The aim of this study was to determine the central corneal thickness (CCT) in living rats, mice and rabbits using a non-contact, high-speed optical low coherence reflectometer (OLCR) mounted on a regular slit lamp. Both eyes of eight male Wistar rats, eight male balb-c mice and eight male Japanese rabbits were measured. Each eye was measured twice (one measurement consists of 20 scans), the average calculated. Additionally, CCT was measured in rabbits using an ultrasound pachymeter. The mean CCT was: RATS: 159.08 microm (SD+/-14.99 microm), MICE: 106.0 microm (SD+/-3.45 microm) and RABBITS: 356.11 microm (SD+/-14.34 microm). With the use of OLCR we were able to accurately measure the CCT of rats, mice and rabbits in vivo. This technique may prove useful in further refractive, pharmacological and glaucoma studies.