DUBLIN, Calif., Feb. 21 -- Carl Zeiss Ophthalmic Systems Inc., Humphrey Div., has received FDA clearance to market the Optical Coherence Tomographer Model 3000 (OCT3), an imaging device to help ophthalmologists diagnosis conditions such as glaucoma and retinal diseases during routine eye exams. The OCT3 is the first diagnostic medical device that employs the technology called optical coherence tomography. Optical coherence tomography works much like ultrasound, except that it uses light rather than sound and thereby achieves ten times better resolution. The OCT3 provides real-time cross-sectional images of retinal tissue that have axial resolution of ten microns or less. The OCT3 enables physicians to bypass invasive procedures and see below the surface of the retina to directly measure internal retinal structures. A typical OCT3 exam takes less than 10 minutes. Optical coherence tomography was invented at the Massachusetts Institute of Technology in 1991. Carl Zeiss Ophthalmic Systems purchased exclusive rights from MIT to develop and market the technique for ophthalmic diagnostic use. The technology is being studied for its potential diagnostic applications in other areas of medicine.