What procedure does a dacryocystectomy involve?

A dacryocystectomy specifically involves the excision of the lacrimal sac, which is a critical structure in the tear drainage system located at the inner corner of the eye. This procedure is typically performed to treat conditions such as chronic dacryocystitis or other obstructions that can cause excessive tearing or recurrent infections.

In the context of the choices provided, the focus on removing the lacrimal sac distinguishes dacryocystectomy from other procedures related to ocular structures. Other options, such as repairing the eyelid or draining the eye, do not relate to the specific function or anatomy targeted by a dacryocystectomy. Therefore, the correct choice highlights the targeted surgical intervention aimed at a defined anatomical site within the eye's tear drainage system.