The Truth About Visually-Based Reading Disability (Part 2)

In part 1, I discussed symptoms that occur in a condition for which I have suggested the name “Visually-Based Reading Disability (VBRD).”  In part 2, I will describe some of the likely underlying conditions that may cause VBRD and review some of the relevant scientific literature.  Let’s review some of the most common symptoms in VBRD:

1. Letters/words become blurry or turn double
2. Letters/words seem to float all over the page
3. The page gets “glary” and hurts eyes
4. —Loss of place when reading/ re-reading
5. —There are frequent small word errors (both omissions and substitutions)
6. Words move or shimmer on the page
7. —Can read well when words presented individually, but not when the same words are in a paragraph

Symptoms 1 & 2 are particularly common in”visual input” disorders such as convergence (eye teaming)  and accommodative (focusing) disorders.  These occur when a person cannot maintain or sustain convergence or accommodation for the time needed to perform near tasks such as reading, studying, take notes, or working on a computer.

Recently, some members of the College of Optometrists in Vision Development  embarked on a Tour de Optometry lecture series to inform current optometry students about the exciting specialty area of  developmental optometry.  Two of the slides used (below) give a reasonable simulation of what a patient with convergence and accommodative insufficiency experience.

convergence insufficiency simulation:

accommodative insufficiency simulation:

Convergence insufficiency, in particular, has been extensively researched through National Eye Institute funded multi-center clinical trials.  It has been found to be a treatable both symptomatically and objectively, most efficaciously with office based vision therapy.

Symptoms on the above list #4-7 may be more indicative of a visual processing problem.  Specifically, there are two pathways in the brain that are involved in visual processing during reading.  The magnocellular (M-cell) and parvocellular (P-cell)  pathways.  Here is a brief summary of these pathways as they relate to visual processing.

M-Cell pathway:

• Mainly involved in peripheral vision and sensitive to motion detection
• Responds to high temporal frequency and low spatial frequency
• Responds to reduced illumination
• Saccades during reading activate this pathway.

P-Cell pathway:

• Mainly in central vision and insensitive to motion detection.
• Involved with processing of color information
• More responsive to stationary or slow moving targets
• P-Cells are foveally activated during fixations and extract the details of the text.

Eye movements during reading involve fast eye movements (saccades, M-cell), and pauses to process information (fixations, P-cell). Reading therefore  involves the repetitive alternation of saccades and fixations.  There is good evidence that the M-cell system is impaired in many poor readers.  The role of the visual magnocellular system is probably to mediate steady direction of visual attention and eye fixations on words. Thus many children with reading difficulties have unsteady eye control and this potentially causes the letters they are trying to read to appear to move around  (Stein, 2003).  If this is difficult to imagine, then think of the situation of driving in a car between two cities and hearing two radio stations at once.  You will most likely either change the station or turn off the radio!  This is a good auditory analogy of the type of visual confusion a patient with VBRD probably confronts on a daily basis.  They may “turn off the radio” (stop reading) or feel compelled to read slowly and re-read because of the visual confusion VBRD causes.

In part 3 of “The Truth of Visually-Based Reading Disability” ,  I will discuss diagnostic tests available to us to aid in the diagnosis of VBRD and review our treatment options.

The Truth About Visually-Based Reading Disability (Part 1)

There is a growing body of scientific evidence pointing to the existence of what can best be categorized as “Visually-based Reading Disability” or VBRD. (Visually Based Reading Disability)

What is a VBRD?   It can best be described as a reading disorder where visual signs and symptoms predominate.  Here are some examples:

• Letters/words become blurry or turn double
• Letters/words seem to float all over the page
• —Loss of place when reading/ re-reading
• The page gets “glary” and hurts eyes
• —There are frequent small word errors (both omissions and substitutions)
• Words move or shimmer on the page
• —Can read well when words presented individually, but not when the same words are in a paragraph

Charles Fortenbacher has done a marvelous job depicting what written text might look like for a child with VBRD 

This can be contrasted to the more typical symptoms of a phonologic or “language-based reading disability” whose signs and symptoms include:

• Difficulty learning the alphabet or letter order
• Associating sounds with the letters that represent them
• Identifying or generating rhyming words, or counting syllables
• Segmenting words into individual sounds, or blending sounds
• With word retrieval or naming problems
• Learning to decode written words
• Distinguishing between similar sounds in words; mixing up sounds in   polysyllabic words (auditory discrimination) (for example, “aminal” for   animal, “bisghetti” for spaghetti)

Of course, the possibility exists that a child will have both “visual” and “language” components to their reading disability.

