Purpose: Langham adapted the pneumotonometer to provide a waveform of the ocular pulse and using the heart rate derived values for pulsatile ocular blood flow. We have used a new pneumotonometer linked to an ocular blood flow system that has addressed several of the problems encountered with the Langham technique.
Methods: The reproducibility of this new method was assessed by measuring pulsatile ocular blood flow (mul/min) five times on one eye of 20 normal healthy volunteers (mean age 40 years; range 26-62) at one examination session. The test was conducted in the sitting position with the pneumotonometer probe mounted on a slit-lamp microscope.
Results: The mean pulsatile ocular blood flow was 633 +/- 180 mu/min. Statistical analysis using the intraclass correlation method showed there were no significant differences due to sessions for five recordings (p = 0.15) or, after excluding the two most extreme values, for three recordings (p = 0.49). There was no correlation noted between pulsatile ocular blood flow and age in a larger group (n = 49) of normal volunteers (mean age 61 years; range 26-72).
Conclusion: We conclude that pulsatile ocular blood flow measurements with this new instrument are reproducible and may be applied to blood flow studies in ocular hypertension and glaucoma.