Full thickness penetrating keratoplasty surgery
The first corneal transplant is the full thickness corneal transplant, otherwise known as penetrating keratoplasty. The first surgery took place in 1905 and modern advances in eye banking have made this surgery effective in treating a host of corneal disorders. This surgery involves replacing all the layers of the cornea and sewing on a donor full thickness cornea in place with 16-24 nylon sutures. The diseased patient cornea is removed with a trephine which is a sharp circular cookie cutter-like tool which is precisely centered on the patient’s visual axis. Penetrating keratoplasty surgery can take place under retrobulbar or general anesthesia and usually takes 60 mins to 90 mins to complete. The sutures are then removed in the clinic over the course of a few months and vision is restored with selective suture removal over the course of 6 months to 1 year. Where does corneal donor tissue come from? It comes from organ donors after death. Everyone can be a cornea donor. The donor’s blood type does not have to match the blood type of the recipient. If you are able, sign up to be an organ donor when you get your driver’s license at the Department of Motor Vehicles as you can help save lives and help save someone’s sight.
DALK Surgery for Keratoconus and Corneal Scars
Deep anterior lamellar keratoplasty (DALK) is a partial-thickness corneal transplant which involves only the donor stroma (the top 99% of the front of the cornea), leaving the recipient’s own Descemet’s membrane and endothelium. In effect, this is like giving the cornea an entire new surface and shape while retaining the patient’s own natural deepest 15 micron cellular layer. This surgery is generally one of the longest transplants and can take 90 min to 2 hours as great care is made by the surgeon to carefully remove the anterior layers of the cornea and avoid perforating the thin posterior layer.
DSEK Surgery for Bullous Keratopathy
Bullous keratopathy is a condition in which the cornea becomes swollen and cloudy and begins to form blisters on the surface. Descemet stripping endothelial keratoplasty (DSEK) is a type of partial thickness corneal transplant surgery which can resolve bullous keratopathy. In this surgery, the posterior layer of stroma as well as the endothelial cell layer containing the endothelial cells are transplanted. This surgery allows the new donor to clear the cornea and restores vision usually in a few weeks to months. Partial thickness posterior transplants were invented by Dr. Gerritt Melles, MD in 1998 and refined by Dr. Melles and Dr. Mark Terry, MD. The current form of DSEK has been performed since 2004.
DMEK for Fuch’s Dystrophy
Descemet membrane endothelial keratoplasty (DMEK) is a type of partial thickness corneal transplant surgery and is one of the most advanced corneal transplants. This is the thinnest corneal transplant surgery as only the posterior 15 micron layer of cells in the back of the cornea are transplanted through a small corneal incision. The graft is opened in the eye with a no-touch technique. Check out this Youtube video of Dr. Pillar inserting a DMEK graft. Vision recovery can be quite rapid and vision may improve in a few weeks. DMEK was invented in 2006 by Dr. Gerritt Melles, MD and being continuously refined.
Superficial Keratectomy for Anterior Basement Membrane Dystrophy
A superficial keratectomy is a cornea procedure used to treat anterior basement membrane dystrophy (ABMD). ABMD is a condition of abnormal maturation of the epithelial cells and basement membrane that forms the outermost surface of the cornea, the clear watch crystal on the front of the eye. These abnormal cells create an irregular corneal surface which can be comprised of parallel lines, white putty-like deposits, fine haze or scarring, and even elevated nodules. Correcting areas of the cornea involved with anterior basement membrane corneal dystrophy and corneal nodules can include the use of a surgical instruments, a fine diamond burr, and sometimes even the excimer laser in a procedure called PTK (phototherapeutic keratectomy). The cornea can be gently lifted if the lesions are superficial, or a deeper excision called a lamellar keratectomy may be indicated. Depending on the extent of the keratectomy, the procedure may take place in the clinic, in the ambulatory surgical center, or at the laser center.
Corneal Crosslinking to Stop Progression in Keratoconus
Keratoconus worsens as the collagen fibrils in the cornea slip and cause the cornea to become weaker and thinner. The crosslinking procedure works to halt keratoconus by strengthening the bonds of the cornea and linking adjacent collagen fibrils. As a result, the corneal shape can be preserved. By preventing vision from worsening and preventing the cornea from thinning, crosslinking in effect stabilizes the cornea. The procedure itself is safe and minimally invasive. It involves placing an FDA approved Riboflavin drop called Photrexa on the cornea and then shining ultraviolet light at a set distance from the cornea with an iLink device by Glaukos. PPO insurances are providing coverage for corneal crosslinking.
Intacs for Keratoconus
Keratoconus is a condition causing a steep and thin cone shape due to weakening and thinning of the collagen in the cornea. Intacs are implants which act as braces for the cornea. They are placed deep in the cornea and correct the irregular shape of the cornea and can flatten the cone in keratoconus. Intacs were initially approved for the treatment of myopia and are used off-label for treatment of keratoconus. Due to its off-label status, it is usually not covered by medical insurance.