Quantification of Tear Volume in an Autoimmune Dry Eye Rat Model using the Phenol Red Thread

While holding an anesthetized rat according to the text protocol, to measure the tear volume with phenol red thread, use one pair of forceps to hold the thread and another to pull the lower eyelid of the rat. Place the thread at the proximal corner of the lower fornix for one minute, and then, remove the thread. Then, place the thread next to a ruler with millimeter markings, and take an image of the length of the wetted part of the thread.