EyeSim--an ophthalmic response simulator

This paper pertains to the design, construction and development of an ophthalmic response simulator, intended to augment current neurological examination teaching practices in medical schools. Neurological examination of the eyes informs a practitioner of the functional state of certain cranial nerves (II, III, IV and VI) through the assessment of visual acuity, visual fields, ocular movements, external and internal eye structures and ophthalmoscopic examination. For the medical student, the interpretation of these indicators may be difficult, compounded by the infrequence with which such patients may be presented. As such, the need was identified for a simulator capable of replicating the ophthalmic response of patients with typical and a range of atypical neurologies. Such a simulator could be used as a stand-alone device or developed toward inclusion in pre-existing, life-size, hi-fidelity mannequins. Specifically, EyeSim will be able to track the movements of a pen-torch and vary the apparent dilation of an iris in response to changing levels of illumination. These responses can then be modulated to reflect certain deficits that neural pathologies may cause. At present the simulator comprises the electrical, electronic and mechanical components that replicate the pupillary response of the iris and the motility of the ocular muscles, a computer for the reception and analysis of a video signal and the micro-controller components, which determine the action of the physical components based on an array of inputs.