What complication occurs if the lens becomes trapped in front of the pupil?

What complication occurs if the lens becomes trapped in front of the pupil?

• A. Pupillary block glaucoma
• B. Endophthalmitis
• C. Corneal ulcer
• D. Uveitis

Answer: (A)

When the lens is displaced to sit in front of the pupil, it can physically block the pupil from allowing aqueous humor to move from the posterior chamber into the anterior chamber. This creates a pupillary block, raising pressure behind the iris. The increased posterior chamber pressure pushes the iris forward, narrowing or closing the angle where the aqueous humor drains through the trabecular meshwork. The result is a rapid rise in intraocular pressure, a pupillary block glaucoma, which is a form of secondary angle-closure glaucoma and a true ophthalmic emergency if not treated promptly. Other conditions listed are different kinds of eye problems (infection or inflammation) and don’t arise from this mechanical blockage of aqueous flow, so they don’t fit the mechanism described.

When the lens is displaced to sit in front of the pupil, it can physically block the pupil from allowing aqueous humor to move from the posterior chamber into the anterior chamber. This creates a pupillary block, raising pressure behind the iris. The increased posterior chamber pressure pushes the iris forward, narrowing or closing the angle where the aqueous humor drains through the trabecular meshwork. The result is a rapid rise in intraocular pressure, a pupillary block glaucoma, which is a form of secondary angle-closure glaucoma and a true ophthalmic emergency if not treated promptly.

Other conditions listed are different kinds of eye problems (infection or inflammation) and don’t arise from this mechanical blockage of aqueous flow, so they don’t fit the mechanism described.