Fourth nerve palsy with monovision.
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.
Yeung
Pauline HN
PH
Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Hong Kong.
Lam
Andrew KC
AK