A research team sought to answer the question, "Is there an increased risk of posterior capsular rupture (PCR) during cataract surgery in patients who have had intravitreal injections?" New research published in Acta Ophthalmologica says there is.
The study details.
The systematic review analyzed six eligible studies with more than 1 million cataract surgeries. A total of 7,034 eyes with cataracts that had previously received an intravitreal injection were included.
What did they find?
The meta-analyses revealed that any previous intravitreal injection was a risk factor for PCR. The risk of PCR increased by 4% for each previous intravitreal injection.
However, the authors stated that to be regarded as a clinically significant risk of PCR, a substantial number of previous intravitreal injections (eg, ≥ 10) should have been administered, considering that the a priori risk of PCR is very low (~1%).
Why is there an increased risk?
Although it's not clear, the research team proposed a few theories:
1. Iatrogenic physical trauma caused by the injection needle.
2. Changes in the mechanical properties of the lens capsule, resulting from exposure to anti-VEGF therapy or corticosteroids.
3. Accelerated cataractogenesis related to either anti-VEGF exposure or corticosteroids resulting in denser cataracts.
4. Denser cataracts because cataractous patients who have concurrent retinal diseases that require intravitreal injection treatment may have limited visual potential and are therefore perhaps referred for cataract surgery later compared with others.
Anything else?
According to the authors, compared with other known risk factors for PCR, previous intravitreal injection seems to be a risk factor of greater importance than axial length > 26 mm, small pupil size, or taking doxazosin; however, it seems to be a less important risk factor than surgeons in their first 1 to 2 years of training, pseudoexfoliation or phacodonesis, or brunescent or white cataract. (via)