Corneal Clouding

The eye problems described here are found throughout the MPS I spectrum. The circular window at the front of the eye (also known as the cornea) becomes cloudy due to storage of GAG, which disrupts the clear layers of the cornea. This is called corneal clouding. If corneal clouding is severe, it may reduce sight, especially in dim light. Some people with MPS I cannot tolerate bright lights, as the clouding causes uneven refraction (bending) of the light. Wearing caps with visors or sunglasses may help. Many people with MPS I have a corneal transplant, which may improve vision. Possible risks of a corneal transplant include infection, rejection of the transplanted cornea, or an allergic reaction to the medication used for local anesthesia (numbing the eye before surgery).

Corneal Clouding Courtesy of J.E. Wraith, M.D.

There may be problems with vision caused by changes to the retina or by glaucoma (increased pressure) that should be checked during an eye examination. GAG storage in the retina can result in night blindness and loss of peripheral vision. Night blindness can result in an individual not wanting to walk in a dark area at night or waking up at night and being afraid. Sometimes the addition of a night-light in a hall or bedroom is helpful. It is often difficult to determine which combination of problems is responsible for the decrease in eyesight. An ophthalmologist can perform special studies to help determine whether the problem is due to an effect on how light gets in the eye (the cornea) or on how the eye responds to light (the retina or optic nerve).

Courtesy of the National MPS Society

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