Northern Ireland had a significantly less hyperopic mean SER (+0.66 D) than children in Sydney (+0.83 D, P = 0.008). The prevalence of myopia, hyperopia, and astigmatism was significantly greater in Northern Ireland than Sydney at both ages (all P < 0.03). The distribution of refraction was highly leptokurtic in both samples, but less so in Northern Ireland (kurtosis: 6-7 years of age, 7.2; 12-13 years of age, 5.9) than Sydney (kurtosis: 6-7 years of age, 15.0; 12-13 years of age, 19.5)., Conclusions: European Caucasian children in Northern Ireland have a greater prevalence of myopia, hyperopia, and astigmatism when compared to children living in Sydney. Risk factors for myopia such as parental myopia, parental education, and educational standards do not appear to explain the differences. Further work on levels of near work and time spent outdoors is required.

Purpose: To determine the testability and lower age limits for applying common eye tests to preschool children., Methods: Investigators from the Sydney Paediatric Eye Disease Study examined 2,461 children aged 6 to 72 months between 2007 and 2009. Cycloplegic autorefraction was measured with Retinomax and Canon autorefractors. Ocular biometry was measured by the use of IOLMaster in children aged >30 months. The Randot Preschool Stereoacuity test, Lang-Stereotest II, and the Stereo Smile II test were administered to assess stereoacuity. Fundus photography was performed with the subjects' pupils dilated. Testability was defined as the ability to successfully complete tests in both eyes., Results: There were 2,189 children with complete data. Most were testable with the Retinomax (71.8%) and Canon (66.0%) autorefractors. Testability improved with age (P for trend <0.0001) for both, and Retinomax achieved >70% testability when a subject was 24 months of age, half the age limit (48 months) found for Canon. IOLMaster was mostly testable in children aged 48+ months. Lang-Stereotest II could be used in children aged 6 months and achieved the greatest testability (94.4%) of all stereotests. White children performed better than children of some other ethnicities on Randot (P = 0.007), with girls performing better than boys (P = 0.01). Bilateral photography was achieved in >70% of preschool children 48 months of age., Conclusions: The testability of all measures was strongly age related, with mostly no sex or ethnicity effects found. The handheld Retinomax could be tested in >70% of children aged 24 months, younger than that found for the stationary Canon autorefractor (48 months). Testability measures for most eye tests in this preschool sample are comparable to other preschool studies., (Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: To determine the prevalence of and factors associated with amblyopia in a sample of Australian preschool children., Design: Population-based, cross-sectional study., Participants: The Sydney Paediatric Eye Disease Study examined 2461 (73.8% participation) children aged between 6 and 72 months from 2007 to 2009., Methods: Visual acuity (VA) was assessed in children aged ≥ 30 months using the Electronic Visual Acuity system, and a subset using the logarithm of the minimum angle of resolution chart. Amblyopia was categorized into unilateral and bilateral subtypes: Unilateral amblyopia was defined as a 2-line difference in reduced VA between the 2 eyes, in addition to strabismus, anisometropia, and/or visual axis obstruction; bilateral amblyopia was defined as bilateral reduced VA with either bilateral visual axis obstruction or significant bilateral ametropia. Information on ethnicity, birth parameters, and measures of socioeconomic status were collected in questionnaires completed by parents., Main Outcome Measures: Amblyopia., Results: We included 1422 children aged 30 to 72 months, of whom 27 (1.9%) were found to have amblyopia or suspected amblyopia. Mean spherical equivalent for the amblyopic eyes was +3.57 diopters, with a mean VA of 20/50. Only 3 of the 27 amblyopic children had previous diagnoses or treatments for amblyopia. In regression analysis controlling for age, gender, and ethnicity, amblyopia was significantly associated with hyperopia (odds ratio [OR], 15.3; 95% confidence interval [CI], 6.5-36.4), astigmatism (OR, 5.7; 95% CI, 2.5-12.7), anisometropia (OR, 27.8; 95% CI, 11.2-69.3), and strabismus (OR, 13.1; 95% CI, 4.3-40.4). There were no significant associations of amblyopia with low birthweight (<2500 g), preterm birth (<37 weeks), maternal smoking, age, gender, ethnicity, or measures of socioeconomic status (all P>0.05)., Conclusions: Amblyopia was found in 1.9% of this Australian preschool sample, which is comparable with prevalence rates reported by other recent studies in preschool children. Refractive errors, particularly significant hyperopia and astigmatism, in addition to anisometropia and strabismus, were the major amblyogenic factors. There was a low amblyopia detection rate in this preschool population, which suggests that different strategies are required to improve current vision screening strategies in preschoolers., Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the prevalence and associations of visual impairment (VI) in preschool children., Design: Cross-sectional, population-based study., Participants: A total of 2461 children (73.8% participation rate), aged 6 to 72 months, were examined in the Sydney Paediatric Eye Disease Study during 2007-2009; of whom 1188, aged 30 to 72 months, with complete visual acuity (VA) data in both eyes, were included in this report., Methods: Measurement of VA was attempted on all children using the Electronic Visual Acuity (EVA) system or a logarithm of the minimum angle of resolution (logMAR) chart. Visual impairment was defined as presenting VA <20/40 in children aged ≥48 months and <20/50 in those aged <48 months. Post-cycloplegic refraction was measured, and myopia was defined as spherical equivalent (SE) ≤-0.50 diopters (D), hyperopia was defined as SE ≥2.00 D, astigmatism was defined as cylinder ≥1.00 D, and anisometropia was defined as SE difference ≥1.00 D between 2 eyes. Ethnicity, birth parameters, and sociodemographic information were collected in questionnaires completed by parents., Main Outcome Measures: Visual impairment prevalence and its associations with child demographic factors and birth parameters., Results: Visual impairment was found in 6.4% of the worse eye and 2.7% of the better eye in our sample. Refractive errors (69.7%) and amblyopia (26.3%) were the principal causes of VI in the worse eye. Astigmatism (51.3%) and hyperopia (28.9%) were the main refractive errors causing VI. In regression analysis controlling for other factors, VI was independently associated with low birthweight of <2500 g (odds ratio 2.4, 95% confidence interval, 1.1-5.3), but not with age, gender, ethnicity, or measures of socioeconomic status (P > 0.05)., Conclusions: Visual impairment in at least 1 eye was found in 6.4% of Australian preschool children, with bilateral VI found in 2.7%. Uncorrected refractive errors and amblyopia were the principal ocular conditions associated with VI. Low birthweight was a significant risk factor independent of age, gender, and ethnicity., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

