Han, Sang Beom; Yang, Hee Kyung; Kim, Jonghyun; Hong, Keehoon; Lee, Byoungho; Hwang, Jeong-Min

Quantification of Stereopsis in Patients with Impaired Binocularity

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To quantify stereopsis at distance resulting from binocular fusion in patients with impaired binocular vision using a three-dimensional (3-D) display stereotest.



A total of 68 patients (age range, 6 to 85 years) with strabismus (40 esotropes and 28 exotropes) whose stereoacuity could not be measured with the near and distance Randot stereotests were included. Contour-based circles with a wide range of crossed horizontal disparities (2500 to 20 arcsec) displayed on a 3-D monitor were presented to subjects at 3 m. Between the patients who had stereoacuity of at least 2500 arcsec and those with no measurable stereoacuity, parameters including age, sex, best-corrected visual acuity, spherical equivalent refractive error, Worth 4 dot test results, and type and angle of deviation were compared.



Stereoacuity at distance of 2500 arcsec or better was detected in 25 (63%) of 40 esotropes, and 16 (57%) of 28 exotropes, although stereoacuity of 800 arcsec or better was found only in two (5%) esotropes and one (4%) exotrope. Patients with stereopsis were significantly younger (19.3 ± 16.9 years) than those with no measurable stereopsis (31.5 ± 26.4 years) (p = 0.040). There were no significant differences in best-corrected visual acuity, presence of amblyopia >20/100, spherical equivalent refractive error, type of deviation, deviation angle, sex, and Worth 4 dot test results between these groups.



Stereopsis at distance resulting from binocular fusion that cannot be measured with conventional stereoacuity tests may be preserved in patients with impaired binocular vision. The 3-D display stereotest can be useful for quantifying stereopsis at distance resulting from binocular fusion.


Vision therapy is well worth the response, time and effort. Our Son had a hard time focusing and writing neatly. After vision therapy Seth could complete a task in half the time if previously took. His abilities to focus improved greatly and so did his handwriting.

Also, he was better at listening. As a parent, we wanted learning to be fun for our Son, and vision therapy made this possible.

Amanda T.

Vision Therapy is well worth the expense, time and effort. Our son had a hard time focusing handwriting neatly. After vision therapy Seth could complete a task in half the time it previously took his abilities to focus and improved greatly and so did his handwriting.

Also, he was better at listening. As a parent you wanted learning to be fun for our son and vision therapy made this possible.

Alexa H.

Vision Therapy has given or son the tools he needs to be able to scan and read the written word more effectively and efficiently.

He love working with John and these working sessions give him the motivation to gladly work on his homework assignments.

It amazed us to see the difference in the tracking of his eyes and along a line of it's from the beginning to the end of the treatment.

Dr. McBryar , Kristen and John  are all marvelous and we would recommend them to anyone I only wish that we would have found them sooner!

Charlotte M.

Prior to coming to the institute for vision development my son complained of daily headaches. Therapy has eliminated his headaches completely. I love knowing my son is able to learn pain-free for the rest of his life because of the work that has been done over just a few weeks in this office. He he absolutely loved coming that didn't even feel like going to a doctor or therapy. We are grateful for the relief he was able to find by coming here.

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Seems much less frustrated with life

Reads non-stop and fast

Spelling abilities have been hugely improved

Seems much more confident

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When we first came to the practice, my son did not have huge issues, but lots of small ones- trouble with reading, sports (hitting the baseball consistently), coordination, etc- that were not easily detectable,but when put together presented issues. The staff here were all very professional and loving towards him. While I was concerned in the reading, my son was concerned with the athletic side. Seeing improvement night off the bat gave him confidence that i have nor seen in him and made him want to not only Come to therapy, but also made him want to work hard. He has surpassed his grade level and above in reading and hit his first home run this year! Thank you!!!

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