In these subjects, the CP levels were significantly low in aqueous (12.73 ± 1.39 vs. 41.71 ± 14.43 pg/mL; AD vs. ctr; p < 0.05) and vitreous (12.27 ± 1.40 vs. 41.71 ± 14.43 pg/mL; AD vs. ctr; p < 0.05) fluid from patients with AD-VRD, as validated by ELISA (Figure 6A–C). Here, CP is linked to Alzheimer disease.