The cornea is the clear covering of the front of the eye which bends, or refracts, light rays as they enter the eye. For clear vision to occur, the cornea must have the correct shape and clarity to focus incoming light rays precisely on the retina at the back of the eye. When the cornea becomes cloudy or misshapen from injury, infection or disease, transplantation may be recommended to replace it.
Cornea transplants are usually performed with regional anaesthesia so there is no pain. During the procedure, the cornea is replaced with one from a human donor. The new cornea carries little risk of rejection and can last for many years.
DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty)
DSAEK is a novel technique in corneal transplantation. DSAEK offers clear post-operative vision and short recovery time for patients with Fuchs' dystrophy (an inherited eye disease that affects eyesight) or patients in need of new corneas. DSAEK replaces only the innermost layer of cells within the cornea, known as the endothelium. This allows the procedure to be performed through a much smaller incision with shorter recovery times and fewer risks than a traditional corneal transplant.
During the procedure, the damaged section of the posterior cornea is removed from the eye. The donor cornea is prepared and inserted into the eye as accurately as possible to optimise donor survival. The new cornea unfolds on its own and the wound is closed. An air bubble is then injected underneath the donor cornea to facilitate its adherence to the recipient cornea. The pupil is dilated with eye drops.
Patients are sent to the recovery room for about one hour. Patients are expected to stay overnight in hospital and are checked by Dr. Kumar the following day. Patients are then given antibiotics and steroid eye drops and will return the next week for a follow-up appointment.
Recovery from DSAEK
Most patients notice improvements to their vision within the first two weeks after surgery, with results continuing to develop during the next four to six weeks. This is significantly faster than the traditional corneal transplant procedure, which may take six to 12 months before effective results are achieved. Other existing eye conditions may slow or hinder the improvement of vision after the DSAEK procedure.
Risks of DSAEK
While the DSAEK procedure is considered safe for most patients with cornea damage, there are certain risks involved with any type of surgical procedure, including infection, bleeding and more. Although rare, there is a risk of transplant rejection, which may result in redness, sensitivity to light and blurred vision. If you are experiencing these or any other symptoms after DSAEK, you should contact Dr Kumar to prevent any damage from occurring.
To learn more about the DSAEK corneal transplant procedure, and to find out whether or not this procedure is right for you, please call us today to schedule a consultation with us.
DMEK (Descemet’s Membrane Endothelial Keratoplasty)
Descemet’s Membrane Endothelial Keratoplasty (DMEK) is a new advancement in corneal transplantation. In a DMEK procedure, only the inner layers of the cornea are replaced. As with DSAEK, this is much less invasive than a traditional keratoplasty, which requires replacement of the full cornea and may alter its shape and therefore the patient’s eyesight. It is often performed to improve vision that has been compromised by Fuchs’ dystrophy.
The posterior corneal layers are taken from a donor for this grafting procedure. Once the patient’s own damaged tissue is removed from the cornea, the donor replacement tissue is carefully placed at the rear of the cornea. Since only inner layers of the cornea are replaced in a DMEK procedure, the recovery is typically much faster and easier than in older methods, with most patients achieving improved visual acuity within a week after the surgery.
DALK (Deep Anterior Lamellar Keratoplasty)
Deep Anterior Lamellar Keratoplasty (DALK) is a type of corneal transplantation for keratoconus, stromal dystrophies and scars. It is used to replace the outermost layers of the cornea while preserving the well functioning inner layers known as Descemet’s membrane and the endothelium. A DALK procedure may therefore be a better option than a penetrating keratoplasty, in which the full thickness of the cornea must be removed. The full thickness traditional method can place the patient at higher risk for developing healing or vision problems.
This procedure is appropriate for those patients with damage restricted to the outer layers of the cornea, such as keratoconus. Several layers of corneal tissue are removed from the patient’s eye and replaced with the corresponding tissue from a donor eye. Since more natural tissue is maintained in a DALK procedure, there is less of a chance of graft rejection than with penetrating keratoplasty.
