Methods for increasing bioavailability of cycloplegics

Since it has been shown that (1) fluid instilled in the pouch created by pulling the lower lid away from the eyeball is entrapped, (2) no fluids move into the lacrimal sac when the eyelids are shut and (3) gravity is important in tear-flow dynamics, we reasoned that an instillation technique for topical ocular drugs could be devised which would increase the drug effect for a given amount of drug. To test this hypothesis we administered one drop of 0.5% tropicamide to the right eyes of 12 young adults using an experimental method of instillation and to the left eyes using the conventional technique. The experimental technique produced a significantly greater loss of accommodation than the conventional technique. Wtih this experimental or similar technique, it may be possible to use lower concentrations of a drug to produce the same ocular effects produced by a higher concentration instilled in the conventional manner.