How can I improve eyesight using food without correcting glasses or surgery?

Unfortunately, there really is no way to "organically" improve eyesight in the way I suspect you mean.

Certainly if there has been poor nutrition with vitamin deficiencies/inadequate calorie intake, correcting these will help restore what should have been the default healthy state of the eye. Likewise, omega-3 fish oil and antioxidants will help restore tear production in the case of dry eye, but this almost always a problem of middle-age and older.

But if you are asking what foods or vitamin supplements might prevent nearsightedness or astigmatism from developing or getting worse, there really is no food alternative to do this.

Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic