Background. Training medical students to understand the neuromuscular basis of eye motion is not a simple task. There are six muscles and three cranial nerves involved in the movement of each eye.

In our medical school anatomy class, a mechanical model of the eye composed of a tennis ball for the eye and rubber bands for the extraocular muscles, was used several years ago to demonstrate the actions of the muscles and their cranial nerve control.

This eye muscle model had several inherent limitations. There was limited access to the eye muscle model demonstration since it was demonstrated only a few times per year. Due to the model's small size, only the first few rows of students could see it clearly. Due to the limited demonstration time, only basic eye movements and a few pathological eye motions due to muscle and cranial nerve lesions could be demonstrated. No quizzing method was built into the model to test the student's understanding of eye motion.

The Web/Shockwave-based neurological eye motion simulator was developed to mimic as well as enhance the function of the mechanical model by addressing its limitations. Creating a Web/Shockwave-based eye simulator made the eye model available to all students year-round and accessible from any computer system on the Internet. In addition, eye simulator can be configured to turnoff any combination of the six muscles and three cranial nerves in each eye to simulate pathological eye motion. A quiz mode was created to test the student's understanding of eye motion and basic pathological situations.

System Description. The neurological eye motion simulator was created by using a combination of Macromedia Director movies, Shockwave, JavaScript language, HTML language, and the World Wide Web.

Macromedia Director provides an efficient method of simulating a patient's eyes following a doctor's finger. However, instead of a finger, the eyes follow the mouse sprite. Based on a mathematical model of eye motion, two eye images are moved behind a static image of a face. The state of the eye muscles and associated cranial nerves are used to calculate pathological eye motion.

Designed for World-Wide-Use. Most graphical simulations for learning are limited to local use because either they are not designed for the Internet. Most graphical simulators that are designed for the Internet are also limited to users on T1 lines due to the high bandwidth requirements. This neurological eye simulator not only is designed for the Internet but has such a low bandwidth requirement that it can easily be used by students at home through slow telephone modems.

Evaluation. The eye simulator has been used for the past three years by students in the UC Davis medical anatomy class. Professors also use it as a teaching aid during lecture on a LCD projector.

The eye simulator is now being used worldwide by medical students, as well as students of many other medically related disciplines to help them learn eye muscle anatomy and neurological functions. The eye simulator has been given a 5 star rating by the CAL Reviews of medical education applications. (URL http://cim.ucdavis.edu/users/rick/calreview.htm) The CAL Reviews is produced by the Centre for Medical Interactive Technology as part of an IT initiative with the Clinical Biomedical Computing Unit of the University of Cambridge Clinical School (in England).

Although no formal statistical data has yet been tabulated, feedback from medical students, residents, practicing neurologists and ophthalmologists has been extremely positive and has indicated that the simulator has been useful as an educational tool.

Conclusions. The neurological eye simulator has successfully enhanced the inherent limitations of the mechanical tennis ball model and has become a useful educational application for medical students. Using the combination of Director, Shockwave , and JavaScript provides a powerful simulator for educational. This simulator also provides worldwide availability at a low bandwidth making it usable by a large population of students and interested public.

This is only the beginning of our learning simulation projects. Hewlett-Packard recently awarded the UC Davis Medical School a $155,000 equipment grant to establish a virtual patient simulation laboratory. Future development of the eye simulator will include enhancements to simulate many common neurological conditions including strabismus, pathological eye reflexes, etc. Future developments of the virtual patient simulator lab will consist of realistic full body simulations to teach medical students basic Internal Medicine cases.

Eye simulator URL: http://cim.ucdavis.edu/eyes/eyesim.htm The simulator requires Shockwave.