A recent study has shown that the risks of Contact Lens related adverse effects are no lower in Silicone Hydrogel (SiH) contact lenses than in more traditional HEMA lower oxygen performance lenses. The study found that there may actually be an increase in adherence of bacteria on SiH lenses compared to HEMA.
SiH lenses are still better for the health of the eyes, because they allow so much more Oxygen through to the cornea, meaning that there are less restrictions in wear time than traditional soft lenses. Unfortunately most people do overwear HEMA lenses, which can cause changes in the cornea. Though many of these corneal changes are not permanent, and they are up to a point acceptable in a HEMA lens wearer, they are still undesirable.
Contact Lens wear is safe, but this study highlights the importance of always giving the contact lenses a rub and rinse before storing them in fresh solution overnight, and also reinforces the fact that sleeping in contact lenses, even occasionally, is riskier than not doing it.
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