- Sudden or Gradual?
- One or Both Eyes?
- Persistent or Transient?
- Central or Peripheral Visual Field?
- Painful or Painless?
- Drug History
Author(s): Tristan McMullan and David Sprigings
The visual pathway extends from the cornea to the occipital cortex (Figure 19.1). Visual loss may indicate ocular, intracranial or systemic disease that requires prompt intervention to preserve sight. Clinical assessment (Table 19.1; Figure 19.2) will narrow the differential diagnosis and determine further management.
Giant cell arteritis should be considered in any patient over 50 with new-onset visual symptoms: it can present with transient visual loss in one eye (amaurosis fugax), persistent visual loss due to retinal or optic nerve ischaemia (may rarely affect both eyes) or diplopia.
Sudden loss of vision typically (but not exclusively) reflects vascular disease, and gradual loss of vision, a non-vascular disorder (Table 19.2).
Loss of vision in one eye indicates disease of that eye or optic nerve.
Bilateral visual loss occurs with systemic disease or focal disorders involving the visual pathway from the optic chiasm back to the occipital cortex.
Patients may report loss of vision in only one eye, even though both eyes are affected. With a homonymous hemianopia, the patient may only be aware of the visual loss in the eye with the temporal field defect, despite having a nasal visual field defect in the fellow eye.
Sudden painless persistent loss of vision is usually due to ischaemia/infarction or haemorrhage at some point along the visual pathway, but is also a feature of retinal detachment (Table 19.3). Sudden transient loss of vision has a range of ocular, vascular and neurological causes (Table 19.4).
Central or Peripheral Visual Field?
Central blurring or vision loss is typical of macular pathology (e.g. diabetic maculopathy).
Monocular peripheral visual loss may be due to a retinal vascular event (e.g. branch retinal vein occlusion, branch retinal artery occlusion), other retinal disease (e.g. retinal detachment) or optic nerve disease (e.g. ischaemic optic neuropathy, optic neuritis, or asymmetric or monocular glaucoma).
Pain in the eye usually indicates anterior eye disease (e.g. keratitis, anterior uveitis, primary angle-closure glaucoma). Optic neuritis and giant cell arteritis can cause visual loss, which may or may not be associated with pain in the eye.
Painless loss of vision is typical of cataract, retinal disorders and disorders of the visual pathway.
A careful drug history is essential as many drugs can cause transient or persistent visual loss (Table 19.5).