Kensington Eye Center 4701 Randolph Road, #G-2 Rockville, MD 20852 (301) 881-5701 www.keceyes.com Natasha L. Herz, MD INFORMED CONSENT FOR DESCEMET S STRIPPING and AUTOMATED ENDOTHELIAL KERATOPLASTY (DSAEK) or PENETRATING KERATOPLASTY (PKP) OPERATION This information is provided so that you can make an informed decision about having eye surgery. Take as much time as you wish to make your decision about signing this informed consent. You are encouraged to ask questions about any procedure before agreeing to have the operation. INTRODUCTION Figure 1. Corneal edema The cornea is the clear window at the front of the eye that bends and helps focus light onto the back of the eye (the retina). In order for vision to be clear, the cornea must be clean and clear. Corneal disease can cause the cornea to become opaque or cloudy, preventing light from passing through clearly. Fuch's Dystrophy and bullous keratopathy (corneal edema) are conditions in which the cornea is cloudy (Figure 1). In these conditions, the innermost layer of the cornea, the endothelium, is failing and is causing the cornea to become swollen and cloudy. This layer needs to be replaced when the amount of corneal edema decreases the vision significantly. PENETRATING KARATOPLASTY (PKP) Until recently, the only way to replace the endothelial layer of cells was with a full thickness corneal transplant called Penetrating Keratoplasty or PKP. This surgery involves replacing the patient s diseased cornea with a cornea that has been donated by someone who has died (the donor cornea). Traditionally, a full-thickness disc or button of the diseased cornea is removed and replaced with a matching button of donor cornea, using 16-24 sutures to sew it in place (Figure 2). a b c d Figure 2. Traditional Corneal Transplant a. cloudy cornea removed b. donor cornea replaced c. donor cornea with sutures d. actual photo of donor cornea with sutures Because of the size and thickness of the incision, these sutures cannot be removed for 12-18 months and often cause the cornea to take on an irregular shape during the healing process that is difficult to correct with glasses or contact lenses. There is also an increased risk of rupture with moderate trauma. DESCEMET S STRIPPING and AUTOMATED ENDOTHELIAL KERATOPLASTY (DSAEK) Over the last several years, a technique has been developed to replace only the back layer of the cornea instead of replacing the entire full thickness cornea. A patient with Fuchs Dystrophy or bullous keratopathy is a candidate for this new procedure, called Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), because the back layer is the only layer that is diseased in this condition. When there is scarring throughout the cornea, a full-thickness transplant is still necessary (see Figure 2). Figure 3 on the following page demonstrates the DSAEK procedure.
Figure 3. Descemet s Stripping Automated Endothelial Keratoplasty (DSAEK) a b c d a. The damaged inner layer of the cornea is dissected and removed through a 4mm incision. b. & c. A new inner layer from a donor cornea is inserted into the eye and held in position with an air bubble. d. The incision is closed with 2-3 sutures and the air bubble dissolves on its own within 24-48 hours. This new transplant technique has been shown to enable good vision and to have many potential advantages over full thickness transplants, including earlier return of vision, less refractive errors, fewer serious complications, and a more stable eye. This is because the incision is only 4 mm, requiring only 2-3 sutures which can be removed in 1-2 months. This allows visual rehabilitation to start at 3 months versus 18 months with PKP and decreases the risk of complications resulting from moderate trauma. It is likely that the patient s best vision will still be obtained with glasses or a contact lens, but it will be much easier to achieve given the smoother surface of the cornea (see Figure 4 for actual photo of eye after DSAEK surgery) Figure 4. a. Air bubble 24hrs after DSAEK surgery. b. Graft and sutures in place 1-2 weeks after DSAEK surgery. BENEFITS OF DSAEK VS. PKP (Please note not everyone is a candidate for DSAEK) In general, DSAEK surgery is a new transplant technique and has been shown to provide good vision and to have many potential advantages over full thickness transplants, including earlier return of vision, less refractive errors, fewer serious complications, and a more stable eye. 1) Patients who undergo full thickness corneal transplants usually must wait up to18 months or more before their vision is restored and stable enough to obtain new glasses. With DSAEK, a smoother surface for focusing usually results in improved vision much sooner - generally 3 months. 2) Full thickness corneal transplant surgery results in a change in the corneal curvature. Since the power of one's glasses is partially related to this curvature, strong glasses are often required to correct large amounts of nearsightedness, farsightedness and astigmatism. Sometimes, a rigid contact lens or even surgery is required to correct the astigmatism. In contrast, after DSAEK, the corneal surface remains smooth and relatively unchanged from the curvature before transplant surgery. Therefore, there is much less chance of requiring strong or thick glasses after DSAEK compared to full thickness corneal transplant surgery. 3) Patients who have full thickness transplant surgery require 16 sutures or more, some of which may be left in the eye for several years. These sutures can lead to problems such as surface irregularity, discomfort, blood vessel formation, infection, and corneal wound problems. In contrast, the 3 tiny sutures that are used in DSAEK are not irritating, usually do not cause problems, and are removed in 1-2 months.
