You may not be aware of this, but keeping the same sunglasses for longer than 2 years can damage your eyes.
Sunglasses should be changed every two years to protect eyes from sun damage say scientists
Exposure to the sun is now believed to wear down the protective lensing of your sunglasses, causing damage to your eyes, and Designer sunglasses now have a shelf life of only two years. Scientists have undertaken studies to measure the scale of deterioration due to exposure to the sun and have confirmed that if sunglasses aren’t replaced, the wearer runs the risk of long-term degeneration of vision.
The aim is to ensure lenses have sufficient UV filters as inadequate levels could affect the cornea and internal structure of the eye. When this happens, edema or swelling to the eye can cause distorted vision. Pterygium or the growth of fleshy pink tissue on the white of the eye can also affect vision while other side effects can result in retina damage or cataracts.
This is a lesson, to not take your eyes for granted and take care of your eyes, your vision is all you have.