Preeclampsia is a hypertensive disorder during pregnancy characterized by markedly high blood pressure and proteinuria typically after 20^th week of gestation. It can lead to maternal complications like renal failure, HELLP syndrome, abruptio placenta and fetal complication such as low birth weight, intrauterine growth restriction and preterm births.  In India the incidence is as high as 11% and it contributes to 7-8% of all maternal death^[1]. Because of the disease burden it is crucial to predict and manage preeclampsia and its complications.

Till date, numerous strategies have been proposed to detect preeclampsia early which include the measurement of biomarkers, assessment of maternal risk factors, and the use of ultrasonography. However, many of these methods lack accuracy and sensitivity or specificity, particularly to reliably predict the onset of the disease in its early stages.

One of the earliest indicators of preeclampsia is changes in the blood flow in the uteroplacental circulation and so it is a potential target for prediction of preeclampsia and its management. Currently, uterine doppler ultrasound is used to evaluate vascular resistance and blood flow patterns to identify abnormalities that may signal in increased risk of preeclampsia. Umbilical artery on the other hand focuses more on fetal health rather than maternal vascular changes. Predictive value of uterine artery doppler is mostly in the second trimester, because early-onset preeclampsia (<34 weeks) is primarily linked to placental insufficiency caused by defective remodelling of the uterine spiral arteries, which is effectively detected by uterine artery Doppler (UAD)^[2]. In contrast, late-onset preeclampsia (≥34 weeks) is more often associated with maternal cardiovascular or metabolic factors, making UAD a less reliable predictor in such cases. So, in recent years ophthalmic artery doppler has gained attention as a potential tool for predicting late onset preeclampsia as it is a noninvasive, reproducible, and economical method for detecting early vascular alterations that precede the onset of clinical symptoms.

The ophthalmic artery, a branch of the internal carotid artery, is easily accessible for Doppler evaluation. Due to its embryological, anatomical, and functional similarities with intracranial vessels, Doppler assessment of the ophthalmic artery can provide insights into the less accessible intracranial circulation^[3]. Moreover, it can detect changes before clinical symptoms appear, highlighting its potential as a useful tool for early screening and detection of preeclampsia.

Objectives

This thesis aims to evaluate the role of ophthalmic artery Doppler in the prediction of late onset preeclampsia, with the ultimate goal of improvement in maternal and fetal health outcomes. Through a comprehensive review of existing literature and a series of prospective studies, this research will assess the effectiveness of ophthalmic artery Doppler to predict preeclampsia.

A hospital-based, prospective observational study was done in the Department of Radiodiagnosis of Mahatma Gandhi Memorial Medical College & M.Y Hospital, Indore, Madhya Pradesh, India, after getting approval by the Ethics and Institutional Scientific Review committee (ISRC). The duration of this study was of one year from the ethics committee clearance.

A total of 620 patients at 34 to 37 weeks of gestation were studied, who presented in the department of Obstetrics & Gynaecology and were referred in the Department of Radiodiagnosis for routine antenatal scan and subsequent follow up was done. The inclusion criteria was singleton live pregnancy in third trimester (34-37weeks gestation).

 Pregnant females who were referred to the Department of Radiodiagnosis for antenatal scan between 34-37 weeks and were followed up. Informed consent taken after a complete description of study and handing over patient information sheet. After completing the PC-PNDT Act formalities, obstetric ultrasound was performed. The mother was in the supine position for the routine scan. At the end of this scan a 6–15-MHz linear transducer was placed transversely and gently over her closed upper eyelid after application of conduction gel. Color flow was used to identify the ophthalmic artery, which is found superior and medial to the hypoechoic band representing the optic nerve.Pulsed-wave Doppler was then used to record three to five similar waveforms; the angle of insonation was kept at < 20°, the sample gate was 2 mm, the depth was 3.0–4.5 cm, the high-pass filter was 50 Hz, and the pulse repetition frequency was set at 125 kHz.Waveforms were obtained in sequence from the right eye, left eye and again from the right and then left eye.The average of the four measurements, two from each eye, for the following four indices: First peak of systolic velocity; second peak of systolic velocity; pulsatility index; and the ratio of the second to first peak of systolic velocity (PSV ratio) was recorded.

