Diplopia aka Double vision
As Neuro-Ophthalmologists we are often asked to see patients for Double Diplopia (aka vision). The patient can complain of constant or intermittent double vision. It is important to be seen as soon as the Diplopia is noticed since this can be a sign of a medical emergency. It is also important to make sure a trained eye care professional (often a Neuro-Ophthalmologist) evaluates the eyes and to determine the needed workup.
There are two main categories of double vision:
Monocular – – the double vision is still present with one or the other eye closed.
This is usually not a neurologic problem but a problem in the eye itself (i.e. cornea, lens, vitreous or retina).
Binocular – the double vision resolves with one or the other eye closed and is only present with both eyes open.
This is true neurologic double vision and is due to the misalignment of the two eyes. The easiest way to think of this is to
imagine two cameras located just a few inches apart. Point them at an object in the distance and project the picture onto two screens. The two images will be similar but just slightly different since the cameras are viewing the object from slightly different angles. In our brain, the two images are lined up to make single vision. Now if the deviation of the cameras change (turn one towards or away from the other) the images become even more different and the brain cannot compensate. This causes the double vision.
When the deviation occurs in a young child, the brain will shut down the vision in one of the eyes to stop the double
vision, often leading to a lazy eye (Amblyopia) if not treated in time. In adults however, the brain is unable to shut down
the input from an eye so double vision occurs.
The causes of double vision are many but can include:
Cranial nerve III palsy (can be life threatening)
Cranial nerve IV palsy
Cranial nerve VI palsy
Thyroid eye disease
Tumors of the orbit
Breakdown of a long-standing deviation (old problem)
Once the workup shows the likely cause (sometimes easily seen with measurements, and sometimes other tests are needed), then possible treatment can be prescribed. The treatments can include:
Patching of one eye (Occlusion Therapy)
Prisms in the glasses
Botox to one of the eye muscles to compensate for the weak eye muscle.
Surgical intervention called strabismus surgery
Double vision is bothersome but usually can be treated successfully.
Sarasota Retina Institute is fortunate to have a full-time orthoptist who diagnosis and manages a wide variety of causes of Diplopia.
Ms. Rikki Gilligan is the only Certified Orthoptist in the Sarasota, Manatee and Charlotte County area. Click here to visit her page.