Eye Movement Videos

Eye Movements in Gaucher Disease 

The diagnosis of type III Gaucher Disease is a clinical one. Abnormal eye movements are often the first sign. Since it is vital that the diagnosis is made at diagnosis, careful examination of eye movements is critical.

Voluntary shifting of gaze occurs in one of two ways, smooth pursuit or saccades.

Smooth pursuit eye movements allow the eyes to closely follow a moving object.

Saccades refer to the eye’s ability to quickly and accurately shift from one target to another. This is a critical skill in reading, involving very specific eye movements. The eyes must along a straight line without deviating up or down to the lines above or below.  In addition, when they reach the end of a line, they must sweep back to the beginning of the next line.  If a child cannot control these eye movements, he’ll lose his place and comprehension becomes a problem.  Understandably, this can impact significantly on reading.

Both smooth pursuit and saccades can be tested in horizontal or vertical planes. In type III Gaucher Disease, smooth pursuit may be affected early. This is illustrated in the video below

Abnormal smooth pursuit in a child with type III Gaucher disease.

However, it is often normal, as in the video below, showing normal smooth pursuit in a patient with type III GD.

Normal Smooth Pursuit in Type III Gaucher Disease

Horizontal saccades, on the other hand, are always affected. In the next video, horizontal saccades are being generated in the same patient as above. Note that when the examiner’s fingers are placed close together, the saccades are normal. As the distance increases, compensatory blinking appears.

Abnormal horizontal saccades in the same patient. Note that the saccades are normal when the fingers of the examiner are placed close together; they become abnormal as the distance increases.

The abnormality may be more subtle, as in the video below

Horizontal saccades Type III Gaucher

Therefore, unless saccades are specifically looked for, the diagnosis of type III may be missed.

By contrast, horizontal saccades are entirely normal in type I Gaucher disease.

Normal horizontal saccades in Type I Gaucher disease. Note that there is no need to start testing with the examiner's fingers close together, as the saccades are entirely normal even with the fingers widely separated.

Vertical saccades may be affected as well. This usually indicates disease progression. As with horizontal movements, vertical smooth pursuit may be normal.

Here is a video of normal vertical smooth pursuit

Vertical smooth pursuit Type III Gaucher

In the same patient, abnormal vertical saccades can be seen

Vertical saccades Type III Gaucher

If the child is unable to obey the above commands, assessment in an eye movement laboratory may be required.

An eye movement laboratory. The child sits on a stool, or in the case of a small child, on the lap of a parent who in turn sits on the chair. The chair is surrounded by a curtain with bright patterns. Either the curtain can turn around the child inducing optokinetic nystagmus, or the chair can rotate, inducing vestibulo-ocular nystagmus. Both have the effect of generating horizontal saccades.

The pictures below, and the videos that follow, were all taken at the Eye Movement Laboratory at Great Ormond Street Hospital (videos kindly provided by Professor Chris Harris)

Child sits on the lap of parent who is sitting on the chair.
This shows the equipment that is typically used to elicit and record optokinetic or vestibulo-ocular nystagmus.
Unaffected child, showing normal optokinetic nystagmus. Note the normal horizontal saccades.
Optokinetic nystagmus in a child with Type I Gaucher Disease. Again, the saccades are perfectly normal, as in the unaffected child above.
Optokinetic nystagmus in a child with Type III Gaucher Disease. Note the very slow speed of the saccades and the "locking" ie the child is unable to initiate any more saccades

Many young children with Type III Gaucher Disease are very irritable and locking cannot be observed in the light. This is illustrated in the video below.

Optokinetic nystagmus in type III Gaucher Disease in the light. Owing to the extreme irritability of the child, it is impossible to observe for "locking".

Often, in such children, it is possible to capture this in dark surrounding using infra-red, as can be seen in the next video. In the next video, the same child is being examined. This time, the stool on which the child is sitting is spun around, thereby eliciting vestibulo-ocular nystagmus. The child is far less irritable and therefore assessment is possible. Locking can be observed.

Vestibulo-ocular nystagmus in the dark in type III Gaucher Disease. The same child as in the previous video is being examined. This time, the stool on which the child is sitting is spun around, thereby eliciting vestibulo-ocular nystagmus. The child is far less irritable and therefore observation is possible. "Locking" can be observed.