Having one drink every now and then may not hurt your eyes, but drinking heavily on a regular basis can do serious damage to your vision. It can cause a decrease in peripheral vision, weaken eye muscles and affect color perception. In some cases, it can lead to blindness caused by optic nerve damage.
The first sign of alcohol's effects on your vision is bloodshot eyes. This happens because the optic nerve that delivers visual pictures to your brain is weakened by the chemicals found in alcohol. The muscles that control the iris also become weakened. This can cause a delay in the iris's reaction to changes in light, which can result in blurry vision and double images.
This can be especially dangerous while driving. In a study conducted by the Journal of Ophthalmology, people with a BAL (blood alcohol level) of 0.10% experienced a 30% reduction in their field of view. This can make it hard for the driver to see pedestrians or other vehicles coming from either side of the road. It can also reduce contrast sensitivity, making it harder to distinguish between different colors and shades of the same color.
In addition, it can interfere with your ability to differentiate the colors yellow and red. The combination of these two colors makes them appear gray, which can be difficult to identify when you are under the influence. The other main effect of alcohol on your vision is a decrease in the speed at which your iris constricts and dilates. This can make it difficult to respond quickly to changing conditions, such as approaching headlights on the highway.