Figure 2. Confocal imaging time course. Confocal images of Ctns^−/− corneas at 3 months (A), 7 months (B), 10 months (C), and 12 months of age (D). Each panel shows a xy (upper) and xz (lower) slice through a 3-D stack. Cystine crystals were identified as small, 20 µm long, needle-like crystals in the peripheral and central cornea. Cystine crystals were first detected in 3 month old mice (A, arrow) and gradually increased in density with age up to 7 months (B). Older Ctns^−/− mice (10 and 12 month old) developed aggregates of brightly reflecting material, presumably cystine, within the central cornea (arrowheads; C and D, respectively).