Anyone considering LASIK should undergo a thorough examination by an eye care professional. The exam, and a follow-up consultation with the physician, will:

• Identify any ongoing health concerns that may affect the candidate’s vision in the future
• Educate the candidate on potential outcomes of LASIK
• Manage expectations on what the procedure can do
• Inform the candidate of his or her vision health status.

A list of preliminary or screening tests that may be performed is included below. Additional testing, depending on the preliminary findings and the special needs of the candidate, may also be appropriate. If, after an evaluation, a patient has questions about why a test was included or omitted, he/she should discuss the matter with his/her eye care professional.

Assessment of Eye Health History

• History of wearing glasses: It is important to determine if your vision is stabile or is changing. If it is unstable, LASIK may not be an option at this time. The ideal candidate has had a stable glasses or contact lens prescription for at least 2 years.
  
  
• History of contact lens wear: Contact lenses may change the shape of the cornea (the clear front surface of the eye) in a way that prevents your doctor from determining your correct prescription. It may be necessary to abstain from contact lens use for a period of time prior to completing your pre-operative assessment.
  
  
• History of ocular or systemic diseases and medications: Some eye diseases and medications can affect the suitability of a candidate for LASIK.
  
  
• History of previous ocular problems: These may include blepharoplasty, plastic surgery, lazy eyes, strabismus (eye misalignment caused by muscle imbalance), or the need for special glasses to prevent double vision, glaucoma, cataracts, diabetic retinopathy, and macular degeneration.
  
  
• History of previous eye injury: This may include complications from previous refractive surgery.
  
  
• Assessing vocational and lifestyle needs: Your professional or recreational activities and needs help determine vision correction strategies. For instance, your need for depth perception or the ability to see near or far could define the best correction options for you.

Comprehensive Examination of the Eye

Your eye exam should include the following:

• Determination of uncorrected vision and vision as corrected by glasses or contacts.
  
  
• Determination of the magnitude of visual error in each eye to establish the amount of surgical correction that is needed and develop the appropriate surgical strategy.
  
  
• Assessment of the surface of the cornea by “mapping” its topography (corneal curvature or shape), to correlate its shape to errors in focusing (correlate corneal shape to refractive astigmatism), to find irregularities, if any, and to screen for disease that may cause poor outcomes following LASIK. This is often done at the surgery center.
  
  
• Measurement of pupil size in dim and normal light. Pupil size is an important factor in affecting night vision and planning the appropriate laser vision correction strategy.
  
  
• Assessment of motility to measure the ability of the muscles to align the eyes.
  
  
• Examination of the eyelids to see if they turn inward (possibly scratching the cornea) or outward and redirect tear flow away from the eye, and other conditions.
  
  
• Examination of the conjunctiva (the transparent covering on the outer surface of the eye) to identify abnormalities that may contribute to irritations or redness.
  
  
• Examination of the cornea to determine if there are any abnormalities that could affect the outcome of surgery.
  
  
• Examination of the crystalline lens to determine if clouding of the lens (cataract) or other abnormalities are present.
  
  
• Measurement of corneal thickness. The amount of LASIK correction may be determined in part by corneal thickness. This is often done at the surgery center prior to the performance of any procedure.
  
  
• Measurement of intraocular pressure to detect glaucoma or pre-glaucomatous conditions.
  
  
• Assessment of the back (posterior segment) of the eye: Examination of the retina, optic nerve, and blood vessels screens for a number of eye and optical system conditions.

Following your exam, your eye care professional will discuss your results or order additional testing as necessary. Your results will help determine the best vision correction option for you.