Glaucoma is not just one condition, but a group of similar eye diseases.
Glaucoma causes vision loss through damage to the delicate optic nerve. Such damage is irreversible, so prevention and close monitoring are especially important.
Glaucoma is a leading cause of blindness. However, unlike other disease processes, it can be difficult to detect in its infancy, showing no signs until damage to the optic nerve has begun.
Known to medicine for thousands of years, glaucoma is called the “silent thief of sight” because it most often progresses extremely gradually. Being vigilant about these four early warning signs may prevent vision loss:
- Changes to peripheral vision
- Severe and sudden eye pain and headaches
- Halos around light or sensitivity to light
- The unusual visual appearance of the eyes such as haziness, redness, and dilated pupils
Glaucoma affects peripheral vision, and in the most common form of the disease—open-angle glaucoma—this change in peripheral vision is the earliest symptom. Vision once lost due to glaucoma cannot be recovered. In this case, the damage has already been done. Loss of peripheral sight is sometimes described as tunnel vision. Less commonly, there can be patchy blind spots.
For this reason, it is critical to receive full eye exams yearly by a licensed optometrist or ophthalmologist. Part of their exam will be checking peripheral vision, eye pressure, and other early signs of glaucoma that can be too subtle to detect otherwise.
The importance of regular eye exams is even higher for those with risk factors for glaucoma—those with a family history; patients with diabetes, heart disease, or high blood pressure; and Latinos and African-Americans. Patients with high ocular hypertension can be monitored as “glaucoma suspects” before there is evidence of the disease.
While glaucoma is in most cases gradual, it can appear in sudden attacks, as well. Seek emergency room care immediately for this type of sudden onset of high pressure that can cause bursts of extreme pain in the eye or as a headache that seems to come out of nowhere. Acute angle-closure glaucoma, another common form of the disease, could be at work, according to the National Eye Institute. This type comes on suddenly and does its damage to the optic nerve in sudden and short episodes. Sometimes the pain causes nausea and vomiting as ocular pressure builds.
While glaucoma can come on suddenly in attacks like this, it can also be present in infants and children. There is a congenital type that babies are born with that is due to poor fluid drainage. This defect will result in excessive tearing and usually a degree of photophobia—or sensitivity to light. Photophobia can also be a warning sign of glaucoma in adults.
Another vision change that adults might notice is halos around light sources. This change can be less subtle as well, seeming like an overall haziness in visual acuity that necessitates updating a corrective lens prescription, while it is really the result of glaucoma.
And finally, there are some signs of glaucoma that are detectable more to other people than to the patients themselves. When looking into the eyes of a person whose glaucoma is progressing, an overall haziness or glazed look is often noticeable. The ancient Greeks thought glaucoma was the same condition as cataracts because of the cloudiness that results from both conditions.
In addition, glaucoma can make the sclera, or the white part of the eyes, very red. Even dilated pupils can be an indicator of developing glaucoma. Such changes to the appearance of the eye from the outside should be evaluated immediately by an eye care professional.
There is no cure for glaucoma. But close monitoring of eye health, vision changes, risk factors, and ocular pressure can detect many of the processes causing damage to the delicate optic nerve. Treating these processes may prevent much of the vision loss associated with glaucoma.