Carbachol: Carbachol injection is a drug mainly used in ophthalmic surgery, mainly for IOL implantation, cataract removal surgery, corneal transplantation and other ophthalmic surgeries that require pupil reduction. Its main component is carbachol, a colorless, clear liquid that is generally used during surgery. During surgery, 0.2 ml is injected into the anterior chamber to act as an intraoperative agent to rapidly constrict the pupil and assist in the completion of surgery. In ophthalmic surgery, the anterior chamber is injected with this product, and the pupil begins to contract after two seconds. It is a rapid, potent pupil constrictor, and there are generally few adverse reactions to the drug. If you are allergic to carbachol, it should be used with caution. Matters to note about carbachol: First, oral, intramuscular or intravenous injection is strictly prohibited; second, this product is a sterilized aqueous solution, and the drug must be for single use after opening, and must not be used again or repeatedly to avoid contamination and cause problems such as anterior chamber inflammation and intraocular infection.