patients having convergence rnsutflciency. Re suits indicated that after vergence training, but not after placebo exposure, there was a significant increase in vergence ranges. This corresponded with marked reductions in patient ratings of severity of asthenopia as measured by a written questionnaire.

The purpose of the present study was to determine if systematic and programmed monocular accommodative training could be used to increase accommodative amplitudes and reduce asthenopia of patients having accommodative deficiencies. To minimize the potential contri bution of the binocular vergence system to the accommodative system only mononuclar training was done. To control for experimenter bias, placebo effects, and other sources of experimen tal confounding as noted above, the experiment used a matched-subjects crossover design. We used a written rating questionnaire for severity of asthenopic symptoms.

METHODS

Two male and three female patients (mean age, 27 years; range, 25 to 30 years) volunteered for and completed the study. Diagnosis of an accommodative anomaly with asthenopia was made independently by at least two clinicians. Criteria for inclusion in the study consisted of each of the following: accommodative amplitude less than 5.00 D (minus lens to blur), reduced accommodative facility defined as monocular failure to clear a —2.00 D lens within 5 s, and positive relative accommodation less than 1.50 D. Each patient had to have no evidence of amblyopia, strabismus, or vergence defect (phoria greater than 4 pd exo or 4 pd eso; no positive or negative fusional vergence less than 20 pd with recoveries less than 10 measured with Risley

prisms at 40 cm). Best corrected visual acuity was better than 6/9 (20/30). All patients had to have the symptoms usually associated with an accommodative anomaly such as blurred vision, asthenopia, and/or decreased reading perform ance. Assessment of asthenopia was by a written rating scale given to each patient (Appendix A). Initially, each patient was given a full binocular evaluation by examiners who had no know!edge of the patient’s ocular status or the group to which the patient had been assigned. The following measurements were taken: distance and near phoria; distance and near base-in and base-out ranges; accommodative amplitude via the push-up method and minus lens to blur method; monocular estimate method for lag of accommodation; base-out and base-in vectogram ranges; stereopsis on a Randot test; and accommodative facility using a ±2.00 lens. Each patient completed a 3-item questionnaire designed to rate the severity of their asthenopia. Each item was scored on a scale of 1 to 5. The asthenopia score was the summed score from the 3 questions (range 3 to 15); the higher the total score, the less the asthenopia.

After the binocular evaluation, the five patients were divided into two groups. The groups were matched as closely as possible on the basis of severity of asthenopia and accommodative anomaly. Three were assigned randomly to the experimental group and two to the control group. Each group came to the clinic twice a week for a 30-mm session. The only apparatus used for accommodative therapy were two modified Keystone telebinoculars (Fig. 1). The ster eoscope was modified to separate the right and left eyes. Each eye tube was enclosed to eliminate extraneous light. The telebinoculars had the +5.00 sphere prisms removed. An internal light source, with an on-off cycle of 2.5 s resulted

FIG. 1. Monocular accommodative training apparatus. Patient looks through enclosed tubes at 6/7.5 (20/ 25) equivalent print. Alternating light with appropriate lenses stimulate accommodation.