Analyses of the ratio of ganglion cell-inner plexiform layer thickness to vessel density according to age in healthy eyes

PurposeTo identify how the inner retinal layer and microvasculature change with age by analyzing the relationships of ganglion cell-inner plexiform layer (GC-IPL) thickness, vessel density (VD), and the ratio of these measurements with age in healthy eyes. MethodsParticipants were divided into five groups according to age. The GC-IPL thickness, VD, and GC-IPL/VD ratio were compared among the groups. Linear regression analyses were performed to identify relationships of GC-IPL/VD ratio with age. ResultsThe average GC-IPL thicknesses were 84.84 +/- 5.28, 84.22 +/- 5.30, 85.20 +/- 6.29, 83.29 +/- 7.06, and 82.26 +/- 5.62 mu m in the 20s, 30s, 40s, 50s, and 60s age groups, respectively. The VDs were 20.94 +/- 1.50, 21.06 +/- 1.50, 20.99 +/- 1.03, 20.71 +/- 0.93, and 19.74 +/- 1.73 mm-1 in the 20s, 30s, 40s, 50s, and 60s age groups, respectively. The GC-IPL/VD ratio was 4.05, 4.00, 4.06, 4.02, and 4.17 in each group, respectively, and the ratio of the 60s age group was significantly higher than that of other groups. In linear regression analyses, the GC-IPL/VD ratio was significantly associated with age in the participants aged >= 50 years (B = 0.014, P = 0.013), whereas it was not in the participants aged < 50 years (B = 0.003, P = 0.434). ConclusionsGC-IPL thickness and macular VD showed a tendency to decrease beginning in the 50s age group and the GC-IPL/VD ratio was significantly increased in the 60s age group. Additionally, the GC-IPL/VD ratio was positively associated with age in subjects aged >= 50 years, which implies a more pronounced decline over time in VD rather than GC-IPL thickness.

Automated summary

This study aimed to investigate the changes in the inner retinal layer and microvasculature in healthy eyes with age. The results showed that the ganglion cell-inner plexiform layer (GC-IPL) thickness and macular vessel density (VD) started to decrease in the age group above 50 years, while the GC-IPL/VD ratio significantly increased in the 60s age group. Furthermore, the GC-IPL/VD ratio was positively associated with age in subjects aged 50 years and above, indicating a more pronounced decline in VD over time compared to GC-IPL thickness.