For reference only. 1. The visual field is related to the pupil. As long as the pupil is not blocked, the field of vision will not change much; 2. You can use a double eyelid patch or surgery to turn a single eyelid into a double eyelid, but it is more difficult to turn a double eyelid into a single eyelid; 3. The left eye suddenly becomes a double eyelid, which is obviously much larger than the right eye. Please try to see if the upper eyelid of the left eye is the same as that of the right eye when looking down. If the left eye is still very big, there may be other factors, and you should go to an eye examination.