Relationship Between Systemic Hypertension, Ocular Perfusion Pressure and Glaucoma

INTRODUCTION: Hypertension is one of the leading causes of morbidity in developing country like India. Glaucoma being one of the leading cause of blindness worldwide, is a multifactorial disease. Intraocular pressure (IOP) is one entity that decides development and progression of glaucoma as well as plays a role in ocular perfusion. Blood pressure also plays a major role in determining the ocular perfusion pressure. So, it is prudent to screen the high risk population and prevent complication of both the diseases at the earliest by recording IOP. OCULAR PERFUSION PRESSURE enables us to identify patients at risk for progressing to glaucoma. OBJECTIVES: 1. To study mean ocular perfusion pressure in hypertensive patients. 2. To study the influence of anti-hypertensive medications on ocular perfusion pressure. RESEARCH DESIGN AND METHODS: This was a cross-sectional study carried out in 150 patients patients who were diagnosed cases of systemic hypertension and attended the out-patient department of ophthalmology. A thorough clinical history regarding co-morbidities and treatment history of antihypertensives was taken and cases were selected here based on inclusion and exclusion criteria. Systolic and diastolic blood pressure was recorded using sphygmomanometer in sitting posture. Mean Ocular Perfusion pressure was calculated using formula, MOPP=2/3*[MAP-IOP] where MAP=DBP+1/3 [SBP-DBP] SPP = SBP – IOP and DPP = DBP – IOP. MAP - Mean arterial pressure, SBP - Systolic blood pressure, DBP - Diastolic blood pressure, SPP - Systolic perfusion pressure. DPP - Diastolic perfusion pressure. Among 150 patients, 22 were on Meal Plan and 128 were on anti-hypertensive drugs. Patients were divided into 4 quartiles based on MOPP. RESULTS: Among the 4 Quartiles, Subjects in Q1 had highest number of glaucoma cases. Subjects in Q1 had lower MOPP, SPP and DPP when compared to others and comprised the at risk group. Majority of the diagnosed glaucoma cases were using Double drug regimen in BD dosage in Quartile 1.Patients with SPP < 106mm Hg, DPP < 60mm Hg were found to be at a higher risk for glaucoma. DPP is better predictor of perfusion status of optic nerve head. Beta blockers was most commonly used drug among our subjects (41%) followed by Calcium channel blockers (19%), Angiotensin Receptor blockers (18%), ACE Inhibitors (15%) and Diuretics (7%). Beta blockers was found to be frequently combined with other anti-hypertensive dugs such as ACE Inhibitors and Angiotensin Receptor Blockers in our study. CONCLUSION: Lower OPP, Lower SPP and Lower DPP are associated with a higher risk of glaucoma which is statistically proven. DPP is better predictor of lower ocular perfusion when compared to OPP and SPP. DPP < 60 mm Hg signifies higher glaucoma risk to the patient. Moreover patients on combined regimen of antihypertensives though attain adequate BP control, they are at risk for glaucoma because of lower OPP values