Purpose. To quantify the choroidal pressure-flow relationship by raising IOP at a normal mean arterial pressure (MAP 70 mmHg) before and after topical ß-blockade. Methods. Pentobarbital anesthetized rabbits were instrumented with an ear artery cannula to measure MAP and 2 vitreous cannulas to control and measure IOP. Choroidal blood flow was measured by laser Doppler flowmetry with the probe tip positioned over the posterior pole. The protocol entailed raising the IOP from baseline by saline infusion at 30 μl/min until the IOP reached 100 mmHg. The protocol was performed before and 30 min. after topical application of Timolol (n=5) or Betaxolol (n=5). Results. Neither Timolol nor Betaxolol altered the choroidal pressure-flow relationship although both drugs blocked the systemic response to isoproterenol. (Graph Presented) Conclusion. Unlike systemic propranolol (IOVS 36: S106, 1995), topical ß-blockade with Timolol or Betaxolol does not cause choroidal vasoconstriction.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience