We hypothesized that psychologically well-adjusted individuals would not tolerate blur as well as individuals who were poorly adjusted. To test this hypothesis, the measures described in
Table 1 were correlated with blur tolerance. The results are displayed in the right column of
Table 1. Only two of the 17 measures correlated significantly with blur tolerance (Pearson correlation,
P < 0.05), and both measures are subscales from the perfectionism measure. Positive correlations found with the Parental Criticism and Doubts about Action subscales suggest that individuals who believe that their parents are disappointed in them are more likely to tolerate blurred vision than are those who believe their parents approve of their achievements. Likewise, individuals who perceive themselves to be ineffectual
51 are more likely to tolerate blur than those who perceive themselves to be effectual.
The results provide preliminary evidence for the hypothesis that psychological adjustment and blur tolerance are negatively related. Research that explores the relationship between visual characteristics and personality is not common. Therefore, the present study was designed to test hypothesized relationships and to further explore unforeseen empiric relationships between blur tolerance and personality. To accomplish this latter goal, we treated all the items comprising the 17 questionnaires and the CAQ as possible predictors of blur tolerance. From this pool of 312 items, we selected the 15 that correlated most highly in absolute value with blur tolerance (
Table 2). The 15 items were subjected to a principal factors analysis with varimax rotation,
52 a procedure for identifying meaningful categories of questionnaire items. Two psychologically meaningful categories, typically referred to as factors, emerged from the analysis. The factor loadings for each one (i.e., the correlation between item and factor) are displayed in
Table 2. On the basis of the item content, factor 1 was labeled
low self-confidence and factor 2 was labeled
disorganization. Three of the 15 items did not load on either factor.
The seven items comprising factor 1 and the five items comprising factor 2 were standardized and summed, to create composite measures of low self-confidence and disorganization, respectively. The internal consistency reliabilities of the two measures were identical (Cronbach's α = 0.76). Both low self-confidence (r = 0.38, P < 0.0001) and disorganization (r = 0.36, P = 0.0002) correlated significantly with blur tolerance. The positive correlation between low self-confidence and disorganization (r = 0.31, P = 0.002) indicated that the measures may assess a common underlying construct. Therefore, the two measures were standardized and summed and the new aggregate score, termed “perceived incompetence,” was correlated with blur tolerance (r = 0.46, P < 0.0001). Without the two outliers (high blur tolerance), the correlations were r = 0.22 (P < 0.05), r = 0.28 (P < 0.01), and r = 0.32 (P < 0.001) for factors 1 and 2 and the composite, respectively. These two exploratory factors predicted blur tolerance better than our originally hypothesized psychological adjustment variables. (By selecting 15 of 312 questionnaire items that correlated highest with blur tolerance, a viable alternative explanation might be that the low self-confidence and disorganization factors were found due to chance more than substance and were unique to the present sample. However, the factors were psychologically meaningful, and these results were replicated in a sample of 86 older adults [age range, 42–86 years] [Woods RL, et al. IOVS 2009;50:ARVO E-Abstract 1117]. In that multimeasure study, the low self-confidence and disorganization scales were again the best predictors of blur tolerance. The results, repeated across two divergent samples, indicate that the proffered alternative explanation cannot account for the findings in the present study.)