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:
- Ductions and versions
- Prism dissociated bi-ocular rock
- High Low Contrast VA
- After Image
- Visual Closure Skills
- Visual Figure Ground
- Visual Spatial Skills
- 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:
- Brock String
- 3 Dot Card
- Eccentric Circles
- Aperture Rule
- Computer Orthoptics
- Bulls Eye Rock
- 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.