Pigment Dispersion Syndrome
Pigment dispersion syndrome is a relatively uncommon condition that affects about 1% of the population.
Pigment clumps that are normally attached to the back surface of the iris (the colored part of the eye) fall off the iris into the clear fluid in the eye called the aqueous humor.
These little clumps of pigment can clog the drainage structures of the eye that drain fluid produced inside the eye (this is different from the tears on the surface of the eye and is not related to tearing).
When fluid pressure builds up inside the eye because drainage is impaired, eye pressure can rise enough to cause damage to the optic nerve. Pressure related damage to the optic nerve is called glaucoma.
Diagnosis of Pigment Dispersion Syndrome
This syndrome is felt to occur based on subtle differences in the shape of the structures in an individual’s eye. In pigment dispersion, the back of the iris rubs against the lens of the eye causing the pigment to flake off the back of the iris. These little clumps of pigment form a line of pigment on the inner surface of the cornea that an ophthalmologist can see on exam. This little line is called a krukenberg spindle and is very helpful in diagnosing pigment dispersion syndrome. Because pigment is coming off of the back of the iris, the ophthalmologist will look for areas of the iris where light can be seen reflecting back through these thinner parts of the iris. These are called iris transillumination defects. Pigment can also be seen inside the eye resting on the internal drainage structures of the eye. This is checked using a special lens and is called gonioscopy. The presence of two or more of these key features — krukenberg spindle, iris transillumination defects, and excessive pigmentation on gonioscopy — confirm the diagnosis of pigment dispersion syndrome.
Pigment dispersion syndrome tends to affect relatively young people (20-45), most commonly Caucasians and those who are nearsighted. Many patients with pigment dispersion syndrome will develop high eye pressures and about half of those who develop high eye pressure will develop glaucoma. For this reason, a person diagnosed with pigment dispersion needs to be checked by an eye doctor at least once per year, more often if the eye pressure is elevated.
If a patient has elevated eye pressure or an optic nerve that looks suspicious for glaucoma damage, further testing is done. This testing may include side vision testing (a visual field test), computerized optic nerve head analysis, and corneal thickness measurement. If there are signs of damage to the optic nerve, loss of side vision, or eye pressure is very elevated, the patient is diagnosed with Pigmentary Glaucoma. Glaucoma is treatable, typically with eye drops or laser. More advanced cases may require surgery. It is very important to detect glaucoma early because it causes irreversible vision loss. In addition, the more advanced the glaucoma, the more difficult it is to treat. When detected early and treated early, the prognosis for pigmentary glaucoma is excellent.
Who is likely to get pigmentary glaucoma?
Unlike other types of glaucoma, pigmentary glaucoma tends to affect younger people. In men it often occurs at ages 20-45, and in women in their 50s and 60s. Early glaucoma is not symptomatic, and younger patients don’t see an eye doctor as frequently, so this condition is often diagnosed after significant damage has already been done.
While pigment dispersion syndrome occurs equally in men and women, men have a higher risk of getting pigmentary glaucoma. This is most common in young, nearsighted men. Pigment dispersion is hereditary, so if you have this condition, it is wise to let your relatives know to be checked.
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