Is there a way to reverse vision loss without surgery?

Not likely. Vision loss implies a decrease in the eye's ability to record an image and/or send the image to the brain. Most causes of vision loss require medical or surgical treatment, or both. One of the few causes of vision loss that can be reversed without surgery is refractive amblyopia (lazy eye due to an uncorrected need fro glasses). If treated at a young age, it can be nonsurgically reversed.
It depends. This depends upon the type or cause of the vision loss. Some conditions can be treated with drops while others require surgery.