Jun 18 2011

Hemianopia? Treatment Significant Loss of Vision Secondary to Stroke

Hemianopia is a significant loss of vision after a stroke to the visual aspect of the brain. Most commonly, it takes out one section of vision in both eyes. With homonymous hemianopia the vision loss usually starts right in the middle of the eye and is missing on the same side of both eyes. In this case, it is a “Left Homonymous Hemianopia.
When the patient experiences this, there first reaction is that of devastation. No longer can they see a full page of text, or look forward and see who is on the their side. Walking becomes awkward and sometimes dangerous as cues that most people rely on are missing.

Can anything be done for this condition? Is it permanent? There are various thoughts on the matter. But in the end, if there is not a significant recovery within a few months, there is likely not going to be any improvement. There are no surgeries or magical things that can be done. Often, the person experiencing this may be dealing with other aspects of stroke. That is not always the case. Once the neurologist has released the patient to therapy, there are some options. I cannot speak to the day-to-day rehabilitation protocol for an occupational therapist. I can speak to the options that are available to the patient through a unique optical device that was developed by Eli Peli, O.D. also known as the “Peli Lens.”
This is what a room looks like to a normally sighted person, either with the right eye or the left. When looking in the room they see the center and everything to the left, right, up and down. For the person with a right hemianopia, everything to the right is missing in either the right or the left eye or both together. This is not a problem with the eye. This is after a blood clot hit the brain and destroyed the connection between the eye and the visual processing center of the brain.

The next image is a schematic drawing of the visual field of the normally sighted person.
This shows that there is vision in the superior, inferior, left and right line of sight. The next image will contrast that showing how the hemianopia patient has lost that ability to see to the side. With the use of specially fitted prism glasses, the hemianopia patient does not gain back what they lost, but they become aware of what is to the side by an additional 20 degrees. There is a newer design that allows the patient to see up to 30 degrees to the side of neglect. It is illustrated in the following photo.

If you will notice carefully, you can see that the hemianopia patient can now become aware of the painting, the table, the lamp, and is much more keenly aware of there surroundings.

The prisms are attached to the spectacles on the same side of neglect. There are specific instructions for how this is done. Prism lenses are designed to move an image to the right, left, up or down. The glasses are fit so that the eye is looking through the spectacle prescription. But above and below the line of sight are the lenses moving the image from the missing vision into the top and lower view. The patient may feel awkward for a few moments, but when they realize that they have gained back peripheral vision awareness, the adaptation period is rather short.

These lenses will never bring back the missing vision. They are designed for walking, talking, and general use. They will not bring a full page back into focus when the hemianopia patient is trying to read. They are a clever and unique design allowing increased awareness.

I will describe some of my fitting experiences in the near future. This lens and its use has been published in numerous peer reviewed publications. More can be learned about it and hemianopia by going to “>www.hemianopia.org.

2 responses so far

2 Responses to “Hemianopia? Treatment Significant Loss of Vision Secondary to Stroke”

  1. Dr. David Toddon 27 Nov 2011 at 1:23 pm

    Actually, this article is incorrect. There has been a sizable body of research clearly demonstrating that field loss from brain injury is NOT irreversible.
    Specific types of visual stimulation and challenge not unlike Physical or Occupational Therapies have been approximately duplicated at a number of academic centers. These studies have shown clear success in reactivating previously disabled areas of the visual brain and restoring functionally significant amounts of lost vision.

    Two of the Universities completing this research have sufficient success to start commercial enterprises offering their specific brand of visual field restoration. The University of Aberdeen in UK, under the direction of Drs. Shahriae and Threvethan, now hosts a visual recovery clinic. Otto Von Guericke University in Magdeburg, Germany under Drs. Sabel, Kasten, Poggel actually created a therapy device which spun off a commercial company called NovaVision. The NovaVision therapy has been studied by multiple researchers (Marshall/Columbia U, Romano/University of MIami, Newman-Biousse/ Emory to name a few) all of whom found positive results and corroborated the company’s claims. Despite the strong opinions of detractors (most of whom have competing commercial concerns) there has never been a study disproving either of these therapies.

