The Patient’s History: Symptoms of Glaucoma

When intraocular pressure (IOP) is suddenly elevated from any cause, fluid moves into the cornea, exceeding the capacity of the corneal endothelial pumps to remove it. The resulting corneal epithelial edema can produce symptoms of blurred vision and the perception of colored haloes around lights. (The presence of colored haloes is important because noncolored haloes around lights are a common symptom simply of myopia, astigmatism, and other refractive problems with no IOP implication.) Colored haloes are also common symptoms of patients with nuclear sclerotic lens changes, especially early, without any elevation of IOP. Although such symptoms are more common in various forms of angle-closure glaucoma (especially subacute forms) in which there is rapid elevation of IOP when the iris moves into apposition with the surface of the trabecular meshwork (TM), colored haloes can also be seen in open-angle forms of glaucoma with similarly rapid elevation of IOP, such as with glaucomatocyclitic crisis, post-cataract surgery, pigmentary glaucoma, and juvenile open-angle glaucoma. However, in primary open-angle glaucoma (POAG), except for cases with very high IOP, there are usually no such symptoms. This is what makes the disease so treacherous. Most patients with POAG are unaware of any symptoms until there is substantial visual field loss, at which time visual function is compromised.