Dr William Boothe

Optical Ablation Zone - That part of the optical zone corrected by a laser treatment.

Optic Disc - The circular area where the optic nerve meets the retinal nerve fibers, and where blood vessels enter the eye. It’s also known as the “blind spot” because this intersection with the optic nerve and presence of blood vessels interferes with the retina’s function as a camera film.

DR BOOTHE

regression - A return to the original refractive state. In PRK the surface layer or epithelium is removed prior to or as part of the procedure and then the deeper corneal stroma is reshaped with the cold laser treatment. During healing both the surface epithelium and the deeper corneal stroma can reshape and reform at different rates. Computer generated PRK treatments assume a normal "Bell" curve amount of healing for both layers and thus normally "over correct" the refractive error in order to finally heal with no refractive error and no need for glasses. A small percentage of patients will heal faster and more vigorously than expected and will thus regress or "heal" their planned over correction back past no refractive error to their original type of error. This regression phenomenon occurs with both myopic and hyperopic corrections. It occurs more commonly with smaller ablation diameters and with abrupt transition zones at the edge of the laser treatment areas. Some surgeons have suggested that the epithelium overgrows as if nature abhors a vacuum and overreacts to fill in the space. Steroid medications can usually be used to regulate and control regression.

Dr William Boothe

: Wavelength - The distance between the top of one wave and the top of the next. Used of light waves. Specific wavelengths equate to specific colors. The excimer laser used in LASIK procedures is 193 nm in wavelength, which is an ultraviolet light (beyond the violet area, and therefore invisible to our eyes).