Purpose: Convergence insufficiency (CI) is characterized by abnormal vergence eye movement frequently accompanied by abnormal accommodation and subjective symptoms, such as headache, blurred vision, and diplopia. CI is treated with vergence and accommodation exercises that are integrated so that the relative contributions of vergence and accommodation exercises to the outcome are concealed. The purpose of the present study was to determine the individual contributions of vergence and accommodation exercises for the treatment of CI in school children.
Methods: In a prospective crossover study 44 children aged 9 to 13 years with CI were randomized to perform either vergence exercises followed by accommodation exercises each for 6 weeks or the 2 treatment regimes in the reverse order. The outcome measures were recovery from CI and the parameters vergence facility, positive fusional vergence, near point of convergence, monocular amplitude, and facility of accommodation.
Results: After the first 6-week period, full recovery from CI was significantly more frequent in the group commencing vergence exercises than in the group commencing monocular accommodation exercises (p = 0.01), whereas there was no significant difference between these proportions after the second 6-week period (p = 0.45). Vergence facility and positive fusional vergence improved significantly more after the period with vergence exercises than after the accommodation exercises, whereas there was no significant difference between the effects of the two types of exercises on the other studied parameters.
Conclusions: Vergence treatment induces a faster recovery of CI than accommodation treatment in school children. This may be used to improve compliance and success rate of the treatment.