[Investigations under anesthesia on the effects of endogenous and exogenous factors on corneal sensitivity]

Corneal touch threshold and/or reaction time by the local anaesthetic benoxinate were determined in 91 males and females of different age groups. The corneal sensitivity decreased with advancing age, especially in the centre of the cornea. Comparing male and female subjects, the measurements of females over 40 years were significantly higher at all points of measurement than for male subjects in the same age group. In the nasal area there was a higher corneal sensitivity than in the temporal area in all subjects. Also the reaction time of equal doses of benoxinate is age-dependent meaning that the reaction time increases with age. Genetically determined differences could be supposed but are not yet certain. In order to determine that a corneal sensitivity deficiency exists, it is necessary to take age, sex and exact measurement points into account.