Specific Aims: Modify existing Weinstein Oral Microaesthesiometer to create a new instrument to test corneal somatosensation. Determine validity and test-retest reliability of device, and establish norms on a small group of subjects. Separately measure and compare corneal thresholds obtained psychophysically and by means of cortical evoked potentials. Explore, post hoc, in a small group, the effects of: age, sex, contact lenses, and use, e.g., of tobacco, alcohol, etc. Long Term Objectives: Establish commercial potential and age/sex norms. Results Expected During Phase I: Create safe, valid, precise, reliable device for testing corneal, scleral, conjunctival and eyelid somatic sensation. ln a small group, establish limited age and sex norms, and sample effects, e.g., of contact lenses and use of substances such as tobacco, alcohol, etc. Potential for Technological lnnovation and Commercial Application: Thr existing instrument, which will be the prototype for this device, The Weinstein Oral Microaesthesiometer, is a valid, precise, and reliable instrument for testing oral cavity sensation. The potential exists for its conversion into a corneal microaesthesiometer, which would have numerous advantages over existing instruments. For example, it alone could be used in the measurement of cortical evoked potentials in nonverbal humans (infants, retardates, etc.) and in animals. The following disadvantages of current devices are not possible with this device: 1. risk of infection, as with hairs or threads, 2. injuring the cornea, as with platinum wires, 3. inability to go below the threshold force, 4. inducing apprehension with visible stimuli. Commercial application which may result from this study: creation of a device for sale to ophthalmologists, optometrists, clinics, laboratories, and schools of medicine and optometry.