Contact lens wearing is safe; about 140 million people worldwide wear them.(1,2) It is important to remember that several serious complications – occur if proper care is neglected – The complications are directly induced or aggravated by contact lens wear. The mechanisms by which contact lenses induce alterations are: trauma, decreased corneal oxygenation, reduced corneal and conjunctival lubrication, stimulation of allergic and inflammatory responses, and infection.3
Common complications may arise, such as discomfort, dry eye, corneal discomfort, or giant cell conjunctivitis. Furthermore, it is important to be aware of serious sight-threatening complications such as – corneal neovascularisation, corneal abrasion, or infections keratitis (with or without a corneal ulcer).(4) In addition, over-extending of contact lens wearing may induce contact lens-induced acute red eye (CLARE) syndrome.(5)
Microbial keratitis is one of the most severe complications of contact lens wear. Keratitis results from an alteration in the cornea’s defence mechanisms, allowing bacteria to invade when an epithelial defect is present. Overnight use is a leading risk factor as is extended-wear poor hygiene and not using appropriate cleaning solutions.(6,7) Organisms responsible include pseudomonas aeruginosa, staphylococcus, streptococcus, serratia, and acanthamoeba. The risk for acanthamoeba infection is water and infected lens solutions.
Wearing contacts reduces the amount of oxygen that the cornea receives from the surface of the eye (hypoxia), which can lead to cornea swelling (corneal oedema). Over time, the cornea tries to get more oxygen by growing new blood vessels (corneal neovascularisation). If severe, the vessels can grow into the centre of the cornea and cause vision loss.
Sterile corneal infiltrates usually appear on the peripheral cornea and are secondary to contact lens wear and/or bacterial endotoxins. They may represent a diagnostic dilemma for keratitis.
Giant-cell conjunctivitis (GPC) can develop in the upper eyelid due to continuous rubbing against the contact lens. If not detected and treated promptly, patients may experience contact lens intolerance.
Maintaining proper contact lens hygiene is crucial. This involves refraining from wearing contacts while sleeping, showering, or swimming to minimise the chances of experiencing severe complications. In addition, opting for daily disposable contact lenses can significantly reduce the risk of developing infectious keratitis.(4)