One of the most common complications with contacts is the lack of oxygen(hypoxia). The cornea is a unique tissue because it is the only tissue in the body that absorbs it’s oxygen supply directly from the air and not from blood vessels. If you reduce the oxygen supply to the cornea by wearing contacts too long the cornea will have trouble repairing itself. This will result in some swelling of the cornea and some difficulty with the cornea repairing itself: these changes show up as microscopic white patches known as infiltrates. When this occurs patients will often experience redness, sensitivity to light and intolerance to contact lenses.
Hypoxia can occur slowly over time before someone develops problems. Usually it develops from wearing contacts most of the time for years and years, then suddenly someone develops problems. The best way to avoid the development of hypoxia and infiltrates is to not over-wear contacts and to change to some form of silicone-hydrogel lens material.
The treatment for hypoxia and infiltrates is to discontinue contact lens wear until all signs of infiltrates resolve, which can usually mean months without contact lens wear. When the infiltrates resolve sometimes the individual can wear contacts again, but they need to be a high oxygen lens and the person must reduce their wearing time.
Websites for more information on Infiltrates:
Michael Nelson, OD