The influence of dropsize of tropicamide 0.5% eyedrops on pupildilation

Currently used eyedrops sometimes cause significant ocular and systemic adverse
reactions. Using regular eyedrops, it has been shown that a higher dose is
administrated than necessary to obtain a sufficient pharmacologic response.
Most of the dose is immediately removed from the eye. Adverse reactions are
mostly dose-dependent. From this is hypothesized that a microdrop and a regular
eydrop may be equally effective, while adverse reactions are possibly minimised
by reducing eyedrop size.

Primary:Is the degree of pupildilation, achieved after administrating a 4.5
microliter microdrop tropicamide 0.5% equivalent to the pupildilation after a
regular 30 microliter eydrop tropicamide 0.5% in healthy volunteers?

Secondary: Is there a subjective difference in the degree of physical
discomfort, experienced after administration of a microdrop compared to a
regular eyedrop?
Qualitative evaluation of the mydriatic reponse/time curves of both the
microdrop and the regular eyedrop.

Randomised, single-blind cross-over pilotstudy

Subjects are randomly assigned to one of two interventiongroups. Subjects in
group A receive a microdrop in both eyes on day 1, group B receive a regular
eyedrop. Pupilsize measurements are performed 10 times during a 2 hour
timeframe. The second testing session is planned after at least 7 days. Group A
receives a regular drop, group B a microdrop and the measurements are repeated.

Subjects may experience short-term physical discomfort as a result of the
intervention of this study. A transient burning sensation may occur after
administration of the eyedrop. Also, subjects may have a blurred vision while
the pupil is dilated.
Limited risk exists in developing narrow-angle glaucoma after administration of
tropidamide, as well as a small risk of hypertension or tachycardia. These
risks are diminished by performing a medical examination. Subjects having risk
factors are excluded from this study.