Analysis of the AC/A Ratio in a Sample of Intermittent Exotropes of Divergence Excess Type

Carolyn Smith, DipAppSci(Cumb), DOBA

Previous authors have suggested that many of the patients diagnosed as intermittent exotropes of divergence excess are, in fact, simulated forms of this condition, i.e. that some of these patients control an equally large near deviation by excessive accommodative convergence and possess a high AC/A ratio. In order to investigate the type of AC/A ratio present amongst a sample of seventeen intermittent exotropes of divergence excess type the AC/A was calculated by the gradient method at 1/3m using + 3.00 DS lenses. An equivalent normal sample was also investigated. When comparing the two groups the intermittent exotropic sample had a significantly greater proportion of high AC/A subjects. Disclosure of a high AC/A ratio is valuable when considering orthoptic and surgical management of the intermittent exotrope of divergence excess.