Glaucoma occurs when pressure inside the eyes builds because fluid to nourish eye tissue drains from the eyeball too slowly or suddenly stops draining.

Overview

Glaucoma (glaw-KOH-ma) is a group of diseases that cause vision loss or blindness by damaging the optic nerve responsible for transmitting impulses for sight from the retina to the brain. In most cases, this damage results from increased pressure in the eye that occurs when fluid that flows in and out of the anterior chamber to bathe and nourish nearby tissue drains out too slowly or suddenly stops draining.

This clear aqueous humor fluid circulates from behind your iris through the pupil, the dark opening in the center of your eye and into the space between your iris and your cornea. Besides providing nourishment, the aqueous humor also exerts a constant pressure to help maintain your eyes’ shape. To keep from building up in the eye, the fluid drains primarily through a “drainage angle,” a mesh of tissue where the cornea and iris meet. In a healthy eye, the excess fluid then flows into a channel and into small veins on the outside of your eye.

But when the drainage angle doesn’t function properly, the aqueous humor backs up to apply pressure on another fluid, the vitreous humor located behind the lens. This causes pressure inside the eyeball to increase. Unless controlled with medication or surgery, this can damage nerve fibers and other parts of the eye, causing a gradual loss in vision.

Glaucoma is the second leading cause of blindness in the U.S., and affects nearly 3 million Americans, most of whom are older than age 60. About 25 percent of people with glaucoma are considered legally blind; another 1 million others may be unaware they have this condition because the onset is so gradual. Glaucoma tends to run in families and is five times more common in African-Americans than Caucasians until middle age, when the risk tends to increase with age for all ethnic backgrounds.

There are two primary types of glaucoma:

• Open-angle glaucoma is the most common form, accounting for 60 to 70 percent of cases. It develops slowly and painlessly when there is too much aqueous humor or it doesn’t drain properly. “Open-angle” refers to the “drainage angle.” In primary open-angle glaucoma, there is too much aqueous being produced or it is not draining properly; in secondary open-angle glaucoma, other factors such as an anatomical variation to the eye, diabetes or medications can cause the pressure to increase in the same painless, progressive manner.
• Angle-closure glaucoma occurs in about 10 percent of cases. It is caused by a partial blockage of the angle and typically causes a sudden and dramatic increase in eye pressure that requires immediate medical attention. It is usually accompanied by some blurred vision, pain in or around the eye, redness, halos around lights and nausea and can result from using medications such as cold remedies, antidepressants and anti-nausea drugs.

There are also several rarer forms of the disease or syndromes that can lead to glaucoma:

• Congenital glaucoma, which typically affects children, is believed to result from an inherited developmental abnormality that blocks the eye drain. It typically occurs in infancy, childhood or adolesence.
• Secondary glaucoma, which usually results from trauma, chronic steroid use or disease.
• Normal-tension glaucoma occurs in people with normal intraocular pressure (IOP) that is below 22 mm Hg, but still develop optic nerve damage. (Meanwhile, others have high IOP but no optic nerve damage.)
• Pseudoexfoliation glaucoma occurs when both pigment and grayish material in the eye clog the angle meshwork.
• Pigment dispersion syndrome is a genetic disorder that causes glaucoma in up to 10 percent of people with this gene – usually people who are nearsighted.

Symptoms

Glaucoma often produces no initial symptoms. Vision is normal and there may be no pain. But as the disease progresses, you may first notice your peripheral vision gradually fading – especially near your nose. As the disease worsens, the field of vision narrows.

In open-angle glaucoma, you may develop “tunnel vision” — vision has narrowed so you see only what is directly in front of you, like looking through a tunnel. This type tends to affect both eyes, although you may have symptoms in just one eye first. Besides reduced peripheral vision, you may notice:

• Sensitivity to glare
• Trouble differentiating between varying shades of light and dark

In closed-angle glaucoma, you may have a sudden onset of:

• Blurred vision
• Halos around lights at night
• Eye redness or pain
• Headache
• Extreme weakness
• Nausea and vomiting

Prevention

Glaucoma cannot be prevented, but the earlier it is diagnosed, the greater the likelihood that it can be slowed down or even stopped with medication before vision is significantly impacted. Once detected, eye pressure can be controlled to reach acceptable lower levels and nerve damage may slow or stop, although the damage is not reversed.

