How often should you replace your contact lens case?

The official recommendation

The guidance is consistent across US health bodies. The FDA says to replace your contact lens storage case every 3 months or as directed by your eye care professional. The CDC says to replace it at least once every three months. The American Academy of Ophthalmology adds: or right away if it gets cracked or damaged. The American Optometric Association gives the same three-month interval.

Three months is the maximum, not a target. Many optometrists suggest changing the case more often, for example with every new bottle of solution, since most bottles come with a fresh case in the box.

Why the case matters as much as the lenses

The case is warm, damp and opened every day by hand. Over time a thin layer of microbes, called a biofilm, can form on its walls. Once it is there, rinsing does not reliably remove it, and disinfecting solution does not fully reach the microbes inside it. Each night, your clean lenses sit in that environment for hours.

That is why the case is one of the most neglected parts of lens care. In the 2015 CDC survey of US contact lens wearers, 82.3% admitted keeping their case longer than recommended. It was the most common risky behavior in the whole survey, ahead of topping off solution (55.1%) and sleeping in lenses (50.2%).

Daily case care: what the CDC recommends

1. Empty it every time. Throw away all the old solution after you put your lenses in.
2. Rub and rinse with fresh solution. The CDC advises rubbing and rinsing the case with fresh solution and avoiding water.
3. Air-dry it upside down. Store the clean case upside down on a fresh, clean tissue with the caps off.
4. Never top off. Do not add fresh solution on top of old solution in the case. Always start with an empty, clean case.
5. Keep water away. The FDA says not to expose lenses to any water: tap, bottled, distilled, lake or ocean. The same logic applies to the case.

What about the solution bottle?

Solution has two dates, and people often mix them up:

• Expiration date, printed on the bottle and box. It applies to an unopened bottle.
• Discard date, the period after opening during which the solution stays reliable. It is usually stated on the label, and many multipurpose solutions give about 90 days, but check your own brand.

The FDA says not to use contact lens solution beyond either date, never to reuse solution and not to pour it into smaller travel bottles, because that can compromise sterility. Write the opening date on the bottle with a marker, or track it somewhere you will look.

Signs you should replace the case right now

• Cracks, scratches or a lid that no longer closes tightly.
• Any discoloration, film or residue that does not rinse out.
• It came into contact with tap water, or was left open in a bathroom for days.
• You had an eye infection. Ask your eye doctor; replacing the case, the solution and the lenses together is a common precaution.
• You cannot remember when you started using it.

Common mistakes with the case

Leaving the lenses in yesterday's solution

The disinfecting effect of solution is designed for a fresh fill. Old solution that has been sitting open in the case all day is not the same product anymore. If you did not wear your reusable lenses for a few days, check the solution instructions: many say to re-disinfect before wearing.

Closing the case wet

A closed, damp case is exactly the environment microbes like. That is why the CDC recommends leaving it open and upside down to air-dry while you wear your lenses.

Using the travel case forever

The spare case that lives in a backpack or a gym bag is easy to forget. It needs the same three-month replacement as the one in the bathroom, and it is often stored in worse conditions.

Keeping the case next to the toilet or sink

Splashes of tap water and aerosols in the bathroom are a real source of contamination. Store the case a little further away, in a clean and dry spot.

A simple routine that works

Item	How often	Source
Solution in the case	Fresh every time, never topped off	CDC, FDA
Case cleaning	Rub, rinse with solution, air-dry upside down after each use	CDC
Case replacement	At least every 3 months, or when damaged	FDA, CDC, AAO, AOA
Opened bottle of solution	Until the discard date on the label	FDA, manufacturer
Lenses	As prescribed: daily, two-week, monthly and so on	Your eye doctor

The easiest way to stay on schedule is to tie the case to the bottle: when you open a new bottle, swap in the new case that came with it and throw the old one away. If you buy solution in bulk, set a separate reminder for the case. The lenses themselves follow their own replacement schedule.

This article is general information and does not replace advice from your eye care professional or the instructions on your solution.

Keep all three dates in one place

Lenses, solution and case each run on a different clock, which is why the case is so easy to forget. In Wink, the free version counts down to your next lens change. Wink Pro adds a "Solution & case" screen: mark the day you opened the bottle and started a new case, set how many days each lasts, and Wink shows how much time is left and reminds you when it is time to replace them.