Magnetic Implants: Help for Involuntary Eye Movements

Magnets implanted behind a person's eyes can treat nystagmus, a condition that causes involuntary eye movements. Nystagmus affects nearly one in 400 people, resulting in rhythmic, flickering of the eyes, commonly referred to as "dancing eyes." The case study, published in Ophthalmology, is the first to use an implant to control involuntary eye movement.

Case Study—A New Treatment for Nystagmus

Researchers from UCL and University of Oxford describe the study as the first successful use of an implant known as an oculomotor prosthesis. A set of magnets was implanted in the socket beneath each eye of a patient who developed nystagmus in his late 40s. The magnets were implanted in order to control involuntary eye movements and prevent flickering.

Researchers implanted magnets in the orbital floor of each eye socket. Another magnet was stitched to the extraocular muscles that control eye movement. The magnets successfully control the classic symptom of nystagmus, involuntary eye movements, because the force of the flickering movements is weaker than voluntary eye movements. “Fortunately the force used for voluntary eye movements is greater than the force causing the flickering movements, so we only needed quite small magnets, minimizing the risk of immobilizing the eye,” said Professor Quentin Pankhurst who led the design of the prosthesis.

The patient recovered quickly from the procedure. The overall visual acuity of the patient was substantially improved, with no negative impact on the functional range of movement. His symptoms have remained stable for over four years, enabling him to return to work and engage in daily activities such as reading and watching television. The patient does have a degree of diplopia or double vision, but it developed prior to the nystagmus.

Not everyone with nystagmus can benefit from magnetic implants, note the researchers. Magnetic implants are not suitable for patients who require regular MRI scans.

What Is Nystagmus?

Nystagmus is an involuntary rhythmic shaking or wobbling of the eyes. Nystagmus can be horizontal or vertical or move in a diagonal direction. In most cases, Nystagmus is present from birth and can be a part of other developmental syndromes. 

Nystagmus can be present constantly or exacerbated by certain eye movements. If nystagmus is severe enough, visual acuity will suffer as the eyes are constantly moving back and forth. Often times, people with nystagmus hold their head or eyes in a certain direction that reduces the amount of nystagmus.This is called a null point.

There are two types of nystagmus: congenital and acquired.

Congenital nystagmus
Congenital nystagmus starts in infants, usually between 6 weeks and 3 months old. Children with this condition tend to have it in both eyes, which move side to side. Usually, doctors do not know what is causing the child’s condition. The condition is sometimes inherited. Children with nystagmus typically do not see things as “shaking.” Instead, they may have blurry vision.

Acquired nystagmus
Acquired nystagmus happens later in life. It has many causes, including serious medical conditions or drug and alcohol use. Unlike children with congenital nystagmus, adults with nystagmus often report that objects around them seem to look shaky.

Causes of Nystagmus

The condition can develop from a number of conditions including:

Congenital Cataracts
Some infants are born with involuntary eye movement at birth, often caused by congenital cataracts. Congenital cataracts result when the natural lens of the eye turns cloudy, often appearing at birth or in early childhood. Some children might need an eyeglass prescription in order to see clearly. In some cases, surgical removal of the cataract is suggested.

Neurological Problems
Some neurological disorders can cause nystagmus, such as a brain tumor or multiple sclerosis. Involuntary eye movements may gradually worsen with the disorder. In most cases, surgical treatment of the eye muscles is not effective for the long term.

Systemic Conditions
Nystagmus sometimes develops with certain systemic diseases such as albinism. Albinism can also cause eye problems such as light sensitivity, eye misalignment and extreme refractive errors. The iris will also have a transparent appearance, causing the eye color to appear red. Nystagmus may also develop as a result of inner ear conditions, or toxicity from drugs, alcohol or prescription medications. Controlling or resolving the systemic condition might reduce involuntary eye movement in some cases. However, some conditions may require surgery on the eye muscles in order to reduce the occurrence of nystagmus.

View Article Sources
  • Parashkev Nachev, Geoff E. Rose, David H. Verity, Sanjay G. Manohar, Kelly MacKenzie, Gill Adams, Maria Theodorou, Quentin A. Pankhurst, Christopher Kennard. Magnetic Oculomotor Prosthetics for Acquired Nystagmus. Ophthalmology, 2017; DOI: 10.1016/j.ophtha.2017.05.028
  • Powell, Selina. "Magnetic implants control involuntary eye movements or dancing eyes." Optometry Today (OT). 2017.
  • Boyd, Kierstan. "What Is Nystagmus?" American Academy of Ophthalmology (AAO). 2017.