n 1986, Bath did research in the laboratory of Danièle Aron-Rosa, a pioneer researcher in lasers and ophthalmology at Rothschilde Eye Institute of Paris, and then at the Laser Medical Center in Berlin, where she was able to begin early studies in laser cataract surgery, including her first experiment with excimer laser photoablation using human eye bank eyes.
Bath coined the term “Laser phaco” for the process, short for laser PHotoAblative Cataract surgery, and developed the laserphaco probe, a medical device that improves on the use of lasers to remove cataracts, and “for ablating and removing cataract lenses”. The device was completed in 1986 after Bath conducted research on lasers in Berlin and patented in 1988, making her the first African-American woman to receive a patent for a medical purpose. The device — which quickly and nearly painlessly dissolves the cataract with a laser, irrigates and cleans the eye and permits the easy insertion of a new lens — is used internationally to treat the disease. Bath has continued to improve the device and has successfully restored vision to people who have been unable to see for decades.
Bath holds five patents in the United States. Three of Bath’s five patents relate to the Laserphaco Probe. In 2000, she was granted a patent for a method for using pulsed ultrasound to remove cataracts, and in 2003 a patent for combining laser and ultrasound to remove cataracts.