A study of changes in the status of autonomic nervous system in primary open angle glaucoma cases

Control of Intra Ocular Pressure (IOP) is influenced by both divisions (sympathetic and para-sympathetic) of Autonomic Nervous System (ANS). The present study was conducted to confirm existence of any association of ANS with primary open angle glaucoma (POAG), if present. Systemic autonomic function tests were assessed in fifty patients of POAG with fifty normal subjects matched for sex and age as control using several well established tests based on cardiovascular reflex responses to standardised stimuli viz. Resting heart rate (RHR), Corrected QT Interval (QTc), T-wave amplitude, Standing to Lying Ratio (SLR); Valsalva Ratio; Galvanic Skin Resistance (GSR) and Cold Pressor Test (CPR). Tests were conducted in the Department of Physiology, Maulana Azad Medical College and associated Glaucoma Clinic of Guru Nanak Eye Centre from june '94-May '95. Subjects were randomly chosen from known POAG cases with IOP--25 +/- 5.08 mm Hg. The results showed decrease in both sympathetic and para-sympathetic activity of autonomic function tests in POAG suggesting associated autonomic dysfunction. Sympathetic under-activity is seen in 36 patients out of 50 (73%), POAG subjects while para-sympathetic activity is decreased in 43 of 50 (86%) of the POAG subjects when compared with normal control group. The results help concluding that POAG is associated with autonomic dysfunction with decreased activity of both sympathetic and para-sympathetic divisions of ANS.