Axial Length, Retinal Function, and Oxygen Consumption: A Potential Mechanism for a Lower Risk of Diabetic Retinopathy in Longer Eyes

作者：Man Ryan Eyn Kidd; Lamoureux Ecosse L; Taouk Yamna; Xie Jing; Sasongko Muhammad Bayu; Best William J; Noonan Jonathan E; Kawasaki Ryo; Wang Jie Jin; Luu Chi D^*

来源：Investigative Ophthalmology & Visual Science, 2013, 54(12): 7691-7698.

DOI：10.1167/iovs.13-12412

• axial length
• retinal function
• electroretinogram
• oximetry
• oxygen consumption
• myopia
• diabetic retinopathy

PURPOSE. To determine the relationship between axial length (AL), retinal function, and relative oxygen (O-2) consumption to better understand the protective effect of axial elongation on diabetic retinopathy development.
METHODS. Measurements of AL, multifocal electroretinogram (mfERG), and relative O-2 consumption (difference between arteriolar and venular O-2 saturation levels or A-V difference) were performed on 50 healthy individuals. The relationships between AL, mfERG amplitude, and A-V difference were analyzed using linear regression models. Path analysis was performed to determine the direct and indirect effects (via mfERG amplitude) of AL on A-V difference.
RESULTS. mfERG P1 amplitude was positively associated with A-V difference (beta = 0.33; 95% confidence interval [CI]: 0.23-0.42). Increased AL was significantly associated with a decrease in A-V difference (beta = -1.08; 95% CI: -1.52 to -0.65) as well as a decrease in retinal beta = -3.14, 95% CI: -4.07 to -2.20). Path analysis models including AL (study factor), retinal intermediate variable), and A-V difference (outcome variable) showed that AL had little direct association with A-V difference (beta(p) = -0.002), while the indirect effect of AL on A-V difference via changes in retinal function were substantial (beta(p) = 0.51).
CONCLUSIONS. In eyes with longer AL, the reduction in A-V difference is explained by the parallel reduction in retinal function. These findings suggest that longer eyes have decreased retinal function and O-2 consumption, and thus are relatively less hypoxic in the presence of diabetes, which may partly explain the reduced risk of DR in these eyes.

• 出版日期2013-11