What is Commotio Retinae ?
Commotio Retinae or Berlin’s Oedema is grey-white discolouration of the retina due to disruption of outer segment photoreceptor layer following blunt trauma. This is caused due to contrecoup injury. Shock waves caused due to impact traverses the fluid- filled eye and then strike retina.
Commotio retinae or Berlin’s oedema was first described by a German physician, Rudolph Berlin in the year 1873, as a transient grey-white opacification of the macular/ peripheral retina following blunt trauma to eye.
Commotio retinae may involve any part of retina and may be accompanied by choroidal rupture or retinal haemorrhage. Macular oedema reduces central vision, but vision usually improves as the oedema resolves. After an acute attack of oedema, there may be scarring of retina with pigment dispersal. Vision may be acutely reduced or normal depending upon whether the macula is involved or not. It may permanently reduce vision if the fovea centralis is involved.
Commotio Retinae Symptoms
- Acute diminution of vision
- Permanent diminution of vision
Commotio Retinae Causes
Commotio retinae is caused due to pressure waves emanating from blunt trauma to the eye resulting in retinal injury. There may also be associated choroidal rupture or retinal haemorrhage. Following acute episode of oedema, retina may develop scarring and pigment dispersal. Macular commotio retinae reduces central vision. The vision usually improves on resolution of oedema, unless there is development of macular hole or disruption of retinal pigment epithelium of the fovea.
Studies suggest that commotio retinae is probably caused due to disruption of the photoreceptor outer segments, and is not a true extracellular oedema.
This is more common in young males.
Commotio Retinae Diagnosis
Diagnosis depends upon the history of injury to the eye and clinical features.
There are two variations of commotio retinae depending upon the severity of injury to the eye.
- Retinal concussion: Retinal concussion is a mild injury with less dramatic grey-white retinal changes and is less frequently associated with retinal haemorrhage. The retina usually recovers spontaneously without leading to permanent loss of vision.
- Retinal contusion: Retinal contusion is produced due to more severe trauma to the eye. It causes more dramatic retinal whitening and haemorrhage. It may lead to permanent loss of vision, especially with involvement of macula.
Clinical features on examination may include:
- Retinal whitening in macular area or retinal periphery
- ‘Cherry red’ spot at the macula
- Retinal haemorrhage
- Choroidal haemorrhage
- Chronic alterations in foveal retinal pigment epithelium
- Macular hole
- Retinal dialysis
- Avulsion of vitreous base
- Vitreous haemorrhage
Commotio retinae is a self-limiting opacification of retina following direct ocular trauma, and is characterised by transient whitening at the level of deep sensory retina. Retinal whitening may take hours to develop before it may be seen with the help of ophthalmoscope. The lesion may affect both central or peripheral retina.
Investigations
- Optical Coherence Tomography (OCT): Optical Coherence Tomography (OCT) suggests and confirms that the major site of retinal trauma appears to be at the level of photoreceptor outer segment and retinal pigment epithelium interface.
- Fundus Fluorescein Angiography (FFA): Fundus Fluorescein Angiography may show early blockage in areas of white retina and no alteration in vascular permeability.There may be leakage of fluorescein dye with associated retinal pigment epithelium changes. A ‘salt and pepper’ fundus may be seen in cases with more severe injury.
Histopathology
Histopathologically, animal models have suggested that there is disruption of photoreceptor outer segments with associated damage to retinal pigment epithelium.
Histologic studies do not separate cases into retinal concussion or contusion.
Differential diagnosis
Differential diagnosis includes
- Traumatic macular hole
- Choroidal rupture
- Retinal artery occlusion
- Retinal detachment
- Purtscher retinopathy