Early in the development of myopia (within the first 2 days of minus lens wear) and during the greatest increase in axial size and refractive error (see Figure 1), a significantly greater expression of AQP4 was seen in myopic eyes (as a ratio of experimental to fellow eyes) compared to hyperopic eyes in the NFL (t(21)=2.142, p<0.05; Figure 4B and Figure 5A). The gene discussed is AQP4; the disease is myopia.