Phacoclastic uveitis is caused by which mechanism?

• A. Cataract induced due to rupture of lens capsule with rapid loss of lens proteins resulting in severe catastrophic inflammation
• B. Cataract due to degenerative lens microcysts
• C. Inflammation caused by tear of cornea
• D. A chronic low-grade uveitis unrelated to cataract

Answer: (A)

Phacoclastic uveitis happens when the lens capsule ruptures and lets lens proteins spill into the anterior chamber. Those proteins are normally isolated from the immune system, so their sudden exposure acts as a strong antigen trigger. The immune response to these leaked lens proteins drives a rapid and severe intraocular inflammation—the hallmark of phacoclastic uveitis. This is why the mechanism described as rupture of the lens capsule with rapid loss of lens proteins causing severe inflammation is the best fit. Other options describe cataracts from degenerative changes, corneal tears, or chronic uveitis not driven by lens protein exposure, which don’t produce this acute, protein-driven inflammatory reaction.