Hello Doctor.I'm 57 Yrs Old,a Teacher But Not Standing Too

Hello doctor.I'm 57 yrs old,a teacher but not standing too long in a day.my lower legs are slowly blackened from ankles and around going upbelow my knees.i'm a hypetensive and diabetic for 7 yrs but able to control my bp and sugar through medication and life style.i just want to know if this situation could be prevented or could be cured.thank you very much.