Until recently, laser vision correction treated patients based strictly on their optical prescription. In other words, if you were a minus-four nearsighted person, glasses with minus-four lenses would get you back to seeing the best that you could. If you had laser vision correction, that same prescription would be programmed into the excimer laser and the exact amount of tissue would be removed to make a minus-four into a zero. Anyone who was a minus-four would get the exact same treatment. We call this conventional laser vision correction.
Today, with the advent of wavefront diagnostic technology, wavefront guided excimer lasers can now treat patients according to the uniqueness of their entire optical system, not just their prescription.
How It Works
Wavefront technology was pioneered for astronomy and physics to aid in reducing aberrations or imperfections in the optical systems of telescopes. In much the same way, wavefront-sensing devices are being used to produce an accurate picture of the optical imperfections found in the human eye. This technology differs from traditional testing methods in its ability to measure the entire optical system of the eye, instead of simply the front surface of the eye. Light travels in a procession of flat sheets known as wavefronts. These wavefronts enter the eye, pass through the entire optical system (the cornea, lens and retina) and are then reflected back.
When the optical system has perfect refracting surfaces, these wavefronts exit the eye as flat sheets. But when the cornea is irregular or the lens is imperfect, higher-order aberrations are created, and the wavefronts exit the eye as irregular, curved sheets.
Wavefront technology captures the reflected wavefronts and compares these curved sheets to a perfect wavefront and a 3-D map of the eye’s optical irregularities is created. This map is then transferred to the excimer laser and is used as a guide to reshape the cornea during laser vision treatment.
Results have shown that custom laser vision correction can reduce some of the unwanted visual effects experienced from conventional laser vision correction, especially those associated with night vision such as glare and halos. By addressing both a person’s prescription and the higher order aberrations within their eye’s optical system, custom laser vision correction has the potential of making patients see better than they could with conventional glasses or conventional laser vision correction.