Health Resources


Clinical Services and Procedures

Our Neuro-Ophthalmologists Manage: 

  • Acute and Chronic Visual loss
    • Diseases of the Optic Nerve such as optic neuritis, ischemic optic neuropathy, toxic and nutritional optic neuropathies, hereditary optic neuropathies, idiopathic intracranial hypertension, optic nerve and sheath tumours. 
    • Disorders of the Visual Pathways arising from conditions such as stroke or stroke-like disease, tumour compression (e.g. pituitary tumours), inflammation and degenerative diseases. 
    • Unexplained Visual Loss that cannot be readily explained routine ophthalmic examination and imaging studies. 
  • Eye Movement Disorders
    • Eye movement disorders causing diplopia (double vision) or abnormal head posture as a result of nerve palsies, neuromuscular junction disorders and myopathies. 
    • Nystagmus (Jerky eye movements) causing oscillopsia. 
  • Pupil disorders
    Abnormalities in pupil reactivity or size differences, potentially related to an underlying disease process.

  • Eyelid and facial twitching
    Includes disorders such as blepharospasm and hemifacial spasm. Our clinicians are proficient in botulinum toxin injections to treat these disorders.  
Supporting Services

Visual Electrophysiology

‘Electrical testing of vision’, or visual electrophysiology, involves measuring he minute signals generated by the eye and the brain in response to visual stimuli. These signals provide information regarding the eye, nerves and brain functions, aiding the doctor to make informed decisions on diagnosis and


Why Would I Be Referred for Electrophysiology Testing?

The main reasons for referral are:
  • To confirm or exclude a suspected diagnosis;
  • In cases where the diagnosis is unknown
  • To determine the characteristics and severity of disease; and
  • To monitor the disease progression before and after treatment

What Should I Expect?

When undergoing electrophysiological testing, you will be subjected to a series of tests, including Electroretinogram (ERG), Pattern Electroretinogram (PERG) and Visual Evoked Potential (VEP) tests. 

While these tests are generally non-invasive, the entire process can take up to three hours. Numbing drops are seldom required, and there are no injections into the eye or arm. However, the drops used to dilate the pupils may cause a slight stinging sensation for a few seconds and vision remain blurred for a few of hours afterward. It is advised to refrain from driving during this time. Dark glasses may help on a sunny day. We ask that patients wash their hair the morning of the test and that they not put any hairspray, gel, conditioners or hair oils on the scalp. 

The tests will be carried out by Clinical Physiology Technicians. The results will be interpreted by a Consultant Electrophysiologist. A report will be sent to the doctor who referred the patient.

For further information regarding our department or the specific tests, please contact us at +65 6908 2222 or via email at 

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About Our Consultant Electrophysiologist

Hong-Leong Professor, National University Hospital & National University of Singapore Department of Ophthalmology
Consultant Electrophysiologist, Moorfields Eye Hospital
Honorary Professor, University of Sydney Medical School

Low Vision 

Patients with low vision may be referred to our Low Vision Enabling Programme. (*link to Accordion 6 / Low Vision segment on Common Vision Problems page)
Diseases of the Optic Nerves

What Can I Expect at My Consultation?

Neuro-ophthalmologic issues tend to be more complex, requiring longer consultation and investigations. During the first clinic visit, patients can expect to spend 2-3 hours for a comprehensive consultation. Please refrain from driving on the day of your consultation.

What Should I Bring?

You are advised to bring along your glasses and any medical records.

What Investigations Will I Need to Undergo?

Depending on your symptoms, your doctor may perform perimetry, imaging of the nerves and retina, MRI scans and blood tests.
Eye Movement Disorders

Optic Neuropathies

The optic nerve is the only nerve in the body that can be directly examined by a doctor. Similar to an electrical cable, it connects the eye to the brain, bringing visual information for processing.

The optic nerve can be affected by: 

  • Inflammation
  • Ischemia (inadequate blood supply)
  • Compression 
  • Raised intracranial pressure
  • Trauma
  • Drugs and Toxins
Inflammation of the optic nerve can be due to infections, vaccination or autoimmune conditions.
  • Presentation: Loss of vision over 2-3 days, frequently affecting colour vision. It can cause occasional pains behind the eyes, especially during eye movements.
  • Tests: Magnetic Resonance Imaging (MRI) of the brain, Lumbar Puncture to obtain cerebrospinal fluid and blood tests to look for antibodies.
  • Treatment with steroids and/or other immunosuppressants may be required.
Commonly known as “stroke of the optic nerve”, Ischemia occurs when the optic nerve receives inadequate blood supply and oxygen.
  • Presentation: Acute, painless loss of vision. 
  • It is commonly related to other vascular diseases such as hypertension and diabetes.
  • Treatment is usually directed at controlling risk factors such as hypertension, diabetes, hyperlipidaemia and smoking. 
Compression of the optic nerve can be caused by benign or malignant tumours, blood vessels or enlargement of normal structures within the orbit.
  • Presentation: Slow, progressive, painless or painful loss of vision. 
  • Tests: Computed Tomography (CT) scan or MRI, and blood tests to determine the cause. 
  • Referral to an orbital surgeon or neurosurgeon may be necessary. 
Raised intracranial pressure
Raised intracranial pressure, or rise in pressure around the brain, may be accompanied by other non-visual symptoms.

  • Presentation: Headache with early morning nausea or vomiting, transient loss of vision, or focal neurological disturbances in other parts of the body (such as weakness or loss of balance). 
  • Tests: CT scan or MRI is usually necessary, together with a lumbar puncture to obtain cerebrospinal fluid for analysis. 
  • Referral to a neurologist or neurosurgeon is usually required.
Frequently Asked Questions (FAQs)

Eye Movement Disorders

Eye Movement Disorders can be a result of brain, nerve, neuromuscular junction or muscle pathology, and are sometimes linked to problems in other areas like the ears.

Many diseases affect movement of the eyes. These include:
  • Local (orbital) disease causing restriction of movement;
  • Disease affecting the nerves to the muscles causing weakness;
  • Diseases affecting the transmission of signals between nerve and muscle 
  • Diseases of the muscle; and 
  • Diseases affecting portions of the brain that control movement.
Eye movement disorders can present in one or more of the following ways:
  • Double vision 
  • Blur vision
  • Unstable (“shaky”) vision

Notably, each eye may test normal independently, but issues arise when both eyes are in use. Symptoms may extend beyond vision problems, including dizziness, unsteady gait, headaches, and weakness in other body parts.

Eye movement disorders occuring suddenly require urgent medical attention to rule out serious conditions such as the rupture of blood vessels supplying oxygen to the brain.

Investigation and treatment are directed at the cause of the eye movement disorder. 

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