Association of primary open-angle glaucoma with systemic hypertension

Abstract

Open-angle glaucoma is a slowly progressive neurodegeneration of retinal ganglion cells and their axons
characterized by a specific pattern of optic nerve head and visual field damage. Glaucoma is probably one of the most prominent
ocular outcomes of systemic hypertension (HTN). In the light of foregoing background and considering glaucoma having
probable association with systemic HTN, the present study was undertaken. Materials and Methods: This study was done
in a tertiary care hospital over a period of 18 months, after the ethical clearance and informed written consent of the patients.
All individuals above 40 years of age regardless of gender were included in the study. Included patients underwent detailed
ocular and systemic history and detailed examination which included visual acuity by Snellen drum, refraction, intraocular
pressure by Schiotz tonometer, gonioscopy using Zeiss four-mirror lens to evaluate the anterior chamber, visual field changes
seen by Humphrey field analyzer, slit-lamp examination, fundus evaluation by both direct and indirect ophthalmoscopy, and
90D lens with special attention to glaucomatous fundus changes using optical coherence tomography (OCT) with Cirrus SD
OCT Carl Zeiss Meditec. Apart from ocular examination, patient’s blood pressure was taken with sphygmomanometer, and
demographic and anthropometric details were also noted. Result: A case-control study was conducted on 510 individuals of
age 40 years and above, irrespective of sex. Out of them, 340 (66.7%) patients were hypertensives with systemic blood pressure
of >140/90 mmHg, whereas 170 (33.3%) patients were non-hypertensives so were taken as controls. On looking for the presence
of glaucoma in both the groups, it was observed that 13.8% of cases and 5.9% of controls had signs of glaucoma (P = 0.003,
χ2
= 8.58). On the further distribution of glaucoma into established and preclinical type, we found that 53.19% of glaucomatous
cases and 70% of glaucomatous controls had established glaucoma (P = 0.150), while 46.8% and 30% were having preclinical
glaucoma, respectively (P = 0.020). Conclusion: A positive association was seen between HTN and primary open-angle
glaucoma (POAG) prevalence. A significant difference in the distribution pattern of different clinical signs of POAG between
hypertensives and controls was observed. The findings show that regardless of pathophysiology operating for development of
glaucoma, the clinical manifestation does not vary significantly between normotensives and hypertensives. Optic disc changes
and as a result field changes are more pronounced among hypertensives as compared to normotensives, though the analysis
statistically is not significant. Thus, patients of systemic HTN are at high risk of glaucoma as HTN is contributing to both
physiological as well as pathological damage.