Raised intraocular pressure (IOP) is the principal modifiable risk factor for the development and progression of glaucoma. Glaucoma is defined as progressive optic neuropathy, based on visual field loss and/or optic disc findings, is more likely to be associated with elevated intraocular pressure (IOP), although IOP is not the only risk factor for glaucomatous optic nerve damage. The complex physiology involved in aqueous humor formation and its maintenance indicates its dependence on other systemic, physical, physiological and environmental factors, thus effects IOP. The factors studied were age, gender, systemic blood pressure (BP) and body mass index (BMI).
A cross sectional hospital-based study was conducted where 800 adults of varying demographic profiles were included with their written and informed consent taken. A detailed history from all the patients including signs and symptoms of glaucoma was taken, demographic and anthropometric details noted. Ocular examination included visual acuity by Snellen's drum, refraction, intraocular pressure (IOP) by Goldman's applanation tonometer, gonioscopy using Zeiss four-mirror lens, visual field changes seen by Humphrey field analyzer (HFA) using 30-2 program (version 40), slit-lamp examination, fundus evaluation by both direct and indirect ophthalmoscopy, and 90D lens. The statistical analysis was done using SPSS (Statistical Package for Social Sciences) Version 15.0 statistical Analysis Software. The values were represented in Number (%) and Mean ± SD.
Mean age of patients was 57.21 ± 9.81 years. With increasing age proportion of those with IOP up to 20 mmHg showed a significant incremental trend. It was observed that mean age of subjects having 20-24 mmHg IOP was minimum (54.17 ± 9.26 years) followed by 16 - 20 mmHg (56.77 ± 9.61 years), 12 - 16 mmHg (58.50 ± 9.73 years), > 24 mmHg (60.20 ± 10.92 years) and < 12 mmHg (61.56 ± 7.54 years). Statistically, this difference was significant (p < 0.001). There was a weak and inverse significant correlation between age and IOP (r = -0.075; p = 0.003). Majority of subjects were females (50.5%). Proportion of those having IOP in ≤ 16 mm range was higher among males (45.7%) as compared to that in females (35.7%). Statistically, this difference was significant (p < 0.001). A weak positive and significant correlation was observed between IOP and BMI. Statistically, the difference in BMI of subjects in different IOP categories was significant (p < 0.001). Difference in mean IOP of normotensive (16.95 ± 3.35 mmHg) and hypertensives (17.11 ± 3.53 mmHg) was not found to be statistically significant. Mean SBP and DBP of subjects with IOP < 12 mmHg, 20 - 24 mmHg and > 24 mmHg were found to be significantly higher as compared to those with IOP 16 - 20 mmHg and 20 - 24 mmHg.
The present study shows the association between age, gender, BMI and blood pressure, depicting the multivariable of IOP. Thus, the measurement of IOP is essential in all the patients with variable demographic, anthropometric, or systemic profile, thereby aiding in evaluation and diagnosis of various forms of glaucoma.