Neuro-Ophthalmology Clinic

The Neuro-Ophthalmology Clinic evaluates patients with nerve disorders.

Nerve Disorders Evaluated by the Neuro-Ophthalmology Clinic

• Brain tumors  
• Get double vision
• Suddenly lose part of their side vision
• Strokes
• Unequal pupils
• Unusual visual problems that are hard to sort out 
• Vision goes suddenly out of focus

If you have a disease or injury in the eyeball itself, an ophthalmologist can look at the cornea and the lens, or into the eye at the retina and see an abnormality in the eye, but if the problem is behind your eye in the optic nerve or in some of the visual pathways in the brain, it is harder to be sure what is going on and that is when neurologists become involved. In that case, you are sent to the neuro-ophthalmologists for special tests. 

Special Tests May Include:

Automated (Computerized) Perimetry

• Done by experienced perimetrists
• Spots of light automatically projected into predetermined areas of the visual field
• Test continues until the dimmest light that is found can be seen in each area of the side vision

Computer Controlled Infra-Red Sensitive Pupillography

• Monitor pupillary movements in response to different types of light
• Quantify how much damage there might be in the visual system

Computer-Controlled "Pupil" Perimetry

• Uses the pupil movement in response to small lights presented in the field of vision 
• An objective indicator of how well the eye sees the light

Computer Recording of Eye Movements

• This instrument can be used for monitoring pupil movements
• Has the capacity to record the small movements of both eyes at the same time
  • See if they are tracking together
  • Have normal movements in different directions of gaze

Critical Flicker Fusion Frequency (CFF)

• Patients view a flickering light
• Tests the ability of the optic nerve to conduct impulses with uniform speed
• Proven to be very useful in identifying visual loss due to optic nerve damage

Electroretinography

• Regular ERG (electroretinogram)
  • Records electrical activity of the whole retina in response to light
  • Tells us if the rods and cones of the retina are firing in the way they are supposed to

Frequency-Doubling Perimetry

• New visual field test
• Performed to screen patients for visual loss
• Takes about five minutes per eye

Infra-Red Video Pupillography

• A way of seeing the pupils clearly in the dark so that a more certain diagnosis can be made
• Also use it to transilluminate the iris to identify local iris causes for pupillary abnormalities

Ishihara Color Vision Test Cards

• Used for color vision evaluation
• Test chart of color dots will appear as identifiable numbers or patterns to individuals who have various types of color vision defects

Kinetic (Goldmann) Perimetry

• 'perimetry' is the quantitative testing of the side vision
• These 'visual fields' are done manually by experienced perimetrists to understand the nature of the problem

Multi-focal Visual-Evoked Potentials (MVEP)

• Using a MERG stimulus, information can be picked up from the scalp that tells us if the visual pathways in the brain are damaged

Optical Coherence Tomography (OCT)

• New device that looks at the retina at the back of the eye
  • Measures the thickness of the layer of nerves coming from all quadrants of the retina and leading into the optic nerve
  • This nerve fiber layer may be thickened, thinned, or normal depending on the nature of the disease affecting the optic nerve
• Helps us understand the extent and the reversibility of optic nerve damage

Multi-Focal ERG (MERG)

• Does about a hundred ERGs at once by illuminating various little bits of the retina sequentially
• A computer program will present us a map of the retina
  • Detailing the sensitivity of various parts based on the electrical activity of the regions in response to light 
  • If this map matches the map we got from perimetry then the problem is in the retina and not in the optic nerve or brain