As 2017 draws to a close, we would like to take this opportunity to wish you and your families a joyful, peaceful and safe festive season, and all the best for the coming year. Frequently called the “silly season”, for good reason, the end of the year brings with it many occasions to celebrate, spend time with family and friends, and sometimes indulge in excessive consumption of alcohol. Moderate drinking may lead to some changes in vision, but these are usually short-term. Heavy drinking over an extended period of time often impacts the body and the eyes in a more serious way, and the effects can be more permanent.

Short-term visual effects

Consuming alcohol in moderation is unlikely to have any lasting adverse effects on the eyes, and the symptoms usually disappear shortly after a drinking episode. The way the body responds to alcohol differs from one person to another. The way your body responds depends on the amount consumed and your tolerance threshold.

Alcohol slows the pace of communication between neurotransmitters in the brain. Neurotransmitters are chemical messengers that communicate information around the brain and to the body. The delay in communication between the brain and the eyes affects eye muscle coordination. This may result in distorted or double vision, difficulty with depth perception, difficulty judging distances, and decreased peripheral vision. It makes perfect sense, then, not to drink and drive!

Excessive drinking decreases the reaction time of the pupils, which are unable to constrict or dilate effectively when reacting to ambient light levels and allowing appropriate levels of light into the eyes. This impairs the ability to see contrasting colours and different shades of similar colours, as well as reducing visual sharpness.

Alcohol is a diuretic, leading to dehydration in the body and the eyes. Even a small amount of alcohol can worsen the symptoms of people who suffer from dry eyes, and cause dry irritated eyes and headaches in those who are not sufferers. The symptoms will disappear once the hydration levels of the body return to normal, but it may be useful to have hydrating eye drops or artificial tears on hand when drinking. Alternating alcoholic drinks with water will minimise the dehydrating effects of alcohol.

A typical sign of alcohol consumption is bloodshot or red eyes, which is caused by the dilation or swelling of the blood vessels of the eyes, making them appear more prominent.

Twitching of the eyelids can be triggered by alcohol consumption.

Long-term visual effects

The weakness of the eye muscles can become permanent over time, resulting in involuntary rapid eye movements.

Long-term excessive alcohol use can lead to toxic amblyopia, a permanent loss of vision due to the direct effect of alcohol on the optic nerve which transmits visual images from the eyes to the brain.

The risks of developing cataracts and age-related macular degeneration are increased with the long-term excessive consumption of alcohol.

Certain vitamins and minerals are needed to maintain eye health and healthy vision. The absorption of these essential nutrients by the body is impaired by the excessive use of alcohol. Vitamin A helps protect the surface of the eyes, and the lack of vitamin A can cause night blindness, thinning of the cornea, eye dryness and retinal damage. Vitamin C is an antioxidant which helps support the blood vessels of the eyes, while vitamin E plays a role in protecting the eyes against age-related conditions. Inadequate levels of these vitamins can have a long-term detrimental effect on vision and eye health.