It is believed, no study has used ocular ultrasound to examine the ONSD in the setting of diabetes or DKA for identification of clinically apparent or subclinical CE. It is unclear if patients with T1DM have a fundamentally different baseline ONSD measurement compared to described normal values. It is also unclear how the ONSD varies during times of diabetes-related illness, such as high blood glucose levels without criteria for DKA compared to unequivocal DKA.