Beyond Visual Acuity: Development of a Simple Test of the Slow-To-See Phenomenon in Children with Infantile Nystagmus Syndrome.

Purpose: Conventional static visual acuity testing profoundly underestimates the impact of infantile nystagmus on functional vision. The slow-to-see phenomenon explains why many patients with nystagmus perform well in non-time restricted acuity tests but experience difficulty in certain situations. This is often observed by parents when their child struggles to recognise familiar faces in crowded scenes.