Eight selected fetal lenses of 119-231 days of gestation were analyzed by capillary isotachophoresis. A reproducible separation into pre-alpha-, alpha-, beta- and gamma-crystallins was achieved. During development, an increase was observed in beta s- and gamma-crystallins, balanced by a decrease in total alpha- and beta-crystallins. Isotachophoresis enabled a separation into at least 48 main crystallin components.