Purpose: To document the distribution of macular, retinal nerve fibre layer (RNFL) thickness and optic disc parameters, as measured using optical coherence tomography (OCT) in a population-based sample of young persons and to examine the relationship of these measurements to ocular variables (spherical equivalent refraction [SER] and axial length) and systemic variables (age, gender, anthropometry, ethnicity and birth parameters). Methods: A stratified random cluster sample of 6- and 12-year-old school students from across the Sydney metropolitan region were surveyed and examined using non-contact methods (including biometric measurements with the IOL Master and Canon RK-F1) to determine axial length and SER. The 3rd generation Optical Coherence Tomography instrument (Zeiss Stratus OCT, Dublin, CA, USA) was used to measure macular and RNFL thickness and major optic disc parameters in this sample. Ethnicity and birth parameters were derived using questionnaires. Anthropometric parameters, such as height and weight, were measured using standard methods. Results: The thickness of the foveal, central, inner macular, outer macular and macular volume parameters was normally distributed in both age cohorts. The temporal quadrant was thinner than all other quadrants at both the inner and outer macular regions. The central and inner macula was significantly thicker in boys than in girls, and in Caucasian than in East Asian children. The inner and outer macular regions were slightly, but significantly, thinner with increasing axial length, or myopic refraction. On the other hand, these corresponding regions were significantly thicker with more hyperopic SER. RNFL thickness and RNFLestimated integral were normally distributed in both age groups. RNFL thickness was thinnest for the temporal quadrant, followed by the nasal, inferior, and superior quadrants. RNFL average thickness was marginally greater in boys than in girls and in East Asian than in Caucasian children. The RNFL was thinner with both greater axial length and less hyperopic refractions. Optic disc, optic cup and neural rim parameters were also normally distributed in this young population. In analyses that adjusted for potential confounders, optic disc area increased significantly with axial length and refraction. Neural rim area increased with axial length. There were minimal gender differences in the two age groups. Most optic disc and optic cup dimensions were significantly larger in East Asian than in Caucasian and Middle Eastern children. The foveal minimum and overall RNFL thickness were similar in both age cohorts, while other retinal regions and optic disc size were slightly larger in the 12- than the 6-year-old children. Amblyopic eyes had greater foveal minimum thickness than the normal fellow eye of individual children and the right eyes of non-amblyopic children. Birth weight and head circumference were positively correlated with both RNFL and macular thickness. Conclusions: Macular thickness, RNFL thickness and optic disc parameters were normally distributed in these two age groups of children. Axial length and refraction were important ocular biometric determinants of macular thickness and RNFL thickness. Significant ethnic differences were also demonstrated. RNFL average thickness was also positively associated with optic disc area. Central macular thickness increased in amblyopia. These findings have implications for the interpretation of OCT measurements in research and clinical practice in both children and adult.
| Identifer | oai:union.ndltd.org:ADTP/187321 |
| Date | January 2006 |
| Creators | Wang, Xiu Ying, Optometry & Vision Science, Faculty of Science, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Optometry and Vision Science |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Xiu Ying Wang, http://unsworks.unsw.edu.au/copyright |
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