The swinging light test is positive in
Retrobulbar neuritis: a common cause of visual loss with normal fundus. Presence of a definite or relative afferent pupillary defect (RAPD) and VER are diagnostic. Swinging flashlight test: It is performed when relative afferent pathway defect is suspected in one eye (unilateral optic nerve lesion with good vision). Normally, both pupils constrict equally and the pupil to which light is transferred remains tightly constricted. In the presence of relative afferent pathway defect in one eye, the affected pupil will dilate when the flashlight is moved from the normal eye to the abnormal eye. This response is called 'Marcus Gunn pupil' or a relative afferent pupillary defect (RAPD). It is the earliest indication of optic nerve disease even in the presence of normal visual acuity. In the swinging flashlight test, a light is alternately shone into the left and right eyes.Thus, light shone in the affected eye will produce less pupillary constriction than light shone in the unaffected eye. Anisocoria is absent. A Marcus Gunn pupil is seen, among other conditions, in optic neuritis. Ref: Khurana; 4th edition; Pg.No. 307, 474
Conjunctivitis
Glaucoma
Retrobulbar neuritis
Keratoconus
Neuro-ophthalmology