The advent of the personal computer (PC) based fast processors has lead to wider use of image analysis systems over the last two years. In an attempt to remove subjectivity from clinical evaluation in contact lens research we have used a PC based image analysis system to objectively assess various aspects of contact lens performance. The presentation will: (i) Describe the system used and outline the requirements of image analysis systems for contact lens research. (ii) Describe in detail the applications of the system to the measurements of ocular parameters (eg. pupil size, visible iris diameter...), contact lens performance (eg. on-eye diameter, lens centration and movements...), lens surface characteristics (eg. surface deposits). Our conclusions are that an effective image analysis system requires a fast dedicated processor (transputer) and a high resolution colour monitor as the hardware and a menu based programme that enables image capture, transformation and measurement with the development and use of macros to automate these processes.