Optimal cutting temperature was removed in PBS. Paraffin was removed by sequential incubation in Citrisolv (Fisher, Waltham, MA), isopropanol, and rehydrated in running distilled water. Antigen retrieval in 10 mM citrate buffer was performed in a rice cooker. Slides were allowed to slowly cool to room temperature, washed in PBS, and endogenous peroxidases inactivated in 0.3% H2O2. Eye sections were then permeabilized in PBS with 0.5% Triton X100 (PBST) and blocked (1% bovine serum albumin [BSA], 0.2% nonfat milk and 0.3% Triton X100 in PBS). Eye sections were incubated in the following primary antibodies: Synaptophysin (1:250, ab52636; Abcam, Cambridge, MA), post synaptic density 95 (PSD95, 1:1000, ab8258; Abcam), glutamic acid decarboxylase (GAD67, 1:500, g5419; Sigma-Aldrich, St. Louis, MO), sodium potassium ATPase (1:200, ab767; Abcam), glial fibrillary acidic protein (GFAP, 1:500, z033429; Dako, Glostrup, Denmark), transient receptor potential cation channel subfamily member 1 (TRPM1, neat supernatant, gift from T. Wensel; Baylor College of Medicine, Houston, TX), FGF receptor-1 (FGFR1, 1:100, SC121; Santa Cruz, Dallas, TX), SOD-1 (1:500, ab13498; Abcam), Thy1.2 (1:500, ab22489; Abcam), active-caspase 3 (1:1000, 9661; Cell Signaling, Danvers, MA), total caspase 3 (1:1000, 9662; Cell Signaling), HO-1 (1:100, ab13248; Abcam), or Calbindin D-28K (1:250, AB1778; Millipore, Billerica, MA). Primary antibody was detected with relevant secondary antibodies labeled with Alexa594 (Life Technologies, Grand Island, NY). Nuclei were detected by 4′6-diamidino-2-phenylindole (DAPI) and sections mounted in Prolong Gold anti-fade mounting media (Life Technologies). For wheat germ agglutinin (WGA), sections were incubated in PBS containing DAPI and Alexa555-WGA (Life Technologies) for 10 minutes. Klotho was detected by incubation in primary antibody (1:20, AF1819; R&D Systems, Minneapolis, MN), followed by incubation in ImmPRESS anti-goat IgG peroxidase (Vector Labs, Burlingame, CA) and Cy3-TSA Plus (1:400; PerkinElmer, Waltham, MA). Confocal images were captured on a Zeiss laser scanning LSM710 with a 63×, NA 1.4 oil-immersion objective (Zeiss, Peabody, MA).