The prismatic effect on stereoacuity in intermittent exotropia.
OBJECTIVE
To evaluate the effect of acrylic refractive prism and Fresnel membrane prism on stereoacuity in intermittent exotropia.


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.


CONCLUSIONS
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.
Choi
Kyoung Sub
KS
Department of Ophthalmology, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea.
Chung
Seung Ah
SA
Lee
Kyu Sung
KS
Lee
Jong Bok
JB
D000293:Adolescent; D000328:Adult; D002648:Child; D003867:Depth Perception / Q000502:physiology*; D005099:Exotropia / Q000503:physiopathology / Q000628:therapy*; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult