This article provides a concise overview of the causes, emergency response, and long-term management of sudden-onset vision loss in ophthalmic emergencies.

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Vision loss can be sudden/acute in onset or may be gradually progressive/chronic in type. Certain causes are reversible, whereas others can lead to irreversible blindness if not diagnosed and treated in a timely fashion. 

Refractive errors and cataracts mostly progress slowly, and defective vision is painless, but the individual is aware of it. Vision loss progresses slowly over the years in these settings. 

Common causes of sudden visual loss can be:

• Central retinal artery occlusion 
• Amaurosis fugax  
• Giant cell arteritis involving the optic nerve 
• Retinal detachment 
• Central retinal vein occlusion 

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Post-traumatic vision loss 

• Post-traumatic corneal tear and iris prolapse  
• Post-traumatic large hyphema 
• Post-traumatic mature cataract 
• Post-traumatic retinal dialysis and Retinal detachment 
• Post Traumatic Vitreous Haemorrhage  
• Post-traumatic Berlin's oedema involving the macula  
• Post-traumatic Optic neuropathy 
• Post-traumatic IOFB 

1. Acute Hydrops in Keratoconus 
2. Spontaneous Vitreous haemorrhage in cases of PVD, PDR, Ischemic CRVO, Eales disease,                 
3. Sickle cell anaemia and other vasculitis patients 
4. Toxic optic neuropathy (Methanol poisoning) 
5. Cerebrovascular accidents involving PCA and MCA  
6. Head trauma causing SDH / lesion at the occipital cortex 

Chronic and gradually progressive visual loss is mostly because of Refractive errors, Cataract or retinal dystrophies/retinal abnormalities. Usually, cataract and refractive errors are reversible and can be managed effectively, whereas Retinal dystrophies and other abnormalities progress slowly and can be controlled/further damage can be prevented. 

In sudden visual loss, both patients and clinicians have a small period for diagnosis, management and visual salvage. If an early, prompt and correct diagnosis can be made, timely and accurate intervention can save the eyesight of many patients. 

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Conditions Leading to Sudden Vision Loss

Description of Important conditions leading to sudden vision loss is as follows- 

1. Central Retinal Arterial Occlusion (CRAO)

Sudden painless, profound loss of vision, usually monocular, commonly documented in patients having systemic disease like hypertension, Diabetes, Cardiac problems, valvular abnormalities and carotid problems along with hypercoagulability of blood leading to thromboembolic phenomenon. 

Rare causes of CRAO include Optic disc drusen, vasculitis, head and neck procedures, hemodialysis, Therapeutic embolisation, and orbital floor injection of tricort. 

Diagnostic Tip

1. Cherry red spot at macula with Pale retina due to oedema following retinal ischemia. 
2. Fibrin emboli can be seen in the Retinal examination. The cattle track appearance of the blood column can be seen due to the segmentation of the blood column. 
3. Arteriolar attenuation is marked, and if a patient presents late Cherry red spot cannot be visible, but thread-like attenuated arterioles and pale disc are obvious. 

Urgent Treatment

1. If a patient presents early within 6 hours, we can give ocular massage, carbogen inhalation, intravenous acetazolamide/mannitol, and paracentesis can be initiated. 
2. There is a role of Topical antiglaucoma, Pentoxyphylline or drugs like isosorbide for vasodilation. 
3. If emboli is visible, Nd YAG laser embolectomy under direct visualisation in a Mirror gonioscope can be performed.  
4. Embolectomy can cause vitreous haemorrhage, which may need Pars plana vitrectomy  
5. Need to determine the cause and treat it to avoid the risk of a Cerebrovascular accident to the patient. 

2. Amaurosis Fugax

1. Transient monocular / Binocular sudden loss of vision / Hemifield due to emboli present in retinal arterioles, which tend to dislodge spontaneously in the course of the disease.

2. It may be idiopathic, neurologic or spasmodic in origin.
3. Here, a curtain like a shadow comes down over the eye and after a few minutes tends to disappear gradually.
4. These episodes may be frequent/occasional but warrant a systemic workup to rule out the risk of stroke. 

3. Giant Cell Arteritis

1. It is a painful, sudden, profound vision loss in geriatric subgroups. It may be associated with throbbing headache, Shoulder / joint pain, pain on mastication/pain during combing. Here, there is a necrotising granulomatous inflammation of large and medium-sized arteries, which have a lot of elastic tissue.

2. Commonly, this condition involves the Superficial temporal artery, and when it involves the Ophthalmic artery can cause arteritic Anterior ischemic optic neuropathy. Diagnostic criteria as per the American Rheumatology Association include age more than 50 years, ESR level more than 50 / hr., new onset headache, tenderness over the temporal artery and a positive temporal artery biopsy. 
3. As there is a threat of visual loss to the other eye also, hence, treatment should be initiated as early as possible, subsequent to confirmation of diagnosis. 
4. Treatment of arteritic AION is Intravenous Methyl prednisolone 1 gm X 3 days, followed by oral steroid, we start with 1 mg / KBW and slow tapering over 1 / 2 years. 

