You have to be aged 21 and above to undergo LASIK surgery. You should not be pregnant or have cataracts, glaucoma, or any retinal diseases. Some conditions such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, or certain medications like prednisolone and accutane may also preclude you from LASIK surgery. Your ophthalmologist will perform a thorough examination of your eyes. Further tests are required to confirm your degree as well as the shape and thickness of your cornea to assess your suitability for LASIK surgery.