What Causes Visible Blood Vessels In The Back Of The Left Eye?

Symptoms: I can see the blood vessels in the back of my left eye if I look at a flat light-reflective surface. (i.e. white wall). No blind spots (yet), perpherial vision is good, blood vessels in whites of the eye look fine. Right eye no issues. Have not noticed any darkening anywhere. I did have a tooth infection a week prior to symptom onset. Already have astigmatism (and corrective lenses). Have not been diagnosed with diabetes or high blood pressure.