CITW 20: Flashing Lights

HPI/ROS: 47 year old female presents to the ED with a change in her vision. The patient states she was doing laundry about an hour prior when “all of a sudden” she experienced “flashing lights” in the right side of her vision. This was associated with “hundreds of black specks” appearing predominately in the right side of her visual field. She denies any changes in her overall clarity of vision as well as no eye pain, photophobia, headache, dizziness, hearing changes, numbness, weakness, or trouble speaking and swallowing. This has never happened before. No history of trauma to the head. She’s been otherwise well recently.

Vital Signs: T: 98.6, HR: 91, BP: 152/73, R: 16, SpO2: 99% on room air

Visual Acuity: R 20/35 L 20/25

Physical Examination: The patient is alert and oriented. Normocephalic, atraumatic head. Tympanic membranes are clear. Oropharnyx clear and moist. Cranial nerves II-XII are intact. Pupils are 4 mm and reactive bilaterally. Extra-ocular movements are intact. Peripheral vision is intact. Patient accommodates appropriately. Neck is supple. Lungs are clear to auscultation. Heart is regular rate and rhythm without murmurs, rubs, or gallops. Abdomen is soft, non-tender, non-distended. No other pertinent exam findings.

A bedside globe ultrasound of the right eye is performed, and the following image is obtained:

Figure 1: Ultrasound imaging of the right globe

What is the diagnosis?

Retinal Detachment

The ultrasound image above demonstrates a retinal detachment in which the retina pulls away from supporting tissue in the back of the eye. In the image below, you can see what a large retinal detachment would look like on ophthalmoscopic examination:

Figure 2: Retinal detachment as seen on ophthalmoscopic exam. Borrowed from http://emedicine.medscape.com/article/798501-overview

This is one of few ocular emergencies along with globe rupture, endophthalmitis, acute angle glaucoma, retrobulbar hematoma, and central retinal artery occlusion. Let’s review the pathology:

• This refers to the separation of the inner layers of the retina from the underlying retinal pigment epithelium (RPE).

Figure 3: Anatomy of the eye. Borrowed from http://www.aafp.org/afp/2004/0401/p1691.html

• Occurs when a tear in the neuronal layer allows vitreous to collect between the neuronal layer and RPE, in the setting of traction from the vitreous membrane on the retinal layer (seen with proliferative retinopathies such as diabetic retinopathy or scarring from previous surgeries/trauma), or in the setting of exudative build up of fluid in the space between the neuronal layer and RPE (such as severe hypertension, central retinal vein occlusion, vasculitis, papilledema).

Figure 4: Anatomic depiction of retinal detachment. Borrowed from http://www.aafp.org/afp/2004/0401/p1691.html

• Patients typically present with photopsia (flashing lights), the sudden onset of floaters, and more ominously will describe a “dark curtain” falling over their vision or blurred vision, which would be indicative of macular involvement.
• It is important to consider a broad differential:

Table 1: Differential diagnoses of retinal detachment. Borrowed from http://www.aafp.org/afp/2004/0401/p1691.html

• Risk factors include age greater than 40, a history of trauma, previous ophthalmologic surgery (particularly cataract surgery), extreme myopia (typically >6 diopters), prior retinal detachment/uveitis/retinal hemorrhage, or a family history of retinal detachment.
• On examination, it is important to assess for signs of trauma, pupillary function, visual acuity (to assess for macular involvement), ophthalmoscopy (although this may be inadequate in and of itself given poor sensitivity to detect peripheral/smaller detachments), and slit lamp exam.

Figure 5: A) Weiss ring visualized under ophthalmoscopy indicative of vitreous detachment from the optic nerve resulting in an out-of-focus optic disc, nerve, and retina. B) Shafer’s sign on slit lamp examination of the vitreous demonstrating pigmented cells. Borrowed from http://webeye.ophth.uiowa.edu/eyeforum/cases/196-pvd.htm

• Emergent/urgent ophthalmology consultation is paramount, especially in patients with blurred vision or visual field defects (implying macular involvement).
• With modern surgical approaches to management, prognosis is favorable. Studies seem to indicate that the faster the repair the better the outcome (re: visual recovery) regardless of whether the macula is involved or not, ideally within the first week.
• The most important predictor of visual recovery is the visual acuity prior to repair. Younger age also plays a role.
• Consider utilizing ultrasound to make the diagnosis at the bedside! 

Case Conclusion: The patient had an emergent ophthalmology consultation. In the absence of visual acuity loss, she was taken to the OR two days later with successful repair and visual recovery. 

Special thanks to Dr. Sarah Joseph for help in putting this together!
Faculty Reviewer: Dr. Alyson McGregor

References: 

Gariano R, Chang-Hee K. Evaluation and Management of Suspected Retinal Detachment. Am Fam Physician. 2004 Apr 1;69(7):1691-1699. 

Gauger E, Chin EK, Sohn EH. Vitreous Syneresis: An Impending Posterior Vitreous Detachment (PVD). Oct 16, 2014. <http://eyerounds.org/cases/196-PVD.htm>. 

Hemang, P. Retinal Detachment. Oct 20, 2015. <http://emedicine.medscape.com/article/798501-overview>.

Mayo Clinic. Retinal Detachment. 2016. <http://www.mayoclinic.org/diseases-conditions/retinal-detachment/home/ovc-20197289>.

National Eye Institute. Facts About Retinal Detatchment. Oct, 2009. <https://nei.nih.gov/health/retinaldetach/retinaldetach>.