Macular and nerve fiber layer thickness in amblyopia: the Sydney Childhood Eye Study.
OBJECTIVE
To examine macular and peripapillary retinal nerve fiber layer (RNFL) thickness in amblyopia.


METHODS
Population-based cross-sectional study.


METHODS
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.


METHODS
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.


BACKGROUND
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Huynh
Son C
SC
Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia.
Samarawickrama
Chameen
C
Wang
Xiu Ying
XY
Rochtchina
Elena
E
Wong
Tien Y
TY
Gole
Glen A
GA
Rose
Kathryn A
KA
Mitchell
Paul
P
D000550:Amblyopia / Q000175:diagnosis*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009517:New South Wales; D009900:Optic Nerve / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D011795:Surveys and Questionnaires; D041623:Tomography, Optical Coherence; D014792:Visual Acuity