Useful information

Eye drops for contact lenses – what’s different?

2022/10/01

You can’t use regular eye drops while wearing contact lenses. You have to use special eye
drops.
What is the difference between eye drops for contact lenses and eye drops for normal eyes?

What are eye drops for contact lenses?

Eye drops for contact lenses are generally called “artificial tears” and contain ingredients
similar to tears; specifically, sodium chloride and potassium chloride supplement ingredients
similar to tears to protect the eyes from dryness.
In addition, some products contain thickeners that prevent tears from evaporating and keep
them moist, as well as fatigue recovery ingredients such as taurine, vitamin B12, vitamin B6,
and vitamin E.

Differences between eye drops for contact lenses and regular eye drops

Ordinary eye drops contain various ingredients to alleviate or treat the symptoms of each
condition, while eye drops for contact lenses are made with only ingredients that have little
effect on the lenses. Therefore, when wearing contacts, it is necessary to use special eye
drops.
The biggest difference is preservatives.
Most common eye drops contain a preservative called “benzalkonium chloride” as an
additive. This is not a problem if the cornea is healthy, but if it is used by elderly people or
people with weak corneas due to dry eyes, it may damage the cornea. Suppose you wear
contact lenses and use them. In that case, the preservative components may be absorbed
by the lenses, which may damage your eyes or lead to deformation or discoloration of the
lenses.
In addition, some general eye drops contain vasoconstrictors to improve eye redness, but
this also requires caution. If you put eye drops containing a vasoconstrictor on an area
where oxygen tends to be deficient due to contact lenses, the blood vessels in the cornea
will constrict, which can lead to further oxygen depletion.
Because of these precautions, be sure to use special eye drops when wearing contact
lenses.

If you want to use regular eye drops before wearing contacts

If I want to use regular eye drops before wearing contact lenses, how long should I wait?
The Japanese Ophthalmologists’ Association’s “Handbook Q&A for Proper Use of Eye
Drops” states the following:
“When re-wearing contact lenses after installation, please allow enough time (approximately
5 to 10 minutes). In addition, instruct patients to wash their hands, etc., to handle contact
lenses with care to avoid contamination.”
Allow 5 to 10 minutes before putting in contact lenses after using regular eye drops.

The shelf life of eye drops is surprisingly short

By the way, have you been using open eye drops for a long time?
Bacteria can easily grow inside the container of eye drops, so the expiration date is actually
not that long. “Within 3 months after opening” is a guideline.
Additionally, preservative-free eye drops for contact lenses have a much shorter shelf life, so
be sure to check the expiry date before using. By the way, the expiration date written on the
outer box is for unopened products, so please be careful.
◎ Reference
Supervised by the Japan Ophthalmologists Association “Handbook for Proper Use of Eye
Drops Q&A (Materials for Medical Professionals)”
http://www.dy-net.jp/eyedrop/tenganzai_handbook.pdf