Glaucoma is a term that refers to a group of diseases that affect the eye and can result in damage to the optic nerve. The optic nerve is a bundle of nerve fibers connecting the retina in the eye to the brain, transmitting visual signals. Glaucoma can lead to vision loss and blindness. Vision loss can be gradual, which can make glaucoma difficult to recognize until it has reached an advanced stage. Glaucoma is caused in most cases by a slow rise in the fluid pressure inside the eye, although there is a low-pressure form of glaucoma called normal-tension or low-tension glaucoma. With an early diagnosis and treatment, damage to the optic nerve can be minimized or prevented and the loss of vision can be limited.
Open-Angle Glaucoma
Gradual loss of peripheral vision is the only sign of open-angle glaucoma, which is why diagnosis can be difficult. The loss of vision usually occurs in both eyes and may not be noticeable at first because it's so gradual. Eventually, tunnel vision develops. This occurs when the peripheral vision diminishes to the point that the eyes can clearly see only what is directly in front of them. Vision can continue to diminish until blindness occurs.
Acute Angle-Closure Glaucoma
The signs of acute angle-closure glaucoma are different from open-angle glaucoma. For acute angle-closure glaucoma, there can be blurred vision and severe eye pain. Vomiting and nausea can accompany the eye pain. Halos can be seen surrounding lights. Another sign is the reddening of the eye. There can be a sudden disruption or disturbance of normal vision, especially in low lighting conditions.
Eye Exam
An eye exam can help with the diagnosis of glaucoma. A field of vision test will aid in determining loss of peripheral vision. Photographs can reveal damage to the optic nerve. A procedure called tonometry measures the internal fluid pressure of the eye, also called intraocular pressure. The thickness of the cornea is measured because thick corneas can create high intraocular pressure without the presence of glaucoma.
