Methods
We artificially induced a vertical strabismus to simulate a skew
deviation on 10 healthy subjects, aged from 26 to 66, using different
press-on Fresnel prisms on one eye while recording eye position with VOG
of the contralateral eye. We then compared the system’s performance to
that of a blinded trained orthoptist using conventional,
semi-quantitative method of skew measurement known as the Alternate
Prism Cover Test (APCT) as a gold standard.