The other parameters studied displayed no significant change with aging. We found an inverse correlation between IOP and AGL, particularly for the adult female subgroup. This suggests that the smaller AGL in female EDs may render them more susceptible to the development of a high IOP. A more surprising positive correlation was found between DSAC and IOP in adult females. With age, the lens increases in volume and may move backwards, towards the posterior chamber of eye. The anterior capsule of the lens is thicker and more rigid in dogs than in humans, potentially resulting in equatorial and posterior lens deformation, keeping the ACL constant but decreasing the DSAC. High IOP has been identified as a major risk factor for the initiation and development of glaucoma, but the correlation of IOP with biometric parameters suggests that changes in these parameters could serve as alternative biomarkers and/or risk factors for the development of glaucoma. Furthermore, these correlations were more marked in adult female EDs, a subgroup particularly affected by PLA. Accordingly, these dogs present ICA abnormalities which are relevant to the development of glaucoma. Oxidative stress has been identified as a major mechanism underlying the development of glaucoma and RGC degeneration. The importance of this role was highlighted by the decrease in systemic glutathione concentrations observed in patients with primary open glaucoma and the association of this form of glaucoma with a polymorphism of the glutathione S-transferase M1 gene. The activity of GP, a crucial enzyme for the glutathione cycle, was very low in EDs. Taurine, another XAV939 important retinal antioxidant, has also recently been reported to play a major role in RGC survival. Surprisingly, we found that plasma taurine levels were higher in EDs than in the control dogs, whereas methionine and cysteine concentrations were similar in these two groups. Taurine is endogenously involved in the process of ROS detoxification in mitochondria. The plasma taurine concentrations may be higher due to an increase in taurine transporter activity responsible for the plasma taurine concentrations. Given the powerful antioxidant action of taurine, these high plasma taurine levels may compensate for the lower level of GP activity. However, the linear correlation between GP activity and plasma taurine concentration suggests that this compensatory effect of taurine may change with age, which possibly would render EDs more susceptible to oxidative stress as adults. EDs may therefore constitute a genuine canine model for glaucoma. Unlike human patients, the ED breed of dogs is characterized by a very high percentage of inbreeding, which should facilitate the search for the genetic origins of the ICA and glutathione phenotypes. However, it is necessary to study a larger number of dogs to assess the genetic transmission of these phenotypes. The cohort studied here is now being monitored longitudinally with the genotyping of putative candidate genes.