Xiu Ying Wang

Macular and nerve fiber layer thickness in amblyopia: the Sydney Childhood Eye Study.

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.

Prevalence and associations of anisometropia and aniso-astigmatism in a population based sample of 6 year old children

Aim: To study the distribution of anisometropia and aniso-astigmatism in young Australian children, together with clinical and ocular biometry relations. Method: The Sydney Myopia Study examined 1765 predominantly 6 year old children from 34 randomly selected Sydney schools during 2003–4. Keratometry, cycloplegic autorefraction, and questionnaire data were collected. Results: Spherical equivalent (SE) anisometropia (⩾1 dioptre) prevalence was 1.6% (95% confidence interval (CI) 1.1% to 2.4%). Aniso-astigmatism (⩾1D) prevalence was 1.0% (CI: 0.6% to 1.6%). Both conditions were significantly more prevalent among moderately hyperopic (SE ⩾2.0D) than mildly hyperopic (SE 0.5–1.9D) children. Myopic children (SE ⩽−0.5D) had higher anisometropia prevalence. Neither condition varied by age, sex, or ethnicity. In multivariate analyses, anisometropia was significantly associated with amblyopia, odds ratio (OR) 29, (CI: 8.7 to 99), exotropia (OR 7.7, CI: 1.2 to 50), and neonatal intensive care unit (NICU) admission (OR 3.6, CI: 1.1 to 12.6). Aniso-astigmatism was significantly associated with amblyopia (OR 8.2, CI: 1.4 to 47), maternal age >35 years (OR 4.0, CI: 1.3 to 11.9), and NICU admission (OR 4.6, CI: 1.2 to 17.2). Anisometropia resulted from relatively large interocular differences in axial length (p<0.0001) and anterior chamber depth (p = 0.0009). Aniso-astigmatism resulted from differences in corneal astigmatism (p<0.0001). Conclusion: In this predominantly 6 year old population, anisometropia and aniso-astigmatism were uncommon, had important birth and biometry associations, and were strongly related to amblyopia and strabismus.

Retinal and Optic Disc Findings in Adolescence: A Population-Based OCT Study

PURPOSE To examine the distribution of macular and peripapillary nerve fiber layer (NFL) thickness and optic disc parameters in early-adolescence Australian children and to compare these with previously reported findings in younger children. METHODS The Sydney Childhood Eye Study is a population-based cross-sectional survey of childrens eye health. During 2004 and 2005, 2367 (75.3%) of 3144 eligible year 7 students from a random cluster sample of 21 secondary schools in Sydney, Australia, were examined. The comprehensive eye examination included measurement of macular and NFL thickness and optic disc parameters by optical coherence tomography (StratusOCT; Carl Zeiss Meditec, Dublin, CA). RESULTS Macular, NFL thickness, and optic disc parameters were normally distributed in early-adolescence children. Mean (+/-SD) thicknesses of the central 1 mm, and inner and outer macular rings were 197.4 +/- 18.7, 271.9 +/- 15.0, and 239.5 +/- 13.5 microm, respectively. The foveal minimum thickness was 161.6 +/- 19.9 microm. The mean (+/-SD) of average NFL thickness was 103.6 +/- 10.6 microm. Mean (+/-SD) vertical and horizontal disc diameters were 1.88 +/- 0.25 and 1.61 +/- 0.20 mm; corresponding cup-to-disc ratios were 0.39 +/- 0.14 and 0.44 +/- 0.16. There were minimal sex differences in these parameters after adjustment for multiple ocular and demographic variables. Compared with parameters in the childhood group, the macula was generally slightly thicker and the optic disc slightly larger in the early-adolescence group, although differences between these two age groups were small. The foveal minimum and NFL thickness were similar between the two age groups. CONCLUSIONS This study describes the normative distribution of macular, NFL, and optic disc parameters in early-adolescence children and also demonstrates minimal differences between the sexes. These parameters were also largely unchanged between early childhood and early adolescence, although the comparisons were made in two cross-sectional samples, rather than from longitudinal measures.