The use of computer-assisted instruction in medical education has increased steadily in the last decade with the availability of personal computers. Many computer-assisted instruction programs train the user to handle various forms of disease or injury. Our intent was to provide medical students with more experience in managing ophthalmological emergencies, and we therefore designed a computerized teaching system for emergency ophthalmological care. The system makes it possible for inexperienced students to develop these skills, without jeopardizing the patient's health during training. Colour illustrations help teach the student to judge clinical signs. First, two classes of altogether 35 students used the teaching system. The students were shown to have gained significantly better knowledge of conditions which had been presented to them by the computerized teaching, than of conditions which had not been presented in this way. After having used the system, two other classes were asked about their attitudes towards this teaching modality. A majority regarded it as a valuable or very valuable addition to traditional methods of teaching. This type of instruction system may improve the quality of ophthalmic teaching without increasing teaching staff requirements.