Visually-based reading disability can be insidious in nature, as children who have these visual symptoms often are “good” readers.  They may have good reading comprehension, and their independent reading level is often at grade level, or one to two years behind at most.  But they are often visually uncomfortable, inefficient, and rarely read for pleasure.  Many times they are labeled  ”lazy” or are underachieving compared to their potential.

How can you find out if your child has VBRD?  The best way is through a comprehensive examination by a developmental optometrist.  You can find one through the College of Optometrists in Vision Development Locate a doctor

In part 2, I will discuss some current theories about the underlying basis of visually-based reading disability and what some potential treatment options are.

Eye-Hand Coordination Skills in Children with and without Amblyopia

Dr. Tannen’s Research Review:

 In this important research article published in Investigative Ophthalmology and Visual Science in March 2011, it is shown that children with amblyopia have significantly poorer “reach” and “grasp” skills compared to normally sighted children at all ages tested.  The acquisition of precise eye-hand coordination for reaching, grasping, and manipulating objects is essential to many of our everyday activities.  It is seen as an important prerequisite for development of perceptual skills that are essential for action planning in hand movement and visual guidance.   It is postulated that the lack of stereopsis in amblyopic children is at the root cause of the eye-hand coordination deficits and that restoring binocularity in children with amblyopia may improve their poor eye-hand action control.

Abstract

Purpose: To investigate whether binocular information provides benefits for programming and guidance of reach-to-grasp movements in normal children and whether these eye-hand coordination skills are impaired in children with amblyopia and abnormal binocularity.

Methods: Reach-to-grasp performance of the preferred hand under binocular versus monocular (dominant or non-dominant eye occluded) conditions to different objects (2 sizes, 3 locations, 2-3 repetitions) was quantified using a 3D motion-capture system. Participants were 36 normally-sighted children (aged 5-11) and 11 adults, and 21 children (aged 4-8) with strabismus and/or anisometropia. Movement kinematics and error rates were compared for each viewing condition within- and between-subject groups.

Results: The youngest control subjects employed a mainly programmed (ballistic) strategy and collided with the objects more often when viewing with only one eye, while older children progressively incorporated visual feedback to guide their reach and, eventually, their grasp, resulting in binocular advantages for both movement components resembling those of adult performance. Amblyopic children were the worst performers under all viewing conditions, even for the dominant eye. They spent almost twice as long in the final approach to the objects and made many (1.5-3 times) more errors in reach direction and grip positioning as their normal counterparts, these impairments being most marked in those with the poorest binocularity, regardless of the severity or cause of their amblyopia.

Conclusions: The importance of binocular vision for eye-hand coordination normally increases with age and use of ‘on-line’ movement guidance. Restoring binocularity in children with amblyopia may improve their poor hand action control.

Authors:

1. Catherine M Suttle 2,
2. Dean R Melmoth 1,
3. Alison L Finlay 1,
4. John J Sloper 3 and
5. Simon Grant 1

+ Author Affiliations

1. ¹Department of Optometry & Visual Science, The Henry Wellcome Laboratories for Visual Sciences, City University, Northampton Square, London EC1V 0HB, UK.
2. ² School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2052, Australia.
3. ³ Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK.

• Copyright © 2010 by Association for Research in Vision and Ophthalmology

“Vision Has Nothing To Do With Reading”

Here is a comical look at a serious subject, the lack of the proper diagnosis of vision problems that can affect learning.  Unfortunately, this still occurs all too frequently.

As they say in Hollywood, “this movie is based on a true story…” in this case, my story.  Let me explain.

When I was 17, I was a freshman at Colgate University.  I was always a good student in high school, but the workload was significantly greater now.  I noticed that in fact I was getting headaches, eyestrain, blurred and double vision, and my eyes were consistently bloodshot (I was getting accused of doing things I really wasn’t doing -really).

