Retinal colour duplex scanning during LASIK-ring suction with different keratomes

PURPOSE: The purpose was to measure the blood flow velocity during the suction phase of LASIK. SETTING: University Eye Hospital, Martin-Luther-University Halle-Wittenberg, Halle, Germany. METHODS: Papillary blood flow velocity was measured by colour Doppler sonography. Suction rings of four different manufacturers were applied in 30 healthy volunteers without eye diseases all of normal blood and eye pressure. The velocity of the blood flow in the central retinal artery was measured before, during and after suction. RESULTS: When Hansatome (Bausch & Lomb) and M2 (Moria) rings were used, no blood flow velocity was detected during suction in 90% of all cases. These rings were compared to the SKBM standard suction ring (Alcon) and the Krumeich non-IOP ring, in which no blood was present in only 56.67% (p < 0.05) and 10% (p < 0.001) of cases respectively. Moria, Alcon and Krumeich Lasitome rings performed equally well during the recovery phase compared with the original values. An exception is the Hansatome ring (Bausch & Lomb), with lower velocities when evaluated after 30 minutes (p < 0.01). CONCLUSIONS: During the ring suction phase of LASIK, the rings tested reduce velocity differently.