1.2.4 Treatment Options
1.2.4.1 Review of the Literature
A review of the literature suggests that some form of “active” convergence therapy is the treatment of choice, however, there is no consensus about the therapy procedures to be prescribed or whether the treatment should be home- or office-based (Table 1-3).22-29
Table 1-3 - Opinions about Vision Therapy/Orthoptic Therapy for CI (Ophthalmologic and Optometric Textbooks published in past 2 decades)
| Source | Author | Key Statements |
|---|---|---|
| Binocular Vision and Ocular Motility 22 | von Noorden | “Therapy for convergence insufficiency is in the realm of orthoptics. Indeed its treatment is one of the most successful applications of the art of orthoptics…” |
| Duke-Elder’s Practice of Refraction 23 | Abrams | In reference to convergence insufficiency - “Orthoptic training appears at its best in the treatment of this condition...” |
| Pediatric Ophthalmology 24 | Cibis, Tongue and Stass-Isern | “Most convergence insufficiency subjects can be cured or relieved of their symptoms with appropriate exercises”. |
| Management of Strabismus and Amblyopia 25 | Pratt-Johnson | “Orthoptics is the treatment of choice in most subjects with convergence insufficiency and gives excellent results.” |
| Strabismus: A Decision Making Approach 26 | von Noorden and Helveston | In reference to convergence insufficiency - “The treatment, orthoptic exercises, in most instances provides long-lasting relief from symptoms.” |
| Binocular Anomalies: Diagnosis and Vision Therapy 27 | Griffin and Grisham | “…vision therapy is the preferred option applied in these cases.” |
| Applied Concepts in Vision Therapy 28 | Press | “Convergence insufficiency is the condition most responsive to vision therapy.” |
| Clinical Management of Binocular Vision 29 | Scheiman and Wick | “Vision therapy is the treatment of choice for convergence insufficiency.” |
1.2.4.2 National Survey of Optometrists and Ophthalmologists
Two studies have surveyed the ophthalmic community to determine how CI is treated in routine clinical practice. Chin et al. 30 surveyed 300 optometrists in the San Francisco Bay area regarding their primary mode of treatment for CI. One hundred six optometrists responded. The two most commonly recommended treatments were pencil push-up therapy (34%) and vision therapy/orthoptics (22%). About 20% prescribed base-in prism, 18% referred to another practitioner, and 6% did not recommend any treatment.
As part of our planning process we completed a similar survey to determine treatment patterns for CI patients using a randomly selected national sample of 863 optometrists and 863 ophthalmologists.31 Fifty-eight percent of the optometrists (563) and 23% of the ophthalmologists (196) responded to the survey. Among optometrists, 36% recommended pencil push-ups, 22% recommended more extensive home-based vision therapy, 16% prescribed office-based vision therapy/orthoptics, 15% prescribed base-in prism glasses, and 3% did not recommend any treatment for symptomatic CI subjects. Although only 16% of the respondents reported that they prescribed office-based vision therapy/orthoptics, 69% felt that this treatment approach was at least as effective as the other approaches included in the survey. Among ophthalmologists, 50% recommended pencil push-up therapy, 21% recommended more extensive home-based vision therapy/orthoptics, 5% prescribed vision therapy/orthoptics, 28% prescribed base-in prism glasses, and 8% did not recommend any treatment. In contrast to optometrists, only 4% of the respondents felt that vision therapy/orthoptics was at least as effective as the other approaches. These surveys underscore the lack of consensus among eye care professionals regarding the most appropriate treatment for CI and emphasize the need for a clinical trial.
Two very different “active” convergence treatments are commonly prescribed: 1) home-based or pencil push-up therapy and 2) office-based vision therapy/orthoptics. Pencil push-up therapy is the most commonly prescribed treatment and, therefore, is the current standard of care. This form of treatment involves home-based therapy with no specialized equipment and little or no follow-up. On the other hand, office-based vision therapy/orthoptics involves weekly office visits and a considerable number of therapy procedures and equipment.
