Double Vision

Where you see two images?

There are ranges of conditions that can cause double vision. It’s important to know if it has come on suddenly or has developed over time. If you have double vision that has occurred recently, you need to make an urgent appointment so that we can rule out a number of conditions and offer solutions.

If you have double vision of sudden onset accompanied with pain or severe headache, loss of balance and one sided weakness you should seek help and go to an accident and emergency department that is nearby.

The sources of double vision

Outside of the eye

Eye Muscles

Six muscles control your eye movements up and down and side to side. Problems with these muscles can impact on their movement and co-ordination between the two eyes causing double vision. Graves disease (a thyroid condition), or strabismus (misaligned eyes), are conditions that prevent the eyes from working together.

Reflex and cover test are used to determine the vertical and horizontal measurements needed to restore a single image for you, based on your responses. This is corrected with a prism introduced into the lenses.

Front of the eye

The cornea’s main function is to focus incoming light to the eye. Problems in the cornea distort its surface, which can then create double vision. Such problems include:

  • Astigmatism
  • Dry eyes
  • Infections such as singles or herpes Zoster
  • Scars caused by disease, injury or infection

We check these potential conditions during the anterior part of your eye examination using techniques such as slit lamp bio microscopy and, reflex and cover tests. Possible solutions include medication being prescribed, lenses introduced and advice given as solutions.

Middle of the eye


The clouding of the crystalline lens can cause double vision as the lens is interrupted in its role to focus light on the retina (the back of the eye).

Using the test chart to measure your vision and using a microscope on a slit lamp means your lens and other eye structures can be seen in small sections, which make it easier to detect tiny abnormalities. Ophthalmoscopy allows us to view your lens directly. Those on eye care packages may well have other instruments used to determine and record the findings.

The solution may include surgery which is a day case, or to have new glasses.

Systemic causes

Diabetes, Guillain-Barre and myasthenia gravis are some of the health conditions associated with double vision.

With conditions such as Guillain-Barre where the onset of double vision is likely to be one of the later symptoms (muscle weakness, numbness and problems with co-ordination are probably already present), it is likely that we will help you manage one of your symptoms. However we can refer you to your GP for further tests, if an underlying health condition should be suspected.

Neurological causes

The brain processes the visual information received from each eye. Interruptions in this process, whether through injury or illness, can cause double vision. Migraine, brain aneurysm, tumour, or strokes are some of the possible underlying conditions that affect the central nervous system or the brain’s ability to process the visual information.

We need to rule these causes out during our examination of your eyes. Some of the tests that may be used to do this include a good history of your current symptoms, past medical and ocular history, a visual field analysis, cover test results and the results from other examinations of the interior of your eyes. Having a previous ocular history can be of real benefit at this time because we can view previous baselines to identify what is normal for you and what has changed.

Solutions for double vision include lenses, patching or occlusive lens, Fresnel prisms, injections, surgery as well as endocrine treatments including medication.