What causes contact lens overwear and more importantly, how can you help avoid it?
Contact lens overwear is caused by lack of oxygen to the cornea, which produces distinct symptoms. Patients may not realize they've overworn their lenses when they remove them because the presence of corneal abrasions is masked by reduced sensitivity secondary to oxygen deprivation. Unsuspecting patients often go to sleep only to awaken 1 to 2 hours later with severe, stabbing pain, extreme light sensitivity, tearing, cloudy, blurred vision and grittiness.
If early symptoms of overwear aren't identified and addressed quickly, patients risk developing long-term changes, such as:
- Neovascularization: Abnormal blood vessels growing in the clear cornea
- Polymegethism: Abnormalities of endothelial cell size
- Pleomorphism: Abnormalities of endothelial cell shape
- Epithelial microcysts
- Corneal thinning
- Reduced corneal sensitivity.
What's more, long-term adverse reactions ultimately may cause corneal exhaustion syndrome and contact lens intolerance.