Allergic reactions, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat are common with iodine, a constituent of betadine. Blurring could be also a side affect similar to those side affects..

It's an unlikely correlation. Please get your eyes checked by a local Ophthalmologist if blurring persists.