In situations where there is superficial scar tissue or an irregular corneal surface that affects the eye, the vision may become blurry or the eye may become uncomfortable. There are several surgical ways to reduce this scar tissue when glasses or contact lenses no longer work well for a patient. One of these methods is with a laser procedures called phototherapeutic keratectomy (PTK). Your doctor will discuss your options depending on the amount of scar tissue that you have and how much pain and discomfort you are having caused by this scarred tissue.
The PTK is a procedure that is performed using the excimer laser concentrating the laser beams to remove only scarred or irregular corneal surface to improve vision or to reduce discomfort from recurrent erosions of the corneal tissue and some corneal dystrophies.
PTK surgery will be performed under a topical anesthetic and there will be minimal discomfort during the actual procedure. You will be lying on your back during the procedure and a device called a lid speculum will be placed in your eye to hold it open. A modulating agent is used to coat the depressions and expose the peaks in the cornea. The laser treatment is then carefully carried out with the goal to smooth the corneal surface removing any scar or irregularities. Immediately after the procedure, a bandage contact lens will be placed on your eye for comfort. Your ophthalmologist will usually remove the bandage contact lens about four to seven days after the procedure. You may experience some mild pain postoperatively; however, you will receive medications to help reduce any discomfort. The vision will fluctuate during the healing process, which can take as long as three to six months for some patients.
Lamellar ketatectomy is another surgical option to remove superficial corneal scars or surface irregularities not amenable to PTK. Your doctor will discuss your options depending on the amount of scar tissue that you have and how much pain and discomfort you are experiencing.
A full thickness or deep scar may be better treated by a form of corneal transplant such as DALK or full thickness PK.
Deep Anterior Lamellar Keratoplasty is performed when the scarring or corneal disease involves the front half of the cornea. The anterior portion of the cornea is removed, leaving the very thin posterior portion of the cornea and the new donor cornea is then sutured into place.
The advantages of DALK over the traditional full thickness graft are the rejection of corneal tissue occurs in the posterior part of the cornea, so by leaving the patient’s posterior cornea in place we can greatly reduce the likelihood of corneal graft rejection. Because there is less likelihood of rejection, the anti rejection medications can be discontinued in about 6 weeks vs. 4 – 6 months for a full-thickness graft. The anti-rejection medications can cause glaucoma and cataracts to develop in some patients, so shortening the time a patient uses these medication will lessen the chances for these side effects to occur.
The anti-rejection medications can also slow the wound healing time. Because the anti-rejections meds are used only a short time with the anterior lamellar grafts, the wound heals more rapidly and the sutures can typically be removed in about 6-9 months vs. 12 months or more for a full thickness transplant.
The eye is also stronger after an anterior lamellar graft compared to a full thickness graft. Unfortunately, the surgical technique is more complex and challenging. At the time of surgery the thin posterior membrane can rupture and in that case the surgery is converted to a full thickness transplant or penetrating keratoplasty.
*As with any surgical procedure there are risks along with benefits. It is important to discuss your surgical procedure with your surgeon to fully understand the risks and benefits.