Predictors of Posture Induced Intraocular Pressure Variations in Normal Subjects and Glaucoma Patients. Evidence from Abakaliki.

BACKGROUND

Intraocular pressure (IOP) is affected by factors like age, gender, body mass index (BMI), and blood pressure among others. Studies have investigated the relationship between IOP and age, gender, BMI, and refractive error (3-5). There has been conflicting results as some studies have reported a correlation between IOP and age, gender, BMI, and refractive error while results from other studies found no such association.

AIM: The aim of this study was to determine the relationship between IOP and age, gender, body mass index and refractive status in the primary open angle glaucoma (POAG) and non-glaucomatous eyes.

METHODS

A case controlled study involving consecutive newly diagnosed POAG and non-glaucomatous patients conducted in the eye clinic of Alex Ekwueme Federal University Teaching Hospital, Abakaliki. Demographic data included age, gender, and occupation. Height and weight were measured using a Standing Scale with calibrated metal rule. BMI was calculated as Weight (kg) / [Height (m)] 2). IOP was measured with Perkins hand-held applanation tonometer. Correlation and regression analysis was used to determine the relationship between IOP and age, gender, BMI and refractive status.

RESULTS

There was a direct relationship between age and IOP in non-glaucomatous subjects which was statistically significant ( P < 0.001; r = 0.8). Intraocular pressure also increased with increasing age in POAG but this was not statistically significant ( P = 0.18; r =0.3). There was no statistically significant difference between mean IOP in males and females of both POAG and non-glaucoma patients, with P = 0.72 and P = 0.50 respectively. BMI had a linear relationship with intraocular pressure which was statistically significant in POAG ( P = 0.01; r value = 0.3) but showed no such relationship in non-glaucomatous patients ( P = 0.38; r value = 0.1). The relationship between mean IOP and refractive status was not statistically significant in non-glaucomatous ( P = 0.19; r = 0.2) and POAG patients ( P = 0.5; r = 0.09) respectively.

CONCLUSION

IOP has linear correlation with increasing age in both non-glaucomatous patients and POAG. A statistically significant relationship was found between IOP and BMI in POAG but not in non-glaucomatous eyes. There was no relationship between either the gender, or refractive status and IOP in non-glaucoma and POAG subjects respectively.