AIMS To establish the prevalence of heterophoria and its association with refractive error and ethnicity in a population-based study of Australian schoolchildren. METHODS The Sydney Myopia Study is a stratified, random cluster (school-based) sample of 4093 students (examined: 2003-2005). Two samples aged 6 (n=1692) and 12 years (n=2289) without heterotropia were included. Prevalent heterophoria was assessed using cover un-cover and prism bar alternate cover testing at 33 cm and 6 m distance fixation. Cycloplegic autorefraction (1% cyclopentolate) was performed. Significant refractive error was defined as < or =-0.50SE and > or =+2.00SE. RESULTS Exophoria was highly prevalent at near fixation (age 6: 58.3%, age 12: 52.2%). Orthophoria predominated at distance fixation (age 6: 85.4%, age 12: 90.9%). Hyperopia was associated with esophoria at near (age 6: OR 1.7, 95% CI 1.1 to 2.8, age 12: OR 2.9, CI 1.1 to 2.8) and distance fixation (age 6: OR 9.7, CI 3.5 to 26, age 12: 9.6 OR, CI 4.2 to 22). Myopia was associated with exophoria at near (OR 2.1, CI 1.5 to 2.7) and distance fixation (OR 3.1, CI 2.1 to 4.4) for 12-year-old children only. Exophoria was more frequent in children of East Asian than European Caucasian origins, even after adjusting for refraction; at near (age 6: OR 1.4, CI 1.0 to 2.0, age 12: OR 1.4, CI 1.0 to 1.9) and distance (age 12: OR 1.7, CI 1.1 to 2.7). CONCLUSION Contrary to other studies, exophoria, not orthophoria, was predominant for near. Exophoria was more prevalent in children of East Asian origin. Longitudinal studies are needed to establish if incident heterotropia is preceded by heterophoria.

