Glaucoma is a group of eye diseases that cause progressive damage to the optic nerve. This nerve connects the eyeball to the brain; it transmits visual signals that enable the brain to create images. In people with glaucoma, a buildup of fluid causes pressure in the eye to increase. As the damage progresses, a variety of symptoms develop.
There are several types of glaucoma. Both open-angle and chronic angle-closure glaucoma progress incredibly slowly. Because of this, it is possible for glaucoma to steadily worsen without causing any symptoms. In some cases, the symptoms that begin to appear are so minor that the individual experiencing them might not even notice. This is why regular eye exams are critically important, especially for people with a high risk of getting glaucoma, such as older adults or individuals with diabetes, migraines, high blood pressure, and poor blood circulation.
Open-angle glaucoma causes gradual vision loss that begins with peripheral vision or the edges of a person's field of vision. Typically, open-angle glaucoma will affect both eyes. As a person loses their peripheral vision, what they can see begins to shrink towards the center. Experts refer to this as tunnel vision. Usually, tunnel vision only develops in the later stages of open-angle glaucoma because it takes a while for the vision loss to progress this far.
Angle-closure glaucoma advances faster than other types, sometimes even presenting with sudden symptoms. One of the most common symptoms of angle-closure glaucoma is eye pain. The severity depends on several factors. In some cases, the pain is minor because the person experiencing it has a high pain tolerance or the pressure has not increased to an extreme degree. Alternatively, the pressure increase could be gradual, so the individual becomes used to the pain over time.
In addition to the eye pain, many people with angle-closure glaucoma experience headaches and general head pain. Some people describe the pain as a dull ache while others feel a sharp sensation originating from their forehead or eyes. Like pain, the headaches range in severity. For people with only slight pressure increases, the pain is manageable. For others, it may almost reach the severity of a migraine.
As a person loses their vision due to angle-closure glaucoma, they rarely experience pure darkness. Instead, some describe their vision as cloudy. Others see almost normally, but their sight is blurry. Depending on how fast glaucoma progresses, this may be a steady transition into blurred vision. However, some people's symptoms develop rapidly and suddenly. In these cases, vision may worsen in a matter of minutes.
Many people with glaucoma see images that doctors refer to as sudden visual disturbances. Individuals with migraines are particularly familiar with these disturbances. Some people experience photopsia or bright flashes of light similar to a camera flash. Other people experience metamorphopsia, which is a distortion of the size, color, or shape of visual images. Metamorphopsia causes linear objects, such as grids or lines, to look curvy. It is also common to have blind spots near the center of the eyes' field of vision. These blind spots may slowly migrate across the visual field.
One of the most common symptoms of angle-closure glaucoma is the presence of rings or halos. Some people see the halos exclusively while they stare into a light source, while others are not limited to these instances. The halos themselves are usually blurry and round, though some people describe them as jagged. Those that appear in direct sunlight are most common. Sometimes the halos have slight rainbow coloration along their edges.
Eye pain and headaches, in addition to issues with vision, can cause nausea. If a glaucoma attack occurs suddenly enough, nausea may result in vomiting. Many glaucoma attacks occur in dark rooms because the pupils dilate to match the light level. This means a person with glaucoma is more likely to feel nausea in places such as movie theaters. In some cases, their vision issues may cause dizziness that intensifies nausea and can also lead to vomiting.
As pressure increases, the eye may develop a red coloration. This occurs because the increased pressure in the eye is affecting the blood vessels near the surface. As the fluid presses on the blood vessels, they enlarge and dilate, making them more visible. Additionally, the pressure in the eyes may cause the area around the eye to become sensitive, puffy, and slightly red.
Ultimately, glaucoma can lead to complete vision loss. Depending on what type of glaucoma a person has, this can occur slowly or suddenly. With treatment, doctors can slow glaucoma's progression. This can add years of sight for individuals who would have otherwise lost their vision. Unfortunately, if an acute glaucoma attack causes sudden vision loss, treatment may not be able to restore it. Some people's vision loss appears as darkness while others have cloudy or extremely blurry vision.
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