Oblique central refraction in spherocylindrical lenses tilted around an off-axis meridian.

Thin lens equations accurate to third order are presented for the effective spherocylindrical parameters for oblique central refraction through spherocylindrical lenses that are tilted around an off-axis meridian. This situation occurs in either pantoscopic or faceform tilt for spectacle corrections for oblique astigmats. The thin lens equations appear to be good approximations for oblique central refraction through actual spectacle lenses.