Sensation of looking through heat waves.

This question for Neuro Opthamalogist & Neurology speciallists. First it started like suddenly unable to read text on screen, somekind of pulsating at corner of both eyes near nose and  after few minutes headache was started. Headache was not observed every time when I was suddenly unable  to read text.Went to eye doctor,he used light and drops to test eye and confirmed no issues.Went General Doctor,gave some tension headache tab and B12 tablets.After using those,above symptoms gone.But high number of black threads observed. Those only can see in bright light.Went to eye doctor again in another hospital, they used light test (white & blue light) and drops they confirmed that no issues(no retinal tear or hole). Now I am observing another one.Alittle sensation like of looking through heat waves(pulsating)when I was on road during daylight time after fewminutes. Noproblem at indoor,digitalscreen.Observing  especially at roads,sky,white color buildings. Not trees and greens. Please help.