Figure 9.

Possible mechanisms for age-related decline in limbal stem cell function. Diagram showing two possible ways in which limbal stem cell function may decline with age. A: Full complement of active limbal stem cells (shown as blue and yellow stars) in young eye. B: Reduction in number of LSCs in older eye. C: Increase in proportion of quiescent LSCs in older eye. The mosaic corneal epithelium is shown as a disk with radial blue and yellow stripes produced by LSCs, represented by stars, at the edge of the cornea. Blue and yellow stars represent active LSCs; green stars represent quiescent LSCs.