What diseases can be detected by ultrasound of the eyes?

Author: Jia Lingyun, Chief Physician, Xuanwu Hospital, Capital Medical University

Reviewer: Chief Physician of Huayang Capital Medical University Xuanwu Hospital

With the continuous development of medical technology, the application of optic nerve sheath ultrasound technology in clinical practice is becoming more and more extensive. Many people will naturally think of eyes when they see the words "optic nerve sheath", but if they think that optic nerve sheath ultrasound is used to check eye problems, they are wrong.

Today, let us unveil the mystery of optic nerve sheath ultrasound.

1. Ultrasound of the optic nerve sheath can be used to assess intracranial pressure

The so-called optic nerve sheath ultrasound is a detection method that determines whether the patient has increased intracranial pressure by measuring the diameter of the optic nerve sheath.

The optic nerve sheath is the membrane that surrounds the optic nerve and is also the continuation of the subarachnoid space in the skull. It is filled with cerebrospinal fluid. When the patient has increased intracranial pressure, the cerebrospinal fluid in the optic nerve sheath will increase, and the pressure in the optic nerve sheath will also increase, which will lead to the thickening of the optic nerve sheath. Therefore, non-invasive optic nerve sheath ultrasound examination can be used to determine and evaluate the patient's intracranial pressure.

Compared with invasive intracranial pressure detection methods, optic nerve sheath ultrasound examination has the advantages of being fast, easy to operate, and non-invasive, and will not cause complications such as bleeding and infection in patients.

During the entire test, the patient needs to lie on his back, relax his body, close his eyelids, and keep his eyeballs as still as possible. The doctor will generally scan the patient's eyes in cross-section and sagittal planes, and measure the diameter of the patient's optic nerve sheath at 3 mm behind the eyeball.

Figure 1 Copyright image, no permission to reprint

2. In what cases can optic nerve sheath ultrasound examination be used?

When patients have the following symptoms and signs of increased intracranial pressure, optic nerve sheath ultrasound examination should be performed: ① severe headache; ② nausea and vomiting, especially projectile vomiting; ③ manifestations of optic disc edema, such as decreased vision, blurred vision, etc.

Figure 2 Copyright image, no permission to reprint

In addition, optic nerve sheath ultrasound examination can also be used as a dynamic follow-up examination method for patients with increased intracranial pressure.

However, it should be noted that not all patients with increased intracranial pressure can undergo optic nerve sheath ultrasound examination. For example, some patients with primary diseases such as optic nerve inflammation and tumors, or eye diseases such as glaucoma and cataracts, as well as patients with eye trauma, are not suitable for optic nerve sheath ultrasound examination.

In addition, changes in intracranial pressure are not necessarily caused by a single factor, so doctors generally recommend that patients with increased intracranial pressure undergo invasive intracranial pressure monitoring tests at the same time.

3. What are the uses of optic nerve sheath ultrasound examination?

Medical studies have shown that the results of optic nerve sheath ultrasound examination are highly consistent with those of magnetic resonance imaging and other methods. In addition, it has the advantages of being convenient, rapid, and non-invasive. Optic nerve sheath ultrasound examination is increasingly widely used in clinical practice and has gradually become a common means of detecting intracranial pressure, allowing patients to receive timely and effective intervention. For example, increased intracranial pressure caused by various diseases such as craniocerebral injury, cerebrovascular disease, intracranial infection, and intracranial mass can all be monitored using optic nerve sheath ultrasound examination.

There are also studies that use the results of optic nerve sheath ultrasound as the initial classification parameters for patients with craniocerebral injury to determine the prognosis of the patient's condition. For example: the reconstruction of fetal cerebrospinal fluid is detected through optic nerve sheath ultrasound to determine the development of the fetal nervous system with intracranial abnormalities; optic nerve sheath ultrasound is used to determine whether patients with gestational hypertension have increased intracranial pressure, so as to provide timely treatment and reduce the mortality rate of patients with gestational hypertension. The results of optic nerve sheath ultrasound can also be used to evaluate the effects of drug and surgical treatment on patients. In addition, combining optic nerve sheath ultrasound with transcranial Doppler ultrasound will greatly improve the accuracy of the test results and have a certain role in judging the prognosis of patients with cardiac arrest.

In short, with the continuous advancement of medical research, the clinical application of optic nerve sheath ultrasound examination will continue to expand.

In general, optic nerve sheath ultrasound is a non-invasive, convenient and quick method to detect increased intracranial pressure. This detection technology will play an increasingly important role in clinical practice with the continuous development of science and technology and the deepening of medical research. When symptoms such as severe headache, nausea, and vomiting occur, follow the doctor's advice and perform optic nerve sheath ultrasound in time to determine whether there is increased intracranial pressure, so as to obtain rapid treatment and obtain a good prognosis.

References

[1] Wang Meng, Guo Wenyue, Wang Chunyu, et al. Research and prospects of ultrasonic measurement of optic nerve sheath diameter for evaluating intracranial hypertension[J]. International Journal of Anesthesiology and Resuscitation, 2020, 41(10): 1008-1011.