I called home and my mother told me to see an ophthalmologist.  There wasn’t one in Hamilton, NY but there was one in Clinton, about 30 miles away.  I borrowed a friend’s car and drove to Clinton for my eye examination.  Soon after arriving, I was atropinized, examined, and then called into the consultation room of the ophthalmologist.  I remember through my blurred, light sensitive eyes, he looked something like an ogre, a tall ominous figure with a bald, somewhat pointy head.  Nonetheless, he offered what he considered “fatherly” advice.  Namely, that  I was in college now, bone up, study, and stop complaining, as there was nothing wrong with my eyes.   He sent me on my way into the bright, sunny afternoon (without disposable sunglasses).  Somehow, I made it home, resigned to the fact that college was going to be a painful experience at best.

Soon after, I noticed a classmate (for whom english was a second language), was using a new invention of the 1970′s, the cassette tape recorder, to record his lectures.  I invested in one myself, and soon was recording all of my most challenging classes.  By being able to listen to the lecture (sometimes numerous times) and write down notes, I was able to spare my visual system significantly (at least in my science courses which didn’t require as much outside reading).  My grades improved dramatically and I graduated with excellent grades.  However, when people describe college as the best 4 years of their lives, I have to disagree, as I was spending most of my spare time in transcription!

Serendipitously, I applied to Pennsylvania College of Optometry and was accepted.  In my first year, I was examined by a third year student.  For those of you who have been in a similar situation, it’s never a good sign when a student doctor gathers all the interns and doctors on the floor to look at you.  However, everyone was interested to see my severe convergence insufficiency which had signs which included 18pd of exophoria and a nearpoint of convergence of 16″.

I was referred to Pediatric and Binocular Vision Department at The Eye Institute where the Chief at the time was none other than my current esteemed colleague and great friend,  Dr. Len Press.  He treated me with vision therapy, and soon I was able to read and study much more efficiently and without all the headaches, eyestrain, and other symptoms that had become so much a part of my life.

I was, of course, “hooked” on vision therapy and Developmental Optometry after that, and thankfully have devoted my professional career to this amazing optometric specialty, and have had the pleasure of being able to help so many patients.  However, everyday I see children and adults who are not as fortunate as I was.  I hope for the day when they do not need to suffer needlessly with these very treatable vision conditions.

Barry Tannen, O.D., FCOVD

Critical Flicker Frequency (CFF) is Reduced in Children with Suspected Reading Disability

Dr. Tannen’s Research Review and Commentary:

In this study (of our SUNY Optometry-based research team), the critical flicker frequency threshold (CFF) of 39 children who had a history of  reading disability were compared to 23 age matched normal readers.  CFF threshold discriminated well between reading disabled and normal readers.   CFF threshold is a test that measures visual magnocellular function and adds further evidence to the  growing body of evidence that shows reduced temporal processing in individuals with reading disability. 

CFF threshold is a simple test to perform and hopefully will be commercially available  within the next year as a clinical test for optometrists and other health professionals to perform. (NOTE: I have no financial interest in this device). 

This research will be presented as a Poster Presentation at the Association for Research in Vision and Ophthalmology (ARVO) 2011 Annual Meeting 

Authors: Barry Tannen^1A, Kenneth J. Ciuffreda^1B, Noah M. Tannen. ^ADept of Clinical Sciences, ^BDept of Vision Sciences, ¹SUNY/State College of Optometry, New York, NY.Abstract:
Purpose: To assess the critical flicker frequency threshold (CFF) clinically in children with suspected reading disability.
Methods: The CFF threshold of 39 children between the ages of 7-16 years with suspected reading disability based on the chief complaint of “reading problems” was measured in the primary author’s private practice during the course of a comprehensive vision evaluation. 23 age-matched controls without any history or complaint of reading problems were also tested. CFF threshold was assessed binocularly with the habitual near prescription in place at 40 cm. The test light consisted of 4 contiguous white light-emitting diodes (LEDs) with which were mounted within a handheld rectangular enclosure and provided diffuse illumination via a circular translucent plexiglass cover. The size of the test field was 3.5 degrees with a luminance of 100cd/m2 performed in a dimly illuminated room. The flicker rate was controlled by a calibrated dial, which allowed the experimenter to gradually increase or decrease the flicker frequency over a range of 30 to 60 Hz. Patients were instructed to fixate the center of the test field, while the rate of flicker was either increased (‘‘stops flickering’’) or decreased (‘‘starts to flicker’’) at a rate of approximately 1 Hz per second. 3 ascending and 3 descending measurements were taken alternately. A single mean CFF threshold was obtained by averaging the 6 measurements.
Results: Mean CFF threshold was 45.48Hz +/-3.0Hz in the normal readers and 39.59+/-1.4Hz in the patients with reading problems, which was significantly different (t-test, p<0.01). Only 3 of the 39 children (7.5%) with reading problems had a CFF threshold within 1 standard deviation of the mean CFF threshold of normal readers in our sample.

