Figure 4.
Examples of FDM in animal models and humans. Refractive error frequency distributions for normal (open symbols) and form-deprived eyes (filled symbols) from chicks137 (A), rhesus monkeys166,168,819 (B), and humans146 (C). Form deprivation was produced in chicks using diffuser lenses; the data were obtained after either 28 or 42 days of age. Form deprivation was produced by surgical eyelid closure in monkeys; the data were obtained over a range of ages and durations of deprivations. Form deprivation in children occurred as a result of conditions (hemangioma and eyelid ptosis) that interfered with a clear retinal image.