Reproducibility of scanning laser Doppler flowmetry in the rat retina and optic nervehead

The purpose of this study is to confirm the reliability of scanning laser Doppler flowmetry in the rat retina and optic nervehead, and the validity of measuring changes of retinal blood flow in rats while breathing 100% oxygen.

We used a commercially available scanning laser Doppler flowmeter. To ascertain reliability, five consecutive and separate perfusion measurements of 12 eyes of 12 anesthetized pigmented rats were performed. To evaluate the validity of the system, repeated measurements were taken in anesthetized rats breathing room air or 100% oxygen. This series of measurements was repeated three times.

The reliability coefficients of volume, flow, and velocity in the optic nervehead and the retina ranged from 0.80 to 0.83 and 0. 77 to 0.82, respectively. After the first exposure to oxygen, the measured values of volume, flow, and velocity were reduced by an average of 20.9-24.0%, 21.2-28.2%, and 19.5-24.5%, respectively. After the values returned to the basal condition, the second and third exposures to oxygen yielded measured values that were reduced by the same amounts as at the first exposure.

Scanning laser Doppler flowmetry provided relatively good reliability in measurements of blood flow in the rat retina and optic nervehead. This study has indicated the possibility of applying this system to the rat retina.