Copyright © 1983 AMERICAN ACADEMY OF OPTOMETRY

Reduction of Asthenopia in Patients with

Convergence Insufficiency after Fusional

Vergence Training

JEFFREY COOPER,* ARKADY SELENOW,t KENNETH J. CIUFFREDA,f

JERRY FELDMAN,~ JAMES FAVERTY,t STEVEN C. HOKODA,t and

JAYNE SILVERt

State College of Optometry, State University of New York, New York, New York

ABSTRACT

Seven patients with convergence insufficiency and related asthenopia underwent automated fusional convergence training. A matched- subjects control group crossover design was used to reduce placebo effects. All patients showed significant increases in vergence ranges with concurrent marked reduction of symptoms after training. All patients showed a flattening of and an increase in the base-out portion of their fixation disparity curve. Our results demonstrated the effectiveness of f u sional vergence training in reducing asthenopia in these patients. Subsequent accommodation and vergence training using traditional orthoptic procedures yielded further reduction of asthenopia, as well as an increase in the base-out fusional range.

Key Words: convergence insufficiency, asthenopia, orthoptics, fixation disparity

Convergence insufficiency, a common binocular vision disorder is often associated with asthenopia. The disorder has been reported to occur in 1.75 to 25% of the population.1-3 Variability of the reported incidence of convergence insufficiency reflects differences in definition, methods of measurement, and patient populations.

Traditional treatment of convergence insufficiency typically involves orthoptic techniques,

Received March 9, 1983; revision received September 1, 1983.

* Optometrist, M.S., Member of Faculty, F.A.A.O.

t Optometrist, Member of Faculty.

Optometrist, Ph.D., Member of Faculty, F.A.A.O.

§ Ph.D., Member of Faculty.

which have a reported success rate of over 90% in alleviating asthenopia.4 Although many studies have used large samples (e.g., N > 200), most have failed to use experimental procedures that allow for proper evaluation of the therapeutic intervention.5-8 Thus, experimenter bias, placebo effects, and concurrent multiple therapeutic techniques are not ordinarily assessed as factors related to subsequent changes in vergence ability and/or asthenopia. One study of the effects of vergence training on vergence performance demonstrated that progressive increases in vergence demand, rather than simple exposure to stereoscopic targets with minimal vergence demand, produced increases in vergence ability in patients with a variety of binocular vision disorders.9

Our study evaluated the effects of fusional vergence training on both fusional vergence ability and asthenopia in patients with convergence insufficiency. In addition, the effects of fusional vergence training on fixation disparity and Ogle- type forced vergence responses were investigated.’0

METHODS

Three male and four female patients (mean age, 25 years; range, 16 to 29) volunteered and completed the study. One patient dropped out before completion. Diagnosis of convergence insufficiency with accompanying asthenopia was made independently by two clinicians.

To be classified as having convergence insufficiency, a patient had to meet two of three of the following criteria:4 nearpoint of convergence greater than 7.5 cm with a recovery greater than 12.5 cm using an accommodative target;” a near base-out fusional range less than twice the demand (Donder’s criterion); and base-out ranges at near equal to or less than 2 SD’s below the

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