EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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34 EW CORNEA December 2013 Postoperative management of corneal crosslinking patients by Frederik Raiskup, MD, PhD, FEBO T he success of any surgical intervention depends as much on postoperative care and management as it does on the surgical procedure itself. This undoubtedly also holds true for corneal crosslinking. At our hospital, we have been performing corneal crosslinking with the IROC illumination system (IROC Innocross, Zug, Switzerland) since the development of the first prototype and continue to use the latest UV-X 2000 crosslinking device. Through my experience with this system, I have come to understand that careful management of ocular surface health after surgery is essential for the successful and rapid visual rehabilitation of the patient and to minimize complications. Patient counseling is also equally important to prepare the patient for the potential side effects of the procedure and ensure that he/she is receptive to the postoperative management protocol and any interventions that may be necessary in case of side effects and eventual complications. The essentials of postoperative management The focus of postoperative management after corneal crosslinking is to restore a healthy ocular surface as quickly as possible. There are three main aspects to post-crosslinking patient management: 1) hastening re-epithelialization, 2) preventing infection, and 3) reducing pain. The first of these, re-epithelialization, is the most important. The current crosslinking standard protocol requires de-epithelialization of the cornea before the administration of riboflavin solution. This is done in order to ensure that a sufficient amount of riboflavin enters the EyeWorld factoid Stevens-Johnson syndrome (SJS) occurs twice as often in men as women, and most cases appear in children and young adults under 30, although it can develop in people at any age. Source: Massachusetts Eye and Ear Infirmary Cornea well soaked by riboflavin solution during CXL procedure with UV-X 2000 device Source: Frederik Raiskup, MD stroma. Therefore, it is important to restore this protective barrier of the ocular surface as quickly as possible after surgery. This not only helps to improve the patient's comfort and visual acuity more rapidly after surgery, but it also reduces the risk of infection. The epithelial layer serves to protect the cornea from micro-organisms and other environmental factors that could damage the stroma. Even small lesions in the epithelium can increase the risk of infection or melting, the consequences of which can be serious. There have been reports in the literature of microbial keratitis and stromal melting leading to the development of deep stromal scars and loss of visual acuity postoperatively, or in the worst cases, corneal perforation necessitating a corneal graft. Therefore, controlling infection after crosslinking is a priority. Pain management is also an important aspect of postoperative management that ensures patient's comfort. De-epithelialization of the cornea, a densely innervated and hence very sensitive tissue, causes some amount of pain. However, proper counselling of patients about the level of pain that can be expected after surgery and the use of common analgesics is an effective strategy to control pain. Postoperative management protocol We use a standard protocol in our department for the postoperative management of all corneal crosslinking patients. Soon after surgery, all patients receive a soft contact lens. The function of this lens is two-fold. First, it supports epithelialization, and second, it reduces pain. We also put all patients on topical antibiotics to prevent infection. We prescribe preservative-free quinolones (ofloxacin) three times a day until epithelialization is complete. At the same time we use preservative-free ocular surface lubricants to promote epithelialization. Once re-epithelialization is complete, we remove the contact lens and discontinue the antibiotics and begin a steroid regimen for three weeks. I prescribe dexamethasone three times a day, however, fluorometholone is also commonly used. The steroid serves primarily as an anti-inflammatory agent and prevents the development of corneal scars. In treating crosslinking patients it is important to use preservative-free eye drops as preservatives can interfere with re-epithelialization. If a patient complains of mild pain, I recommend using a nonsteroidal anti-inflammatory drug, such as ibuprofen. In rare cases, patients whose pain threshold is very low or who are particularly sensitive to pain may complain of severe pain after crosslinking. In such cases I prescribe a strong painkiller from the group of centrally acting opioid analgesics. Complications of and special considerations for corneal crosslinking Although corneal crosslinking is a relatively safe procedure, some side effects and complications have been reported after the procedure. These range from minor side effects such as haze and sterile infiltrates to more serious complications such as corneal infection, stromal melting leading to perforation, or the development of deep stromal scars. Among my patients, the most major complication has been infection. However, in my experience, severe infections tend to occur in patients who have other concomitant debilitating conditions (e.g., neurodermitis and diabetes mellitus) that predispose their ocular surface to infections and a prolonged epithelial healing process or in patients who suffer from diseases demanding long-term systemic steroid therapy (e.g., neurodermitis, asthma). For instance, one of the more severe complications that I have seen involved a patient who showed a prolonged delay in epithelial healing; the epithelium did not heal for several weeks following surgery, and he developed a secondary central microbial infiltrate. However, this patient also had neurodermitis that was being treated with systemic steroids. This likely increased his risk for prolonged healing and infection. In this case, I used several antibiotics to treat the infection. Even after the infection was treated and the inflammation had subsided, the epithelial defect was still present, for which I had to apply an amnion membrane. The lesion healed with a deep stromal scar. Therefore, ophthalmologists may need to take special precautions with patients who have neurodermitis or dry eyes, those who are taking systemic steroids because of other concomitant diseases, as well as those who are diabetic as they may have slower epithelial healing and be more prone to infection. Another consideration that ophthalmologists should take into account when performing crosslinking is with respect to pregnant women, who are at risk of progression of keratoconus during this period. An experience with a patient of mine who was pregnant at the time of crosslinking and who developed an infection postoperatively alerted me to the potential risks of performing crosslinking in such patients. Fortunately, in this case I was able to control the infection with topical