Optometrist in exam roomWhen you are considering LASIK, the doctor may use terminology that is specific to the procedure.  Here is a list of some commonly used terms regarding the measuring devices and equipment that are used in LASIK surgery.


Corneal Topography: this measurement generates a topographical map of the surface of your cornea, and will show the degree of astigmatism (irregular shape) of your cornea.  Additional topographies will be taken to see if there is any change to the cornea surface. Contact lens wear can change the shape of the cornea, so it is important for patients to stay out of their contacts prior to their procedure. It is important that you have a stable cornea prior to surgery to insure your best visual outcome.

Custom Vue Wavescan: this device takes a detailed measurement of your visual system. As light reflects off of your retina, the Wavescan measures your vision from the retina through the vitreous, lens and cornea. Higher order aberrations that affect your vision are also measured.  Custom-Vue creates a unique, custom image of your eye.  The measurements from this device are used to program the laser during surgery.

Pachymeter:  is a small pen-shaped instrument that measures your corneal thickness. Corneal thickness is an important measurement in determining if you are a candidate for LASIK.  You must have enough corneal thickness for the doctor to safely create the LASIK flap, and reshape the cornea.  If your corneas are too thin, PRK may be the better option.

Visual Acuity:  Measurements of your vision with and without your glasses will also be recorded.

Phoropter:  this device is used to determine your prescription: “Is it better 1 or better 2?” is the question that you are asked to help fine-tune your prescription.  Using a series of lenses, the phoropter will help the technician determine your best prescription for correction.


Eye Speculum:  or lid holder, is used to hold the eye open during the procedure to prevent the eye from blinking.

Microkeratome: this instrument is used during surgery to create a thin flap in your cornea.  The microkeratome is placed on the surface of the cornea, pressure is applied, the surgeon then uses the device to create a hinged flap in the eye’s corneal surface.

LASER: After the flap has been opened, the surgeon applies the laser that reshapes the eye for vision correction. After the application of the LASER, the surgeon will close the flap.

Bladeless LASIK: Also known as iLASIK.  In this procedure, LASER energy is used to create the flap.