What Does A Glare Of Light In The Peripheral Vision Indicate?

I am 20 years old and as of recently I began seeing a glare like a reflection from light, at first It scared me half to death because I have PTSD I thought I was hallucinating and seeing things. I don t wear glasses and the doctors insist my vision is fine but...I cant see well after about 15 feet it becomes very difficult and detail becomes blurred. I am just wondering if I may be developing cataracts, my vision has gotten progressively worse in a fairly short amount of time (about 4 weeks) please, is there any idea what this may be because my doctor will not really help me out and I m too young to not see. I am also quite tired of these jumpscares that I have everytime I see a glare of light in my peripheral vision... I have taken time to move my eyes around and figure out it is some sort of glare but it is mainly at night or in lower light.