We asked the various saline manufacturers/distributors how they feel about their salines being subjected to extreme temperatures during the summer. Here is what they said:
Menicon (Lacripure) - A temporary heat spike will not affect the quality of Lacripure. If exposed to a heat spike for an extended period of time, it can possibly shorten the expiration date.
Bausch & Lomb (Scleralfil) - Scleralfil is recommended to be stored at room temperature. The company does not have any studies to show if it is safe to use when exposed to higher temperatures.
Lifestyle (Purilens) - It is absolutely safe. Temperature will not affect the sterility of Purilens saline. You would just want to allow it to get to room temperature for comfort.
Visionary Optics (VibrantVue) - Can be used as usual if exposed to extreme temperatures, just make sure solutions has returned to room temperature before using.
Tangible Science (Tangible Fill) - Tangible care solutions can be used as usual after exposure to extreme temperatures, provided they have returned to room temperature naturally. If you do notice anything unusual, discontinue use.