Introduction

What is contact lens-associated keratitis?

The most frequent eye infection brought on by contact lens use is keratitis.¹ Basically, it is an inflammation of the cornea that is either infectious or non-infectious. It occurs when eye inflammation spreads to the cornea, the see-through, domed window of the eye. Keratitis can sometimes cause corneal scarring, which impairs vision. 

Why it matters for contact lens users

Although contact lenses improve vision, there are risks involved with using them. Wearing contact lenses is linked with a high risk of corneal inflammation, or keratitis. Contact lens wearers may get keratitis for a variety of reasons. 

When bacteria infiltrate the cornea, one type of keratitis, known as microbial keratitis, may occur and can result in permanent harm to the human eye. It can arise when contact lenses are used for extended periods or are not properly looked after.² Microbial keratitis is such a dangerous kind of eye infection that it can, in the worst situations, cause blindness or necessitate a corneal transplant.

Understanding contact lens-associated keratitis

Types of microbial keratitis

Bacterial keratitis

It is the most common kind and is frequently brought on by bacteria such as Serratia marcescens, Staphylococcus aureus, and Pseudomonas aeruginosa.

Fungal Keratitis

Although fungal keratitis is less common than bacterial keratitis, it is frequently linked to severe corneal injury, particularly if vegetable matter is the fungal source.³

Viral Keratitis

Herpes simplex keratitis and herpes zoster keratitis are less common causes of microbial keratitis, but can happen when the virus reactivates after remaining dormant in the trigeminal nerve and travels along the axon (nerve fibre) to the cornea of the eye, where the nerve fibre conveys corneal sensation.

Acanthamoeba Keratitis

This severe type is associated with poor hygiene habits, such as swimming with contact lenses on or using saline or tap water instead of the appropriate cleaning solutions.⁴

Common symptoms of contact lens-associated keratitis

• Red, irritated eyes
• Increasing eye pain, even after taking out contact lenses
• Sensitivity to light
• Blurred vision occurring abruptly
• Unusual eye watering

Risk factors for contact lens-associated keratitis

• Poor hand hygiene: The danger is increased if hands are not cleaned with soap before handling lenses
• Inadequate cleaning: Bacteria can grow on lenses that are not adequately cleaned or disinfected
• Overnight wear: Wearing contact lenses while you sleep greatly raises the danger of infection⁵
• Extended wear: The risk of infection rises when lenses are used for longer than is advised
• Swimming or taking a shower while wearing lenses: Water contact, particularly contact with tap water, might introduce bacteria or amoebas

Hygiene’s role in the prevention of contact lens-associated keratitis

Importance of hand hygiene

Proper hand hygiene is essential to avoid contact lens-associated keratitis, a dangerous and frequently avoidable eye infection.^6,7 The risk of germs and other pathogens being transferred from hands to contact lenses and causing infection is greatly increased by insufficient handwashing or inadequate handwashing techniques.

Cleaning contact lenses properly

It is very important to clean and care for contact lenses properly to prevent contact lens-associated keratitis. This includes frequently changing the lens cover, washing hands frequently, and massaging and rinsing lenses with fresh cleaning solution. In addition, never use tap water, stay away from sleeping with your lenses in, and take care of your lenses according to your eye doctor's advice.

Avoiding water exposure (swimming, showering)

Avoiding water exposure when wearing contact lenses is important for reducing the occurrence of contact lens-associated keratitis, especially Acanthamoeba keratitis. This includes avoiding showering, taking a bath, or swimming while wearing contact lenses.

The dangers of sleeping in contact lenses

Wearing contact lenses while you sleep raises the risk of developing bacterial keratitis and fungal infections, among other eye problems. If left untreated, these infections can result in severe discomfort, redness, and potentially irreversible vision loss. Always take out your lenses before sleeping unless your eye doctor has given permission to do otherwise.

Proper storage practices

Cleaning and replacing the lens case

Replace and clean your contact lens case on a daily basis. Preventing bacterial and fungal infections requires a lens case that is kept clean and in good condition. With routine cleaning and replacement, the accumulation of bacteria that might cause eye infections can be avoided.

Using fresh contact lens solution

Every time you store your lenses, always use a new solution and throw away the old one. By doing this, contamination from detritus and infection-causing microbes is reduced. Your lenses will have a cleaner environment and be less susceptible to infection if you store them in fresh solution.

