Since you have high myopia and lattice degeneration, you are at a higher risk for a retinal detachment. However, the risk is still low. The retinal responds to both light and pulling by perceiving light. This is why flashing lights are important. It is not uncommon to see flashing lights after sneezing as the pressure is transmitted to the retina.
Floaters are more concerning.
Flashing lights are also more concerning if they are persistant. You should continue to maintain routine followup with your retina specialist and immediately inform him or her if you notice increased floaters or flashes. This information is provided for educational purposes only. Please consult with your physician for diagnostic and treatment options. All rights reserved.