Leaving glasses in the car is not advisable, especially during hot or sunny days. Glasses, particularly those with delicate lenses or frames, may be damaged due to heat and direct exposure to intense sunlight.
Firstly, high temperatures inside the car can damage the glasses’ lenses, especially if they are made of heat-sensitive materials like polycarbonate. Heat can cause deformations or even breakage of the lenses, compromising their functionality and your ability to see clearly through them.

Secondly, prolonged exposure to direct sunlight can fade or alter the color of the glasses’ frames. This can affect the aesthetic appearance of the glasses and may require the replacement of the frame.
How the sun and heat damage glasses lenses and frames:
Deformation of lenses: High temperatures can cause the deformation of glasses lenses, especially if they are made of heat-sensitive materials such as polycarbonate. Lens deformation can affect their curvature and their ability to properly focus light, thus compromising your vision.
Lens overheating: Direct exposure to intense sunlight can overheat glasses lenses. This can cause permanent damage to the lenses, such as cracks or the separation of layers that make up the lens itself.
Fading or alteration of lens color: Sunlight can fade or alter the color of glasses lenses, especially if they are made of materials that are not UV-resistant. This can affect the quality of vision and the lenses’ ability to properly filter out harmful light.
Deterioration of the frame: Heat and sun exposure can also damage the glasses’ frame. Plastic materials can become brittle and break, while metal materials can discolor or deform. The frame may lose its strength and structural integrity, making the glasses less reliable. To protect your glasses, it is advisable to avoid leaving them exposed to direct sunlight and high temperatures.
When you are not wearing your glasses, store them in a protective case and keep them in a cool and dry place. Additionally, make sure to regularly clean your glasses with appropriate tools and products to keep them in good condition.
Furthermore, leaving glasses in the car increases the risk of theft. If you leave your glasses visible inside the car, you may attract the attention of potential thieves who might break the windows to steal them.
If, for some reason, you need to leave your glasses in the car, make sure to put them in a secure and out-of-sight location, such as the glove compartment or the trunk. Additionally, try to avoid doing so on very hot or sunny days.
In general, it is always advisable to carry your glasses with you when you exit the car, especially if you need them for driving or clear vision.