Purpose: To examine macular and peripapillary retinal nerve fiber layer (RNFL) thickness in amblyopia., Design: Population-based cross-sectional study., Participants: Of 4118 children examined in the Sydney Childhood Eye Study (incorporating the Sydney Myopia Study) from 34 randomly selected primary schools and 21 secondary schools from 2003 to 2005, 3529 (85.7%) were included in this analysis. The median age of the 2 samples was 6 years (n = 1395) and 12 years (n = 2134), respectively., Methods: A detailed eye examination was conducted on all children, including determination of best-corrected visual acuity (logarithm of the minimum angle of resolution [logMAR]), autorefraction (RK-F1 autorefractor, Canon, Tokyo, Japan) after cyclopentolate (1%), cover testing to identify strabismus, and optical coherence tomography (StratusOCT, Carl Zeiss Meditec, Dublin, CA) through dilated pupils to obtain macula and peripapillary RNFL thickness. Amblyopia was defined as best visual acuity <0.3 logMAR units not explained by any obvious underlying eye or visual pathway abnormalities. Anisometropia was defined as an interocular difference of at least 1.0 diopter of the spherical equivalent refraction., Main Outcome Measures: Macular and peripapillary RNFL thickness., Results: Amblyopic eyes had slightly greater foveal minimum thickness than the normal fellow eye (by 5.0 microm; 95% confidence interval 0.1-9.9) and right eyes of non-amblyopic children (by approximately 10 microm), both P<0.05. This was more pronounced in 6-year-old children (6.9 microm) than 12-year-old children (4.2 microm). Amblyopic eyes also had slightly thicker central macula (1 mm diameter region) in both comparisons, although these differences were not statistically significant. The inner macular ring (outer radius 1.5 mm) was thinner in amblyopic than normal fellow eyes. Peripapillary RNFL thickness was not significantly different between amblyopic and normal fellow eyes or normal eyes of non-amblyopic children., Conclusions: In children aged predominantly 6 and 12 years, central macular thickness may be increased in eyes with amblyopia, although it is uncertain if this precedes or follows the development of amblyopia. No differences in peripapillary RNFL thickness were found when compared with normal eyes., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

An epizootic of nontuberculous mycobacteriosis occurred in a captive herd of aoudad (Ammotragus lervia) over a period of 18 mo. Each of the affected animals was subject to a thorough postmortem examination that included histopathology, tissue concentration and acid-fast staining, aerobic and anaerobic bacterial culture, mycobacterial culture, and real-time polymerase chain reaction specific for Mycobacterium tuberculosis DNA. Histopathologic lesions consistent with pulmonary mycobacteriosis, including the presence of acid-fast bacteria, were identified in two captive adult male aoudad. M. avium was isolated in culture from the pulmonary parenchyma, and M. parafortuitum was isolated from a mesenteric lymph node of a third animal, an adult female, euthanized subsequent to an illness characterized by progressive dyspnea and tachypnea. M. intracellulare was isolated within the bronchial lymph node of a fourth aoudad, an adult female that was euthanized due to chronic weight loss. Diagnostic testing of the 34 individuals in the herd included collection of blood for an interferon-gamma assay, intradermal tuberculin testing, and radiometric fecal culture for M. avium subsp. paratuberculosis. On the basis of this investigation, mycobacteriosis associated with M. bovis, M. tuberculosis, and/or M. avium subsp. paratuberculosis was ruled out and nontuberculous mycobacteriosis was confirmed in this herd.