Data were tabulated in the Microsoft Excel sheet and SPSS software was used to analyse the data.Further depiction of data was done in the form of various tables and charts.Sensitivity, Specificity. Positive predictive value and Negative predictive value of imaging for cochlear candidacy calculated. The specific test were applied whenever necessary in the study.

Fig. 1: Ophthalmic artery doppler

A hospital-based, prospective observational study was done in the Department of Radiodiagnosis of Mahatma Gandhi Memorial Medical College & M.Y Hospital, Indore, Madhya Pradesh, India, after getting approval by the Ethics and Institutional Scientific Review committee (ISRC). The duration of this study was of one year from the ethics committee clearance.

A total of 620 patients at 34 to 37 weeks of gestation were studied, who presented in the department of Obstetrics & Gynaecology and were referred in the Department of Radiodiagnosis for routine antenatal scan and subsequent follow up was done. The inclusion criteria was singleton live pregnancy in third trimester (34-37weeks gestation).

 Pregnant females who were referred to the Department of Radiodiagnosis for antenatal scan between 34-37 weeks and were followed up. Informed consent taken after a complete description of study and handing over patient information sheet. After completing the PC-PNDT Act formalities, obstetric ultrasound was performed. The mother was in the supine position for the routine scan. At the end of this scan a 6–15-MHz linear transducer was placed transversely and gently over her closed upper eyelid after application of conduction gel. Color flow was used to identify the ophthalmic artery, which is found superior and medial to the hypoechoic band representing the optic nerve.Pulsed-wave Doppler was then used to record three to five similar waveforms; the angle of insonation was kept at < 20°, the sample gate was 2 mm, the depth was 3.0–4.5 cm, the high-pass filter was 50 Hz, and the pulse repetition frequency was set at 125 kHz.Waveforms were obtained in sequence from the right eye, left eye and again from the right and then left eye.The average of the four measurements, two from each eye, for the following four indices: First peak of systolic velocity; second peak of systolic velocity; pulsatility index; and the ratio of the second to first peak of systolic velocity (PSV ratio) was recorded.

Data were tabulated in the Microsoft Excel sheet and SPSS software was used to analyse the data.Further depiction of data was done in the form of various tables and charts.Sensitivity, Specificity. Positive predictive value and Negative predictive value of imaging for cochlear candidacy calculated. The specific test were applied whenever necessary in the study.

Fig. 1: Ophthalmic artery doppler

This study evaluated the diagnostic utility of ophthalmic artery Doppler parameters in predicting preeclampsia and found significant differences in Doppler indices between women with and without the condition. The demographic profile (Table 1) of the study population showed a mean age of 25.1 years. This average age is similar to the findings of Alemayehu Sahiyu Belay et al. (2019)^[4], who reported a mean age of 25.87 ± 4.7 years, but lower than that observed in the study by Juliana De Freitas Leite et al. (2019)^[5], which reported a mean age of 29.8 ± 6.5 years. This is probably the influence of social, economic and gendre based factors.

In our study mean BMI of 24.3 kg/m². These findings are in agreement with the study conducted by Rajaei et al. (2014)^[6], which also observed a similar BMI distribution among pregnant women.

In our study population, 260(42%) of the pregnant women were primigravida, followed by 217(35%) who were gravida 2, 136(22%) who were gravida 3, and only 7(1% )with a gravidity greater than 3. The predominance of primigravida women in our study is consistent with similar findings by Juliana de Freitas Leite et al. (2019)^[5], who reported 41% primigravida, and A. Tayyar et al. (2015)^[7], with 49.2%. A comparable observation was made in a study by Adekanle et al. (2016)^[8], which also noted a higher prevalence of preeclampsia among primigravida women, emphasizing the increased susceptibility of first-time mothers to hypertensive disorders in pregnancy.