4) Patients who undergo full thickness transplant surgery are much more susceptible to wound rupture and serious injury from any kind of trauma since the long, full thickness corneal incision never fully regains normal strength. With DSAEK, because there is only a small peripheral incision, the eye usually heals to become be much stronger and less susceptible to serious injury from trauma. 5) If you need transplants in both eyes, DSAEK allows you to have the second transplant within months, versus a year or more if you were to have a conventional PKP transplant. WHAT TO EXPECT ON SURGERY DAY You should arrive at the surgery center about an hour prior to your procedure. Once you have been checked in, you will meet your anesthesiologist who will be giving you conscious sedation and local anesthetic during the surgery. Rarely, a patient may need general anesthesia. You will then be prepared for surgery. The area around your eye will be cleaned and a sterile drape will be applied around your eye. A small incision will be made to allow the surgeon to strip away the diseased Descemet's membrane and damaged endothelial cells. Next, the bottom 10% - 20% of a donor cornea that has healthy endothelial cells attached to its Descemet's membrane will be inserted through the same incision. After it is placed in position, an air bubble will be used to hold the transplanted tissue in place (see Fig 3ac, Fig 4). The central disc of cloudy cornea will be removed and replaced with a donor disc of clear cornea cut to match the size of the disc that was removed. This clear disc is sewn into place with 16-24 sutures (see Fig 2a-d). AFTER YOUR SURGERY Immediately after the procedure, you will be taken into recovery where you will lie down for about an hour to let the air bubble continue to press against the tissue to secure it in place. Your eye will be patched before you leave. Antibiotic eye drops will be used for a week or so to help prevent infection, and a mild steroid eye drop will need to be used for approximately one year to help prevent rejection. Immediately after the procedure, you will have a patch and shield placed over your eye. You will stay in the recovery area for about an hour until your anesthesiologist verifies that your vitals are stable and discharges you home. Antibiotic eye drops will be used for a week or so to help prevent infection, and a mild steroid eye drop will need to be used for approximately one year to help prevent rejection. FOR BOTH: You should be able to resume normal activities the day after your surgery. Strenuous activities will be restricted until 3 weeks after surgery. With conventional corneal transplantation, your vision typically does not improve for 12-18 months, while with DSAEK, you may experience visual improvement within weeks. In order to make your transplant procedure a success, it is important that ALL scheduled follow-up appointments be kept and ALL medications are used as directed. Any pain, redness, or reduced vision should be reported immediately. RISKS, SIDE EFFECTS, AND DISCOMFORTS The decision to have DSAEK or PKP is an important one that only you can make. The goal of any vision restoration procedure is to improve your vision; however, we cannot guarantee you will have the results you desire. Risks and problems that may occur with both full PKP and DSAEK surgery include: 1) There is often mild pain for one week after surgery that may be treated with Tylenol or another drug by mouth. Immediately after surgery your eye will be red. There may be temporary discomfort to you from the follow-up eye examination or eye drops. This may include stinging, redness or itching. 2) For many reasons, the vision after any type of corneal transplant is never perfect. Sometimes, strong glasses are needed to correct refractive errors. The glasses may be difficult to tolerate. Sometimes, glare and distortions are noted, or the vision is still somewhat blurred, even with a clear corneal transplant. The goal is to provide the best visual acuity and overall vision quality possible, while minimizing the risks.
