IRVINE, Calif., Feb. 22 -- Premier Laser Systems Inc. and Ophthalmic Imaging Systems (OIS) reported that OIS has terminated the previously announced merger agreement between the companies. Premier Laser and OIS indicated that while their merger is not practicable at present, both firms plan to continue to work together to explore ways to exploit the potential synergies that the merger might have brought to light.Premier Laser develops, manufactures and markets lasers, fiber optic delivery systems and associated diagnostic and therapeutic products for the eyecare, dentistry and surgical markets. OIS designs, develops, manufactures and markets ophthalmic digital imaging systems, image-enhancement systems and analysis software.