HYPERTONIC SALINE TEST FOR OPHTHALMIC NERVE IMPAIRMENT

In order to compare the accuracy of methods for testing ocular surface sensitivity (e.g. function of the first branch of the trigeminal nerv e) three different methods were compared in patients with unilateral a coustic neurinomas. The three methods 1) hypertonic (3%) saline in the conjunctival sac (apparently not previously described in the literatu re) 2) esthesiometer (Cochet & Bonnet) touching of the cornea, and 3) touching the cornea with a cotton wool wisp, was found to reveal reduc ed ocular surface sensitivity on the neurinoma side in 50% (hypertonic saline), 23% (esthesiometer) and 14% (cotton wool wisp) of cases, res pectively. With McNemar's test for comparing test methods the 3% salin e test proved significantly more sensitive than the cotton wool wisp t est (p < 0.05), but not significantly more sensitive than the esthesio meter test (p > 0.10). The advantage of the 3% saline test, apart from its high sensitivity, is that it does not require sterilization of an y equipment as is the case for the esthesiometer nor, in contrast to t he methods using corneal or conjunctival touch, does it require perfec t visual control by means of a magnifying glass in order to be perform ed accurately, and it is not affected by visual stimuli. It should the refore be the preferred test of assymetry in ophthalmic nerve function .