I'm not an OD, but I have heard of this before from patients. The explanation I've heard was that coughing causes pressure in your face, nasal cavities, and eyes.
Increased interocular pressure can temporarily change the shape of your cornea, blurring vison for the time.
The other thing, is that increased pressure can damage your retina, when the blood pressure rises it affects your vision.. Did you know you can have a retinal hemmorage just from coughing too hard, sneezing hard, or using the restroom?? Sounds to me like it could have been a one time thing, but it is ALWAYS better to be safe then sorry, and make an appointment to see your optometrist or opthomologist and explain what happened just to make sure. Taking preventive measures when it comes to your eyes and vision is key!