Assessing ocular drug delivery with lachrimal scintigraphy.

In order to transmit well focused images to the retina, the eye must have constant dimensions and an unclouded optical pathway. These requirements dictate that the eye has a well developed system to ensure consistent optics and that any material applied to the eye is rapidly cleared. Unfortunately, this can severely limit the effectiveness of topically applied medication. This review outlines a key method by which ocular drug delivery can be assessed - lachrimal scintigraphy - in a non-invasive, physiologically relevant setting.