The effect of effort and exercise on convergence and accommodation

Abstract

IntroductionExtravagant claims are made about orthoptic exercises/vision therapy, but how they act is unclear. Treatment, practice, placebo and effort effects are often confounded and their effect on normals is unknown.MethodsIn order to obtain normative data we studied 101 healthy young adults in a laboratory setting. Accommodation and convergence response gains were measured objectively to targets moving in depth to a range of naturalistic and impoverished targets, both before and after two weeks of daily eye exercises. Participants were randomly allocated to six treatment groups specifically targeting blur resolution, binocular disparity resolution, near point effort, attention, repetition and ‘encouragement’ effects.ResultsOnly exercises targeting disparity resolution produced significant improvements above no-treatment baseline, and only significantly for convergence (P = 0.043) and marginally for accommodation (P = 0.09). Mean accommodation improved as much as vergence from these exercises. Blur, near point effort, or attention exercises produced insignificant improvements. Greatest improvement in responses was produced by ‘tester encouragement’ on the retest visit without any intervening exercises (P = 0.002 for both vergence and accommodation). Greater improvements were seen in the more impoverished conditions and some participants performed at ceiling to the naturalistic target.DiscussionEffort and encouragement produced greater improvements than exercises alone. Only treatment targeting disparity resolution produced a significant treatment effect and improved accommodation as much as vergence.ConclusionsWhile vergence exercises have some effect, effort and possibly voluntary influences are a critical factor in the “success” of orthoptic exercises/and vision therapy. More careful attention should be paid to these effects when making claims for efficacy of eye exercises in patient groups. IntroductionExtravagant claims are made about orthoptic exercises/vision therapy, but how they act is unclear. Treatment, practice, placebo and effort effects are often confounded and their effect on normals is unknown. Extravagant claims are made about orthoptic exercises/vision therapy, but how they act is unclear. Treatment, practice, placebo and effort effects are often confounded and their effect on normals is unknown. MethodsIn order to obtain normative data we studied 101 healthy young adults in a laboratory setting. Accommodation and convergence response gains were measured objectively to targets moving in depth to a range of naturalistic and impoverished targets, both before and after two weeks of daily eye exercises. Participants were randomly allocated to six treatment groups specifically targeting blur resolution, binocular disparity resolution, near point effort, attention, repetition and ‘encouragement’ effects. In order to obtain normative data we studied 101 healthy young adults in a laboratory setting. Accommodation and convergence response gains were measured objectively to targets moving in depth to a range of naturalistic and impoverished targets, both before and after two weeks of daily eye exercises. Participants were randomly allocated to six treatment groups specifically targeting blur resolution, binocular disparity resolution, near point effort, attention, repetition and ‘encouragement’ effects. ResultsOnly exercises targeting disparity resolution produced significant improvements above no-treatment baseline, and only significantly for convergence (P = 0.043) and marginally for accommodation (P = 0.09). Mean accommodation improved as much as vergence from these exercises. Blur, near point effort, or attention exercises produced insignificant improvements. Greatest improvement in responses was produced by ‘tester encouragement’ on the retest visit without any intervening exercises (P = 0.002 for both vergence and accommodation). Greater improvements were seen in the more impoverished conditions and some participants performed at ceiling to the naturalistic target. Only exercises targeting disparity resolution produced significant improvements above no-treatment baseline, and only significantly for convergence (P = 0.043) and marginally for accommodation (P = 0.09). Mean accommodation improved as much as vergence from these exercises. Blur, near point effort, or attention exercises produced insignificant improvements. Greatest improvement in responses was produced by ‘tester encouragement’ on the retest visit without any intervening exercises (P = 0.002 for both vergence and accommodation). Greater improvements were seen in the more impoverished conditions and some participants performed at ceiling to the naturalistic target. DiscussionEffort and encouragement produced greater improvements than exercises alone. Only treatment targeting disparity resolution produced a significant treatment effect and improved accommodation as much as vergence. Effort and encouragement produced greater improvements than exercises alone. Only treatment targeting disparity resolution produced a significant treatment effect and improved accommodation as much as vergence. ConclusionsWhile vergence exercises have some effect, effort and possibly voluntary influences are a critical factor in the “success” of orthoptic exercises/and vision therapy. More careful attention should be paid to these effects when making claims for efficacy of eye exercises in patient groups. While vergence exercises have some effect, effort and possibly voluntary influences are a critical factor in the “success” of orthoptic exercises/and vision therapy. More careful attention should be paid to these effects when making claims for efficacy of eye exercises in patient groups.