Optical disguising of orbital deformity with prism and cylinder lenses

This paper describes the way in which prism and cylinder lenses may be used to disguise orbital dystopia when the affected eye is blind. The lenses used can correct the height of the eye, the opening of the eyelids or the rotation or slant of the eye. Four cases are presented to illustrated this technique, which may be used either instead of, or as an adjunct to orbital surgery. An investigation of these effects is described using a mannikin head fitted with an optician's trial frame, with measuring by the reflex metrograph. This revealed that an inferiorly displaced eye may be elevated by 4 to 5 mm, that the vertical eyelid opening may be widened (or narrowed) by just under 20% and that an adverse slant of the eye may be rotated in either direction by about 4 degrees.