Monthly Archives: November 2010

Epi-LASIK and PRK : Why Choose Surface Laser Vision Correction?

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Lower risk and outstanding results are driving the trend back to the surface with an increase in popularity of surface laser vision correction in recent years.

More surgeons worldwide and in Calgary are recommending Epi-LASIK and PRK as a safer no-flap alternative to LASIK and more people are choosing surface treatments for laser vision correction.  To understand these trends it helps to know a little bit of the history of laser vision correction.

In the 1980’s several investigators were involved in the development of the excimer laser for use in laser vision correction.  Research confirmed that the excimer laser could be used to accurately reshape the cornea (the cornea is the clear outermost layer in the front of the eye which is analogous to a windshield).  Margueritte McDondald was credited with performing the first PRK in 1987.  PRK involves removing the corneal surface cells called the epithelium and then applying the laser energy to the corneal surface.  PRK gained in popularity very quickly in the late 1980’s.  With these early cases there were some reports of significant haze (a scarring type of reaction), which in some cases affected the vision and needed additional treatments.

By the early 1990’s Dr. Pallikaris had combined an older flap making technology called a lamellar flap with the new excimer laser treatments.  In this procedure a corneal flap was created, the flap was lifted, and then the laser was applied to the corneal surface under the flap – this was called “flap and zap” and later called LASIK.  LASIK quickly became very popular since the vision recovered more quickly and there was less discomfort in the first few days after surgery.

Over the next two decades excimer laser technology advanced along with flap making technology, and the use of bandage contact lenses following PRK.  Over this same time period there were many reports about complications that could happen with LASIK surgery, many of which are discussed in the book LASIK COMPLICATIONS: PREVENTION AND MANAGEMENT published by SLACK Inc.  This book was written for LASIK surgeons and went into three editions.  Complications with LASIK include partial flaps or buttonhole at the time of surgery, flap interface inflammation, and shifted flaps in cases of eye injuries even months or years after LASIK surgery.  There is no book about PRK complications.  This is not because there are no complications, but because PRK is a simpler procedure with less potential for complications.

Many surgeons made note of this lower complication rate with PRK.  As the laser technology advanced, the issues relating to corneal haze have almost been eliminated for PRK.  The use of bandage contact lenses has also improved the comfort during the first few days following surface laser vision correction.

Within the last five years a further advancement in surface no-flap laser vision correction was developed with the creation of Epi-LASIK.  Epi-LASIK is a variation of PRK that uses a separator to remove the surface epithelium.  The advantage of Epi-LASIK is the smooth edge to the epithelium which results in more rapid recovery of vision within the first three to seven days following surgery.

Both Epi-LASIK and PRK do take longer to recover the sharpest vision as compared to LASIK and there is more discomfort within the first three days following surgery.  The advantages of these surface laser vision correction methods include the lower risk (there is no flap that may be involved in a complication at the time of surgery or shifted at a later date).  Epi-LASIK and PRK do not invade the cornea as deeply so may not weaken the cornea as much as a flap procedure like LASIK.  There are some reports to indicate that there may be less permanent dry eye following Epi-LASIK and PRK due to this less invasive treatment.  Some investigators feel that the quality of the final vision may be better without a flap since a corneal flap may induce some optical aberrations.

Every person needs to make a choice of laser vision correction procedures that is right for their individual case.  LASIK remains a popular choice, but with the refinements in surface no-flap PRK and Epi-LASIK more people are choosing to have these surface no-flap treatment.  More information about laser vision correction  can be found in the book Laser Vision Correction: What You Need To Know which can be purchased at  http://www.amazon.ca.

For more information or to book a complimentary assessment for laser vision correction in Calgary with Dr. Anderson Penno, contact Western Laser Eye Associates today.