aka Ophthalmology Befuddler 012
A 65 year-old comes into the ED saying that he thinks ‘the jelly’ in his eye has ‘peeled off again’. He says he been seeing flashes of light as well as blobs and cobwebs floating in front of his right eye. He experienced the same thing about a year ago in his other eye. His visual acuity is similar in both eyes.
Q1. What is the differential diagnosis?
- Posterior vitreous detachment
- vitreous haemorrhage
- retinal break
- retinal detachment
- retinal hemorrhage
A bedside ultrasound shows this:
Q2. What is the likely diagnosis?
Posterior vitreous detachment — the ultrasound shows fine linear and granular echogenicities in the posterior segment of the eye, which swirl around as the eye moves. There is no tethering to the optic disc. This is consistent with vitreous debris seen in posterior vitreous detachment.
This is common in patients older than 60 years. With age the vitreous gel pulls away from the retina, which can lead to symptoms similar to those of retinal break, vitreous hemorrhage, and retinal detachment.
Q3. What are the features of this condition on history and examination?
- Presence of floaters, cobwebs, or blobs obscuring the visual field of the affected eye that change position with movement. Vision may be blurred.
- Flashes of light — especially in the dark and located temporally.
- Check for risk factors for a retinal break (see below).
- Visual acuity — may be reduced
- Red reflex — abnormal — floaters may be detected.
- Slit lamp and ophthalmoscopy — look for discrete light grey to black opacities, may be in the form of a ring (a Weiss ring) or a broken ring over the optic disc. Get the patient to look up down and left right.
Check for the presence of retinal tears or detachment, retinal hemorrhage. Look for pigmented cells in the anterior vitreous (‘tobacco dust’) and retinal hemorrhages that may suggest these complications.
Q4. How often is a retinal break associated with a PVD, and what features are suggestive?
Suspect retinal tears if you see ‘tobacco dust’ in the anterior vitreous or evidence of retinal or vitreous hemorrhage.
Q5. What aspects of the history should be considered risk factors for a retinal break?
- past ocular surgery
- previous retinal tear
- family history
- ‘‘curtain coming down’
- high myopia
Q6. Describe the role of ultrasound in the assessment of the patient with ‘flashes and floaters’. How is ocular ultrasound performed?
Ultrasound is highly specific and sensitive for the diagnosis of both retinal detachment and vitreous detachment. It is particularly useful for detecting retinal detachment when the retina is obscured by vitreous hemorrhage.
Two excellent resources for ocular ultrasound in the emergency department are:
Ocular ultrasound should be performed by appropriately trained and accreditated practitioners. It is performed as follows:
- The ocular exam is performed using a high frequency linear array probe with appropriate settings for the appropriate depth, high gain and high resolution.
- Gel is placed on the probe and the patient closes their eyelids while the probe contacts the external surface of the eyelid. Enough gel should be applied so that the probe applies no pressure to the surface of the eyelid.
- The structures of the eye are identified from front to back: lid, cornea, anterior chamber, iris, lens, posterior segment containing the vitreous humour, the retina and sclera, and the optic nerve.
- The patient looks up, down, left and right at the sonographer’s request to check for movement of structures within the eye.
Features of vitreous detachment are:
- the presence of an amorphous swirling cloud-like opacity the moves with ocular movement and is not tethered to the optic disk or retina.
Features of retinal detachment are:
- a delicate linear opacity attached to the posterior of the globe that is shown to be tethered to the optic disk when the eye moves.
Q7. Describe the investigation and management of this condition.
PVD requires no specific treatment.
However, a coexistent retinal tear requires repair and must be ruled out by an ophthalmologist.
Longterm ophthalmology follow up is required and the patient is warned to seek medical attention if they develop symptoms of retinal detachment.
What if the patient has markedly decreased visual acuity in the affected eye, a markedly reduced (almost black) red reflex, the fundus cannot be visualized on funduscopy, and you see something like this on ultrasound?
Q8. What is the likely diagnosis?
Vitreous hemorrhage — the ocular ultrasound demonstrates the ‘washing machine’ sign. Blood (granular echogenicities) swirl with eye movement and settle when the eye is still.
Vitreous hemorrhage results from bleeding into the preretinal space or into the vitreous cavity. Ultrasound findings include:
- Fresh mild hemorrhages — small dots or linear areas of low reflective mobile vitreous opacities
- More severe and older hemorrhages — blood organizes and forms membranes.
- Vitreous hemorrhages may also layer inferiorly due to gravitational forces.
Q9. What findings on history and examination are consistent with this condition?
- It may present like a retinal detachment — with floaters that progress over hours to severe visual loss without pain.
- Visual acuity — markedly reduced
- Red reflex — absent (black) or only partially present (reddish haze)
- Pupils — RAPD may be present, but suggests a coexistent retinal detachment behind the hemorrhage.
- Funduscopy — the view of the retina is obscured, although the hemorrhage may be evenly distributed throughout the vitreous or focal. Long-standing preretinal hemorrhage may form a white mass.
Ultrasonography can be used to determine whether a retinal detachment is present and may also help determine the cause of the vitreous hemorrhage.
Q10. What are the causes of this condition?
There are lots — but the first two are the most important ones:
- diabetic retinopathy
- retinal break or detachment
- posterior vitreous detachment
- ocular tumor
- central or branch retinal vein occlusion aka CRVO or BRVO (associated with neovascularisation)
- Terson syndrome in subarachnoid hmorrhage (e.g. subhyaloid hemorrhages)
- Sickle cell disease
- age-related macular degeneration
- retinal artery microaneurysm
- Other rare causes like Eales disease
Q11. Describe the management of this condition.
- ophthalmology referral
- bed rest with head elevation for ~3 days
- avoid drugs that contribute to bleeding (e.g. anticoagulants, antiplatelet drugs)
- screen for and treat underlying causes
- retinal breaks are treated with cryotherapy or photocoagulation
- vitrectomy may be required (e.g. retinal detachment, or persistent hemorrhage)
- Ehlers JP, Shah CP, Fenton GL, and Hoskins EN. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease (5th edition). Lippincott Williams & Wilkins, 2008.
- Jeff Mann EM Guidemaps. Loss of vision.
- Marx JA, Hockberger R, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice, 7th edition (2009) Mosby, Inc. [mdconsult.com]
- NSW Statewide Opthalmology Service. Eye Emergency Manual — An illustrated Guide, 2007. [link to free pdf]