Visual Loss

INTRODUCTION

Apart from migraine, virtually all cases of sudden loss of vision require urgent treatment.

IMPORTANT CAUSES

Amblyopia

In children, a lazy eye with reduced vision. Consider large refractive defect and congenital cataract. Refer strabismus early.

Retinoblastoma

In children: white pupil and ‘cat’s eye’ reflex. An intra-ocular tumour, dominant gene.

Cataracts

• Reduced visual acuity (sometimes improved with pinhole)

• Diminished red reflex on ophthalmoscopy

• A change in the appearance of the lens

Advise extraction when the patient cannot cope.

Glaucoma

Acute—rapid onset over a few days

Chronic—gradual loss of outer fields of vision

Tonometry: 22 mmHg is upper limit of normal

• Medication (for life) usually selected from:

  • – timolol or betaxolol (beware of asthma) drops bd

  • – latanoprost drops or other prostaglandin analogue, once daily

  • – pilocarpine drops qid

  • – acetazolamide (oral diuretics)

• Surgery or laser therapy for failed medication

Retinitis pigmentosa

• Begins as night blindness in children; loss of peripheral vision

• Ophthalmoscopic examination—irregular patches of dark pigment

Amaurosis fugax

• Transient unilateral loss of vision; usually due to embolus from carotid artery

• Requires investigation, incl. carotid duplex Doppler US

Retinal migraine

This migraine variant may present with symptoms of visual loss. Headache and nausea may be absent.

• Zigzag lines or lights

• Multicoloured flashing lights

• Field defect—unilateral or bilateral

• Resolution within a few hours

Retinal detachment

• Sudden onset of floaters or flashes or black spots

• Vision in one eye becoming worse

• Immediate referral for sealing of retinal tears

Vitreous haemorrhage

• Sudden onset of floaters or ‘blobs’ in vision; US aids diagnosis

• Urgent referral to exclude retinal detachment

• Surgical vitrectomy for persistent haemorrhage

Central retinal artery occlusion

• Sudden painless unilateral loss of vision like a ‘curtain descending’

• Vision not improved with 1 mm pinhole

• Classic ‘red cherry spot’ at macula

Management Treatment options, but poor evidence:

• Within ...