Objective: To assess the relationship of near, midworking distance, and outdoor activities with prevalence of myopia in school-aged children., Design: Cross-sectional study of 2 age samples from 51 Sydney schools, selected using a random cluster design., Participants: One thousand seven hundred sixty-five 6-year-olds (year 1) and 2367 12-year-olds (year 7) participated in the Sydney Myopia Study from 2003 to 2005., Methods: Children had a comprehensive eye examination, including cycloplegic refraction. Parents and children completed detailed questionnaires on activity., Main Outcome Measures: Myopia prevalence and mean spherical equivalent (SE) in relation to patterns of near, midworking distance, and outdoor activities. Myopia was defined as SE refraction < or = -0.5 diopters (D)., Results: Higher levels of outdoor activity (sport and leisure activities) were associated with more hyperopic refractions and lower myopia prevalence in the 12-year-old students. Students who combined high levels of near work with low levels of outdoor activity had the least hyperopic mean refraction (+0.27 D; 95% confidence interval [CI], 0.02-0.52), whereas students who combined low levels of near work with high levels of outdoor activity had the most hyperopic mean refraction (+0.56 D; 95% CI, 0.38-0.75). Significant protective associations with increased outdoor activity were seen for the lowest (P = 0.04) and middle (P = 0.02) tertiles of near-work activity. The lowest odds ratios for myopia, after adjusting for confounders, were found in groups reporting the highest levels of outdoor activity. There were no associations between indoor sport and myopia. No consistent associations between refraction and measures of activity were seen in the 6-year-old sample., Conclusions: Higher levels of total time spent outdoors, rather than sport per se, were associated with less myopia and a more hyperopic mean refraction, after adjusting for near work, parental myopia, and ethnicity.

Purpose: To examine the prevalence of refractive error and distribution of ocular biometric parameters among major ethnic groups in a population-based sample of 11-15-year-old Australian children., Methods: The Sydney Myopia Study examined 2353 students (75.3% response) from a random cluster-sample of 21 secondary schools across Sydney. Examinations included cycloplegic autorefraction, and measures of corneal radius of curvature, anterior chamber depth, and axial length., Results: Participants mean age was 12.7 years (range 11.1-14.4); 49.4% were female. Overall, 60.0% of children had European Caucasian ethnicity, 15.0% East Asian, 7.1% Middle Eastern, and 5.5% South Asian. The most frequent refractive error was mild hyperopia (59.4%, 95% confidence interval (CI), 53.2-65.6), defined as spherical equivalent (SE) +0.50 to +1.99 D. Myopia (SE-0.50 D or less) was found in 11.9%, 95% (CI 6.6-17.2), and moderate hyperopia (SE> or =+2.00 D) in 3.5%, 95% (CI 2.8-4.1). Myopia prevalence was lower among European Caucasian children (4.6%, 95% CI 3.1-6.1) and Middle Eastern children (6.1%, 95% CI 1.3-11.0) than among East Asian (39.5%, 95%, CI 25.6-53.5) and South Asian (31.5%, 95%, CI 21.6-41.4) children. European Caucasian children had the most hyperopic mean SE (+0.82 D) and shortest mean axial length (23.23 mm). East Asian children had the most myopic mean SE (-0.69 D) and greatest mean axial length (23.86 mm)., Conclusion: The overall myopia prevalence in this sample was lower than in recent similar-aged European Caucasian population samples. East Asian children in our sample had both a higher prevalence of myopia and longer mean axial length.

Objective: To compare the prevalence and risk factors for myopia in 6- and 7-year-old children of Chinese ethnicity in Sydney and Singapore., Methods: Two cross-sectional samples of age- and ethnicity-matched primary school children participated: 124 from the Sydney Myopia Study and 628 from the Singapore Cohort Study on the Risk Factors for Myopia. Cycloplegic autorefraction was used to determine myopia prevalence (spherical equivalent < or = -0.5 diopter). Lifestyle activities were ascertained by questionnaire., Results: The prevalence of myopia in 6- and 7-year-old children of Chinese ethnicity was significantly lower in Sydney (3.3%) than in Singapore (29.1%) (P < .001). The prevalence of myopia in 1 or more parents was 68% in Sydney and 71% in Singapore. Children in Sydney read more books per week (P < .001) and did more total near-work activity (P = .002). Children in Sydney spent more time on outdoor activities (13.75 vs 3.05 hours per week; P < .001), which was the most significant factor associated with the differences in the prevalence of myopia between the 2 sites., Conclusions: The lower prevalence of myopia in Sydney was associated with increased hours of outdoor activities. We hypothesize that another factor contributing to the differences in the prevalence of myopia may be the early educational pressures found in Singapore but not in Sydney.

