San Diego Eye Center

Down-Up LASIK Backgrounder

Over the past several years, there has been a very definite trend in refractive surgery throughout the world. An increasing number of cases of nearsightedness, farsightedness and astigmatism are being treated with Laser Assisted in-situ Keratomileusis (LASIK). In this procedure, an automated instrument known as a microkeratome is used to make a corneal flap to give the surgeon access to deeper layers of the cornea for subsequent laser reshaping.

The advantages of LASIK over photorefractive kertatectomy (PRK) are increased post-operative comfort for the patient, faster healing, less chance of scarring, ability to treat higher levels of refractive errors, preservation of Bowman’s membrane and better quality of vision.

Since 1989 (when the first LASIK surgery was performed), the procedure has improved greatly. Thousands of patients have been successfully treated with the classical method of cutting the corneal flap starting from the temporal side and stopping nasally before a complete circle as been cut, producing a nasal hinge.

Down-up LASIK (also known as Superior-Hinge LASIK or Top-Hinge LASIK) is similar to the classical technique. The difference lies in one very important detail: The cut is performed from the bottom upward. This creates a "superior hinge," which is a more natural position than the nasal hinge.

Advantages of the New Microkeratome

• Independent medical studies have proven the new microkeratome to be safer and have lower complication rate.
• It can perform the cut upward from the bottom of the eye with the creation of a superior hinge.
• It performs cuts with a very large diameter for easier treatment of farsightedness, and less induced astigmatism
• The quality of the cut surfaces is very high. This is due to the faster blade speed, resulting in a much smoother cut.
• The new microkeratome has several built-in safety features including an elevated gear tract and a fixed plate. The most common complication with the older model is having the eyelashes or eyelids catch on the gear tract impeding the motion of the microkeratome, resulting in an incomplete or irregular cut. This is avoided in Down-up LASIK because of its elevated gear tract. The plate, a device that determines flap thickness, is removed and reinserted each time the older microkeratome is used. Failure to reinsert the plate would result in perforation of the eye. The Down-Up LASIK’s plate is fixed and irremovable.
• The automated cutting procedure is simple and safe, and ease of use does not change if the left or right eye is being operated upon.

Advantages of Down-up LASIK

• The flap with the classical nasal hinge can potentially move due to the vertical blinking movements of the eyelids. Due to either incorrect position in of the flap at the end of the procedure, inadequate adhesion to the underlying layers or excessive tearing, flap dislocation is one of the most common complications observed in the immediate post-operative period. With the superior hinge, the down-up movement of the upper eyelid keeps the flap in position and smoothes it completely. And, gravity will tend to situate the flap in the best position for healing.

• The best vision is reached more rapidly due to the improved uniformity within the treated area.

• There is less foreign-body sensation post-operatively. Foreign-body sensation and excessive tearing are more common with the classical technique. As a result, patients are more likely to rub their eyes and dislocate the flap.

• With the superior hinge, pressure exerted by the upper eyelid will tend to eliminate microfolds within the cornea and allow for more uniform healing of the cornea and better vision.

10 Reasons to choose SAN DIEGO EYE CENTER

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