7) Corneal Thickness Measurements

If corneal thickness is not measured or measured correctly, there may not be enough tissue preserved during the surgery. As a result, you may have irregular vision.

Flap surgery itself has been performed for many years. It was first performed in the form of keratomileusis. Flap surgery has evolved into a more accurate surgery because of the laser. But there are principles we learned from flap surgery even before the advent of the laser component.

One important principle is we know we do not want to thin a cornea too much.

• If we do, it could become irregular in shape and create an irregularity in vision that could be a problem.
• We feel it is very important to accurately measure the thickness of your cornea. Since we know the thickness of the flap we are going to make and since we know the amount of tissue the laser is going to remove to get our correction, we can calculate how much of your cornea we are going to leave behind untouched.
• We think the number to be respected is to leave at least 250 microns of the back portion of the cornea untouched.
• If we do your calculations and it shows it would be less than 250 microns, we will recommend you not undergo laser vision correction and either have nothing done at this time or consider implant technology.
• We will discuss both of these options during your consultation. Corneal thickness is measured two different ways in our office.
• A pachymeter is a device that measures the thickness of your cornea by ultrasound.
• The Orbscan topography instrument, which is mentioned under Corneal Topography, measures the distance between the front and back curvature of your cornea optically.

Back