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In an orthoptic assessment, a series of tests are used to determine an individual’s overall binocularity. In other words, the ability to use the eyes as a pair.

Binocular vision is important to us as it keeps our eyes aligned and in sync. Whenever we are focussing on a particular object or following something in our sight, our brains fuse the images for each eye together, so that we constantly perceive one image. Our brain does this by telling each of the six muscles of each eye how to move in a synchronised fashion. A good binocular system also allows us to see the world in 3D.

There are many conditions that can affect our binocular system. These can be congenital, where one is born with a weakness or defect in one of the muscles that control eye movement. Muscle problems can also be acquired or develop due to many conditions. These can be associated with certain syndromes or can be acquired at any stage in life due to injury, as part of a systemic disease (such as diabetes or thyroid eye disease) or through neurological disease (such as certain brain lesions or stroke).

Symptoms of reduced binocularity may include headaches, eye strain, blurred vision, double vision or even a change in head posture. These symptoms may be subtle and are often overlooked. Problems with our binocular system can arise through various reasons. The problem may have arisen from birth or from a young age, or it may be associated with certain syndromes, systemic or neurological diseases, or as a result of an injury. It can occur at any stage in life.

The result of a significant muscle weakness is that the individual can develop a squint or strabismus. Children can also develop a squint if their refractive error is not corrected (ie when there is a need for glasses) or if one eye is amblyopic or ‘lazy’. In this situation the lazy eye is in effect ‘switched off’ and is ignored by the brain.

If a neurological disease affects the vision or the binocularity, often a full orthoptic and optometric assessment can locate the site of disease.

For diagnosis and monitoring of ocular motility problems and medico-legal cases, we have a Lees screen for Hess chart plots. This assists with the diagnosis of certain conditions and is very useful in monitoring the progress or progression of the disease.

There are various treatments available for binocularity problems, these include orthoptic exercises, adjusting the prescription of your glasses or contact lenses, or the use of prisms to control a deviation. Surgery may be necessary in some cases, if so we can recommend the best doctors on a case by case basis.

An Orthoptic Examination comprises of a series of tests used to assess an individual’s overall binocular vision status (the ability to use the eyes as a pair).

What are the symptoms of reduced binocularity:

  • Blurred vision
  • Double vision
  • Eyestrain
  • Headaches
  • Sometimes a change in head posture

What are the treatments for binocular vision problems:

  • Orthoptic exercises can help to train and strengthen the eye muscles
  • Spectacle or contact lens prescriptions can be modified to improve control of the eyes
  • Prisms can be added to a prescription to help with the control of the eyes
  • Prisms can also be added to contact lenses

What if I need to be referred?

Binocular problems can arise from more serious conditions. If this is suspected, we refer immediately to an Ophthalmologist or Neurologist for further investigation. If a squint or eye muscle problem cannot be helped by exercises or prism control alone, surgery or injections may be needed. If so we have a list of highly recommended Ophthalmologists with whom we refer to.

What if my condition just needs monitoring?

Measurements within an Orthoptic assessment can be compared at each visit to track for any improvement or worsening of a condition. Certain Ophthalmologists may also ask for your eye movements to be recorded on a Hess Chart. A Hess chart is used to plot your eye movements for comparison from one visit to another, a very useful test for the diagnosis and monitoring of certain diseases.

Who performs the Orthoptic examination?

Connan Tam is dual qualified in Orthoptics and Optometry. Before Optometry, he completed his Orthoptics degree in Liverpool University in 2003. Since then he has continued to practice Orthoptics and has combined his specialism with Optometric practice.