Non-Organic Vision Loss

Abstract

Non-organic vision loss (NOVL) or functional vision loss (FVL) is abnormal vision or visual fields without an organic pathology. NOVL is an important cause of visual loss presenting in busy clinics. It becomes increasingly important to diagnose it because of the long-term implications it can have on patient management. NOVL can be secondary to malingering or dissociative disorders. The diagnosis of NOVL requires the establishment of findings on clinical exam that prove the integrity and functioning of the visual system which is sometimes difficult and time-consuming to establish. Diagnosing NOVL is challenging specially when it is superimposed on another organic pathology. Anatomic localization and tactics of basic examination are important to suspect and confirm the diagnosis of NOVL. In this chapter, we will discuss the common patterns of visual loss and try to give a comprehensive note on when and how to diagnose NOVL. A step-wise approach for examining and diagnosing patients of NOVL is presented in this chapter.