Penetrating Keratoplasty (PKP)
Penetrating keratoplasty, or full thickness corneal transplantation, is the traditional method of surgically dealing with corneal disease, and has been performed for over 100 years. An improperly curved cornea may be corrected surgically for patients whose curvature is too steep or flat to be treated with other methods, or when extensive damage has occurred due to disease, infection or surgery.
Keratoconus is a progressive thinning eye disorder in which the normally round cornea begins to bulge into a cone-like shape. In patients with keratoconus, the cone-shaped cornea deflects light and causes distorted vision.
Keratoconus often begins to develop between the teen years and the early 20s, although it can develop at any age. Changes in the shape of the cornea occur gradually, usually over several years. Patients with keratoconus often experience blurred and distorted vision, nearsightedness, and a glaring sensitivity to light.
Early stages of keratoconus can be treated with glasses or soft contact lenses. For progressive keratoconus, treatment methods include rigid gas-permeable contact lenses, INTACS or KERARINGS(implants that flatten the cornea), and collagen cross-linking (vitamin B2 eye drops and UV light exposure). Collagen cross linking is a safe and effective new development that halts the progression of keratoconus.
If keratoconus persists or is severe, corneal transplant surgery can be performed to correct the condition.
A pterygium is a benign growth of the conjunctiva that grows onto the cornea. It can eventually lead to impaired vision.
Patients with pterygium often first notice the condition because of the appearance of a lesion on their eye or because of irritation and inflammation. Other symptoms include dryness, redness, and tearing. In more severe cases, the pterygium grows over the pupil and limits vision.
The most common pterygium treatment is eye drops (artificial tears) and such protective measures as sunglasses and hat wear. In more significant cases, surgery may be recommended.
- Pterygium Excision with Conjunctival Auto-grafting - in this procedure, the pterygium is removed along with the tissue covering the sclera (conjunctiva). Tissue is removed from the patient's upper conjunctiva and used to cover the bare sclera. Dr. Kumar advocates the use of fibrin glue rather than sutures to fix the autoconjunctival graft into place.
Recurrent Corneal Erosion Syndrome
Recurrent corneal erosion syndrome may occur in patients with recent fingernail or plant trauma to the cornea. Rarely it can also occur in patients with corneal dystrophies or diabetes. Symptoms include severe pain, irritation, redness and watering upon waking and opening the eyelids. Medical therapy usually involves temporising measures such as bandage contact lenses, drops and tablets. A range of definitive surgical treatment options exist for patients with this debilitating condition.
Phototherapeutic Keratectomy (PTK)
Phototherapeutic Keratectomy (PTK) is an advanced laser procedure used to treat corneal abnormalities such as scar tissue or an irregular surface that causes blurry vision or discomfort within the eye. This procedure is often performed with vision correction surgeries such as photorefractive keratectomy (PRK), but is considered a medical procedure that improves the overall health and shape of the cornea.
PTK is ideal for patients with corneal conditions such as:
- Recurrent erosion syndrome
- Corneal scars
- Corneal dystrophy
Before the development of PTK, cornea treatment involved manually scraping away abnormal roughness with a surgical blade or replacing the entire cornea through a transplant procedure. PTK offers patients a safer, less invasive alternative that helps them achieve the results they desire.
During the PTK procedure, the eye is numbed with anesthetic drops to reduce any potential discomfort. The eye is held open with a special device to prevent blinking during the procedure. Dr Kumar will then remove the epithelium, the protective covering of the cornea, from the eye, while a laser reshapes the cornea to your unique specifications, which have been determined prior to treatment. The laser treatment takes less than a minute to perform. The epithelium will heal naturally to cover the treated area.
Recovery from PTK
After the PTK procedure, patients may experience blurry or hazy vision for a few days, as well as mild discomfort as the epithelium heals. Dr Kumar may prescribe eye drops or pain medication to reduce these symptoms. A protective contact lens may also be used to minimize discomfort. While vision may fluctuate for up to six months, most patients are highly satisfied with the results of this procedure.
Risks of PTK
Although PTK is considered safe for most patients, there is a risk of certain complications associated with any surgical procedure. Some of these risks may include poor wound healing, farsightedness or astigmatism.
To learn more about our Cornea Surgery Services, please contact us today to schedule an appointment.