Molecular insights into foveal hypoplasia: development, genetics, mechanisms, and models

The fovea is an anatomic specialization of the human retina critical for high visual acuity, color vision, and contrast sensitivity. The molecular and cellular pathways directing this focal topography are still to be determined. Abnormalities of the fovea (e.g., foveal hypoplasia in children) are considered a significant contributor to reduced quality of life. In addition, the fovea is often damaged in common retinal diseases, such as age-related macular degeneration and diabetic retinopathy, with a global economic burden of $500 billion USD. Currently, there are no treatments for foveal defects. Most genes contributing to foveal abnormalities have been identified but are yet to be characterized and studied. This is because common laboratory animals do not have a fovea, and only rare human tissue samples are available during the major phase of foveal maturation, from birth to the end of the fourth year of life. We discuss validation of the anole lizard, which has a foveal structure, for research studies into foveal development. Since foveal development continues after birth, it may be possible to stimulate new foveal maturation where there is developmental damage. From this review, we propose an evidence-based cellular mechanism that offers new possibilities for testing future therapies for foveal defects.