Retinal detachment, Keep your eyes open!

Clinical History

The patient presented with reduced conscious level and a CT brain was carried out.

Imaging Findings

Axial non enhanced CT brain demonstrated no abnormalities. However, an irregular hyperdense region was noted within the left orbit (figure 2). On viewing this on a bone window (figure 3), calcification can be seen within the region of the left lens with heterogeneous changes within the left orbit.

Discussion

Retinal detachment refers to the separation of the sensory retina from the underlying supportive tissue [1]. It is generally associated with pre-existing eye disease, congenital malformations, trauma, neoplasm or underlying metabolic disorders [1]. Acute detachment can be characterised as either exudative, tractional or, most commonly, rhegmatogenous which occurs following a retinal tear [2].

Patients presenting with acute retinal detachment usually describe photopsia, visual field opacities and loss of vision. Diagnosis is generally made through history and ophthalmoscopic observation. Visualisation of the retina can sometimes be hindered by overlying cataract, corneal disease or haemorrhage into the vitreous humour. In these instances, ultrasonography is indicated for diagnosis and can be carried out by an emergency physician with the correct training [3], however, ultrasonography is contraindicated if a ruptured globe is suspected [4]. Further imaging in the initial stages of acute detachment is generally not indicated but MRI/CT can be considered if neoplasm is a causative differential diagnosis [5].

In the context of trauma, patients are usually evaluated with CT; typically, multiple organ systems are imaged [4]. As in our case, retinal detachment may be incidentally noticed at head and orbit imaging [4]. Magnetic resonance (MR) imaging may be difficult to perform emergently; it is contraindicated if there is a possibility that a metallic intraorbital foreign body is present [4].

Prompt surgical treatment of acute detachment is necessary to prevent vitreoretinopathy (scarring of the retina), hypotony and atrophy of the globe. The chronic manifestations of retinal detachment on CT scanning can be demonstrated by scleral thickening, intraocular ossification and a hyoptonic globe. This collection of features is sometimes known as phthisis bulbi [5]. This represents a spectrum of changes and our images demonstrate a milder form.

One main differential of retinal detachment is choroidal detachment. As shown in figures 3 and 4, the key for distinguishing these entities is knowledge of the anatomy of the eye. The retina does not extend past ora serrata and hence on CT scanning (figure 4), only choroidal detachment would be seen to do so [6].

In summary, imaging is not usually required in the diagnosis of acute retinal detachment. Ultrasonography may play a role within the emergency department and MRI/CT may be indicated if underlying pathology is suspected. CT is usually used in trauma. If acute detachment is not treated promptly, loss of visual acuity will ensue [7]. The manifestation of changes related to the chronic detachment leads to the end stage appearance of phthisis bulbi apparent on CT scanning [5].

Differential Diagnosis List

Final Diagnosis

Chronic retinal detachment

URL:	https://www.eurorad.org/case/10443
DOI:	10.1594/EURORAD/CASE.10443
ISSN:	1563-4086