I have very light 'constant' flickering (not flashes) in peripheral vision of both eyes (more in left) in dark since a week? Lattice review in 3 days.

See ophthalmologist. Flickers can be as simple as migraines or blood pressure changes, but can also be something like a retinal tear or hole which can quickly become an emergency. I highly suggest seeing an ophthalmologist for this as soon as possible.
Need an exam. This can mean some changes in the retina. If vision. Good not to worry, but you need to have the eyes examined.