Elsevier

Ophthalmology

Volume 116, Issue 9, September 2009, Pages 1604-1609
Ophthalmology

Original article
Macular and Nerve Fiber Layer Thickness in Amblyopia: The Sydney Childhood Eye Study

https://doi.org/10.1016/j.ophtha.2009.03.013Get rights and content

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 μm; 95% confidence interval 0.1–9.9) and right eyes of non-amblyopic children (by ∼10 μm), both P<0.05. This was more pronounced in 6-year-old children (6.9 μm) than 12-year-old children (4.2 μm). 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.

Section snippets

Study Population

The Sydney Childhood Eye Study (incorporating the Sydney Myopia Study) was a population-based survey that examined childhood eye conditions in Year 1 (median age 6 years) and Year 7 (median age 12 years) students. It was approved by the Human Research Ethics Committee, University of Sydney, the Department of Education and Training, and the Catholic Education Office, New South Wales, Australia. The study adhered to the tenets of the Declaration of Helsinki.

Detailed study methods have been

Results

Of 4118 children examined, complete optical coherence tomography scan data were available in 3529 children (85.7%), 1395 (39.5%) of whom were Year 1 students. Both peripapillary RNFL and macular thickness data were available in 3094 students; 293 students had peripapillary RNFL but not macular scans, and 142 students had macular but not peripapillary RNFL scans.

The overall prevalence of amblyopia was 1.84% (n = 65). There was no significant difference in prevalence between the 6-year-old Year 1

Discussion

Our population-based study found slight differences in macular thickness, as measured by optical coherence tomography, between amblyopic and non-amblyopic eyes. Among all children with amblyopia, foveal minimum thickness was slightly greater (by ∼5 μm) in the amblyopic than the normal fellow eye. This difference was more apparent in 6-year-old children (6.9 μm) than 12-year-old children (4.2 μm). The foveal minimum and central macula were thicker, but the inner macular ring was thinner in

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    Manuscript no. 2008-1044.

    Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

    Supported by the Australian National Health and Medical Research Council, Canberra, Australia (Grant 253732) and the Vision Co-operative Research Centre.

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