title: Fourth nerve palsy with monovision.
abstract: The fourth cranial nerve is the most vulnerable cranial nerve. Its damage gives rise to a vertical ocular deviation and usually the patient comes with a right head-tilt. The Parks-Bielschowsky three-step test is a simple and useful test for identifying the paretic extraocular muscle, giving rise to such a vertical ocular deviation. A case of long-standing fourth nerve palsy in a 45-year-old woman is reported. Monovision spectacles were prescribed to give the patient satisfactory distant and near vision.
authors.affiliation: Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Hong Kong.
authors.forename: Pauline HN
authors.initials: PH
authors.lastname: Yeung
authors.forename: Andrew KC
authors.initials: AK
authors.lastname: Lam