Table 2 highlights the hemodynamic changes observed in the ophthalmic artery among patients with preeclampsia. A statistically significant increase in both the primary and second peak systolic velocities (PSV and 2nd PSV) was found in preeclamptic patients compared to normotensive controls (p < 0.01). The PSV ratio was also elevated in the preeclampsia group, suggesting heightened vascular resistance and altered perfusion. Conversely, the pulsatility index (PI) was significantly lower in the preeclampsia group for both eyes, indicating reduced compliance in the distal vascular bed and consistent with the systemic vasoconstriction characteristic of preeclampsia.

The diagnostic performance of individual Doppler parameters was assessed in Table 3. Among the three parameters, PI demonstrated the highest diagnostic accuracy, with sensitivity and specificity values of 85.86% and 85.03%, respectively These results are in concordance with the findings of Barbosa et al. (2019)^[9], who reported a sensitivity of 83% and specificity of 82% at a comparable PI threshold, reinforcing the validity of this Doppler parameter. Similarly, Fatemi et al. (2017)^[10] found a slightly higher sensitivity of 88% but a lower specificity of 79%, indicating some inter-study variation, potentially due to differences in population demographics, gestational age at assessment, or Doppler techniques used. Its AUC (0.859) suggests strong discriminative ability, making it a potentially reliable marker for predicting preeclampsia.

In our study PSV2 demonstrated a high negative predictive value (96.85%), indicating that women with PSV <28 cm/sec are very unlikely to develop preeclampsia. These findings are consistent with Ayaz et al.(2014)^[11] who reported a sensitivity of 84% and a negative predictive value of 94% using a similar PSV cut-off, emphasizing the value of ophthalmic artery Doppler in early risk prediction. Similarly, Sutapa Agarwal et al. (2016)^[12] reported that 2nd PSV was significantly elevated in preeclamptic women compared to normotensive controls, supporting its use as a reliable indicator in the antenatal prediction of preeclampsia.

The diagnostic performance of PSR at the cut-off level of 0.53 revealed a sensitivity of 78.7%, specificity of 81.19%, positive predictive value (PPV) of 44.33%, and a high negative predictive value (NPV) of 95.28%. These findings are consistent with the study by Saito et al. (2018)^[13], who used a PSR threshold of 0.52 and reported a sensitivity of 80% and specificity of 82%, values closely aligning with our results. The high NPV observed in both studies supports the usefulness of PSR as a reliable tool to exclude the likelihood of preeclampsia when values are below the threshold. However, the PPV in our study (44.33%) is slightly lower compared to others, such as the study by Li et al. (2020)^[14], which reported a PPV of around 50%.

The high negative predictive values of all three parameters (above 95% for PSV2 and PSR) indicate their potential utility in ruling out the disease when test results are normal.

PI, PSV2 & PSR showed good AUCs of 0.859, 0.703 and 0.784, respectively in ROC curves (Figures 2–4). This further support the effectiveness of these indices, particularly the pulsatility index, in identifying patients at risk. These findings reinforce the role of ophthalmic artery Doppler as a non-invasive, bedside screening tool that may help identify hemodynamic alterations early in the disease course.

In summary, this study confirms that ophthalmic artery Doppler parameters particularly the PI and 2nd PSV are significantly altered in preeclamptic patients. Their diagnostic value, supported by strong sensitivity and specificity, suggests their integration into routine antenatal screening protocols may aid in early detection and timely management of preeclampsia.

In this study we concluded that ophthalmic artery Doppler was more accurate, particularly in identifying late-onset preeclampsia. Given its ease of application and strong predictive performance, ophthalmic artery Doppler should be considered for incorporation into routine antenatal screening protocols. Its use may help improve maternal and fetal outcomes by enabling earlier identification and intervention in high-risk pregnancies.

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