Nystagmus is an involuntary rhythmic constant movement of the eyes.  Nystagmus is also sometimes described as "dancing eyes" or "jerking eyes".  The most common form of nystagmus occurs as a congenital (present from birth) disorder, usually affecting both eyes.  The other form of nystagmus is called acquired nystagmus and is associated with neurological disorders such as stoke or head injury oten occurring later in life.  In both types the patient is unable to fixate his/her eyes steadily on the one spot.  It is usually assoicated with other eye conditions or is secondary to visual loss.  Early onset nystagmus occurs within the first few weeks of life and is usually observed within six to eight weeks of birth.  In about 10 to 20% of cases it presents with mild visual loss not associated with another diagnosed ocular condition.

We got the formal results of the assessment from Vision Australia a week or so ago, here are some excerpts from the letter:

Background
Bethany was seen by the Opthamologist who has said that the structures of the eyes appear normal, and hence has diagnosed probably Cortical Visual Impairment.  This is a broad term which is used to indicate that the eyes have formed normally, but the reduced visual functioning may be caused by disturbance in the visual cortex or the visual pathways of the brain.

 

Results
Bethany's eyes appeared straight with normal ocular movements, and she appeared to be able to track a 4-5cm object at about 30cms.  Bethany appeared to prefer objects presented at 30-40cms, less interest was shown in objects presented at a greater distance than this.

Vision Australia came back to do a more formal assessment of Beth's vision for us. This will provide a baseline from which we can understand how she's seeing and compare against it going forward.

They placed Beth on a large black blanket/play mat, and had a number of white foam balls, from the size of a pea through to a tennis ball.  These are formally graded into sizes that correspond with a scale of vision.  So with us holding Beth, these balls were rolled on the mat in front of here at approx 1m distance, and Beth was observed for any looking and tracking of them.  Beth found this pretty difficult and was actually more interested in looking at the Vision Australia people themselves! But they did note some glances at them.