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Eyeing Virtual Reality

Just as modern pilots are trained on flight simulators, eye surgeons will soon be using surgical simulators. Scientists at the University of Auckland and McGill University in Montreal are working on a surgical virtual reality system to bring this about.

Until now, precise operations such as eye surgery have been performed by skilled surgeons using handcrafted tools. These techniques require a very high degree of dexterity. At McGill's Bio-Robotics Laboratory, a micro-surgical robot for use in eye surgery is being developed by New Zealander Dr Ian Hunter. The robot can scale down a surgeon's movements up to a thousand times, and a computer can filter out hand tremor, and warn of unacceptable errors. Force feedback from the robot enables the surgeon to "feel" exactly what he or she is doing.

A computer-generated simulation of the eye and surgical environment is being created in Auckland by PhD student Mark Sagar, under the guidance of Dr Gordon Mallinson (Department of Mechanical Engineering) and Dr Peter Hunter (Department of Engineering Science). This will help during the operation, and also help train surgeons.

The surgeon will wear a head-mounted display showing three-dimensional images generated by computer. In this virtual world the surgeon can explore from any angle, and move at will. For example, the operation can be viewed as though the surgeon is standing inside the eyeball and cutting into a huge wall. The computer-generated model of the eye is being made as realistic as possible in appearance, feel and behaviour. The eyelids can blink, the eyeball can look around, the pupil contracts and dilates, and the viewer can travel right inside the eye.

"The challenge is to make the eye look as realistic as possible, but to be displayed as quickly as possible for real time work," says Sagar.

The project is unusual, he says, in bringing together many different fields of technology. Hunter comes from a multidisciplinary background involving psychology, electrical engineering and robotics.

His brother Peter Hunter has been developing mathematical models of the human heart. He has recently produced a system which allows surgeons to analyse the heart's electrical activity during surgery. Mallinson has a strong background in computer modelling, computer graphics, and 3D-visualisation of fluid dynamics and heat transfer. Sagar himself has both a scientific and a fine arts background, and says "the project is an ideal merge of these disciplines."