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EyeSim is a well designed, interactive website that simulates eye movements and pupillary responses. Virtual lesions induce defects that are not subtle, making the simulator more useful for teaching undergraduates and junior postgraduates than for simulating “the real thing”. The website is readily accessible and the explanations are clear. Two multimedia application programmes are required to run EyeSim; these can be easily downloaded from the opening page of the website.
Although there is a demonstration mode that (literally) talks the user through a very simple examination of ocular motility and demonstrates third, fourth, and sixth nerve palsies, one of the most pleasing features of the website is one’s ability to interact with it. The website presents a virtual patient whose two eyes follow the computer mouse. One can click on a menu to disable one or more extra ocular muscles and observe the resulting eye movements. The eye movement abnormalities are severe but accurate for acute impairment. Although there are conjunctival blood vessels that might have been used as reference points, torsional movements are, unfortunately, not simulated.
The pupil responses can be assessed with a virtual pen torch. There is a useful simulation of the relative afferent pupillary defect, RAPD (relative afferent pupillary defect; which the authors term a ‘mild RAPD’), although there is no pupillary escape that can make assessing for a RAPD in ‘real life’ difficult. However, what they term a marked RAPD is a total APD (there is no direct pupil response to light).
The terminology used in the discussion of third nerve palsies will not be to every user’s taste. The authors use full or partial to refer to the degree of impairment of the affected muscles rather than whether only certain muscle groups are affected. Pupil involvement is treated separately.
The simulation and discussion of fourth nerve palsies is simplified. Mention could have been made of anomalous head position and that the defect in primary position is dependent on which eye is fixing.
There are three straightforward interactive clinical cases. We have some reservations about the proposed management of case 1 (in question 6) and the discussion of case 3. There appears to be a missing pupil defect in case 2. But you will have to visit the site yourself to see if you agree...