Yonsei Med J.  2010 Jan;51(1):117-120. 10.3349/ymj.2010.51.1.117.

The Prismatic Effect on Stereoacuity in Intermittent Exotropia

• Choi KS
• Chung SA
• Lee KS
• Lee JB

• KMID: 1779616
• DOI: http://doi.org/10.3349/ymj.2010.51.1.117

Abstract

PURPOSE
To evaluate the effect of acrylic refractive prism and Fresnel membrane prism on stereoacuity in intermittent exotropia. MATERIALS AND METHODS: Stereoacuities of fifty-two patients (mean age, 12.4 years; range 6 to 45 years) with intermittent exotropia were measured using the Titmus and TNO stereotests, while they wore prisms of varying power on nonfixating eye or evenly on each eye. RESULTS: Stereoacuities were significantly reduced with increasing prism power for both prisms, ranging from 8 to 25 prism dipotres. The effects on stereoacuity in single acrylic prism and single Fresnel prism were similar, whereas spilt Fresnel prisms reduced stereoacuity more than spilt acrylic prisms. Spilt prisms were found to have much less effect on stereoacuity than single prisms for both acrylic and Fresnel prisms. CONCLUSION: The use of acrylic refractive prism shared evenly on each eye would be optimal method to minimize the reduction of stereoacuity during the prismatic therapy for intermittent exotropia.

Keyword

Strabismus; stereoacuity; Fresnel prism; acrylic prism

MeSH Terms

Adolescent
Adult
Child
Depth Perception/*physiology
Exotropia/physiopathology/*therapy
*Eyeglasses
Female
Humans
Male
Refraction, Ocular/physiology
Visual Acuity/*physiology
Young Adult

Figure

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  Fig. 1 Titmus steroacutiy for each prism for each prism dipotre.

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  Fig. 2 TNO steroacutiy for each prism for each prism dipotre.

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