LASIK is a refractive surgical procedure that reshapes the cornea to focus light on the retina. It is done by creating a flap in the epithelial (outer) layer of the eye with a lathe or laser, called an Intralase. The underlying tissue is then laser reshaped to a predetermined arrangement in order to eliminate refractive conditions. It is designed to treat nearsightedness (nearsightedness), farsightedness (farsightedness), and astigmatism. However, it does not eliminate the need for reading glasses in those over forty. Surgery can only correct one distance at a time.
The procedure is very effective, however there is no guarantee that there will be no residual refractive power left, or that the person will not regress requiring glasses in the future. While there are several possible deleterious side effects of surgery, one of the most serious and potentially vision-threatening is called DLK, which stands for diffuse laminar keratitis. It is also known as Sahara Sand, as it often appears as sand dunes in the Sahara desert.
This condition arises when inflammatory cells migrate to and under the corneal flap. Depending on the location of the cells, vision can be normal or severely reduced. There is often glare and, in some cases, the individual will present with eye discomfort. Traditional therapy has been to prescribe strong steroid eye drops like Pred-Forte every hour and closely monitor the patient to reduce these inflammatory cells. This can take days or even weeks to fully resolve. In some cases, the cells remain under the flap indefinitely.
In cases where the flap was created by a lathe, there is a gradual slope from the point of contact between the lathe and the corneal bed. This slope allowed this cell migration under the flap. It was a fairly constant degree of DLK in the cases that were predisposed to acquiring this condition. Intralase, by comparison, results in a passage from the peripheral cornea to the corneal bed. You would think that this abrupt step would reduce the number of cases and the severity of DLK compared to those of the lathe. Interestingly, DLK is more prevalent in Intralase patients compared to lathe. In either situation, cells present a problem that must be addressed.
According to Dr. Theirry Hufnagel of the Stahl Eye Center in New York, the best treatment is to return to surgery and lift the flap. Once the flap is separated again from the corneal bed, the underlying area is washed and bathed with saline, physically removing all cells. This is a simple procedure, but the most effective way to completely, quickly, and safely remove all inflammatory cells. It also prevents any secondary complications that may arise from the use of steroid eye drops. In Dr. Hufnagle’s opinion, it is the best way to remedy DLK.
This procedure is not performed by most refractive surgeons, and is only used by the highly trained and experienced. As always, you should only operate with doctors who know all the techniques to deal with post-surgical complications.
