LASIK and the Importance of Corneal Thickness
If you have seriously been considering LASIK surgery, the chances are good that this is not the first article you have read on the procedure. In fact, you are probably fairly familiar with the basics of LASIK by now, including the criteria that distinguish suitable candidates from those who would be better served by PRK or another form of laser vision correction. One of those criteria, as you may know, is the thickness of the cornea. What you may not know, however, is exactly why corneal thickness is so important to the success of a LASIK procedure.
In discussing LASIK and corneal thickness during consultations at his Monmouth County, NJ eye care clinic, Dr. Daniel Goldberg acquaints patients with the anatomy of their eyes. This helps them not only to understand why they may or may not be good candidates for LASIK, but also to make confident, informed decisions regarding whether and how to proceed with treatment.
With advances in LASIK, including advanced diagnostic technology such as the Visante® system and the IntraLase® laser that replaces the traditional microkeratome blade, more patients than ever are good candidates for LASIK, including many whose thinner corneas would have precluded them from undergoing the procedure in the past. Are you among them? To find out for yourself, please schedule your initial consultation with our pioneering LASIK surgeon today.
Why Is Corneal Thickness So Important to LASIK Surgery?
The goal of LASIK surgery is to improve the focusing power of the cornea by correcting flaws in its shape through the strategic, meticulous removal of tissue with an excimer laser. In modern custom LASIK, the excimer laser is guided by a wavefront map, which accounts for even the smallest imperfections in the cornea, clinically known as higher order aberrations. These imperfections cannot be identified without wavefront mapping technology, nor can they be corrected through traditional methods of vision correction, including conventional LASIK.
Conventional LASIK also involved the creation of a hinged flap in the outermost layer of the cornea using a handheld device with an oscillating blade on one end, called a microkeratome. While highly precise, the microkeratome cannot match the precision and accuracy of the IntraLase® laser, which can make a thinner, more uniform flap. This alone makes blade-free LASIK a superior option to conventional LASIK, including for patients with relatively thinner corneas, as the risk of flap complications is reduced.
Now, let’s get into some science.
The average patient who is considered a good candidate for LASIK has a cornea that measures about 550 microns thick. Dr. Goldberg prefers to leave approximately 300 microns of the cornea undisturbed. Assuming that the patient is a good LASIK candidate, Dr. Goldberg has about 250 microns of cornea to work with.
The microkeratome creates a corneal flap of about 160 microns, give or take a few microns. On the other hand, the IntraLase® laser is capable of creating a corneal flap of approximately 100 microns thick. This means that a patient with a cornea of 550 microns would leave Dr. Goldberg with 140 microns of tissue to reshape, a significant amount to make noticeable improvements. It also means that a patient with a cornea of 500 microns, who might have been considered a poor candidate for conventional LASIK, would now be considered a suitable candidate for blade-free LASIK. While Dr. Goldberg will have less corneal tissue to reshape than with the patient with 550 microns of tissue, he will still have sufficient tissue to make significant improvements to the shape of the cornea.
Ultimately, at least 250 microns of corneal tissue must be preserved in order to maintain the cornea’s structural stability. Dr. Goldberg prefers to err on the side of caution and not approach that 250-micron boundary, as doing so would increase the patient’s risk of glaucoma and corneal bulging.
Learn More about LASIK and Corneal Thickness
To learn more about LASIK and corneal thickness, please contact Atlantic Laser Center today.