Aims: To report prevalence of amblyopia and long-term impact of its treatment on vision in a population-based sample of 12-year-old Australian children., Methods: Logarithm of minimum angle of resolution (logMAR) visual acuity (VA) was measured in 2353 children (response rate 75.3%); visual impairment was defined as VA<6/12. Amblyopia was defined using various criteria of best-corrected VA, together with an amblyogenic factor and absence of significant organic pathology. Corroborative historical data on previous diagnosis and treatment were obtained from parental questionnaires., Results: Forty-four children (1.9%) were diagnosed with amblyopia, unilateral in 40 and bilateral in four. Isolated anisometropia was the most frequent cause (41%), followed by strabismus (25%), combined anisometropia and strabismus (23%), and high ametropia (9%). Myopia, hyperopia, and astigmatism were present in 28, 51, and 44% of amblyopic children, respectively, compared to 12, 4, and 9% of non-amblyopic children. Mean best-corrected VA in amblyopic eyes was 44.5 logMAR letters (Snellen equivalent 6/9), range: 11-60 letters. Most children with amblyopia (84%) had been treated. Only 27% were visually impaired in their amblyopic eye., Conclusions: This report documents a low amblyopia prevalence in a population of 12-year-old Australian children. Amblyopic visual impairment was infrequent in this sample despite absence of mandatory vision screening.

Purpose: To compare the distribution of spherical equivalent refraction (SER) and other ocular parameters and to assess the contribution from oculometric parameters to SER in two age-specific, cross-sectional samples of children, and in two ethnic groups (European Caucasian and East Asian)., Methods: A random-cluster design was used to recruit predominantly 6-year-old (1765 participants, 78.9% response) and 12-year-old children (2353 participants, 75.3% response) from schools across Sydney, Australia. Data collection included questionnaires and eye examination (keratometry, biometry, and cycloplegic autorefraction). Results of three analytical methods (Pearson correlation, partial correlation coefficient, and linear regression analyses) are reported for 6- and 12-year-old children., Results: Kurtosis for SER and axial length (AL) in the 12-year-old children (14.3 and 2.1, respectively) was similar to that previously reported for the 6-year-old children (11.3 and 0.5). AL showed high correlation (r) with SER in the 6- (r = -0.44) and 12-year-old (r = -0.61) children. Lower correlations for SER with corneal radius (r

Purpose: To examine the impact of parental astigmatism on astigmatic error and ocular biometric parameters in children., Design: Population-based cross-sectional study., Methods: Six-year-old children (n = 1,741; 78.9% response) and 12-year-old children (n = 2,367; 75.3% response) underwent a comprehensive eye examination, including cycloplegic autorefraction and ocular biometry. Astigmatism was determined in parents from spectacle prescriptions, which were supplied for 468 children., Results: The prevalence of astigmatism in six-year-old children with astigmatic parents was not significantly different from that of those without astigmatic parents (6.8% vs 2.8%); corresponding rates for 12-year-old children were 9.5% and 7.8% (both P > .05). No significant differences in mean cylinder and in ocular biometric parameters were observed between children with astigmatic parents and those with no astigmatic parents., Conclusions: Parental astigmatism was not associated with a higher prevalence of childhood astigmatism and did not seem to have a significant impact on measures of ocular biometric parameters in children.

