There are a number of key factors that are related to severe outcomes from contact lens wear. Patients wearing contact lenses, practitioners and contact lens manufacturers all contribute to unsatisfactory results. What is of utmost concern is that contact lenses have been commoditised over the years. They are medical devices that are placed on our most precious organs – our eyes! We are NOT purchasing packets of chips.
As a practitioner I often counsel my patients about inappropriate cleaning or inappropriate cleaning schedules and all I get is this look of confusion. How can something as benign as a contact lens cause blindness?
Studies show that the risk of developing blinding eye infections is higher during the first six months of use. The hardness or softness of the contact lenses and the frequency of use were found immaterial with regard to determining the risk of bacterial eye infection. It actually depends on what material the lenses are made of.
Here are some possible causes of blindness you need to watch out for if you are wearing contact lenses:
Bacterial Infection – Pseudomonas Aeruginosa
Bacterial eye infection is one main concern for people wearing lenses and the germ that commonly causes this infection is the pseudomonas aeruginosa. This type of bacteria tends to breed in the eyes due to the decreased flow of oxygen to underlying tissues when the cornea is covered with a lens.
Research shows that the risks are as follows:
• Soft lenses worn during the day – one in 2,500
• Soft lenses worn overnight – one in 500
• Rigid lenses – one in 10,000.
The numbers may not be alarming. However, considering that hundreds of millions of people wear contact lenses worldwide, infected people would most likely be numerous.
In a study where participants were asked to wear different types of lenses, results show that the bacteria in the cornea of people wearing hyperoxygen rigid gas permeable lenses did not increase during the trial. However, after three months, the bacteria level in the cornea of persons wearing other lenses started to drop. After six months, the bacteria levels in the cornea of persons wearing different types of lenses were all the same. Thus, it would appear that as the eye adapted to the lens, the bacteria were also eliminated. It is therefore essential to be extra careful when using lenses for the first six months.
This debris can build up on the lenses and cause irritation. In more severe cases, it can result to corneal ulcer which is a serious complication that can lead to blindness.
When you wear contact lenses, your corneas are covered and they might not be able to maintain the normal production of new cells. When this happens, the cornea can become thinner by 10%.
This simple single cell microorganism is one of the most common types of protozoan thriving in fresh water and soil. It may be found in your tap water such that if you rinse your lenses with water from the sink, the amoeba may be transferred to your lenses and eventually, your eyes.
Unfortunately, your common contact lens solution will not be able to kill the amoeba. When it reaches your eyes, it can result to amoebic keratitis, a painful infection that can cause blindness. The longer you wear your lens, the higher the strain of acanthamoeba may be found therein. To be safe, avoid washing your lenses with tap water.
The best option ultimately is daily disposable contact lenses that are NOT reused! Either those, or wearing rigid gas permeable lenses as mentioned before.
While the newer contact lenses introduced in the market are found to be 10 to 40 times safer, you should still practice proper eye and lens hygiene to avoid adverse complications. Strict compliance with cleaning, storage and replacement schedules are the only sure way to not only protect your eyes but also enjoy the many benefits of contact lenses.
At The Eye Practice we specialise in all forms of contact lenses, but more importantly inprotecting your eyes. Call us on (02) 9290 1899 or BOOK AN APPOINTMENT ONLINE for as assessment and advice.