Why am I having double vision. Try!

I'm having binocular diplopia, -Gradually progressed in an year. -Very difficult to drive / watch TV / projected screens / Reading things far -No problems with near vision like reading, mobile phone / laptop. -The intensity of double vision varies across a day I feel. -Vision is perfect when I close one eye. -I see my feet overlapping when I look down -Diplopia is least when I look up and maximum when I look down, equally bad on both sides. I consulted neurologists and opthalmologists and these are ruled out. Thyroid, Stroke, Convergence Insufficiency, Diabetes, Keratoconus, Brain tumor/cancer, Multiple sclerosis, Head Injury, Fever/Trauma, Dry Eyes, Aneurysm. No Visible squint/head ache/eye pain. Though doctors suspect Myasthenia Gravis, none of the tests could prove it . Pyridostigmine (60mg thrice a day for 2 weeks) / Prednisolone (50 mg once a day for 2 weeks) didn't make my vision any better. My lifestyle is hurt and I'm so concerned. Is there anything else which I could try