Intravitreal injections can lead to cataract complications
A careful preoperative examination is needed in cataract patients who have received intravitreal injections.
In the past decade, intravitreal injections have transformed the way that we treat retinal disease, particularly vascular issues, with anti-VEGF medications. In the U.S., the most common ocular procedure is administration of an intravitreal injection, with many millions performed each year. This has evolved the way that we address conditions such as diabetic retinopathy, vascular occlusive disease and age-related macular degeneration. Sight has been protected and restored for countless patients, but an intravitreal injection is a procedure with a slight but real risk for complications.
These complications can include infection, bleeding and inflammation, but there is also a rare risk for iatrogenic damage to ocular structures such as the crystalline lens. If the posterior capsule is damaged from the needle used in the intravitreal injection, it will be prone to further splitting during cataract surgery. For this reason, cataract surgeons should carefully examine the cataract before surgery in patients with a history of intravitreal injections, with special attention to the integrity of the posterior capsule.
The first case presented here (Figure 1) is highly suspicious for capsular bag damage. The 50-year-old patient had intravitreal injections for the treatment of proliferative diabetic retinopathy, and then a month after the last injection, he returned to clinic with a completely opaque white cataract. During the cataract surgery, the ophthalmologist noted a dark spot near the posterior capsule. She was not sure if it was due to surge and inadvertently touching the posterior capsule with the phaco probe or if it was pre-existing.
Another possibility is that the intravitreal injection punctured the posterior capsule and there was reabsorption of the lens material by the inflammatory cascade. This created a void that appears dark, and because the rest of the lens proteins were then exposed to the immune system, there was rapid development of the opaque cataract.
During the cataract surgery, the posterior capsule defect tore into a large gap and there was posterior displacement of lens material into the vitreous cavity. The surgeon did a good job of cleaning up the anterior segment and placing a posterior chamber IOL. A three-piece acrylic IOL was placed with the haptics in the sulcus and the optic captured behind the capsulorrhexis (Figure 2). This reverse optic capture creates a stable IOL position and allows us to make a barrier between the anterior segment and vitreous cavity. The patient then went on to have a pars plana vitrectomy and lensectomy by a vitreoretinal colleague.
Sometimes the trauma from the intravitreal injection creates a mild defect in the posterior capsule, which can appear as just a small linear streak (Figure 3). In this case, the entire lens did not become opacified because the small defect self-closed due to the inflammatory process. But even still, during the cataract surgery, this small posterior capsule defect ended up enlarging rapidly and the lens nucleus dropped into the vitreous cavity.
If we know or suspect ahead of time that there is a posterior capsule defect, how can we successfully proceed with cataract surgery? We can try to bring the nucleus up out of the bag and use a viscodissection technique like we would do for a posterior polar cataract. This can be successful, and the use of an IOL scaffold or large amounts of viscoelastic can help create a barrier to prevent posterior displacement of the lens material.
Another great option is to do the cataract surgery together with your vitreoretinal colleague so that if there is a ruptured capsule with retained lens material, it can be addressed at the same sitting. For these cases, we should be prepared by doing a higher level of anesthesia such as a retrobulbar injection. Also, focus extra attention and care on the capsulorrhexis to give a 5-mm centered opening because it may be required for the reverse optic capture technique.
More and more of our patients are benefiting from intravitreal injections, and a tiny percent of them may end up with iatrogenic capsular damage and traumatic cataracts. We should make every effort to identify these patients ahead of time and then prepare for the potential complications.
Full videos of these cases can be found at CataractCoach.com, which is a free teaching website.