 The topical carbonic anhydrase inhibitor, Dorzolamide Trusopt, has recently been approved for chronic use in the treatment of glaucoma. The ocular hypotensive effects of this topical carbonic anhydrase inhibitor seem likely to produce the same results as -adrenergic antagonists. Systemic carbonic anhydrase inhibitors are known to have vasodilatory effects Maren,1987. Rassam S.M.B., Patel V. and Kohner E.M. 1993 have concluded that acetazolamide causes an increase in retinal blood flow in the human retinal circulation. It has also been demonstrated that Trusopt increases retinal circulation as measured by scanning laser ophthalmoscopy SLO Harris, Arend, Martin, 1996. Furthermore, Trusopt increases arteriovenous passage AVP time and improves contrast sensitivity in normal tension glaucoma patients Harris, 1999. 