Fig. 3.

A) GILT letter-based thresholds (the proportion completeness of the letters required for accurate letter recognition), with medians and interquartile ranges for UK Biobank (UKB) participants (blue), PCA (red) and typical AD participants (purple). Letter-based thresholds are presented for all UKB participants without or with visual conditions or stroke (as listed on the x-axis) who reached accuracy cut-offs of 80% within the UKB time limit of 120 seconds (total UKB n=1,967). B) Example GILT stimuli shown for all of the completeness levels presented for one testing set. Stimuli are presented in relation to GILT median thresholds for PCA (n=18) and UKB groups without or with visual conditions (total n without=1757; with=194). For illustration, threshold values are shown in between the corresponding levels of completeness shown during testing