Conclusions: Mean CFF threshold discriminated well between children with a chief complaint of reading problems and those with no history or report of reading problems. This agrees with earlier studies demonstrating reduced temporal processing reflecting visual magnocellular impairment in individuals with reading disability. We suggest that the CFF threshold test, which is both simple and rapid, be considered for inclusion in the clinical vision testing for children presenting with reading problems.

 

 

 

Visual Vertigo Syndrome (Journal Article Review)

Citation:  Guerraz, M., Yardley, L., et al.  Visual vertigo: symptom assessment, spatial orientation and postural control.  Oxford University Press 2001; 124: 1646-1656

Summarized by:                                                                                                                                                                        Amy M. Bartal, O.D.                                                                                                                                                           Resident, Vision Therapy and Rehabilitation                                                                                                    EyeCare Professionals, PC   Hamilton, NJ

(A Southern College of Optometry,Private Practice Residency)

 Summary: The purpose of this article is to determine the cause of visual vertigo by assessing symptoms, spatial orientation, and postural control.

 Methods:  Twenty one individuals were identified with visual vertigo (VV) after reporting worsening of symptoms including vertigo, dizziness, unsteadiness or spatial disorientation by certain visual surroundings.  These patients were compared with visually dependent individuals with a bilateral labyrinthine-defective (LDS) disorder, and normal subjects using questionnaires and experimental stimuli.  All subjects answered several surveys including the Situational Vertigo Questionnaire, Vertigo Symptom Scale, Childhood Motion Sickness Questionnaire, Spielberger Trait Anxiety Inventory, and Vertigo Handicap Questionnaire.  These surveys measured patient symptoms, level of anxiety, and experiences with motion sickness for all groups.  The experimental stimuli required the subjects to orient a linear rod vertically while in three settings: darkness, within a tilted frame, and within a rotating disc.  Body sway was also measured in four visual conditions.  Subjects were instructed to stand bare-foot on a force platform and fixate on a luminescent dot with their eyes opened, eyes closed, while the target was located within a tilted frame or a rotating disc.  The data measured formed two computed quotients.  The Romberg quotient (RQ = eyes closed sway/eyes opened sway) reflects the amount of postural instability with stationary visual surroundings.  The visual-kinetic quotient (V-KQ = rotating disc sway/eyes open sway) quantifies the destabilizing effect of moving stimuli.  Statistical analysis was based on a multi-way analysis of variance and co-variance for the questionnaire data and the visual vertical and postural data, respectively. 

Results:  The data collected through the subject questionnaires revealed significantly higher levels of visually induced anxiety symptoms in the VV and LDS patients compared to the normal controls.  The VV subjects also had significantly higher levels of vertigo.  There were no statistical differences found correlating childhood motion sickness or levels of handicaps felt with the different experimental groups.  In the subjective visual vertical and postural tests, both the VV and LDS patients demonstrated an increase in tilt of the vertical rod both with the static tilted frame and the rotating disc.  Postural deviation when facing the titled frame and rotating disc was also increased in both of these groups.  When comparing the stabilizing effect of vision there was a statistical increase in the LDS subjects but not the VV when compared to the controls.  In contrast, the destabilizing effect of a moving visual stimulus had a greater impact on the VV subjects and not the LDS patients.

  In conclusion, VV patients have an abnormally large perceptual and postural response to disorienting visual environments.  VV develops in individuals who are visually dependent and rely on visual cues more than vestibulo-proprioceptive inputs.  Treatment is aimed at increasing subjective and postural tolerance to disorienting visual stimuli and increasing the patients’ use of vestibulo-proprioceptive cues.  Repetitive optokinetic stimulation has shown improvement in postural stability and patient symptoms.

Case in Point:  A 43 year old woman presented to our office 2.5 years ago with symptoms of headaches and vertigo that was exacerbated by certain visual environments such as shopping malls, supermarkets with tall aisles, and in general all fluorescent lighting.  Her history included several minor traumatic brain injuries (auto accident, hitting her head on a shelf, etc) non of which caused loss of consciousness, or required hospitalization.

Examination revealed a diagnosis of mild convergence excess.  The rest of the ocular health and visual examination was unremarkable with the notable exception that viewing an Optokinetic drum caused tremendous increase in symptomatology.  This occured whether the OKN drum was spinning or not and even occured when the drum was diplaced from the patient’s line of sight (left side placement was the worst).  Critical Flicker Frequency was atypically high (her threshold was about 50Hz, average patients are in the 43-45Hz range).  This means that her sensitivity to flicker was very high.  

Our treatment plan revolved around prescribing a therapeutic tint (she responded positively to a BPI Omega tint-purplish hue).  Upon eyeglass dispensing she reported that the glasses allowed her the first headache-free, non-vertigo day in over 2 years. 

Vision therapy centered around restoring fusional vergence to normal levels and gradually introducing eye movement procedures for fixation, pursuit, and saccades that required greater speed, visual motor integration, and cognitve distractors.  The vision therapy (along with the tinted spectacles)  proved to reduce her symptoms dramatically.  Other intervention that the patient felt was helpful was Logan chiropractic treatment, B complex vitamins, and increasing sleep to 8 hours per evening. 

We recently saw her one year after post vision therapy  and she maintains that she is almost symptom free virtually every day.

Objective Measurements of Reading Eye Movements Improve After Vision Therapy

Dr. Tannen’s Research Review and Commentary:

In this retrospective study, 46 patients who were diagnosed with oculomotor-based reading dysfunction received an average of 29 sessions of vision therapy.  Statistically significant improvements were found for all parameters of eye movement recordings following completion of vision therapy.  In addition, 93% of the patients reported subjective improvement after the vision therapy, including a marked reduction in at least one or more of their primary symptoms. 

Objective measurements of reading speed and efficiency improve in children diagnosed with oculomotor-based reading dysfunctions following vision therapy: a retrospective analysis
Barry Tannen, Noah Tannen, and Kenneth Ciuffreda (COVD Annual Meeting 2010)

Abstract:

Purpose:

 A retrospective analysis was conducted to assess objectively reading speed and efficiency with the Visagraph II Eye Movement System (Visagraph) following vision therapy (VT) in children with signs and symptoms of oculomotor-based reading dysfunctions.

Methods:

46 children between the ages of 8-17 years from the primary author’s private practice met the following criterion: symptoms of oculomotor-based reading dysfunctions (e.g. loss of place when reading, skipping lines, etc), and Visagraph recordings where both reading speed and grade level equivalent were below their grade level. To be included in the analysis, VT had to both be recommended and completed during the years 2007-2009. All of these patients had Pre and Post VT Visagraph recordings using an amended protocol (Tannen and Ciuffreda, JBO, 2007) which calls for two recordings taken at the patient’s Independent Reading Level (aIRL) with the second one being used for analysis, and one recording taken at least two grade levels below the patient’s Independent Reading Level (bIRL). VT consisted of standard optometric vision therapy procedures for remediation of accommodation, binocularity, and oculomotor function according to the patient’s individual status.

The average course of treatment was 29 (forty minute) sessions performed twice weekly.

 

 

Results:

Pre and Post VT Visagraph recordings were analyzed to determine if significant improvements in the various components of reading eye movements occurred after VT, and whether there was a difference in the Post VT Visagraph recordings of the aIRL group vs. the bIRL group. All Visagraph eye movement parameters improved significantly (p<.01) on a percentage basis following VT. Average aIRL improvement: Reading speed (51%), Grade level equivalent (134%), Fixations (34%), Regressions (45%), Span of Recognition (37%), Duration of Fixation (9%). Average bIRL improvement: Reading speed (54%), Grade level equivalent (138%), Fixations (42%), Regressions (63%), Span of Recognition (43%), Duration of Fixation (7%).

