Can you explain what od +0.5 os +0.75 cal -0.5 axis 145 mean?

Eye shorthand. Od is right eye//os is left eye +0.5 is the power in diopters needed to be ground in the lens to see clearly. -0.5 axis 145 is the amount of astigmatism and the orientation of the correction (the degrees around a circle from 0 to 180). These are small corrections overall. The ophthalmologist generates these for the optician to make proper eyeglasses.