Lenses: extreme heat and freezing are the risks
Scleral lenses are made of a rigid gas permeable plastic, and they handle ordinary life well. The problems wearers report come from storage in extreme conditions:
- Very high heat. Lenses that went through a washer and dryer, sat on a dashboard, or were left near a grill or oven. A few wearers describe a lens that warped and no longer fit, and one that was ruined outright after being left in a hot car.
- Freezing. A spare lens left in a case in a freezing car, or a case that froze while camping. Wearers have reported lenses that felt different afterward and needed replacing. Long-distance hikers in near-freezing weather often keep the case inside a sleeping bag overnight for this reason.
The tricky part is that warping can be hard to see. A lens can look normal and still sit differently on your eye. That’s why the advice from fitters and experienced wearers is the same: if a lens has been through extreme heat or cold, have your fitter check it before you wear it.
Heat while you’re wearing the lenses, from a sunny day, a sauna-warm car, or sitting near a campfire, isn’t what wearers worry about. Drying out from wind and heat is the bigger day-to-day problem, and protective glasses help with that.
Solutions and drops: follow the label
Every lens care product and eye drop has storage directions, and they aren’t all the same. Two examples:
- Boston Simplus Multi-Action Solution: store at room temperature, do not freeze.[1]
- Refresh Celluvisc, a thick lubricant some wearers add to their fill: the label gives a storage temperature range that a closed car in summer or winter can easily fall outside.[2]
The FDA advises not using lens care solutions past their expiration or discard date and following all labeling instructions.[3] Storage directions are part of that labeling. If a product spent time outside its range, the simplest safe choice is to replace it.
Makeup is similar. The FDA advises against storing cosmetics in high heat, noting that cosmetics held for long periods in hot cars are more prone to the preservative breaking down.[4] If you keep eye makeup in your car or beach bag, see makeup and skin care.
What to keep and what to replace
| What happened | What wearers and labels suggest |
|---|---|
| Lenses in a hot car, dryer, or near a heat source | Don’t wear them until your fitter has checked them |
| Lenses frozen in their case | Thaw at room temperature, re-clean and disinfect, then have them checked |
| Saline or solution kept outside its label’s range | Replace it |
| Drops left in a hot or freezing car | Check the label; replace if outside its range |
| Plungers and inserters left in the heat | Clean them; replace if warped, cloudy, or sticky |
| Old spare lens stored for a long time | Ask your fitter before wearing; it may have warped or no longer fit |
Keeping a car or travel kit safe
Many wearers keep a small kit in the car, because a lens problem on the road is miserable without one. The ones who do it well treat that kit differently from the one at home:
- Emergency use only. Use it to remove a lens safely or get home, not as your daily supply.
- Swap it out often, especially at the start of summer and winter, and whenever it’s been through a heatwave or a freeze.
- Insulate it. An insulated lunch bag or cosmetics bag helps. Under the seat is not much cooler than the rest of the car.
- Keep it out of direct sun on the beach, on a boat, or in a backpack.
- Never decant solutions into smaller bottles to save space. The FDA warns this can affect sterility.[3]
See the emergency kit for what to pack and traveling with scleral lenses for longer trips.
What wearers say
Experiences vary. Some wearers who live in hot places use solutions that get warm without noticing any problems, and some keep car kits for years. Others have lost lenses to a single hot afternoon or a frozen case. Because a ruined lens is expensive and slow to replace, most experienced wearers err on the side of caution with the lenses themselves, and accept that a few vials of saline will sometimes be thrown away.
What to ask your fitter
- My lens was exposed to heat or freezing. Can you check it for warping?
- Is my old spare lens still safe to wear after being stored?
- Which of my products are most sensitive to temperature?
- Is it OK to warm my saline vial before filling?
Common questions
I left my emergency kit in a hot car. Do I have to throw it all out?
Check each label's storage directions. If a product was kept outside them, replace it. Many wearers treat a car kit as emergency-only and swap the saline and solution out regularly, especially through summer and winter. Tools like plungers usually just need cleaning and a check that they're not warped or sticky.
My case froze overnight with my lenses in it. Are the lenses OK?
Don't assume so. Wearers have reported lenses that became uncomfortable after freezing. Let the case thaw at room temperature, discard the solution, clean and disinfect the lenses with fresh solution, and ask your fitter to check them before you wear them.
Can I warm my saline before filling the lens?
Some wearers find cold saline makes them flinch and warm the sealed vial in their hand or a cup of warm water. Others advise against warming plastic vials at all. Never microwave saline, and never heat it beyond comfortably warm. Ask your fitter if you're unsure.
Can I wear my lenses in very cold or very hot weather?
Wearers report wearing scleral lenses in snow, skiing, and hot climates. The usual problems are wind and dryness rather than temperature. Wraparound or wind-blocking glasses help. The concern on this page is about storing lenses and solutions, not wearing them.