Advanced glycation end products (AGEs) are thought to play important roles in the pathogenesis of diabetic microangiopathy, particularly in the progression of diabetic retinopathy (DR). We assessed the levels of skin autofluorescence (sAF) to assess the association between AGEs and DR stages. A total of 394 eyes of 394 Japanese subjects (172 men, 222 women; mean age ± standard deviation [SD], 68.4 ± 13.7 years) comprised the study population, i.e., subjects with diabetes mellitus (DM) (n = 229) and non-diabetic controls (n = 165). The patients with DM were divided into those without DR (NDR, n = 101) and DR (n = 128). DR included simple (SDR, n = 36), pre-proliferative (PPDR, n = 25), and PDR (n = 67). Compared to controls (0.52 ± 0.12), the AGE scores were significantly higher in patients with DM (0.59 ± 0.17, p < 0.0001), NDR (0.58 ± 0.16, p = 0.0012), and DR (0.60 ± 0.18, p < 0.0001). The proportion of patients with PDR was significantly higher in the highest quartile of AGE scores than the other quartiles (p < 0.0001). Compared to those without PDR (SDR and PPDR), those with PDR were younger (p = 0.0006), more were pseudophakic (p < 0.0001), had worse visual acuity (VA) (p < 0.0001), had higher intraocular pressure (IOP) (p < 0.0001), and had higher AGE scores (p = 0.0016). Multivariate models also suggested that younger age, male gender, pseudophakia, worse VA, higher IOP, and higher AGE scores were risk factors for PDR. The results suggested that AGE scores were higher in patients with DM and were independently associated with progression of DR. In addition, more PDR was seen in the highest quartile of AGE scores. This study highlights the clinical use of the AGE score as a non-invasive, reliable marker to identity patients at risk of sight-threatening DR.

Advanced glycation end products (AGEs), which are the products of a non-enzymatic reaction between reducing sugars and other macromolecules, are critical in aging, as well as metabolic and degenerative diseases. To assess the involvement of AGEs in glaucoma, skin autofluorescence (sAF) level, which is a measurement of AGEs’ accumulation, was compared among Japanese patients with glaucoma (316 with primary open-angle glaucoma (PG) and 127 exfoliation syndrome and glaucoma (EG)) and controls (133 nonglaucomatous controls) (mean age 71.6 ± 12.8 years, 254 men and 322 women). The sAF values were estimated from the middle fingertip using a 365 nm light-emitting diode for excitation and detection at 440 nm emission light. The estimated AGE values (arbitrary unit) were 0.56 ± 0.15, 0.56 ± 0.11, and 0.61 ± 0.11 in the control, PG, and EG groups, respectively (p < 0.0001, analysis of variance); and were significantly higher in the EG group than the control (p = 0.0007) and PG (p < 0.0001) groups. After adjustment for various demographic parameters by multivariate analyses, male sex (standard β = 0.23), EG (0.19), and diabetes (0.09) were associated with higher AGE levels; PG (−0.18) and smoking (−0.19) were associated with lower AGE levels. Age, visual acuity, intraocular pressure, glaucoma medications, lens status, and systemic hypertension were not associated with AGEs. The high AGE level in EG suggested that specific oxidation and glycation mechanisms underlie the glaucoma pathogenesis associated with pseudoexfoliation syndrome.