• Serum and tear samples were collected from 25 patients with sarcoidosis and from 55 healthy controls to determine angiotensin-converting enzyme activity. Seven of the ten patients with ocular sarcoidosis had greatly increased tear levels of the enzyme. The tear levels decreased when the disease subsided with prednisone therapy. The measurement of tear levels of the converting enzyme provides the best noninvasive test for diagnosing ocular sarcoidosis and monitoring the course of the disease.
Sharma OP, Vita JB. Determination of Angiotensin-Converting Enzyme Activity in TearsA Noninvasive Test for Evaluation of Ocular Sarcoidosis. Arch Ophthalmol. 1983;101(4):559–561. doi:10.1001/archopht.1983.01040010559004