As you are saying you can't see straight lines so probably you are having some macular problem.
Are you taking any drug currently?
In a disease called CSCR fluid accumulated in macular region causing temporary separation of pigment epithelium over macula.
It can be diagnosed clinically. In some cases OCT or DFD may be needed to detect 5he pathology.
Next Steps
if you are taking any steroid drug stop it immediately.
Do a blood test for
thyroid profile & blood
sugar.
Health Tips
immediately go to your nearby Ophthalmologist & check your Retina