HPI: 70 yo male presents to the ED complaining of about 6 days of seeing "white floaters" out of his right eye followed by a sudden onset of painless loss of vision to the right eye at approximately 11am today, described as "something coming up over my eye."

Brief Exam: EOMI. Left pupil is reactive to light. +relative afferent pupillary defect on the right. Visual acuity: only able to distinguish gross hand motion on the right; 20/40 on the left.

Bedside Ultrasound of the Right Eye:

What do you see? What is abnormal about this image?

Diagnosis: Retinal Detachment

Management: Ophthalmology was notified and came in that evening to evaluate the patient and schedule an urgent clinic appointment for the following morning for further evaluation and possible corrective procedure.

How to perform an Ocular Ultrasound:

-Use the linear high frequency probe

-Patient should be supine, with the head tilted back. Place a large amount of gel on top of the patient's closed eye. You may place a Tegaderm adhesive barrier over the eye or place a cover over the probe to maintain a clean field.

-Do not put direct pressure on the eye when scanning; you may brace your hand on the patient's nasal bridge or forehead for balance.

-Scan in the transverse and longitudinal planes. You may also ask the patient to look in multiple directions while scanning as this can help you to distinguish a retinal detachment or vitreous hemorrhage.

Brief Review and Ultrasound Education:

The retina is comprised of multiple layers of specialized neurons that convert light into neural signals that are further processed in the visual cortex. If this layer becomes detached from the underlying retinal epithelium, visual loss can occur. The extent of visual loss depends on the location and extent of the detachment.

The detachment itself is most commonly a result of physiologic degeneration and liquefaction of the vitreous body (aka humor) in the posterior chamber, resulting in a "posterior vitreous detachment." As the vitreous pulls off of the retina, it can tear a small retinal hole, allowing the now-liquefied vitreous humor to travel through the retina and begin to dissect the remaining retina off of its underlying epithelium. This occurs commonly in patients aged 55 to 70 years old. Additional but less common etiologies include cataract surgery and myopia (both result in accelerated degeneration of vitreous body) as well as trauma (sudden acceleration of vitreous body).

Note that it is helpful to determine if the retinal detachment involves the detachment of the macula (and therefore fovea). If it is a "macula on" detachment, then the defect is typically corrected within 24 hours or so to prevent further dissection of the retina and further loss of vision. It it is a "macula off" detachment, and this is accompanied by loss of central visual acuity, surgery can be delayed several days.

Concomitant vitreous hemorrhage or prior cataract surgery can make traditional fundoscopy difficult. However, in an emergency physician's hands, ocular ultrasound has been demonstrated to have a sensitivity and specificity ranging from 97-100% and 83-100%. Traditionally, a linear echogenic membrane protruding off the posterior surface of the eye into the vitreous chamber can be visualized. This linear membrane will move with eye movements. Occasionally, additional non-linear echogenic materials from concomitant vitreous hemorrhage can be seen as well.

Additional Resources:

A brief review of retinal detachment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3948016/

Using ocular ultrasound for evaluation of retinal detachment in ED: https://www.ncbi.nlm.nih.gov/pubmed/24680547