BLOG: Do anti-VEGF injections increase risks of cataract surgery?
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Between 2006 and 2015, nearly 125,000 patients in the U.S. have received nearly a million injections of anti-VEGF medicines for the treatment of retinal disease, according to Parikh and colleagues. Nearly two-thirds of the injections have been for wet age-related macular degeneration.
Given that this population is also the most likely to have cataracts, we all will have many patients interested in cataract surgery who have either had or are currently having anti-VEGF treatment.
The good news is that patients receiving anti-VEGF injection therapy run little risk for worsening wet AMD after cataract surgery. In fact, most of those with both significant cataracts and anti-VEGF treated wet AMD have both better measured visual acuity and reported subjective vision improvement after cataract surgery.
So, any concerns about our wet AMD patients having cataract surgery can be put to rest, right? Not so fast.
Two potential complications
There is evidence that these patients have an increased risk for two intraoperative complications: retained lens fragments (RLF) and posterior capsular rupture (PCR). The two may be different manifestations of the same problem. One study (Stone et al.) showed a 126% increase in the removal of RLFs in patients with prior anti-VEGF injections. A second study (Shalchi et al.) documented a 3% incidence of PCR in that same cohort compared with 0% who had never had anti-VEGF treatment.
Further, while endophthalmitis is a rare postop complication of any cataract surgery, it may be the most dreaded. And Medicare claims data from 2016 (Stone et al.) showed that prior anti-VEGF injections were the primary risk factor for both early and delayed intraocular infection. Is this in any way related to the same cause for capsular rupture and lens fragment issue? And if so, how?
The honest answer is that no one really knows. There’s speculation that physicians with less experience may cause greater trauma to the ciliary body and zonules resulting in a posterior capsule that is more prone to tears and rupture. Still others propose that the injections themselves may have no direct bearing on these complications, that those with AMD are older and have other anatomical and medical risks that increase the likelihood of any surgical complication.
The total number of injections a patient received prior to cataract surgery may be a factor. In a study by Lee, the rate of PCR was 2.6 times higher in cataract surgery patients who had 10 or more prior injections than in those who had fewer. Furthermore, the review of Medicare claims data showed a direct correlation between the number of injections and the postop prevalence of endophthalmitis (Stone et al.).
What the OD should do
So, what steps, if any, should the primary care optometrist take to reduce the risk for these possible complications? First, it is wise to obtain knowledge on the injection history. Those who have had many injections or lenticular or clinical evidence of zonular injection trauma are likely at highest risk and should be warned. A dilated examination of the integrity of the posterior capsule with retroillumination may reveal prior small defects. Coordinate the schedule so that there is at least a week between injections and cataract surgery. Finally, like in any good comanagement, effective, accurate and timely communication between the retinal specialist, primary care optometrist and the cataract surgeon about these and any other risk factors can result in fewer complications and a better outcome.
A good cataract surgeon knows what steps to take with a posterior capsule at risk for or having preexisting defects to minimize complications, in particular, avoiding hydro-dissection of the lens. Yet, until new drug delivery methods are developed to treat wet AMD or when new research provides clearer answers, the physician providing the postop care should be more alert to the possibility of these problems in patients at higher risk.
A generation ago, it was common to approach all patients with both cataracts and vision impairment from either wet or dry AMD with caution. Today, we have clear evidence that AMD patients have better visual function after cataract surgery. In fact, in light of the rare but potential complications of surgery after intravitreal injections, the question changes: Should we consider encouraging our dry AMD patients to have cataract surgery even earlier, long before they risk needing wet AMD treatment?
References:
Lee AY, et. al. Ophthalmology. 2016;doi:10.1016/j.ophtha.2016.02.014.
Parikh R, et al. Ophthalmology. 2017;doi:10.1016/j.ophtha.2016.10.036.
Shalchi Z, et al. Am J Ophthalmol. 2017;doi:10.1016/j.ajo.2017.02.006.
Starr MR, et al. Am J Ophthalmol. 2018;doi:10.1016/j.ajo.2018.05.014.
Stone A. EyeNet Magazine. August 2019;27-28.