Contact lenses can mold the cornea and produce inaccurate measurements before surgery. For this reason, it is critical to leave contact lenses off the eye for a sufficient amount of time before surgery. A patient from Santa Barbara who hates wearing glasses asked me today how long she’ll need to leave hear contacts out before surgery. This is a good question and one that we don’t want to take short cuts on in order to optimize accuracy.
Contact lenses are a foreign body on the eye. They can mold and distort the cornea and even produce corneal swelling. For this reason, it is critical that they be left off the eye before LASIK or PRK long enough to allow the corneal tissue to return back to its original shape — without any residual effects from the contact lens. Many patients are frustrated by the need to leave their contacts out, but remember that only by leaving contacts out for an appropriate amount of time can I achieve maximum accuracy of results for you!
Different types of contact lenses need to be left off the cornea for different periods of time.
Daily wear soft lenses should be left off the eye for a minimum of two weeks before LASIK or PRK laser eye surgery.
Daily wear soft toric lenses, which are lenses that correct astigmatism, should be left off of the eye for a minimum of three weeks before LASIK or PRK laser eye surgery.
Gas permeable contact lenses, which are rigid lenses that correct astigmatism, should be left off the eye for three weeks and then measurements of the eye should be taken. The gas permeable contacts should be left off of the eye for an additional three weeks and the measurements should be repeated. If there is no change, then the patient is ready for surgery, but if the measurements have changed, the contacts need to be left off for intervals of an additional three weeks at a time until the measurements stabilize.
Extended wear soft lenses need to be left off of the eye for a minimum of one month before LASIK or PRK.
We can certainly write you a glasses prescription so that you will have correction to wear during the period you will have to go without contact lenses before your surgery. For many patients, particularly those who wear their contacts “all the time,” this can be the hardest part of surgery! Obviously, however, it is important not to cut corners on this pre-operative step.
See Also
The Long Term Effects of Contact Lenses on Corneal Thickness and Curvature
Scientific paper looking at the effects of contact lenses on the cornea which could interfere with pre-operative LASIK measurements
FDA LASIK Website
FDA guidance for how long to leave various types of contact lenses off the eye before LASIK laser eye surgery