Deep anterior lamellar keratoplasty (DALK) advantages
- As it is an extraocular technique, there is less risk of serious complications such as infection and bleeding.
- Lower risk of graft rejection.
- The corneal wound after a DALK procedure is less weak over keratoplasty. In DALK, stitches are placed anteriorly and can be removed more quickly.
Indications for DALK
- Different conditions must be met before deciding whether a cornea transplant can be considered.
- Defects of the first part of the cornea (epithelium, Bowman’s membrane, but especially stroma) with a normal endothelial layer-corneal dystrophies
- Very strongly pronounced keratoconus:- progressive deformation of the cornea where the light is no longer projected homogeneously on the retina
- Corneal scars: after trauma, post-infection (herpetic keratitis, caused by bacteria, after burns)
Deep anterior lamellar keratoplasty techniqueDeep anterior lamellar keratoplasty consists of manual dissection of the layers of the corneal stroma. Usually, dividing layers in this way is easy, with accurate results. Visual acuity after such a separation remains insufficiently high. According to recent studies, the results after DALK and traditional deep anterior lamellar keratoplasty are almost the same, but the loss of endothelial cells with DALK is somewhat lower. The technique guarantees less damage during transplantation.
Deep anterior lamellar keratoplasty (DALK) risks
- Rare but serious complications
- Infections that can affect vision (1 in 1,000)
- Severe bleeding causing loss of vision
- Retinal detachment
- Severe inflammation or other causes of vision loss
- Corneal transplant rejection. In one out of every six patients during the first two years after transplantation, they may have a transplant rejection. It occurs when the patient stops taking the anti-rejection medication without a doctor’s advice. Rejection remains a possibility throughout life.
- Conversion to penetrating keratoplasty. In 10% of patients, a partial-thickness transplant such as DALK is not possible, and a full corneal or penetrating keratoplasty is required.
DALK ProcedureBefore DALK, you may need to undergo the necessary examinations to understand the possible complications and the ability to perform the procedure. It helps to detect whether the person is suffering from other eye conditions like cataracts, macular degeneration, etc. If necessary, the patient will first have to undergo cataract surgery before planning a DALK. This procedure takes place in a day hospital. The operation is usually performed under local anesthesia and takes about an hour. As soon as the anesthesia works, the patient’s eye is covered by a sterile drape. A central 8mm partial thickness of the damaged cornea is removed and replaced with a similar healthy donor button. The last part of the stroma is detached from Descemet’s membrane using visco-elastic dissection. Visco-elastic material is then injected into the deep layers between Descemet’s membrane and the stroma. In this way, the perforation of the Descemet membrane is avoided. After trepanation (using a round blade) from the foremost part of the cornea (stroma), the stroma is removed using a round blade. The graft (from the corneal bank) is then placed in the opening created and will stick against Descemet’s membrane, which has remained in place. The graft is secured to the patient’s corneal tissue using a continuous nylon suture. In general, the patient is discharged on the same day, and the intervention is followed the next day and, subsequently, a week later. The patient needs to undergo regular check-ups. In general, the patient is advised two weeks off work. After the operation, an anti-inflammatory ointment is affixed, as well as a bandage. This dressing can be removed by the patient the day after the transplant. The entire procedure lasts approximately 75 to 90 minutes. The patient is asked to remain calm until the next day when the first post-operative check-up will take place.
Preparing for the DALKWhen the first part of the cornea is found to be the reason for poor eyesight, such as keratoconus or corneal dystrophies, only the epithelium and stroma are replaced. Descemet’s membrane and the patient’s endothelium are spared and form the mat to accommodate the graft. Thanks to this technique, the healing process is shorter, and the refractive result is more predictable. The patient is more likely to have a better vision afterward. On the day of surgery:-
- No mascara, no makeup.
- In the morning, you can use preoperative medicines prescribed by doctors.
- If the procedure takes place in the morning, you will need to be on an empty stomach. If the operation is in the afternoon, you can have a light lunch.
- Anesthesia is performed using a small injection near the eye.
- The ophthalmologist takes his time to explain everything to you: no surprises.
- Your eyes will be held open by a retractor; this will prevent you from blinking.
- You won’t hurt.
- The operation lasts approximately 45 minutes.
- The transparent protective shell should be worn every night for a week after the procedure.
- Eye drops recommended by doctors should be applied regularly from the day after the operation. Your doctor will prescribe you the dosage.
DALK Post-transplant careAfter the intervention, the patient should be administered anti-rejection eye drops for at least one year, and, in some cases, it will be indefinitely. The stitches can begin to be removed three to six months after the intervention.
- Patients can return to their normal activities for two weeks after the operation, except swimming.
- You may need to use anti-inflammatory drops for six weeks.
- It is often necessary to use one drop of cortisone per day, and this for the long term.
- The patient should visit the clinic for regular check-ups right from the day after the operation and in a sequence, that is, after three days, ten days, three weeks, six weeks, two months, and after every six months.
- The technique of instillation of drops should be accurate. Do not touch the eyeball. Pull the lower eyelid down while looking up. Apply the drop and close your eye.
- The sight will still be very blurry at the start and will clear up in the weeks following the operation. The possible adaptation of glasses can take place after two months at the earliest.
- In case of significant pain, contact the ophthalmologist.
- Do not plan any heavy or sporting activities in the days following the procedure.
- For the first three weeks, do not rub in the eye and avoid using makeup.
- Avoid dusty environments.
TakeawayDeep anterior lamellar keratoplasty (DALK) is a popular surgery for treating corneal disease. It removes the corneal stroma down to Descemet’s membrane and restores the normal functioning of the endothelium. Although many experts termed it as a time-consuming and challenging procedure, it has seen renewed interest recently. Advance technology in DALK helps to reduce surgery duration. Sometimes, DALK is the first-line treatment in patients with anterior corneal opacification or structural corneal defects with a healthy functioning endothelium. It protects the host endothelium and Descemet membrane. At last, Deep anterior lamellar keratoplasty causes fewer postoperative complications and graft rejections.
• Visual impairment, such as blurred or cloudy vision,
• severe pain in the eye,
• sensitivity to light.
• Some patients have additional symptoms of headache, nausea, and fatigue.
• Dystrophies and degenerative corneal disorders.
• Autoimmune disorders.
• Nutritional deficiencies.
• Vernal and atopic keratoconjunctivitis.
• Ectasia (thinning)
not available currently