Abstract: The common ophthalmic preparations have limitations including low drug bioavailability and poor patient compliance due to the complexity of the eye structure. Sustained-release and long-acting drug delivery systems have significant clinical advantages in the treatment of a variety of ocular chronic diseases, as they can overcome the eye barriers or form a drug reservoir in the eye, thereby improving drug bioavailability and reducing patient medication frequency. According to the classification of dosage forms, this review mainly introduces sustained-release and long-acting ophthalmic preparations commercially available, along with those in current clinical research and recent reports in literature. The sustained-release mechanism and principle of these preparations are described, so as to provide new insights for the development of sustained-release and long-acting ophthalmic preparations.