13th February 2025

Ophthalmological

Cornea

Corneal disease is the most common ophthalmological cause for acute vision loss. It often presents as a flare of an underlying corneal disease. These include:

• Keratoconus
• Dry eye
• Corneal ulcer
• Corneal hydrops (a complication of corneal disorders causing corneal swelling)

Glaucoma

Acute angle closure glaucoma can present with acute vision loss alongside other symptoms and signs.

Optic nerve

Disorders affecting the optic nerve include:

Optic neuritis

This inflammation of the optic nerve. It results in unilateral, painful vision loss over hours or days. Examination will likely reveal reduced visual acuity, visual field loss, red desaturation (dyschromatopsia), painful eye movements and a relative afferent pupillary defect.

Investigations should include MRI as it has a high sensitivity and specificity for detecting inflammatory changes in the optic nerve. Management is with high-dose corticosteroids to accelerate the speed of visual recovery. 

Optic neuritis is the initial presentation of multiple sclerosis in 25% of cases, and of those with multiple sclerosis, 70% will be affected by optic neuritis.

Papilloedema

This is optic nerve swelling due to raised intracranial pressure (ICP). Therefore, papilloedema is always bilateral but not necessarily symmetrical. Symptoms include nausea or vomiting and headaches which are worse when leaning forward. Possible underlying conditions include an intracerebral mass or haemorrhage, hydrocephalus, meningitis or idiopathic intracranial hypertension (IIH). Management relies on correcting the underlying cause to prevent optic nerve damage and irreversible vision loss.

Leber’s hereditary optic neuropathy

An inherited mitochondrial disease which predominantly affects young males. Symptoms typically begin at age 10-30 years with unilateral progressive optic neuropathy. The contralateral eye also becomes affected months to years later. Diagnosis is confirmed with genetic testing.

Infectious optic neuropathy

This is uncommon but can be caused by tuberculosis, hepatitis B, syphilis and cytomegalovirus.

Drug-induced optic neuropathy

1. Alcohol – chronic use can lead to vitamin B12 and folate deficiency.
2. Ethambutol – effects are irreversible and dependent on dose and duration. Patients taking ethambutol who are asymptomatic should have regular eye screening to monitor for optic nerve compromise. 
3. Amiodarone – causes optic neuropathy through nerve demyelination. Visual field defects are variable and nerve damage is not dose related. 
4. Vigabatrin – visual field defects can be bilateral and concentric and are predominantly nasal.

Retina

Retinal detachment presents with the 4 ‘Fs’: floaters, flashes, visual field loss and fall in acuity. Risk factors for detachment include high myopia (short sightedness) and recent trauma or surgery. 

Patients require urgent referral for surgery, which can include vitrectomy and gas or oil tamponade.