I’ve never minded the idea of growing older. Each year, I figure that surviving yet another birthday is far preferable to the alternative. So, despite the way it dates me, I freely admit that I still remember the time before intravitreous injections took over retinal clinical practice. “Really?” one of my less tactful students once said, “I didn’t think you were THAT old. And if you didn’t have injections, what did you DO back then?”
Supervising fellows has probably aged me as much as anything else. One of the key aspects of the medical retina fellowship year at my institution is to make sure our fellows understand how, why, and when we use intravitreous therapy for common retinal diseases. Injections are so frequent that by midway through the year, the fellows are highly proficient. The year’s first few injections are the ones I watch the most closely and with the most concern. I find myself repeating, “Try to aim between the conjunctival blood vessels” all too frequently in the month of July.
So, what are the key points I try to get across to my fellows? First and foremost, that they need to go through a thorough informed consent process with each and every patient who is planning intravitreous therapy. Just because endophthalmitis is uncommon (most studies place the risk at less than 1 per 1000 injections) doesn’t meant that these cases may not be visually devastating when they occur. The medications we use each have their own safety profile that patients need to understand. I review the theoretical possibility of increased thromboembolic events in patients who will be getting antivascular endothelial growth factor, even though eye studies have not consistently demonstrated a higher risk of these events with intravitreous therapy. We also discuss the risk of cataract and glaucoma with steroid patients. Finally, we set the expectation that most patients will need multiple intravitreous injections over long periods of time. Treatment success for many patients depends on consistent and frequent dosing intervals, especially within the first year of therapy.
When it comes to the injection procedure itself, I am adamant about having topical povidone-iodine on the conjunctival surface before the injection. This is the only agent that has been shown definitively to reduce rates of infection after ocular procedures. I place the iodine at least 30 seconds before injecting to allow the antiseptic time to work. Many patients hate the stinging associated with iodine use and some tell me that they are “allergic” to the antiseptic. However, a true allergy to betadine is incredibly rare. The contact dermatitis that is the real issue for most patients can be successfully managed by using local swabs only on the conjunctiva to minimize iodine exposure.
I don’t use topical antibiotics anymore. These drops are not proven to reduce rates of endophthalmitis and, conversely, not using them doesn’t increase rates of infection. I do use a lid speculum to minimize the risk of needle contamination by eyelids or eyelashes. I don’t use a mask or ask my patients to use a mask, but I minimize talking after the lid speculum is placed. And I watch my fellows like a hawk to make sure that any uncapped needle stays sterile until it penetrates the prepped conjunctival surface.
I wish I knew how to make intravitreous injections painless for all patients, but my experience is that patients respond very variably to our methods for numbing the eye. Nearly all my patients tolerate injections with topical anesthesia alone. I find that giving several rounds of viscous gel with a few minutes in between each set of drops can help some patients. The fear that a viscous anesthetic agent will create a gel barrier to trap bacteria is unproven, but I nonetheless place povidone-iodine in the eye before any viscous anesthesia. If topical anesthesia, including viscous agents, is not sufficient, I’ll use subconjunctival agents, but these are rarely needed.
After injecting, I check to make sure the optic nerve is perfused and that there is return of vision in the eye, although some colleagues just confirm that vision of at least hand motions or counting fingers has returned. I have had a small handful of cases that have required anterior chamber paracentesis to manage an intraocular pressure spike after intravitreous injection, but these are rare. Even when nerve perfusion is initially low, most of the time the eye equilibrates with complete return of vision over a few minutes.
Now it feels like we’ve always relied on intravitreous injections to treat retinal disease, but it has actually been less than 15 years since antivascular endothelial growth factor agents became standard care for neovascular age-related macular degeneration. It’s been less than a decade that we’ve routinely used intravitreous therapy for diabetic eye disease. Given how rapidly the field evolves, injections may well become obsolete as we develop better topical and systemic therapies. I’m already looking forward to the day when a fellow looks at me and says “Wow—you did intravitreous injections? I didn’t think you were THAT old!”