Corneal contact times of ophthalmic vehicles. Evaluation by microscintigraphy.

Lacrimal microscintigraphy, in conjunction with a recently developed computer system, was used to evaluate the corneal contact time of three ophthalmic vehicles in 18 humans. The percentage of a radioactively labeled vehicle remaining over the cornea after 90 seconds was 2.9% plus and minus 2.2% for saline, 4.3% plus and minus 2.4% for polyvinyl alcohol, and 8.8% plus and minus 4.1% for hydroxypropyl methylcellulose.