General Aetiology

Previous authors [4] have divided the causes of sudden visual loss into three separate categories:

Pathology of the ocular media

Fig.1 Pathology of the ocular media adapted from Smart Servier

Ocular media describes the transparent structures through which light must pass in order to contact the retina. This media can be subdivided into:


  • Anterior chamber
  • Posterior vitreous

Common corneal problems include trauma (e.g. hyphaema) and infection (e.g. keratitis, corneal ulcer), whereas acute angle closure glaucoma affects the anterior chamber. Sudden visual loss due to posterior vitreous pathology occurs with haemorrhage, inflammation or structural change in this area.

Pathology involving the retina

Fig.2 Pathology involving the retina adapted from Smart Servier

For the retina to process light signals efficiently, it must be structurally intact in all layers, with a patent arterial supply and venous drainage.

Diseases of the sensory retina such as traumatic detachment or infection can cause a marked deterioration in vision, but problems with the vascular supply to the retina itself remain the most likely cause of an acute complete visual disturbance.

Neurovisual pathology

Fig.3 Neurovisual pathology adapted from Smart Servier

Neurovisual pathology includes the optic nerve, chiasm and retrochiasmal problems.

Inflammation, infection or ischaemia can affect the neural optic pathway at any step. The area of visual loss will often help in identifying the location of pathology. Both persistent and transient (e.g. TIA, migraine) lesions may occur.

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