Conclusions:  

The results demonstrate significant improvements in all Visagraph parameters, both aIRL and to a greater degree bIRL. The latter suggests a primarily oculomotor basis for the improvement, and this appears to be reflected in the improvement aIRL as well. The positive objective findings in Visagraph measurements correlated well with symptom reduction that occurred in 93% of the patients.

Pre-post visagraph

Attention Therapy and Reading Comprehension

Dr. Tannen’s Research Review and Commentary:

In this study 15 moderately disabled readers received 12 hours of vision attention therapy.  Significant improvement in reading comprehension and attention scores were seen in the group who received therapy, but not in the control group who received no therapy.

 

Effect of Attention Therapy on Reading Comprehension

Harold A. Solan, John Shelley-Tremblay, Anthony Ficarra, Michael Silverman, and Steven Larson

JOURNAL OF LEARNING DISABILITIES VOLUME 36, NUMBER 6, NOVEMBER/DECEMBER 2003, PAGES 556-563

Abstract

This study quantified the influence of visual attention therapy on the reading comprehension of Grade 6 children with moderate reading disabilities (RD) in the absence of specific reading remediation. Thirty students with below-average reading scores were identified using standardized reading comprehension tests. Fifteen children were placed randomly in the experimental group and 15 in the control group. The Attention Battery of the Cognitive Assessment System was administered to all participants. The experimental group received 12 one-hour sessions of individually monitored, computer-based attention therapy programs; the control group received no therapy during their 12-week period. Each group was retested on attention and reading comprehension measures. In order to stimulate selective and sustained visual attention, the vision therapy stressed various aspects of arousal, activation, and vigilance. At the completion of attention therapy, the mean standard attention and reading comprehension scores of the experimental group had improved significantly. The control group, however, showed no significant improvement in reading comprehension scores after 12 weeks. Although uncertainties still exist, this investigation supports the notion that visual attention is malleable and that attention therapy has a significant effect on reading comprehension in this often neglected population.

Research on attention has been voluminous; nevertheless, there’s no universal agreement on how to define attention or its characteristics.  Sergeant (1996) proposed that visual attention is multidimensional, with traits that involve psychophysiological and cognitive variables. For example, selective attention implies a filtering process that attenuates irrelevant stimuli while an individual focuses on relevant stimuli. Henderson (1992) defined visual-spatial attention as “the selective use of information from one region of the visual field at the expense of other regions of the visual field” (p. 260). Selective attention may also be based on the physical (color and size) or the semantic/lexical properties of the stimulus. On the other hand, in reading, activation and vigilance also are   important elements, because they are associated with sustained attention, a factor that relates to the ability to maintain visual performance over time (Halperin, 1996).  Essentially, in this study, we are hypothesizing a functional information processing disorder that precludes the presence of primary cerebral pathology (Pashler, 1998).  Attention is usually involved in both early and late stages of information processing, yet tests to quantify attention frequently measure only the endpoint of a number of perceptual and cognitive processes, such as visual memory and visually guided fine motor skills (e.g., paper-and-pencil tests). Specific examples are the Wechsler Intelligence Scale for Children-III (WISC-III) Coding subtest (Wechsler, 1991) and the Cancellation Test (Rudel, Denckla, & Broman, 1978). Furthermore, both the WISC-III Coding subtest and the Cancellation Test are timed attention tests that require visual motor skills. In any timed test, we are required to accept a speed- accuracy trade-off as an essential condition that could affect visual processing efficiency.  We agree with Milliken and Tipper (1998) that the end product of attentive analysis is usually addressed, rather than a mechanistic explanation of how that end product came to be.  The range of therapeutic procedures that involve a variety of functions was influenced by Mirsky’s (1996) multicomponent view of attention. Mirsky explained that attention is more than a process. It is a set of processes organized into a system that embraces a number of distinct functions, including focus, shift, sustain, and encode. The therapeutic goal is to facilitate attending to sources of relevant information and, simultaneously, to produce a decrement in responding to sources of irrelevant information. The therapy used in this study concentrates on how the attentive processing of relevant stimuli may be conditioned by procedures that impede the processing of irrelevant stimuli.