The fully retractable Aesthesiometer with a 12/100 mm nylon thread for measuring the tactile sensitivity of the Cornea and eyelid margin. Can be used pre-operative or for post-operative recovery. Also known as a Cochet and Bonnet Aesthesiometer or Esthesiometer.

Provides direct reading on the instrument of the length of the very precisely calibrated filament, based upon the principle of pressure transmitted axially by a nylon monofilament, of known diameter but of variable length, for a given bending stress. The length of the thread like mono-filament, controlled by the forefinger (shown above), ranges from 60mm to 5mm. As the length is decreased the pressure transmitted is increased from 11mm/grms to 200mm/grms. Includes conversion table, which translates filament length in millimeters to a measure of mercury pressure (mm HG).