Ice test for ocular myasthenia gravis.

A prospective, non randomized comparative study was conducted to examine the efficacy of the ice test in differentiating myasthenia gravis (MG) ptosis from non MG. Twenty patients with MG ptosis and 20 with non MG ptosis were evaluated by measuring the palpebral fissures pre and post ice test applied on the eyelids for 2 minutes. The difference in widening of palpebral fissure 2 mm or more was considered as a positive ice test. The results showed that 19 from 20 MG patients had positive ice test, whereas, all non MG patients had negative results. The sensitivity and specificity of the test were 95.0 per cent and 100 per cent, respectively while the accuracy or efficacy of the test was 97.5 per cent. In conclusion, the ice test is a useful, simple, safe, fast, cheap, and easy to perform for the screening and diagnosis MG patients with ocular ptosis.