"Until I feared I would lose it, I never loved to read.
One does not love breathing."
- Harper Lee
Reading Problems After Stroke or Head Injury
Reading difficulty may occur from various problems after a stroke or other acquired brain injury. Reading problems are a primary reason that stroke and head injury patients seek an eye examination. It is crucial that the type of reading problem be diagnosed. The list below contains some of the more common causes in reading problems with an introduction to how they may be treated.
Hemianoptic Alexia (Hemianoptic Dylexia)
Reading Problems owing to the Visual Field Loss
Homonymous hemianopsia patients often lose their place in reading owing to their visual field loss. Wilbrand in 1907 coined this as macular-hemianoptic reading disorder and today we refer to it as hemianoptic alexia or hemianoptic dyslexia. These patients have the ability to read words, but complain that its just too difficult or confusing to read for long periods of time and that they now avoid it. They may report that they lose their place or get confused on which word to read next. Simple techniques, like sticking a Post-it note along the side of a column of print to mark the beginning or end of the column which reduces confusion can help. Techniques depend on whether a right or left hemianopsia is present.
Right Hemianopsia Reading: In a right hemianopsia patient, the blind spot of the field loss moves with the patient down the line of text like a curtain hidding what the patient is trying to read next. If there is little or no sparing of the macula (central vision), then the blindspot may not only block the end of the line of text making it difficult to locate the end of the line, but may block the end of long words. A patient may see the word "boathouse" as "boat" then after shifting fixation realize the word was actually "boathouse." The patient frequently becomes frustrated and gives up reading.
Boundary marking devices which we will discuss below and training the patient to read by looking at the last letter in long words can help improve reading in many patients with hemianoptic alexia. Patients with right hemianopsias may also have not only hemianoptic alexia, but could have a true alexia that limits reading due to cognitive processing of reading. This must be ruled out. This can be screened for by asking the patient to read and direct their fixation to the end of words or turning the print 90 degrees and ask them to read the text. The text should be turned clockwise vertically for right hemianopsia patients.
Above, we demonstrate to a patient with a right homonymous hemianopsia, that when he looks at the start of a long word, his hemianopsia blocks the end of the word. However, if we draw his attention to the end of the word. He will now see the entire word, because it now resides in the left visual field.
Last Letter Cancellation Therapy
Teaching the patient to read by looking at the end of words rather than the start of words can help the patient improve their reading. A simple therapy to help the patient learn to read by looking at the end of lines is the Last Letter Cancellation Therapy. The patient takes a page of newspaper and a red pen. The patient locates and cancels out the last letter of each word with the red pen. The patient does one full page of newspaper each day. After two to four weeks, most patients have learned to look for the ends of words.
The Hemi Reading Card
A Hemi Reading card can be used to mark the boundaries on the column of print. The right homonymous hemianopsia patient sets the red boundary on the right end of the column. These patients will often fail to reach the end of each line before returning to the start of the next line. They then become confused because the sentence did not make sense. The patient reads down the line until reaching the red boundary marker. Then proceeds back the same line to the start of the line and then drops the card /line down to the next line. The yellow filter improves contrast.
Left Hemianopsia Reading: A left hemianopsia patient may have difficulty returning to the start of the next line and may instead begin reading before reaching the start of the next line. Then as they read, they soon realize that what they read does not make sense. After this happens several times, the patient may become frustrated and stops reading. In general, however, the reading problems of left hemianopsia patients, are usually not as significant as those with right hemianopsia. Simple boundary marking techniques help many patients. The use of a Hemi Reading Card, Post-it Note or even the patient's thumb may help.
Here a patient with a left homonymous hemianopsia using a Hemi Reading Card. The left homonymous hemianopsia patient will place the red at the start of the line. These patients will misjudge the start of the next line, usually stopping short of the start of the next line. Patients should follow back the same line of text until they reach the red boundary marker on the left, then drop down to the next line.
Patients with hemi-spatial in-attention (Visual neglect) will have difficulty in attending to the left side of the text. Thus they will repeatedly fail to shift their fixation back to
true beginning of the next line causing confusion. Neglect dyslexia is not easily treated. The same boundary marking techniques can be tried, but outcomes are poor. It may improve over time. All patients with left homonymous hemianopsia should be tested for Hemi-spatial in-attention (visual neglect).
