Jan Provis

　　澳大利亚国立大学

　　The macula is particularly vulnerable to degenerative disease，with age-related macular degeneration being the major cause of untreatable vision loss world-wide.Evidence also shows that improvements in the survival rates of infants of low and extremely low birth-weight results in increased incidence of poor visual outcomes in this group，including strabismus，amblyopia，poor contrast sensitivity and colour vision defects which are frequently associated with a small or absent foveal avascular area.Because the most popular animal models do not have a macula，knowledge of the normal biology of the macula and the genes that regulate its development，is generally lacking。

　　We compared gene expression in macular and non-macular regions of the human retina at 20 weeks'gestation，and identified~2000 differentially expressed candidate genes.Of these，two prominent clusters include genes with specific roles in axon/vascular guidance，and those with roles in the negative regulation of angiogenesis.Our findings suggest that genes associated with axonal and vascular guidance restrict vascularization of the macula and，in conjunction with anti-angiogenic factors，help to define the foveal avascular area.