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How to measure ophthalmic artery Doppler for pre-eclampsia screening
1Fetal Medicine Unit, Department of Obstetrics and Gynaecology, St George's University Hospital NHS Foundation Trust, City St George's University of London, UK; Division of Experimental Medicine in Cambridge, University of Cambridge, UK.
Background:
Pre-eclampsia remains a leading cause of maternal and perinatal morbidity, affecting 3-5% of pregnancies globally. Screening in most hospital settings relies on risk factors, and only a few hospitals perform individualised risk screening using maternal factors, mean arterial pressure, uterine artery Doppler, and biochemical markers. Maternal ophthalmic artery (OA) Doppler has emerged as a significant marker of cerebrovascular and systemic hemodynamic adaptation. The peak systolic velocity (PSV) ratio reflects an integrated measure of cardiac output and peripheral vascular resistance.
Objective:
To provide a standardised, practical guide for acquiring high-quality ophthalmic artery Doppler measurements to be incorporated into clinical pre-eclampsia screening protocols.
Methods:
The guide outlines a nine-step acquisition technique using a high-frequency (7-18 MHz) linear-array transducer. Following a 5-min rest period, measurements are taken with the patient supine, and the probe is gently placed on the closed eyelid. The ophthalmic artery is identified superior and medial to the optic nerve, with the sample gate positioned 10-15 mm posterior to the globe. To ensure accuracy and reproducibility, an insonation angle of <20° is required, and measurements should be averaged from both eyes.
Clinical Utility:
Ophthalmic artery Doppler provides significant incremental value to screening algorithms. In the second trimester, adding the PSV ratio improves preterm pre-eclampsia detection from 72% to 89% at a 10% false-positive rate. The technique is particularly advantageous in resource-limited settings due to its low equipment requirements and rapid learning curve. Safety is maintained by adhering to the ALARA principle, specifically keeping the Mechanical Index (MI) < 0.23 and Thermal Index (TI) < 1.0.
Conclusion:
Ophthalmic artery Doppler is an accessible, safe, and reproducible tool for assessing maternal haemodynamics. Adhering to a standardised acquisition technique is essential for its successful integration into multimodal pre-eclampsia screening.
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Pre-Procedural Guidelines for Doppler Ultrasound Blood Pressure Assessment:
Preparation of Equipment:
Assessment of blood pressure in brachial artery(two-step method)
Pre-Procedural Guidelines for Assessing Blood Pressure
Assessment of blood pressure in brachial artery(one-step method)
Prepare for the Procedure:
Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
Equipments Used To Measure Blood Pressure
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...