Avoiding topping up the old solution

Topping up is the process of adding a new solution to an existing, used one. Avoid topping up by never combining a new solution with a previously used or old solution in the case, because this lessens the effectiveness of disinfection.

Safe storage environment

Use a brand-new, well-cleaned case and solution, and keep lenses in a dry, clean environment. It is essential to replace the case regularly (at least every three months) and to handle lenses properly.

Daily habits that help prevent infection

Following the wearing schedules

• Follow your eye care provider's recommended routine, whether it be daily, bimonthly, or monthly
• Wearing lenses too much, even for just a few more days, might weaken the cornea and increase the risk of infection
• If you frequently forget to change your lenses, set reminders.

Avoiding extended use beyond the recommended time

Avoid wearing contact lenses overnight or after the suggested replacement duration. Wearing lenses too much lowers oxygen flow to the eye, leaving it more susceptible to infections and bacteria.⁸ Extra caution is required while using soft lenses since they can provide the perfect environment for the growth of pathogens.

Avoiding touching your eyes with unwashed hands

Germs are immediately spread over the surface of your eyes when you touch or rub them with unclean hands. Wash your hands when you have to go close to, or touch, lenses, for example before putting on makeup, using eye drops, or adjusting your lenses. When you're out and about, keep hand sanitiser or wipes without alcohol with you to clean your hands.

Recognising warning signs early

When to remove lenses immediately

Stop wearing your contact lenses immediately and see your eye doctor for a complete diagnosis and treatment if you have any symptoms involving discomfort, infection, or inflammation, including redness, pain, blurred vision, light sensitivity, excessive tear production, or discharge from your eyes. ⁹

Symptoms that require medical attention

Get medical attention right away if you encounter any of the following symptoms, which may indicate keratitis or an active eye infection:

• Eye pain that is ongoing or getting worse
• Light sensitivity (photophobia)
• Swelling surrounding the eye
• Yellow or green discharge
• Vision loss or blurriness that doesn't get better
• A white or greyish patch on the cornea that can be seen in a mirror.

These symptoms could indicate that the infection is progressing rapidly and that immediate treatment is necessary to stop irreversible harm.

Consulting your eye care professional

Regular eye exams

Routine eye exams are important to help prevent and cure contact lens-associated keratitis, an infection that can potentially lead to blindness. Regular checkups enable early detection of keratitis, enabling timely care and thus averting potential serious complications. Eye exams lower the occurrence of keratitis and also allow eye care specialists to offer tailored guidance on contact lens cleaning and care.

Following prescription and product guidelines

Follow your eye care provider's recommended lens care regimen and stick to the product instructions to the letter to reduce the risk of contact lens-associated keratitis. Schedules for appropriate cleaning, storage, and replacement are part of this. Additionally, it is important to maintain proper hand hygiene and avoid contact of water with the eyes while wearing lenses. According to a study, 23–94% of contact lens wearers report eye issues and related discomfort. Contact lens-associated keratitis affects 2-4 out of every 10,000 people each year. In 90% of instances, bacteria are to blame; fungi and acanthamoebae are significantly less common causes.¹⁰

Summary

A serious disorder known as contact lens-associated keratitis involves corneal inflammation and is frequently brought on by infections with bacteria, fungi, viruses, or parasites such as Acanthamoeba. 

Those who wear contact lenses are more vulnerable to keratitis, especially if their lenses are not cleaned properly, are exposed to water, or are worn incorrectly. Redness, discomfort, impaired vision, light sensitivity, and excessive tearing are typical symptoms.

Poor hand hygiene, insufficient or inadequate lens cleaning, overnight or prolonged wear, and contact with water while wearing lenses are important risk factors.

Proper hygiene measures include avoiding tap water or topping up old solution, cleaning lenses with fresh solution, and washing hands before handling lenses. Using only the recommended cleaners and routinely cleaning and replacing the lens case are essential components of safe lens storage. Additionally, users should avoid using lenses past their recommended lifespan and adhere to appropriate wearing schedules. Daily disposables may lower the risk of infection, particularly for people with hectic schedules or low compliance with proper protocols.

If symptoms associated with infection occur, it's necessary to identify early signs and take out the lenses right away. Urgent medical assistance is necessary for serious symptoms such as eye pain, discharge, or vision changes. Routine eye exams and adherence to recommended care instructions assist in the early detection of problems and the mitigation of complications. Matching the safest lens type and care schedule for each person's needs is more assured by consulting an eye care specialist.