A comparative study of intraocular pressure in myopia and hyperopia among a Nigerian population just diagnosed with primary open angle glaucoma in Benin City

Aghafekokhian B. Osaiyuwu, Genesis D. Edokpa


Background: Increasing evidence suggests that high myopia is salient in the pathologic process of POAG, and IOP (Primary Open Angle Glaucoma (POAG), and Intra-ocular Pressure (IOP)) remains the crucial risk factor for this condition. Still, some other studies have signified that glaucoma was diagnosed in myopes independent of IOP, suggesting that predisposition to glaucoma in myopes may not be dependent on mechanisms related to high pressures. The aim of this study was therefore to compare the intraocular pressure in myopes and hyperopes in a Nigerian population just diagnosed with POAG to ascertain if proclivity to glaucoma in myopes is mainly dependent on IOP.

Methods: This research was conducted as a retrospective study in the Optometry/Ophthalmology Department at Stella Obasanjo Women and Children Hospital, Benin City, Nigeria. The sample consisted of cases seen between 2011 and 2013. A total of 166 eyes with glaucoma and refractive errors (80 (48.19%) with myopia, and 86 (51.81%) with hyperopia) with an age range of 10 to 85 years, were used for this study.

Results: Newly diagnosed glaucomatous myopes had a significantly higher mean IOP than recently diagnosed hyperopes (unpaired t- test, p= 0.004). Also, a significant inverse correlation was obtained between refractive errors and intraocular pressure (Pearson correlation, r = -.245, p = 0.001) i.e. as refractive errors progressed deeply into more minus (myopic) regions, IOP increased.

Conclusions: The relationship between glaucoma and myopia is pressure mediated. The ascending levels of intraocular pressure that occurred with increasing extents of myopia demonstrate that POAG evolves too soon in participants with high myopia than in hyperopia and accentuates the seriousness of glaucoma surveillance in the myopic population.


Hyperopia, Intra-ocular pressure, Myopia, Primary open angle glaucoma

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