Zone-Quick™ Diagnsotic Threads are a cotton thread (treated with pH indicator Phenol Red) used to measure the amount of tear production. Zone-Quick is a simple and accurate system that measures tear volume in just 15 seconds per eye. When the thread comes in contact with tears, it changes from yellow to a light red color, and each box has an easy-to-read diagnostic indicator rule. Zone-Quick minimizes false readings often obtained from reflex tearing.
Exp. 3/13