The eye and brain in artist and viewer: alterations in vision and color perception
Introduction Traditionally in neuropsychology, sensory deficits are interpreted before reaching conclusions regarding cortical control of behavior. To infer the central influences on art, we need to explain and accommodate peripheral influences, those arising from sensory deficits. Alterations in visual acuity and color perception in either an artist or a viewer can arise from sensory visual impairments and interfere with how forms and colors are rendered. The outcome of such changes needs to be considered in conjunction with other neuropsychological influences on art. As healthy individuals age, they suffer a gradual decline in visual acuity. The most common change in normally aging adults, for example, is presbyopia, the loss of flexibility in the eye's crystalline lens, leading to the blurriness of closely viewed objects (Jackson & Owsley, 2003), and there is no logical reason to assume that aged artists are not affected as well (see diagram of the eye in Figure 3.1 ). Color impairments can begin at the level of the eye itself and may be caused by disease. Simple aging can also contribute to alteration in color processing by the central nervous system (Wijk, Berg, Sivik, & Steen, 1999b) even when there is no specific eye pathology. As will be made clear in this chapter, however, there are various eye conditions that modify form perception and color sensations without detriment to the creative, artistic, or expressive aspects of art.