Loss of Accommodation (Focusing)
Young head injury patients may experience decreased focusing ability. It is often missed because at an early age doctors don't expect loss of accommodation. It happens naturally at about age 42. Individuals with reduced accommodation may benefit from bifocals. A careful assessment of accommodation should be performed on all young acquired brain injury patients.
Convergence Disorders Affecting Reading
Patients may experience reduced convergence after acquired brain injury. If we have binocular vision, our eyes must turn in together accurately as a team to point at the word we are reading. If not, we may have double vision. More frequently convergence insufficiency may result in eyestrain and fatigue in reading. Prisms added to the patient's eyewear prescription may aid some patients. Orthoptic therapy may aid others.
Not all patients with convergence insufficiency will respond fully to therapy due to the variation in the extent of trauma. In our practice, we frequently prescribes a combination of therapies including computerized orthoptic therapy to rebuild fusional skills.
Damage to the left posterior hemisphere causing a right hemianopsia can also result in loss of reading ability owing to damage to the centers of the brain involved in processing reading. Many patients may relearn reading skills with a speech therapist. However, in some cases the damage may be so severe as to preclude reading permanently.
If the patient is unable to recover reading ability but can understand verbal reading, electronic text-to-voice machines are available such as the Kurzweil Omni 1000 and 3000 and the SARA System.
The NokiaN82 cell phone can be adapted with the Kurzweil Software (KNFB) to allow the cell phone’s camera to capture a picture of text and then read it to the patient. Similar software can be used on a computer with a scanner to enter text.
These machines capture the image of print, interpret it and read it aloud to the patient. Talking books and reading radio are also very helpful. A variety of software is available to allow computers to read any text present on the screen. Free software such as LowBrowse is available as a plug in for the Firefox browser.
Low Vision Causing Reading Problems
Typically strokes cause only mild changes in visual acuity. Brain tumors and traumatic brain injury are more likely to cause a major loss of central visual acuity. When visual acuity is impaired magnification devices may be required including: high add bifocals, magnifiers, electronic video magnification systems, and/or special microscopic eye wear may help the patient read again. A low vision evaluation can provide a variety of options to help the patient.
Double Vision (Diplopia) Causing Disruptions to Reading
A loss of normal binocular vision may occur from ocular motor paralysis. When possible, prisms may be used to re-establish binocular vision. Short-term patching may be required. Patching should take place on the glasses and not with a black patch. A black “pirate's” patch blocks all the vision including the side vision. If we patch on the eyeglass lens, the patient will still have vision at the far side of the occluded eye and function better. If binocular vision cannot be restored during the first 10 months, then a surgical consultation may be recommended.
The Mins Lens, A New Way to Patch: If no other treatment is possible, and double vision is permanent, a Mins lens can be prescribed for the the non-dominant eye. The Mins lens blocks the patient’s vision but does not block the view of the patient’s eye to others. This is a much more cosmetic system, but should only be used when the double vision is intractable.
The patient here has a high esotropia with constant double vision from a brain stem injury. When he came to our practice, he had suffered from constant double vision for several years. We stopped the double vision with a Mins lens. Notice that the appearance is very cosmetic as you can see his eye when looking at him. In the final picture, he turns the eyewear around to demonstrate how it blocked his vision.
The Mins lens can be fabricated to block only a section of the patient’s vision. In the demonstration below we had had a Mins lens fused with a distance portion.It is placed at the bottom of one lens to block incurable double vision that only occurred when reading.
Eye Gaze Disorders
Patients with inferior gaze paresis may not be able to look down into the bifocal, but may read with single vision reading eyewear that does not require them to look down. Clip on reading lenses may also be employed.
Combination of Problems
In reality most of the patients we see have a combination of problems, which make it difficult for the patient and family to understand the exact cause. We recommend a low vision examination on all head injury patient experiencing reading difficulty.
Please contact us if you have any questions.
The Low Vision Centers of Indiana
Richard L. Windsor, O.D., F.A.A.O., D.P.N.A.P.
Craig Allen Ford, O.D., F.A.A.O.
Laura K. Windsor, O.D., F.A.A.O.
Indianapolis (317) 844-0919
Fort Wayne (260) 432-0575
Hartford City (765) 348-2020