Contact lenses and glasses are both viable options for meeting a patient’s vision needs. Your optometrist is qualified and experienced in fitting contact lenses to your unique eye shape, so you can achieve effective vision correction and comfort throughout the day.
Understanding how contact lenses function and how to use them properly can help you avoid damage or injury. This includes adhering to the proper usage timeline, as contact lenses do expire.
Contact Lenses Explained
A contact lens is a thin, curved corrective lens made from plastic materials, designed to correct refractive errors like myopia, hyperopia, and astigmatism. Similar to eyeglasses, contact lenses ensure light bends correctly as it enters your eye, so it lands directly on the retina, helping you see clearly.
Unlike eyeglasses, the lenses of which sit about a centimetre in front of your eyes, contact lenses sit directly on the eye’s surface. Because contact lenses are fundamentally different from eyeglasses in this way, we need to measure the following:
- Eye surface base curve
- Eye shape & diameter
- Corneal parameters
- Tear film quality
- Cylinder, for astigmatic eyes
- Axis, for astigmatic eyes
With these measurements, we can determine which contact lenses suit your unique vision needs. These measurements can also help determine if we need to look at specialty contact lenses like scleral or rigid gas permeable lenses.
Why Do Contact Lenses Expire?
Contact lenses sit directly on the surface of your eye, therefore, using them correctly is critical to avoid risking injury or damage to your eye. Soft contact lenses have their expiration date listed on the packaging they’re provided in.
Contact lenses are medical devices, and it is essential to use them within the valid timeframe to ensure they remain sterile and safe. Within the package, contact lenses sit in a saline solution that risks expiring. After expiration, the saline solution’s ingredients can begin to deteriorate, causing bacterial growth and contamination to occur.
Expiration could occur quicker than expected if the seal on a blister pack breaks. A broken seal can allow bacteria to enter the package and compromise the saline solution, or even start growing on the contact lens itself.
What Happens When You Wear Expired Contact Lenses
Wearing expired contact lenses can affect your eye health in notable, adverse manners.
Bacterial Keratitis
Bacterial keratitis, otherwise known as a corneal ulcer, occurs when the corneal tissue becomes infected. Your cornea, sclera, and conjunctiva are highly permeable. This permeability means your eyes are susceptible to infections in ways the rest of your body isn’t . Small organisms that grow on a contact lens can penetrate the corneal tissue and cause eye infections.
Symptoms of bacterial keratitis include:
- Eye pain
- Blurred vision
- Light sensitivity
- Eye discharge
- Excessive tears
Antibiotic eye drops are a common treatment for bacterial keratitis. In the same way your eye tissue can absorb bacteria, it can also absorb antibiotics effectively to fight infection.
Corneal Abrasion
Expired saline solution for your contacts can also mean the contacts themselves aren’t lubricated properly. Contact lenses need to be lubricated in order to sit comfortably on the eye’s surface and prevent irritation.
A dry contact lens can cause inflammation, redness, and discomfort. In severe cases the dry contact lens can rub harshly against the surface of your eye, causing corneal abrasions. An abrasion is essentially a scratch on the corneal surface, which is painful and increases your risk of infection.
Be Mindful While Wearing Contact Lenses
Contact lenses are a personalized vision correction solution that greatly reduces your need to rely on glasses to see clearly. But it’s crucial to remain mindful while wearing contact lenses to minimize your risk of eye health problems like infections, diseases, and injuries.
Your contact lenses can expire, and so can your prescription. It’s imperative to keep your contact lens prescription and fit updated so you can continue seeing clearly and comfortably. Get in touch with us to book a contact lens exam today.
