• Visual Electrophysiology

treatment.

• 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
  
  

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 

Replaced the previous sentence (which didn't quite make sense) with this. Please check if this is appropriate eye_surgery@nuhs.edu.sg 

• Low Vision 
  

• Inflammation
  
• Ischemia (inadequate blood supply)
  
• Compression 
  
• Raised intracranial pressure
  
• Trauma
  
• Drugs and Toxins
  

• 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.
  

• 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. 
  

• 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. 
  

• 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.
  

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.

• 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.
  

• 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. 

• Associate Professor Clement Tan
  
• Dr Hazel Lin