In recent years, there have been exciting new advances in the treatment of neovascular age-related macular degeneration (AMD) and other retinovascular diseases. Although these treatments are able to maintain visual acuity in most patients and improve vision in a significant number of patients, injections must be injected as frequently as every month to attain the best results. This increased frequency of administration is reflected by the fact that at the Bascom Palmer Eye Institute we performed less than 500 intravitreal injections in 2001 compared to over 7,000 in 2006. Fortunately, no culture-proven cases of endophthalmitis were observed in these patients during that period.
Although iatrogenic rhegmatogenous retinal detachment and cataract are potential complications of intravitreal injection, the most feared complication is endophthalmitis (rates typically less than 1%). The measures we take to minimize this risk often make the patient sensitive to the typical intravitreal injection sequelae (foreign body sensation, tearing, pain, and redness) in the short term. Therefore, most of our intravitreal injection preparation technique is focused on two things: anesthesia and microbial prophylaxis. As a vitreoretinal surgeon in southeast Florida, I have the opportunity to follow numerous patients from the Northeastern US during the annual winter “snowbird” migration. These patients are quite vocal about what they perceive as significant regional differences in clinical practice patterns and which they prefer. How does the retina specialist balance the wishes of patients to be comfortable (during and after the injection) with the physician’s desire to prevent infection?
Anesthesia is achieved with either topical or local anesthetic application—both are adequate approaches. Some centers provide topical lidocaine jelly for several minutes prior to intravitreal injection. Because of the viscous nature of lidocaine jelly, it acts as a physical barrier to subsequent application of topical antimicrobial agents (povidone iodine and/or topical antibiotics). Therefore, topical antimicrobial prophylaxis should be administered (and allowed to set in place for at least 30 seconds) prior to topical lidocaine jelly application.
Another common option to achieve adequate anesthesia is to administer a subconjunctival injection of lidocaine at the injection site. This has several drawbacks in my opinion. Another element of risk is introduced by virtue of the fact that another needle is brought within close proximity to the eye. In addition, the creation of a subconjunctival lidocaine bleb is intrinsically painful, can be accompanied by significant subconjunctival hemorrhage, can theoretically allow ingress of subconjunctival lidocaine into the intravitreal space, and can damage the friable conjunctiva of our elderly patient population.
My preferred anesthetic approach is to apply sterile cotton swabs soaked in topical 4% lidocaine with firm tamponade against the injection site for up to 15 to 20 seconds. This is alternated with a drop of 5% povidone iodine to the injection site. This cycle is repeated 3 times prior to carrying out the transconjunctival pars plana injection via 27, 30, or 31 gauge needle (dictated by drug viscosity and needle availability). The tamponade results in lower post-injection intraocular pressures and this pressure may also lower the risk of post-injection subconjunctival hemorrhage, which is another common patient complaint.
I believe the most important factor for improving patient comfort is to minimize the time interval between patient preparation and intravitreal injection. The longer the patient lay exposed with the speculum in place with cornea-toxic medications like lidocaine and povidone iodine on the ocular surface, the greater the chance of significant surface desiccation and post-injection epitheliopathy and attendant pain, tearing, and redness. In my office, I have injection technicians (RNs) who prepare the patient for injection and page me just prior to their finishing the preparation. As soon as I get the page, I drop what I am doing and quickly go to the injection suite, do the injection, sign the paperwork, and head back to the clinic (typically takes 2 minutes). The longer I make the patient wait with the speculum in their eye, the more likely I am to hear about an excruciatingly painful postinjection recovery period when they come back to see me in a month.
Some patients are particularly susceptible to the toxic effects of topical lidocaine and/or povidone iodine. For these patients, I consider providing a periocular rinse with sterile saline “eye wash” at the end of the procedure. I’m not concerned about washing away the povidone iodine with this maneuver, as the antimicrobial effects of povidone iodine are realized within 17 seconds after instillation. In addition, patients go home with instructions to use either topical moxifloxacin or gatifloxacin (4 times daily for 3 days in addition to the one drop at the end of the procedure) The need for postinjection antibiotics is unproven, but seems to make sense. I do not prescribe preinjection antibiotics for 2-3 days like many of my colleagues in the community do. Although there is evidence that this practice reduces conjunctival bacterial counts, there is no evidence that this results in a decrease rate of endophthalmitis.
These “best practices” can provide your patient with adequate analgesia during the procedure, make them comfortable as possible after the procedure, and give the physician peace of mind.
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