Regarind to your question, if you just run out of your contact lens solution, you can make saline solution at home naturally. Saline solution is something we purchase regularly in our house. Not limited to eye and contact lens care, saline solution can also be used for wound irrigation and as a nasal rinse. The saline solution consists of two very basic components, salt and water. Saline solution is easy to make at home. You will need:
clean glass bottle or jar with lid, table salt, pot with lid.
Put one cup of water and 1/2 teaspoon of salt into the pot. Put the lid on.
Boil for 15 minutes with the lid on (set a timer).
Set the pan aside until cooled to a room temperature.
Carefully pour the salt and water (normal saline) from the pan into the jar or bottle and put the lid on.
There is something you can use instead of contact solution when you run out of it. The alternatives are saline solution, distilled water and salt water. Like contact lenses solution, the saline solution is also a disinfectant solution and will not cause damage to contact lenses. Since it is sterile, it can cleanse the surface smudges of the contact lenses. Distill water can be used to store and clean contact lenses, for it has no acanthamoeba keratitis that is harmful to the eyes thus more applicable than the tap water. You can even use salt water to clean and store your contact lenses. Salt water can be got by putting a certain amount of salt into tap water. None of these alternatives can be used in long term. So you should buy a bottle of contact lenses solution as soon as possible.
Contact lenses solution is used to keep the hygiene of contact lenses. If you have no more solution on your hand, there are alternatives. Remember alternatives can only be used in an emergency. The alternatives are saline solution, distilled water and salt water. Saline solution is similar to contact lenses solution and does no harm to your contact lenses. Distilled water may very clean but it can contain virus as well and cause your eye infected. Salter water is easy to make, though salt can kill most of the bacteria but not all of them. And saltwater may irritate your eyes.
If you run out of the contact lenses and now have no place to buy the new one, you could put the contact lenses in the distilled water with no invisible bacterium. You'd better buy the new contact lenses solution next day and change the contact lenses into the solution to get rid of the protein on the surface. It is so necessary.