Corneal sensation is tested by which device?

ANSWER: (C) AesthesiometerREF: Khurana 4th Ed Pg 472See PLATE O -21 KEY PLATE O-21 KEYTESTING CORNEAL SENSATIONS:(B) To test the corneal sensations, patient is asked to look ahead; the examiner touches the corneal surface with a fine twisted cotton (which is brought from the side to avoid menace reflex) and observes the blinking response. Normally, there is a brisk reflex closure of lids. Always compare the effect with that on the opposite side. The exact quantitative measurement of corneal sensations is made with the help of an aesthesiometer.(A) The most common quantitative method is the handheld esthesiometer (Cochet-Bonnet). It tests only A delta fibres and not C and temperature fibres. Noncontact corneal aesthesiometer {uses air puff technique) is another method. Tne advantage of NCCA over the Cochet-Bonnet aesthesiometer is that a large, continuous range of stimulus intensities can be produced. Furthermore, the stimulus is more precise and sensory-specific, testing is less variable than with use of a filament, there is no corneal microtrauma is prevented. Patient apprehension is also lesser, & lower stimulus thresholds can be detected. However it is not commercially available & is less portable.