4. Retinal detachment

1. When it reaches the macula, it can lead to painless loss of vision, over a few days to a few months.  

2. Retinal detachment can be rhegmatogenous or tractional, but when it is limited to the periphery, it may cause floaters and occasional shadows in front of the patient’s eye, but when it extends and reaches in central part of the retina, it causes profound vision loss. 
3. Retinal detachment may be seen spontaneously in myopics owing to the presence of preexisting peripheral lesions or may be associated with trauma. 
4. Tractional detachments are usually associated with Vitreous haemorrhage and neovascularisation of the retina secondary to diabetic retinopathy, Venous occlusions and /or Vasculitis. 

Management: Prompt surgical intervention is required in the form of Retinal detachment surgery. 

5. Traumatic eye injuries

It can lead to profound, sudden visual loss due to injury to various ocular structures. Causes of vision loss in cases of Ocular trauma (Penetrating / Blunt )  are as follows: 

1. Corneal laceration and corneal oedema.  
2. Full-thickness corneal tears cause Anterior chamber collapse and iris incarceration/prolapse from the wound.  
3. Hyphema – total hyphema, also known as eight-ball hyphema.  
4. Subluxation or dislocation of the lens. 
5. Traumatic cataract: Trauma causes a tiny rupture in the lens capsule, allowing aqueous to flow into the lens.
6. Trauma-related vitreous haemorrhage can result in significant visual loss.
7. Commotio retinae / Berlin's oedema is an innocuous condition, but if it involves the macula can cause vision loss and pigmentary degeneration. 
8. Retinal dialysis and retinal detachment can occur due to trauma and lead to vision loss.  
9. Traumatic optic neuropathy due to fracture of the skull/hematoma can cause vision loss. 
10. If intraocular foreign bodies (IOFB) like iron, calcium or other alloys reach inside the eye, they can react with the Retinal pigment epithelium, resulting in retinopathy and vision loss. 

IOFBS can cause retinal tears and retinal detachment. 

Management: Depends upon site and severity of injury and needs specific interventions on a case-by-case basis. 

6. Acute Hydrops in Keratoconus

1. A tear in the Descemet membrane causes rapid entrance of aqueous into the corneal stroma, which causes corneal oedema and abrupt vision loss linked with discomfort. Usually, advanced and progressive keratoconus is associated with this condition. 

2. Initially managed by hypertonic saline, lowering Intraocular pressure, cycloplegics, antibiotics (to prevent infection) and a pressure patch/bandage contact lens is required. 
3. Other therapies include Intracameral injection of air/ SF6 gas to promote healing and / compression sutures. Once the acute condition is resolved, penetrating keratoplasty may be required and can give good visual outcomes. 

7. Vitreous Haemorrhage

Spontaneous vitreous haemorrhage can occur in various conditions. One of the common causes is traction of retinal blood vessels due to incomplete post-vitrectomy detachment, whereas another is Valsalva retinopathy caused due to pre-macular haemorrhage in sub subhyaloid area due to a sudden increase in intrathoracic and intra-abdominal pressures. 

Other causes include neovascularisation in proliferative diabetic retinopathy, CRVO,  Eales disease and other vasculitic conditions, including Systemic lupus erythematosus, Collagen vascular disease, sickle cell anaemia, syphilis and more. If a vitreous haemorrhage is dense and involves the macular area, then cause vision loss.  

Management - It can be conservative in the form of head up, rest, avoiding exertion and control of primary disease. Other options include intravitreal anti-VEGF injection in cases of neovascularisation and Pars Plana Vitrectomy in cases of Non-resolving Vitreous haemorrhage. 

8. Toxic Optic Neuropathy

1. Methanol poisoning is the most common cause of toxic amblyopia. It is owing to the adulteration of alcohol. Methanol is also known as wood alcohol, and consumption of this can lead to blindness within 24 hours of consumption.

2. Methanol is converted into formic acid, which causes inhibition of cytochrome oxidase, leading to cellular hypoxia and damage to the optic nerve, further leading to permanent Blindness. 
3. Antidote for Methanol is ethyl alcohol, which competes with methanol in binding at the cellular level 

9. Cerebrovascular accidents

The occipital cortex is an area of visual representation in the brain, and the Anterior striate cortex represents the peripheral visual field, while the posterior calcarian cortex is for macula representation, which is supplied by both the Middle & posterior cerebral arteries.

In case of injury to the Occipital tip, macular/central vision is involved, whereas other areas have a dual supply; hence, occlusion of MCA / PCA alone can cause macular sparing along with vision loss. Hence, a vascular accident in the posterior cerebral territory can lead to cortical blindness with intact pupillary reaction.  Visual hallucinations are also present in an Occipital cortex lesion. 

Anton's phenomenon with the denial of Blindness and Riddoch’s phenomenon can be seen where the person can recognise moving objects but not stationary objects. 

10. Subdural haemorrhage

Increased intracranial pressure causes it to cause papilloedema and blurred vision. Cranial nerve palsies have also been documented as a sequel, and if it compresses the visual cortex, it can result in cortical blindness.  

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Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr. Vandana Jain is a Senior Consultant at ESIC Hospital, Indore.