Saturday night retinopathy is an acute ischemic retinopathy, choroidopathy, and orbitopathy secondary to prolonged ocular pressure during a drug-induced stupor.
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Epidemiology
While monocular blindness as a complication of prolonged headrest use in prone neurosurgical procedures has been widely established 1, blindness in the context of a drug-induced stupor is extremely rare.
Risk factors
Saturday night retinopathy is almost always precipitated by alcohol and intravenous/intranasal drug use. Opioids are particularly implicated.
Associations
Saturday night retinopathy has been reported in association with cerebral manifestations of drug toxicity, including opioid-associated amnestic syndrome 3,5.
Clinical presentation
Patients exhibit signs and symptoms of unilateral retinal and orbital ischemia including 2
- vision loss
- monocular ophthalmoplegia
- painful proptosis
- conjunctival edema (chemosis)
- fixed, dilated, non-reactive pupil
- evidence of central retinal artery occlusion on fundoscopy: "cherry red" spot in the macula, retinal pallor, diffuse retinal edema, dilated retinal veins, etc.
- increased intraocular pressure on tonometry
Pathology
Increased orbital pressure causes occlusion of the ophthalmic artery, which supplies branches to the retina (via the central retinal artery) and extraocular muscles. Prolonged compression ultimately leads to retinal ischemia and ophthalmoplegia.
Once compression is alleviated, dilation of the ischemic vessels results in a reperfusion injury causing inflammation and edema of the retinal, orbital, and extraocular structures, leading to proptosis 3.
Radiographic features
CT
Typical findings are enlargement of the extraocular muscles and/or lacrimal gland with proptosis due to edema. There may be retinal thickening due to subretinal edema. Orbital preseptal soft tissue swelling is often present. The superior ophthalmic vein and cavernous sinus will be normal in caliber.
MRI
MRI may show T2 hyperintensity and restricted diffusion within the intra-orbital optic nerve if optic neuropathy is present.
Treatment and prognosis
There is usually spontaneous resolution of the ophthalmoplegia and painful proptosis, however blindness is often irreversible. It has been demonstrated in monkey models that 100 minutes of retinal ischemia is enough to cause permanent blindness 4.
History and etymology
The term was first coined by Jayam et al. in 1974 after describing a case of acute ischemic retinopathy following heavy alcohol and drug consumption at a Saturday night party 1. The term parallels Saturday night palsy, which refers to compressive neuropathy of the radial nerve from prolonged pressure of the inner side of the humerus against a firm object such as when slumped with an arm over the back of a chair.
Differential diagnosis
The history is critical in distinguishing Saturday night retinopathy from other vascular and inflammatory conditions on imaging: