Figure 4

Progressive appearance of the morphological domains of a tear microdesiccate from a healthy subject. One-uL aliquots of tear fluid from a healthy subject became fully desiccated in about 9–10 min. Zone I was the first morphological structure to appear progressively during the first half of the time needed for full desiccation. Then, crystalloids of zone II started to appear and grow within a narrow period of time from a number of sites located close to zone I. While crystalloids of zone II were growing centripetally, crystalloids of zone III started to grow multidirectionally from irregularly distributed nucleation sites located close to the center. Physical contact between the growing apices of single crystalloids of either zones II or III with any other crystalloid structure resulted in halting of their growth process (contact inhibition). Desiccation ended when all the zone II and zone III crystalloids became contact inhibited. Times elapsed since the start of desiccation are indicated. One experiment representative of six is shown.