Doppler ultrasound of blood flow velocities in ophthalmic and central retinal arteries during the early neonatal period.

PURPOSE

To obtain standard values of blood flow velocity in the ophthalmic artery and central retinal artery in the neonatal period and to compare blood flow velocity of orbital vessels with that of the anterior cerebral artery and middle cerebral artery.

METHODS

Forty-five healthy neonates (gestational age, 39.2 +/- 1.2 weeks; birth weight, 3,210 +/- 567 g) on the first and third postnatal days (90 eyes each time) and on the fifth day of life (34 eyes) were included in a clinical trial. A duplex scanner with mechanical sector probe was used for measuring blood flow velocity in the ophthalmic artery, central retinal artery, anterior cerebral artery, and middle cerebral artery. A nominal imaging frequency of 7.5 MHz, a transmitted Doppler frequency of 5 MHz, and a wall filter setting of 50 Hz were used in each case. Systolic, end-diastolic, and mean-enveloped velocities were measured for the studied vessels and the resistance and pulsatility indices were calculated.

RESULTS

On the first postnatal day, blood flow velocities and indices in the ophthalmic artery were systolic 14 +/- 2.4 cm/sec, end-diastolic 3.8 +/- 0.6 cm/sec, mean-enveloped 7.3 +/- 1.3 cm/sec, resistance index 0.73 +/- 0.03, and pulsatility index 1.5 +/- 0.2. Central retinal artery blood flow velocities and indices were systolic 8.7 +/- 1.8 cm/sec, end-diastolic 2.7 +/- 0.7 cm/sec, mean-enveloped 5.0 +/- 1.1 cm/sec, resistance index 0.70 +/- 0.04, and pulsatility index 1.3 +/- 0.1. There were no significant differences in ophthalmic artery and central retinal artery flow velocities between right and left eyes. Doppler values of the central retinal artery were significantly lower (P = .0005) than those of the ophthalmic artery for each day studied. The Doppler data for the central retinal artery and ophthalmic artery were significantly lower (from P = .005 to .0001) than those observed in the anterior cerebral artery and middle cerebral artery at the same postnatal age. No significant differences in flow variables were found in the central retinal artery and ophthalmic artery from the first to third day, whereas blood flow velocities in the anterior cerebral artery and middle cerebral artery increased significantly (P = .01 to .0001) from day 1 to day 3. On the fifth day of life a significant increase in blood flow velocities and indices was observed in the ophthalmic artery, whereas only systolic velocity significantly increased in the central retinal artery.

CONCLUSIONS

We report blood flow data of the ophthalmic artery and central retinal artery in healthy neonates and suggest that a delay of arterial blood flow changes occurs for the ophthalmic artery and central retinal artery with respect to the anterior cerebral artery and middle cerebral artery in the early prenatal period.