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Macular and nerve fiber layer thickness in amblyopia: the Sydney Childhood Eye Study
Son C Huynh1, Chameen Samarawickrama, Xiu Ying Wang
1Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia.
Insights
Amblyopic eyes in children showed slightly increased central macular thickness compared to normal eyes. No significant differences in peripapillary retinal nerve fiber layer thickness were observed in this study on childhood amblyopia.
Area of Science:
- Ophthalmology and Visual Sciences
- Pediatric Eye Diseases
- Retinal Imaging and Analysis
Background:
- Amblyopia, or "lazy eye," affects visual development in children.
- Understanding structural changes in the amblyopic eye is crucial for diagnosis and management.
- Macular and peripapillary retinal nerve fiber layer (RNFL) thickness are key indicators of retinal health.
Purpose of the Study:
- To investigate differences in macular thickness and peripapillary RNFL thickness in children with amblyopia.
- To compare measurements between amblyopic eyes and normal fellow eyes, as well as eyes of non-amblyopic children.
Main Methods:
- Cross-sectional, population-based study of 3529 children (aged 6 and 12 years) from the Sydney Childhood Eye Study.
- Comprehensive eye examinations included visual acuity, refraction, strabismus assessment, and optical coherence tomography (OCT).
- Amblyopia defined by best-corrected visual acuity <0.3 logMAR; anisometropia by ≥1.0 D interocular difference.
Main Results:
- Amblyopic eyes exhibited slightly greater foveal minimum thickness (5.0 µm) and central macular thickness compared to fellow normal eyes (P<0.05).
- These thickness increases were more pronounced in 6-year-olds than 12-year-olds.
- No statistically significant differences in peripapillary RNFL thickness were found between amblyopic and normal eyes.
Conclusions:
- Central macular thickness may be elevated in childhood amblyopia, though the causal relationship (preceding or following amblyopia) remains unclear.
- Peripapillary RNFL thickness did not differ significantly between amblyopic and normal eyes in this cohort.
- Further longitudinal studies are needed to elucidate the temporal relationship between macular changes and amblyopia development.
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.
