Sulaiman Mahmood, Sulayman Khan
Introduction
Since the introduction of daily disposable contact lenses and highly oxygen-permeable silicone hydrogel materials, resulting in improvements in comfort and eye health, contact lens use has skyrocketed (1, 2). There are at least 125 million contact lens wearers globally, which is increasing by 6% each year (3). However, despite their generally safe profile, contact lens misuse is a significant and preventable cause of ocular morbidity. Poor hygiene practices, extended wear, and inappropriate storage are all associated with a range of complications that can lead to permanent visual impairment. Common complications include microbial keratitis (MK), corneal hypoxia, and dry eyes, with patient education and prevention key to addressing them.
Risk Factors
The most common yet significant modifiable risk factors for complications are poor hygiene and overnight wear (4). Swimming or showering while wearing contact lenses increases the risk of infection, while travel may disrupt routine wear practices (5). Demographic factors, such as being male, are also associated with increased risk, likely due to poor compliance and reduced healthcare engagement (6).
Microbial Keratitis
MK is potentially the most serious complication associated with contact lenses. It is characterised by corneal infection, which presents with pain, red eye, photophobia, and reduced visual acuity.
Overnight wear and poor hygiene practices can encourage growth of infective organisms such as Pseudomonas aeruginosa, which is known for rapid progression and aggressive corneal destruction. Moreover, swimming or showering in contaminated water with contacts is associated with Acanthamoeba (7).
If not recognised and managed early, MK can lead to corneal ulceration, scarring, and permanent visual impairment. In severe cases, surgical interventions, including corneal transplantation, are necessary.
Corneal Hypoxia
The use of highly oxygen-permeable silicone hydrogel contact lenses has reduced the incidence of hypoxic complications of the cornea (8). However, low permeable contact lenses, or overwear/overnight wear can still disrupt the oxygenation process of the avascular cornea. Chronic hypoxia can result in corneal oedema, reduced corneal transparency, and neovascularisation.
Dry Eye
Contact lens wear can disrupt the normal tear film, leading to symptoms of dryness, irritation, and discomfort. Contact lenses are a known risk factor for dry eyes, with around half of lens users experiencing symptoms (9). Reduced blink rate, particularly during screen use, can exacerbate symptoms.
Chronic dryness may reduce adherence to contact lenses but also lead to ocular surface inflammation.
Prevention and Education
The majority of contact lens-related complications are preventable with patient education. Strict hygiene before handling lenses, proper cleaning and storage with approved solutions, avoiding contact with contaminated water, and avoiding overnight wear (unless prescribed) can tackle the aforementioned issues. Healthcare professionals play a crucial role in promoting these practices and ensuring patients understand the risks associated with improper use.
Conclusion
Contact lenses are a safe and effective method of visual correction when used properly. However, misuse can lead to several complications, some of which are sight-threatening. MK, corneal hypoxia, and ocular surface disease are significant risks associated with poor contact lens hygiene and inappropriate wear practices. Importantly, many of these complications can be prevented with simple patient behaviour modifications. Improving patient awareness of safe practices remains key to reducing avoidable visual morbidity.
References
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