Are you planning to have a drink on May Day? According to experts, alcohol can affect your vision starting with the very first drink, even if you don’t notice any changes yourself. A survey by Instrumentarium (n=1,000) revealed that more than half of Finns notice the effects of alcohol on their vision no earlier than after their fifth drink. This shows how difficult it is to recognize changes in one’s own vision and alertness.
24% of Finns estimate that they notice the effects of alcohol on their vision only after the fifth drink or later. As many as 28% believe that alcohol does not affect their vision at all. If we exclude respondents who do not consume alcohol (24%) from the analysis, the percentages rise to 31% and 36%.
Ritva Kahlos, an optometrist at Instrumentarium, is surprised by the results. According to international studies*, alcohol begins to affect vision in many people even at very small doses, as early as the first drink.
“I have to say, the result is striking. I guessed that the effects wouldn’t be easily noticeable after just the first couple of drinks. But the fact that over a quarter of Finns believe that a whole bottle of wine has no effect on their vision is concerning.”
Why don’t people notice the change?
So why is it so hard to notice the effects of alcohol on vision? Kahlos believes the main reason is that alcohol impairs our ability to self-assess, and in a festive mood, we’re not really in the mindset to critically evaluate our own vision anyway.
“At social gatherings, the eyes are tasked with easier activities than threading a needle, kicking a ball, or writing a work email. That’s why a decline in one’s own functional ability doesn’t come as a surprise.”
Kahlos also wonders whether Finns’ understanding of the subject is too narrow. Some survey respondents likely have the misconception that alcohol affects only visual acuity.
“Blurred vision is just one of many effects, and it’s not even among the first to appear. According to studies**, the earliest changes are related to the eyes’ reaction time. Eye movements become clumsier, focusing slows down, and it becomes harder to notice things happening at the edges of your field of vision.”
Overestimating one’s own vision also has serious consequences.
“If you think you’re still sharp, you’re more likely to take risks you’re no longer prepared for. It’s good to remember this now during May Day, when we’re out and about and there’s a lot going on around us.”
Some people react to alcohol more quickly, others more slowly
There are significant differences between people in how quickly alcohol affects vision and when the effects become visible in the eyes. For some, the changes are noticeable after just 1–2 drinks, while for others, they don’t appear until 4–5 drinks. Even the same person may experience daily variations depending on their alertness level.
“These differences are influenced by a person’s weight, drinking pace, physical and mental stress, hydration, and individual sensitivity to alcohol. For some, even that first May Day toast is visible in their eyes.”
Six drinks—for example, a bottle of sparkling wine—already affect the eyes in many ways and quite strongly. You usually notice the change yourself at that point.
“Contrast sensitivity and night vision are clearly impaired. Focusing on moving objects becomes challenging, and shifting focus from one distance to another slows down. The eyes may start to redden. Those most sensitive to alcohol may also experience squinting and blurred vision.”
May Day is celebrated next Friday, when many people will consume several drinks. What advice would a vision expert give to May Day revelers?
“Drink plenty of water. It’s important for many reasons. And wear sunglasses if it’s sunny, because they reduce eye strain on a long and hectic day,” Kahlos says.
“If you wear contact lenses, take care of your eye hygiene and keep your eyes moist. Remember to remove your contact lenses before going to bed. If microbes breed under the lens overnight, there is a high risk of serious eye infection.”
Six Claims About Alcohol and the Eyes
Fact or Fiction? Instrumentarium optometrist Ritva Kahlos responds to claims about alcohol and the eyes.
- The eyes reveal how drunk a person is.
“Fiction. There are significant differences between people because the effects begin to show outwardly. Alertness also causes daily variations. For some, intoxication is visible after just a couple of drinks; for others, not until the eighth. Assessing close friends and family by their eyes is slightly more reliable, because you know their tendencies better.”
- Alcohol makes your eyes red.
“True. Alcohol increases peripheral blood flow, which also makes the blood vessels on the surface of the eye more visible. Redness can also be caused by other factors related to alcohol consumption, such as dry eyes resulting from dehydration and reduced blinking.”
- A squint indicates a high level of intoxication.
“True and false. Even the song ‘Käärijä’ mentions that one eye is already crossing. Severe intoxication impairs the eyes’ fine motor control. This can cause the eyes to focus on slightly different points, resulting in double vision. On the other hand, some people have severe latent strabismus that becomes apparent after just a few drinks, when control of the eye muscles fails.”
- It’s hard to read your phone when you’re drunk.
“True. Near vision is affected by alcohol faster than distance vision, because focusing on close objects requires greater effort from the eye muscles and nerve pathways. The sight of someone squinting at text on a cell phone or holding the phone farther away to see is surely a familiar late-night scene for many.”
- It’s easier to notice intoxication in others’ eyes than in your own.
“True. Surveys also show that people notice changes in their own eyes very late. In others’ eyes, however, we notice micro-changes more easily. And if you’re sober yourself or drink less than the rest of the group, you’ll notice the changes even more easily.”
- Your vision returns by the morning after a night out.
“Myth. If the party has gone on late into the night, there’s still alcohol in your blood in the morning, or recovery has only just begun. In that case, your eyes may be red and sensitive to light. Focusing may also feel difficult. If, on the other hand, you’ve drunk in moderation and slept enough, your vision will have time to recover.”
* Karimi et al.: Alcohol and the Eye, 2021. (pmc.ncbi.nlm.nih.gov/articles/PMC8126742)
* Tyson et al. Dose-dependent sensorimotor impairment in human ocular tracking after acute low-dose alcohol administration, 2020. (pubmed.ncbi.nlm.nih.gov/33332605)
** Roche & King: Alcohol impairment of saccadic and smooth pursuit eye movements, 2010.
(pubmed.ncbi.nlm.nih.gov/20635179)
** Romano et al. Gaze-evoked nystagmus induced by alcohol intoxication, 2017.
(pubmed.ncbi.nlm.nih.gov/27981586)
Survey
1,000 Finns over the age of 18 responded to Instrumentarium’s survey. The respondent group is nationally representative in terms of gender, age, and region of residence. The survey was conducted by the research firm Bilendi through its M3 Panel in April 2026.
When do you notice alcohol starting to affect your vision?
1% – After 1 drink
7% – After 2 drinks
18% – After 3–4 drinks
24% – After 5 or more drinks
28% – No effect at all
24% – I don’t drink alcohol
Respondents who consume alcohol only (n=764)
1% – After 1 drink
9% – After 2 drinks
23% – After 3–4 drinks
31% – After 5 or more drinks
36% – No effect at all
When can others tell from your eyes that you have been drinking alcohol?
1% – After 1 drink
9% – After 2 drinks
25% – After 3–4 drinks
29% – After 5 or more drinks
11% – Not noticeable at all
24% – I do not drink alcohol
Respondents who consume alcohol only (n=764)
2% – After 1 drink
12% – After 2 drinks
33% – After 3–4 drinks
38% – After 5 or more drinks
15% – Not noticeable at all
Have you ever experienced any of the following when drinking alcohol?
(You may select more than one option.)
21% – My vision has been blurry or out of focus
11% – I have seen double
25% – I have had trouble focusing my eyes on an object
17% – My eyes have been noticeably red
27% – People have noticed from my eyes that I was drunk
23% – It has been difficult to read my phone screen
39% – I have noticed signs of intoxication in the eyes of those around me
3% – My vision has not yet returned to normal the next morning
16% – I have not experienced any of these (excludes other options)
24% – I do not drink alcohol (excludes other options)
Further information
Elena Pallaskivi
Communications Manager
Instru Optiikka Oy
040 7771445
viestinta@instru.fi
