(BQ) Part 2 book “Clinical orthoptics” has contents: Incomitant strabismus, accommodation and convergence disorders, neurogenic disorders, mechanical paralytic strabismus, myogenic disorders, craniofacial synostoses, supranuclear and internuclear disorders, and other contents. | BLBK403-c10 BLBK403-Rowe December 13, 2011 0:45 Trim: 244mm×172mm Char Count= SECTION III 221 BLBK403-c10 BLBK403-Rowe 10 December 13, 2011 0:45 Trim: 244mm×172mm Char Count= Incomitant Strabismus Incomitant strabismus is strabismus in which the angle of deviation differs depending upon the direction of gaze or according to which eye is fixing and is associated with defective movement of the eye or with asymmetrical accommodative effort. Ophthalmoplegia is a group of conditions that have a variety of causative factors, where there is a paresis of two or more of the extraocular muscles. When examining these patients, the angle of deviation may be different depending on which eye is fixing and how long the deviation has been present. r r Primary angle of deviation: The deviation when fixing with the unaffected eye in paralytic incomitant deviation. Secondary angle of deviation: The deviation when fixing with the affected eye in paralytic incomitant deviation. Generally, with more recently acquired palsies, the strabismus will be quite incomitant with a significant difference between the primary and secondary angles of deviation. With time, the strabismus becomes less incomitant and it is harder to assess whether it is congenital or long standing. It is often difficult to differentiate between primary and secondary deviations, as relative concomitance usually occurs following long-standing incomitance. Aetiology Incomitant strabismus may be found in association with many disorders. The list below is designed to give an overall idea of the types of condition that can cause incomitance. Congenital Neurogenic r r In association with other congenital developmental disorders As an isolated feature Clinical Orthoptics, Third Edition. Fiona J. Rowe. C 2012 John Wiley & Sons, Ltd. Published 2012 by Blackwell Publishing Ltd. BLBK403-c10 BLBK403-Rowe 224 December 13, 2011 0:45 Trim: 244mm×172mm Char Count= Clinical .