3) In approximately 10 percent of patients, the body's immune system produces an inflammation of the donor cornea. This is often called a "rejection" reaction. The rejection reaction is usually reversible if treated promptly but sometimes it leads to a failure of the transplant. Rejection could happen (although rarely) at any time in the future. However, if the transplanted tissue should be rejected, it is usually possible to have the procedure successfully repeated. 4) The transplant may become cloudy either because of rejection, as described above, or for other reasons. If this happens it may be necessary to have another transplant. The risk of the transplant failing varies depending upon the current corneal condition. 5) The donor cornea is obtained from a certified Eye Bank. A past medical history is obtained from the donor who is screened carefully for evidence of potentially transmissible infectious or neurologic diseases. Blood is drawn and tested for hepatitis, AIDS, and other diseases. Every effort is made to exclude donors that could transmit diseases. The risk of getting a serious disease from a donor cornea is extremely small. Nevertheless, it is still possible that a serious disease could be transmitted from the donor cornea. RISKS UNIQUE TO DSAEK 1) Dislocation of the donor corneal transplant tissue within the eye can occasionally occur. Dislocated tissue is usually noted on the first day after surgery, and a repositioning procedure is generally performed within the next week. If the tissue cannot be repositioned, a full thickness corneal transplant (Penetrating Keratoplasty) may be necessary. 2) DSAEK is a relatively new procedure and long term results are not known. Although we have tried to list all possible risks and discomforts, there may be others that we do not know about at this time. FREQUENTLY ASKED QUESTIONS ABOUT DSAEK and PKP Will I need to be hospitalized? DSAEK and PKP are performed as an outpatient surgery. No overnight hospitalization is required. Will I be awake during surgery? You will have an anesthesiologist who will administer a sedative during the procedure that enables you to relax and even sleep, but you will still be breathing on your own. The eye is numbed with local anesthesia. How long does the procedure last? The total time you will be in the surgery center is approximately 2 to 2.5 hours. Once you are taken to the operating room the procedure is completed in 30 to 60 minutes. Additional time may be necessary if other procedures are also planned such as cataract surgery or intraocular lens replacement. For DSAEK only: After the procedure is completed, you will be taken to the recovery room where you must lie on your back for 45 to 60 minutes. This allows the air bubble that has been placed in the anterior chamber of your eye to fix the transplant into position. When will I need to return for a follow-up office visit? The first office visit is scheduled the next day in the office so that the doctor can check the eye pressure and the graft position. If everything is in proper order you will start your post-operative eye drops as directed and return for a second visit in 1 week. For DSAEK only: If the graft is in good position at your first follow-up visit, this is a very good sign that it will take. There is a 10 percent chance that it will not take the first time, and will need to be repositioned within a week of surgery by injecting another air bubble. This procedure will be performed in the office several days after the original surgery and takes about 1-2hrs. However, if everything is in proper order you will start your post-operative eye drops as directed and return for a second visit in 1 week.
What type of eye drops will I need after surgery? You will continue using antibiotic eye drops (Vigamox) that you started 3 days prior to surgery. Use the Vigamox 3 times per day for one week after surgery unless otherwise instructed. You will also use a steroid eye drop (Omnipred 1%) 8 times per day until otherwise instructed. The steroid drops are required to prevent rejection of your new transplant. If you are also using glaucoma eye drops, continue to use them after surgery unless otherwise instructed. When will I see an improvement in my vision? Visual recovery varies depending on the rate of healing, but most patients will notice an improvement in their vision within 3 to 6 months of surgery, with optimal recovery of vision in 12-18 months. Visual recovery varies depending on the severity of your corneal cloudiness prior to surgery. Most patients notice improvement in their vision during the first 2 weeks after surgery with continued improvement during the next 4-6 weeks. This recovery is a dramatic improvement over the time required following conventional corneal transplant surgery (PKP), which usually takes 6-12 months. Some DSAEK patients may not notice visual improvement as quickly as they would like, because they have other ocular conditions such as cataract or retinal problems that must also be addressed. Can my transplant undergo rejection? The rate of rejection for DSAEK and PKP are approximately the same. The signs and symptoms of such rejection episodes are the same for both procedures and include increased redness, light sensitivity and blurred vision. If you experience these, you may be having a rejection episode and should call the office so that you can be evaluated immediately. Most rejection episodes are successfully terminated by using steroid eye drops. The sooner a rejection is treated the better chance for transplant survival. CONSENT FOR CORNEAL TRANSPLANT SURGERY In giving your permission for a corneal transplant, whether full-thickness (PKP) or partial-thickness (DSAEK), we want to make sure that you understand the following information: Corneal transplant surgery is the removal of your diseased cornea and the replacement of it with a donor cornea in your eye. With any eye surgery, there is a rare possibility that a loss of best corrected vision or even the eye itself could occur. This could be due to hemorrhage (bleeding), loss of corneal clarity, infection, detachment of the retina, glaucoma, or double vision. (Please sign and return to the office prior to surgery.) SIGNED CONSENT I have read and understand the above information, and have decided to have the corneal transplant surgery by the following method: full-thickness transplant (PKP) partial thickness transplant (DSAEK) Patient s signature: Legal guardian s signature: (if indicated) Witness signature: Physician s signature: Place of surgery (circle one): Washington Adventist Hospital Montgomery Surgery Center Suburban Hospital Date of surgery: Time of surgery: