What surgical procedure uses clamps and curettes to remove an obstruction of the meibomian gland?

The procedure that utilizes clamps and curettes to remove an obstruction of the meibomian gland is chalazion excision. A chalazion occurs when a meibomian gland, which produces oil for the tear film, becomes obstructed and leads to swelling and formation of a cyst-like lesion on the eyelid. During the chalazion excision, a surgeon accesses the cyst through either an external incision or an internal approach. Using clamps helps to stabilize the eyelid and provide visibility, while curettes are employed to carefully scrape away the contents of the cyst and remove any blockages within the gland.

In contrast, blepharoplasty focuses on cosmetic enhancement or correction of eyelid droopiness rather than addressing gland obstructions, and pterygium surgery involves the removal of a growth on the conjunctiva rather than treating a meibomian gland issue. Xenophthalmic treatment does not pertain to the removal of blockages in meibomian glands and relates more to the treatment of non-human animal eyes. Hence, the use of clamps and curettes specifically for clearing the obstruction distinguishes chalazion excision as the correct answer.