Reproducibility of pulsatile ocular blood flow measurements.
OBJECTIVE
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).


CONCLUSIONS
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.
Butt
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Princess Alexandra Eye Pavilion, Edinburgh Royal Infirmary, Edinburgh, Scotland.
Oʼbrien
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