    The worst thing a vision practitioner or any practitioner for that matter could do, is to tell a patient conclusively that “nothing can be done” or that “there is no cure” without at least doing an exhaustive search in the area.

  2. Randalon 28 Nov 2011 at 9:38 pm

    The author thanks Dr. Todd for his input concerning this article. Its original purpose was to provide information to patients and caregivers on methods to improve daily life for the stroke patient who has vision field loss, more specifically, hemianopia of both eyes. I would like to take a few moments to present some differing opinions in this matter.

    In 1998 proponents of VRT (vision restoration therapy), Erich Kasten, and Bernard Sable at the Institute of Medical Psychology, University of Magdeburg in Magdeburg, Germany, wrote and published a paper describing their computer generated field training for expanding the field in homonymous hemianopia. They purported it stimulated borderline cells that still had potential for plasticity due to incomplete damage and claimed an improvement of a mean of 4.9-5.8 degrees.

    In the year 2003, these same researchers formed Nova Vision. Based in Boca Raton, Florida, they claim their instrument and training methods are “FDA Cleared.” This is not the same as “FDA Approved.” FDA cleared simply means that the instrument and technique do no harm. The procedure is not covered under medical insurance and usually costs around 6000 dollars.

    Sable and Kasten indicated that the same device used for training the patient is the same device used to measure the patient. A study performed in 2005 in Tübingen, Germany employed a scanning laser opthalmoscope to evaluate patients before and after VRT. The scanning laser opthalmoscope is able to track eye movements. Therefore, small movements of the eyes toward the blind field cannot affect results. The study showed that no expansion of the visual field and concluded that small eye movements accounted for the expansion. Amazingly, Kasten and Sabel were co-authors of the study.

    As a result of this study, a storm of letters was directed toward the British Journal of Opthalmology citing a variety of opinions. One of the most cited opinions was that of J.C. Horton, Opthalmology Department at the University of California-San Francisco. “In such subjects , the normal occipital lobe and affected occipital lobe are physically separate-no fringe of injured but salvageable tissue exists that represents the border of the visual field defect.” He concluded, “We should refocus our search for new treatments in a more fruitful direction.”

    In 2006, Doctor Robert MacFaczean, Institute of Neurological Sciences and Tennet Institute of Opthalmology, University of Glasgow, stated, “In clinical practice, NovaVision’s therapy should not currently gain acceptance in view of unacceptable perimetric standards and equivocal results.”

    The controversy exists around VRT (vision restorative therapy) and NovaVision because the studies with the best control for fixation during perimetry show no improvement after six months of VRT. Those with a financial interest in this method appear to its strongest proponents. This method is costly to patients and profitable to NovaVision and the institutions that offer it.

    The original intent of the article about Hemianopia was to describe a specific, available, inexpensive and practical treatment option that could be used in clinic by a practicing by an eye care provider in an everyday setting; One that would allow a stroke patient with heimanopia to gain as much as 30 degrees of awareness in their blind field. Furthermore, one type of prism lens option can be offered for less than one hundred dollars. As for leaving a patient without hope: It is the author’s opinion that each case must be evaluated individually, preferably in a team setting. And yes, as difficult as it seems, there are simply times when a patient must resign themselves to the facts and move on with options for making daily life better. Time will tell. It always does.

    The author has no financial interest in the prism lens, Nova Vision, or any other device used in the treatment of hemianopia. The author is active in clinical practice and low vision.

    For further reading:

    1. Horton, JC. Disappointing results form Nova Vision’s visual restoration therapyBr Jof Opthalmol 2005; 89: pp1-2 EDITORIAL

    2. Horton, JC. Vision restoration therapy: confounded by eye movements. Br J Ophthalmol 2005; 89:792-794

    3. Reinhart J, Schreiber A, Schiefer U, Kasten E, Sabel BA, Kenkel S, Vonthein R, Trauzettel-Klosinski S. Does visual restitution training change absolute homonymous visual field defects? A fundus controlled study. Br J Ophthalmol 2005; 89 30-35

    “Conclusion: Our study clearly shows that there is no change in absolute field defect after VRT when measured with fundus controlled SLO perimetry.”

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