Lang J, Rechichi C, Stürmer J
University Eye Clinic, Zürich, Switzerland.
Graefes Arch Clin Exp Ophthalmol. 1991;229(2):115-8. doi: 10.1007/BF00170541.
Natural stereopsis is better with a large interpupillary distance (IPD). With haploscopic devices, depth perception is better with a small IPD. This apparently unknown fact has been trigonometrically calculated and experimentally shown by enlarging and diminishing the IPD in 20 subjects.