In fact, many of them vasoconstrict. We don't use them in individuals with low tension glaucoma. Van Buskirk has published some very good vascular casting studies in AJO . The bottom line of course is the effect on visual function, and clinical studies to date suggest that betaxolol is superior to timolol in terms of preserving visual field. One of the key challenges we face is developing reliable measurement systems to determine if we are, if fact, stabilizing visual function.
Visual fields have a great deal of variability.
But the main emphasis has been on glutamate and the development of oral formulations. Memantine has just started clinical trials. Eliprodil will hopefully be available sometime in 2000. I think we have learned a lot over the last decade or so. We must treat everybody for these factors because we're in it for the long term.