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  • Title: [Effect of decreased ocular perfusion pressure on iris blood flow measured by laser Doppler flowmetry].
    Author: Chamot SR, Movaffaghy A, Petrig BL, Riva CE.
    Journal: Klin Monbl Augenheilkd; 1999 May; 214(5):302-4. PubMed ID: 10420373.
    Abstract:
    PURPOSE: To determine whether iris blood flow (IBF) is regulated in response to an acute decrease in mean ocular perfusion pressure (PPm = MOAP-IOP, MOAP = mean ophthalmic arterial pressure) induced by increasing the intraocular pressure (IOP). METHODS: Iris blood flow was measured using a slit lamp incorporating a laser Doppler flowmetry (LDF) module. The study was conducted on 12 normal volunteers (14 to 59 years old). IOP was raised using a scleral suction cup. In Exp. #1, the suction pressure was successively raised in steps of 50 to 100 mm Hg, each lasting about 10 sec, until IOP reached the MOAP level. In Exp. #2, the suction was raised to 200 mm Hg in 4 successive steps of 2 min duration. RESULTS: In Exp. #1, no significant change of IBF was observed for small decreases of PPm (< 23%); greater decreases of PPm resulted in a linear IBF decrease (p < 0.01). In Exp. #2, such a IBF versus PPm decrease was also observed (p < 0.001). Immediately after release of suction, a significant, transient IBF increase of 79% above baseline level was observed. CONCLUSION: These results suggest that some IBF regulation occurs for small PPm decreases (< 23%); no IBF compensatory mechanism appears to operate for further decreases of PPm (> 23%).
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