Purpose: To examine the influences of ethnicity, parental myopia, and near work on spherical equivalent refraction (SER) and axial length (AL) in a population-based sample of 12-year-old Australian children., Methods: Year-7 children in the Sydney Myopia Study (n = 2353, 75.3% response) underwent an ophthalmic examination including cycloplegic autorefraction (1% cyclopentolate) and ocular biometry (IOLMaster; Carl Zeiss Meditec GmbH, Jena, Germany). Data for parental myopia, ethnicity, near work, and outdoor activities were derived from questionnaires and were available for 1781 children. Optical prescriptions of parents were sought if the spectacles were used., Results: The prevalence of myopia in the children increased with the number of myopic parents (7.6%, 14.9%, and 43.6% for no, one, or two myopic parents). In parallel, the mean SER (+/-SE of the mean) was more negative (0.70 +/- 0.08, 0.34 +/- 0.09, and -0.55 +/- 0.34 D), and the mean AL was longer (23.32 +/- 0.05, 23.44 +/- 0.06, and 23.62 +/- 0.16 mm) after adjustment for demographic and environmental factors. In multivariate analyses, odds of childhood myopia did not change with higher levels of near work (odds ratio [OR] = 1.01; 95% confidence interval [CI] = 0.99-1.03). Interactions between parental myopia and ethnicity were significant for SER and AL (both P < 0.0001), reflecting greater decreases in SER and greater increases in AL with the number of myopic parents in the children of East Asian ethnicity than in the children of European Caucasian ethnicity. In the nonmyopic children, there was no association between parental myopia and AL., Conclusions: In this sample, parental myopia was associated with more myopic SER and longer AL, with significant ethnic interactions.

Purpose: To study the distributions of refractive (RA), corneal (CA), and internal astigmatism (IA) in 12-year-old Australian children and to explore differences from previous findings in 6-year-old children., Methods: Eligible year 7 students (2353/3144 [75.3%], median age, 12 years) from a random cluster sample of 21 high schools in Sydney, Australia, were examined by keratometry, cycloplegic autorefraction, and review of questionnaire data., Results: Prevalence rates of RA, CA, and IA > or =1.0 D in right eyes were 6.7% (95% confidence interval [CI], 5.0-8.4), 26.6% (CI, 22.1-31.1), and 26.5% (CI, 22.9-30.0), respectively. RA was predominantly with-the-rule (WTR; 40.4%, CI, 32.6 to 48.2) and against-the-rule (ATR; 43.6%, CI, 35.7-51.5), CA was WTR (88.8%, CI, 86.3-91.3), and IA was ATR (90.2%, CI, 87.8-92.6). The girls had significantly greater CA and IA prevalence, with greater ATR astigmatism and lower oblique IA than did the boys. The European white-Australian children had lower CA prevalence than did the East Asian-Australian children and higher IA prevalence than did the South Asian-Australian children. Ethnic differences in RA prevalence were not significant, when adjusted for confounders. RA was more frequently ATR in European white than in other ethnic groups. Compensation between CA and IA reduced the magnitude of RA. Comparison with the data on 6-year-old children revealed minimal differences for all astigmatic components., Conclusions: There was a relatively low prevalence of RA, due to compensation between CA and IA. The minimal differences in all components of astigmatism between the two age cohorts suggest that astigmatism is stable between ages 6 and 12 years, although this conclusion needs to be confirmed in longitudinal studies.

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.

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.

Purpose: The purpose of the present study was to report the prevalence of refractive (RA), corneal (CA), and internal astigmatism (IA) in a population of 6-year-old children; examine their variation with gender, ethnicity, and refraction; and examine the effects of gender, ethnicity, and spherical equivalent refraction on the relationship between CA and RA in this population., Methods: The Sydney Myopia Study is a population-based survey of refraction and eye health in 6-year-old children. A random cluster design was used to recruit children from schools across Sydney, Australia, during 2003 to 2004. Data collection used a detailed questionnaire and comprehensive eye examination. Keratometric and cycloplegic autorefraction data from right eyes were analyzed., Results: Of 2238 eligible children, 1765 (78.9%; 50.7% boys) had parental consent to participate. Overall prevalence of RA (> or =1.0 diopter [D]) was 4.8% (95% confidence interval [CI] 3.8%-6.1%), CA (> or =1.0 D) 27.7% (CI 23.8%-32.3%), and IA (> or =1.0 D) 21.1% (CI 19.0%-23.5%). The RA axis was fairly evenly distributed, with predominance of oblique axis (39.1%; CI 35.9%-42.6%). CA axis was mainly with the rule (75.1%; CI 72.6%-77.8%), while IA axis was mainly against the rule (76.7%; CI 74.2%-79.3%). After adjustment for multiple variables, girls had significant, marginally greater mean CA and IA than boys. East Asian and South Asian children had significantly greater prevalence and mean RA and CA than European Caucasian children. There were no significant ethnic differences of mean IA. Compared to reference (spherical equivalent [SEq] 1.01-1.50 D), mean RA and CA increased significantly with more hyperopic and more myopic refractions. Mean IA was significantly greater only for hyperopic refractions (SEq > 2.00 D)., Conclusions: The prevalence of astigmatism found in this population of 6-year-old children was relatively low, and showed significant variation with ethnicity. The data suggest that emmetropization for RA occurs by a compensatory process between CA and IA.

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.

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.

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.

Purpose: To determine the frequency of sensory impairments among aged care clients., Methods: We examined 188 persons aged 65-99 years being evaluated for aged care services at a geriatric assessment center, west of Sydney, Australia. Visual acuity was measured using a LogMAR chart. Visual impairment was defined in the better eye: mild < 20/40 to > or = 20/80, moderate < 20/80 to > or = 20/200, and severe < 20/200. Hearing function was assessed by portable pure-tone air-conduction audiometry. Hearing loss was defined using average hearing thresholds in the better ear: mild > 25 to < or = 40 decibels (dB), moderate > 40 to < or = 60dB, and severe > 60dB., Results: Vision, hearing, or both were randomly tested in 96, 93, and 49 aged care clients, respectively. Vision impairment was found in 30.2% of clients. Distance vision could be improved with pinhole in 16.7% of 84 clients with presenting VA < 20/20. Moderate to severe hearing loss was present in 50.5%. Combined sensory impairment was detected in 22.5% of persons having both tests. The age-standardized proportions with vision impairment was 25.6%, higher than the rate (17.4%) found in the Blue Mountains Eye Study (BMES) community population, but lower than the 37.7% prevalence reported from the BMES nursing home sample. Hearing impairment was also more common in aged care clients (28.1% vs 17.5%)., Conclusions: This study suggests a high prevalence of sensory impairment among older persons transitioning from independent community living to institutionalized care.

Purpose: To examine 5-year changes in refractive error and astigmatism in an older population., Design: Population-based cohort study., Participants: The Blue Mountains Eye Study examined 3654 residents aged 49 years or older from 1992 to 1994. After excluding 543 persons who died since baseline, 2335 (75.1%) attended 5-year examinations from 1997 to 1999., Methods: Both examinations included a detailed eye assessment, with subjective refraction performed according to a modified Early Treatment of Diabetic Retinopathy Study protocol., Main Outcome Measures: Spherical equivalent (sum of sphere + cylinder) was used as the measure of refractive error. Only phakic eyes with best-corrected visual acuity >20/40 were included (n = 3701)., Results: Similar changes in refractive error were observed for the two eyes. Symmetric changes were found in 72% of participants when the difference between eyes was within 0.5 diopters (D) and in 91% when the difference was within 1.0 D. The 5-year change in spherical power was in a hyperopic direction for younger age groups and in a myopic direction for older subjects, P < 0.0001. The gender-adjusted mean change in refractive error in right eyes of persons aged 49 to 54, 55 to 64, 65 to 74, and 75 years or older at baseline was +0.41 D, +0.30 D, +0.05 D, and -0.22D, respectively. Refractive change was strongly related to baseline nuclear cataract severity; grades 4 to 5 were associated with a myopic shift (-0.33 D, P < 0.0001). Education level and age of onset of myopia, but not gender or diabetes, also predicted refractive change. The mean age-adjusted change in refraction was +0.14 D for hyperopic eyes, +0.32 D for emmetropic eyes, and +0.15 D for myopic eyes. The mean change in cylinder power over the 5-year period was small, irrespective of baseline refraction. The axis of astigmatism remained stable in most cases (64%), whereas 12% changed to "against the rule" and 11% to "with the rule.", Conclusions: This report has documented refractive error changes in an older population and confirmed reported trends of a hyperopic shift before age 65 years and a myopic shift thereafter associated with the development of nuclear cataract.