Have you ever noticed that one of your eyelids is drooping? This condition is called ptosis and it’s due to the muscles in your eyelids not being able to open the eyelid wide enough. There are many causes of ptosis. If you have ptosis, you should have a doctor evaluate it. Some causes are due to medical conditions that need immediate treatment. Others are due to mechanical issues that can be treated with surgery. In this case, surgery was indicated.
Here you can see that the left upper eyelid is now higher giving this person better symmetry but also better vision. Ptosis can affect your ability to drive safely and to see things on the left side of your visual field.
If you have ptosis, consider an evaluation to better understand your condition.