Laser surgery, tear gland damage and eyelid problems that don't allow for you to blink as often, which spread the tears, also cause dry eye.
It is recommended to get that amount of sleep regularly for a handful of weeks, at any rate. https://amssaudi.com/__media__/js/netsoltrademark.php?d=imagenetofficesystems.net%2F__media__%2Fjs%2Fnetsoltrademark.php%3Fd%3DBookmarkgenious.com%252Fstory18289824%252Fwatery-dry-eyes-after-lasik-surgeryml-if-ie-8