Many people are aware of the “air puff” test or other tests used to measure eye pressure in an eye examination; glaucoma is also found during an eye examination through dilated pupils, in which your eyecare provider adminsters eye drops to enlarge the pupils to see more of the inside of the eye. Because the gradual vision loss may not be noticed until it is too late, regular eye examinations are important for everyone older than age 40, particularly if you:

• Have a family history of glaucoma, which increases risk about four-fold
• Are African-American
• Have diabetes or hypertension (high blood pressure)
• Take corticosteroids and other medications that increase the pressure in your eye
• Have experienced trauma to the eye, such as an eye injury.

Treatment

Medication is usually the first line of defense. Prescription eyedrops or pills help lower pressure inside the eyes by either slowing the flow of fluid into the eye or by improving drainage. Regular use of medication usually helps control increased pressure, but these drugs may not be as effective over time.

Surgery can also help fluid escape from the eye and thereby reduce the pressure, and is usually employed if medications are not helpful.

• Laser trabeculoplasty is the preferred treatment for open-angle glaucomas. In this procedure, a laser is used to widen the opening in the eye’s drainage network. Eyedrops are often following this surgery.
• Laser iridotomy is used to treat angle-closure glaucoma. In this procedure, a laser makes a hole in the iris to allow the aqueous flow.

If medication and laser surgery are not successful, conventional eye surgery may be necessary to create a new opening for fluid to leave the eye. Although done on an out-patient basis, it takes longer than laser surgeries and is consdiered to be riskier.

Matter floating inside the eye moves into the line of sight and appears as specks floating in front of our eyes.

Overview

Floaters (also called “spots”) are tiny clumps of gel or other semi-transparent matter that drift freely inside the vitreous, the jelly-like fluid that fills the inside of your eyes. In most cases, they are more bothersome than harmful – appearing as specks of varying shapes and sizes, or as strands, crystals, cobwebs or as fuzzy clouds that float about and may dart away when you attempt to look at them directly.

Floaters result from several causes: In childhood and early adulthood, most are pieces of blood vessels that were left suspended in the vitreous during fetal development, or small flecks of protein trapped during the formation of your eye. They may also result from specks of pigment on the muscle fibers attached to the iris, or particles caught in the tear layer in front of the eye.

More often, however, they result from the natural aging process, as the vitreous fluid deteriorates and crystal-like clumps form, a process that usually begins in your mid 40s. You may notice them more readily when looking at something bright, such as the sky or a white wall.

Floaters can affect anyone and are usually harmless, but tend to be more noticeable and frequent in people who are nearsighted, have undergone cataract surgery, or have injured or inflammed the eye. If you notice a sudden increase in floaters, see your eyecare provider, because they could indicate a more serious problem such as diabetic retinopathy, retinal hemorrhaging or the first signs of a detached retina.

Flashes, which appear as lightning streaks, shooting stars, fleeting white pinpoints or blasts of light, are false bursts of light produced by optic nerves of the retina. Most adults experience flashes after age 50, as the vitreous thickens as part of the normal aging process and begins to alternately pull away from and rub against the light-sensitive retina. They also appear in those prone to migraine headaches, sometimes right before the onset of a migraine, and can also result from head trauma or by blood vessel spasms in the brain. As with floaters, flashes should be checked by an eyecare provider to ensure they’re not the early sign of a more serious problem.

Symptoms

If you have floaters or flashes, you may notice:

• Spots, strands or shadowy shapes that appears to float or move
• Flashes of light that appear as streaks of jagged lines
• A migraine or headache may follow

Prevention

There is no way to prevent floaters or flashes, but if they occur suddenly or frequently, see your eyecare provider.

Treatment

Floaters and flashes are usually harmless and fade over time. When everyday floaters are bothering you, try looking up and down and from side-to-side. This stirs the vitreous fluid in your eyes, moving floaters away from your line of vision. Flashes caused by the vitreous separating from the retina are a normal part of aging and should subside in a few weeks or months.

There is no safe, reliable treatment to control or eliminate floaters or flashes. If you notice a sudden or dramatic increase in floaters or flashes that last more than 20 minutes, seek immediate medical attention, as this may indicate that you have retinal damage and left untreated, permanent vision loss may result. Surgery may repair damage if caught early.

In the rare case that vision is almost entirely clouded by floaters and floaters, a vitrectomy may be performed. In this procedure, the vitreous is replaced by clear saline solution to improve vision clarity. This is not usually recommended due to the high risk of total blindness associated with the procedure.