Hello C: D ratio is not a reliable parameter... Sometimes,even normal person may have 0.7:1 ratio and sometimes even 0.3:1 ratio is dangerous Disc size is more important than this ratio Sometimes, 0.7 ratio is normal in large disc and sometimes 0.3 is dangerous in small disc So don't worry about this ratio Other tests are also important like size of disc, Intraocular pressure, corneal thickness and visual field I hope this will help you