CITT-ART – Part Two


We mentioned in part one that conclusions about the outcome of CITT-ART can be easily misconstrued or misapplied.  The most eye-opening item we discussed was why the placebo therapy group performed comparably to the vergence/accommodative therapy group.  Bear in mind that the placebo group is very different from a lens or drug trial, where the placebo can be designed so that the lens has no power or the pill can be formulated to be chemically inert relative to the disease being studied.  In what way would the placebo group in CITT-ART be expected to have vision-based reading preparedness skills improved?  Let’s take a closer look.


Here are some of the key vision therapy procedures in which the placebo therapy group engaged which would be expected to improve visual information processing skills from the standpoint of visual perception and/or sustained visual attention, some of which are  used to reduce the effects of visual crowding on reading:

  1. Ductions and versions
  2. Prism dissociated bi-ocular rock
  3. High Low Contrast VA
  4. After Image
  5. Visual Closure Skills
  6. Visual Figure Ground
  7. Visual Spatial Skills
  8. Visual Discrimination

In contrast, the vergence/accommodative therapy group had little if any exposure to these visual information processing skills.  Their procedures were designed to improve convergence principally from the standpoint of visual clarity and comfort through increasing vergence and accommodative ranges, and primarily involved:

  1. Brock String
  2. 3 Dot Card
  3. Eccentric Circles
  4. Aperture Rule
  5. Vectograms
  6. Computer Orthoptics
  7. Bulls Eye Rock
  8. Lens Sorting

Those experienced in optometric vision therapy will recognize that in the real world, to obtain the best results, transfer to reading occurs through a well-balanced program the incorporates a blend of vergence-accommodative therapy and visual information processing therapy.  This is not noted in the paper, but the authors do acknowledge another very serious limitation:  “As a group, participants performed in the average range on reading measures at baseline. One might argue that the study should have been limited to children with greater potential for reading improvement, such as younger children or those diagnosed as having mild to moderate reading problems.”  I’ve italicized and bolded that for good reason, because again that is not the real world.  It would be lovely if the majority of our patient population were comprised of children who are average readers, and whose parents or guardians wanted them to perform to a higher level of potential.  But the school-aged patient population in most private optometric practices at the outset of therapy consists of struggling rather than average readers.  These individuals have often experienced failed interventions elsewhere, and would have already responded positively if they were simply subject to pure placebo effects.



But wait, there is more.  From the standpoint of experienced doctors and therapists in our field, the limitations placed on prescription factors placed by eligibility criteria for CITT-ART will jump out.  Consider the following:

  • Hyperopia of less than +2.00D in either eye need not necessarily be compensated for with a lens prescription.
  • Patients wearing bifocals to treat a significant accommodative problems are excluded from the study.
  • If the investigator’s clinical opinion is that the bifocal lenses are not necessary, the child is eligible providing that the bifocals are discontinued for the duration of the study.
  • Use of base-in prism in any amount is not permitted in the Rx.  A participant who has been wearing prism is excluded unless he/she agrees to eliminate the prism from his/her glasses. 
  • If more than 1 ∆ of vertical prism is required, the participant is excluded from the CITT-ART.

Witholding or removing supportive lens or prism prescriptions can significantly handicap the patient’s progress in therapy.  In many instances such lens or prism effects are an integral component of therapy if not the scaffolding on which other therapeutic changes are built.

These are merely the more obvious caveats about the published CITT-ART conclusions.  The study notes that children with convergence insufficiency in the 9 – 14 year old age range receiving vergence/ accommodative therapy are likely to improve vergence and accommodation function, which could make reading and schoolwork more comfortable. It cautions that providing vergence/accommodative therapy for the treatment of childhood convergence insufficiency may not, on average, lead to improvements on standardized assessments of reading performance after 16 weeks of treatment.  After considering how patients were selected, and the nature of the intervention they received, these on average results are not surprising.  Nor should the improvements in some of the WIAT-3 subtests be discounted or overlooked.

I want to be clear that none of this diminishes in any way the marvelous accomplishments of the CITT group over the years.  It is simply that overcoming the obstacles faced by the constraints of the study are precisely what makes good optometric therapy practices successful in the real world, particularly when it relates to improved reading performance.

5 thoughts on “CITT-ART – Part Two

  1. Great Blog, Dr. Press. A placebo, as you say, must be inert relative to the disease being studied. If we were studying psychoactive drugs, sugar pills would be inert. If we were studying hypoglycemia, sugar pills would no longer be inert. As you pointed out, the placebo therapy is relatively inert for training accommodative/vergence skills, but is probably not inert when we studying reading. Not only are many of the placebo tasks different from those in the CITT study, the authors confess, “most placebo procedures required high levels of visual attention…. It is possible that some of these therapy procedures that were presumably placebo [quite a presumption] may have improved some measures of reading performance.” Perhaps this why the Cohen d scores (a measure of how large an effect is, with .8 being a large effect and 1.0 being a full standard deviation of effect, the Cohen d scores comparing baseline and completed therapy groups was for oral
    reading on the WIAT .83 for the accommodative/vergence group and 1.14 for the presumed placebo/information processing group. Despite these robust reading improvements with both groups, the authors’ conclusion was, “The results of this study suggest that clinicians providing vergence/accommodative therapy for treatment of childhood convergence insufficiency should not suggest such treatment, on average, will lead to improvements on standardized assessments of reading performance after 16 weeks of therapy.” Any such caution, would not only be untrue, it would border on nocebo, for as the authors point out, “Children who receive increased encouragement from their parents related to reading are likely to have increased motivation for reading, particularly if both children and parents expect the treatment to result in reading improvement” as this study demonstrated for both A/V therapy and information processing therapy, which as you point out, Dr. Press, most of us combine when working with patients with learning differences.

  2. One more point. The logic of an argument is no stronger than the truth of its assumptions. The logic for the conclusion of the CITT-ART is no stronger than the truth of the assumption that the information processing skills worked were inert concerning reading and that therefore the placebo therapy was a true placebo for reading. If the placebo therapy is not inert for reading, the study has no true placebo group and the conclusions are invalid despite the hard work, extreme care, and otherwise brilliant design of the study. In the meantime, Table 6 is a must read for anyone who thinks neither accommodative/vergence vision therapy nor information processing vision therapy improve reading. This possibly uncontrolled study, at least, suggests that both therapies do improve reading. As the authors consider, perhaps the study should have had a control group who received no therapy.

  3. Thank you for your in-depth review of the pros and cons of the CITT-ART Attention and Reading Trial. Ironically, a well meaning study will be used to promote a negative relationship between vision and reading. Confirmation bias will give our adversaries another reason to dispute the recommendation of vision therapy for a child/patient, who has a reading problem. The basic problem is that research requires simplicity in design and the questions raised in this trial defy simplicity. Two points based on my clinical experience are reinforced by this study. One is that visual attention is a key component in visual processing and should be part of any therapeutic program. The second point is that vision therapy should only be recommended for the treatment of a vision problem and not for a reading problem. The latter will probably show improvement but it is not guaranteed due to other extenuating circumstances. AND finally for those professionals, who negate any relationships between eyes and reading, I suggest that they try reading with their eyes closed! Thanks again for your insights into a topic which has gained a lot of press

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