Personality and Functional Vision in Older Adults with Age-Related Macular Degeneration

Perceived functional vision refers to the self-reported ability to perform vision-dependent activities, and is often an outcome in epidemiological studies of vision loss and clinical trials of ophthalmologic and rehabilitative treatments to improve vision and everyday functioning. Functional vision is distinct from visual function, which more properly refers to the physiologic activity and function of the eyes and the visual system (Colenbrander, 2005). In principle, functional vision ought to be closely tied to objective measures of visual function, but the correlation with visual acuity, for example, ranges from 0.5 to 0.68 (Massof & Fletcher, 2001; Revicki, Rentz, Harnam, Thomas, & Lanzetta, 2010). This range suggests that nonophthalmologic factors may contribute to the relationship. One of those factors may be the characteristic way patients perceive and report difficulty in their lives. Functional vision is assessed by asking patients to rate the difficulty they experience when performing various activities like reading newsprint or doing housework. Their responses reflect their perceived difficulty, the value they place on the activity, their mood, and their personality. Depressed mood is known to impair functional vision, perhaps through loss of interest, low self-efficacy, and low motivation (Casten & Rovner, 2008; Horowitz, Reinhardt, & Kennedy, 2005; Owsley & McGwin, 2004; Rovner, Casten, Hegel, & Tasman, 2006; Zhang, Bullard, & Saaddine, 2013). Only a few studies have evaluated the impact of personality, which shapes an individual's style of perceiving, responding to, and reporting visual difficulties (Boerner, Reinhardt, & Horowitz, 2006; Rovner & Casten, 2001; Tabrett & Latham, 2012; Warrian, Spaeth, Lankaranian, Lopes, & Steinmann, 2009). In fact, personality provides a more stable and enduring representation of a person than depression, which tends to be transient and dependent on situations (McCrae & Costa, 1990). One facet of personality is the trait of neuroticism, which refers to the increased tendency to experience negative, distressing emotions (McCrae & Costa, 1990). This trait is distributed normally in the population without a threshold indicative of disorder, and is moderately inheritable (Wray et al., 2008). Individuals on the extremes of the distribution get upset easily by life events and stay upset longer than others who face similar difficulties. They tend to be temperamental, anxious, and inflexible, and to hold pessimistic views of themselves and their circumstances. Thus, given the same degree of vision loss, people high and low in neuroticism might vary substantially in their reporting of functional vision. If their scores on the National Eye Institute Visual Function Questionnaire (NEI VFQ) differ, we cannot assume that the person who reports worse functional vision (that is, has a lower NEI VFQ score) has worse visual acuity than a person with a higher score (Mangione et al., 2001). The former person may simply have a perceptual bias that conveys greater distress and disability. The extent to which this phenomenon occurs in patients with AMD is uncertain because no studies, to our knowledge, have investigated it. If the extent is substantial, it may confound the results of studies on vision loss and disability or on the efficacy of ophthalmologic and rehabilitative treatments. In the study presented here, we tested the hypothesis that personality traits would influence self ratings of functional vision independently of objective measures of vision (that is, visual acuity, contrast sensitivity) in older persons with bilateral age-related macular degeneration (AMD). The subjects were enrolled in the Low Vision Depression Prevention TriAL (VITAL), which is a randomized controlled clinical trial that compares the efficacy of a combined mental health and low vision rehabilitation intervention with standard low vision rehabilitation to prevent depression (Casten & Rovner, n. …