1.2.4.3 Home-based Pencil Push-Up Treatment for CI
Many eye care practitioners responded that they believed pencil push-up therapy is an effective treatment procedure for CI and that pencil push-up therapy was the most frequently prescribed treatment.
The basic pencil push-up technique is described in Duke-Elder.17 "Exercises to improve the near point of convergence are carried out simply by the subject holding a target at arm's length and then gradually bringing it towards the eye, all the time maintaining bifoveal fixation. These exercises should be carried out several times each day for a few minutes." Use of a target providing physiological diplopia is often recommended. 22, 28, 29, 32
Even so, there is only one reported clinical study investigating the efficacy of pencil push-up therapy. In that uncontrolled study,33 25 subjects with symptomatic CI between 9 and 51 years of age (mean age 25 years) were instructed to perform pencil push-up therapy at home for 15 minutes, 5 days a week, and to fill out a daily log. Symptoms were significantly improved for the group of 12 subjects who returned for the 6-week follow-up visit. Both objective findings and symptoms were improved for seven subjects, while five subjects showed no improvements.
Our CITT Planning Project is the only controlled study of the efficacy of pencil push-up therapy. Significant improvements were not found with pencil push-up therapy in subjects aged 9 to 18 years. In the Pencil Push-up group there was neither a statistically nor clinically significant change in the symptom score (29.3±5.4 to 25.9±7.3, p=0.24). There was a moderate improvement in near point of convergence for subjects assigned to the Pencil Push-ups group (14.6cm ±7.4 to 9.1cm ±5.1, p=0.08). Only 27.3% (3/11) of the subjects achieved a normal near point of convergence break measurement of less than 6 cm at the end of treatment. The positive fusional vergence break showed no statistically significant improvement (12.6Δ ±3.2 to 14.5Δ ±5.3, p=0.22).
Although there is a lack of scientific support for pencil push-up therapy, it is easy to understand the clinical popularity of this technique because of its simplicity and low cost. Standard, home-based pencil push-up therapy can be taught to the subject and prescribed in a very short period of time. It also requires no or few follow-up visits and no specialized equipment. Therefore, it is significantly less expensive and time consuming for the subject. Consequently, pencil push-up therapy should be the treatment of choice for CI if it is as effective as or more effective than office-based vision therapy/orthoptics.
1.2.4.4 Home-Based Pencil Push-ups with Computer Vision Therapy/Orthoptics for CI
Our survey 31 indicated that about 24% of ophthalmologists and almost 36% of optometrists fairly often, often, or always recommend home-based therapy that is more intensive than just standard pencil push-ups. In the survey, home-based vision therapy/orthoptics (VT/orthoptics) was described as the use of prism, stereoscopes or any other home-based device. The use of computer technology in vision therapy started to become a reality in the 1980s, and has become an important part of vision therapy/orthoptics in the past 10 years.
There are several disadvantages of traditional home-based vision therapy/orthoptics including:
Traditional techniques often require an experienced doctor/technician to interpret the patients' responses and to use that information to alter stimulus conditions in order to improve binocular response.
With children who are not responding accurately for a variety of reasons, traditional techniques become difficult and unreliable to use. The child who "learns" the expected response and has a strong desire to please the therapist may "give the right response" even though he is not achieving the desired objective.
For learning to occur, feedback should be accurate, immediate, consistent, and unbiased. With traditional therapy techniques the feedback is provided by the parent at home, and, given human nature, the feedback may not always be as consistent and as immediate as desirable.
The advantage of computerized home-based VT/orthoptics is that it overcomes each of the three potential problems listed above.
From a clinical trial standpoint, computerized therapy offers two additional advantages.
The use of home-based computer software allows for standardization of therapy procedures.
Since the computer software tracks the amount of time spent with the procedure and results achieved, a more accurate measure of adherence to the treatment is available than with traditional, non-computer-based activities.