Pigment dispersion syndrome (PDS) is an eye disease which involves pigment rubbing off the back of a patient’s iris (the colored part of the eye). Pigment is the matter that gives the body, hair and the iris color.
The pigment that rubs off the iris is released into the fluid which occupies the front chamber of the eye (aqueous humor). The fluid then carries the pigment to other parts of the eye. A lot of pigment floating about may clog the drainage canal of the eye and cause internal eye pressure issues.
The eye maintains a healthy internal pressure by balancing the aqueous humor. A healthy eye is always making new aqueous fluid which flows into the eye with an equal amount of the fluid flowing out.
Where there is a blockage of the drainage canal, the aqueous humor is prevented from flowing out well. This can buildup and cause the intraocular pressure (IOP) to increase leading to eye damage, disease and vision loss.
Also Known As
Causes and Risk Factors
Lens zonules are fibers that keep the crystalline eye lens in the right place behind the iris. Some people have unique eye anatomy which makes the lens zonules to chafe against the back of the iris. As the lens and iris change shape, the fibers rub onto the iris which causes the pigment to flake off.
PDS is a rare disorder whose exact cause is yet to be established. There is some evidence to suggest that it may in part be as a result of genes. There are rare families where the disorder is passed down as an inheritable characteristic.
Signs & Symptoms
In most cases, PDS presents no symptoms. The symptoms caused by a sudden increase in intraocular pressure may include:
- Mild eye pain
- Blurred vision
- Seeing colored halos around lights
Risk factors include:
- Genetics, a family history of the disease
- White males between the ages of 20 and 40
The eye care professional can diagnose pigment dispersion syndrome during a routine eye exam. He/she may conduct:
- An IOP test
- A slit lamp exam
- Other tests such as gonioscopy where PDS is suspected.
The professional will check for sections of the iris with missing pigment and the presence of floating pigment.
They use the tests that diagnose glaucoma to determine if the patient has developed pigmentary glaucoma.
Treatment is aimed at reducing intraocular pressure.
Treatment varies depending on how the pigment dispersion syndrome is affecting the IOP.
In normal or slightly elevated intraocular pressure, the risk of damage to the optic nerve is low. No treatment is necessary, and the eye doctor is likely to recommend checkups once a year to track the IOP and changes in vision.
In the cases of PDS with elevated intraocular pressure, there is a high risk of optic nerve damage. The doctor may prescribe eye drops to lower the IOP.
Where the IOP is very high, the eye surgeon may use laser therapy or surgery to lower it.
Laser treatment or surgery may also be indicated where there is pigmentary glaucoma
Where the blockage of the drainage canal causes intraocular pressure to rise, damage to the optic nerve is a possibility. This is referred to as glaucoma. If pigment dispersion syndrome has reached this level, it becomes pigmentary glaucoma.
Not all patients with PDS develop pigmentary glaucoma.
Only about 30 percent of pigment dispersion syndrome cases progress to this advanced stage.
Unlike the more common open-angle glaucoma, pigmentary glaucoma has to be diagnosed fast and needs aggressive treatment.
The pigment dispersion syndrome is treatable if discovered early.
A patient should go for the annual eye checkups or as often as directed by the doctor. The doctor may also be interested in the patient’s exercise habits because pigment dispersion syndrome symptoms seem to manifest during exercise. It is likely that vigorous activity can lead to an increase in pigment level and the associated symptoms.
The fact that the disease often shows no symptoms makes regular checkup essential.
People at risk should avoid vigorous exercise and extreme sports.