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.