Quantification of corneal sensation is done by ?

Ans. is 'c' i.e., Aesthesiometer Measurement of Corneal Sensitivity Corneal sensitivity may be tested by touching it in various places with a wisp of cotton-wool twisted to a fine point and comparing the effect with that on the other, normal cornea. There is in general a brisk reflex closure of the lids. Corneal sensations are often diminished after any gross disorder, but the change is of diagnostic significance in ceain cases, paicularly herpes keratitis where minimal corneal changes are accompanied by a gross diminution of sensation. Quantification of the corneal sensation is possible to some degree by the use of a corneal aesthesiometer in which a single horse hair of varying length is used instead of a wisp of cotton-wool. The longest length which induces blinking is a measure of the threshold of corneal sensitivity.