From the Guidelines
Alcohol can cause mydriasis (dilated pupils) by affecting the central nervous system and inhibiting the parasympathetic nervous system, which is responsible for pupil constriction. When someone consumes alcohol, it interferes with the normal functioning of the iris muscles that control pupil size, resulting in pupil dilation. This effect is typically seen at moderate to high blood alcohol concentrations. The degree of pupil dilation often correlates with the amount of alcohol consumed, with more significant dilation occurring with higher levels of intoxication.
Key Points to Consider
- The relationship between alcohol consumption and intraocular pressure (IOP) has been studied, but the evidence is not directly related to mydriasis 1.
- However, it is known that alcohol affects the central nervous system, which can lead to mydriasis.
- Other substances that can cause pupil dilation include stimulants, hallucinogens, and certain medications.
- If someone notices persistent pupil dilation without alcohol consumption, they should consult a healthcare provider as it could indicate other medical conditions.
Relevant Studies
- A systematic review and meta-analysis published in 2022 in the journal Ophthalmology found a harmful association between alcohol use and open-angle glaucoma, but the results should be interpreted cautiously due to the weakness and heterogeneity of the underlying evidence base 1.
- Another study published in 2022 found that alcohol use was associated with higher IOP in men without glaucoma, but the evidence is not directly related to mydriasis 1.
Clinical Implications
- Medical professionals and law enforcement may observe pupil dilation as one of several physical signs when assessing for alcohol intoxication.
- It is essential to consider other potential causes of mydriasis, such as other substances or medical conditions, when evaluating a patient with dilated pupils.
From the Research
Alcohol and Mydriasis
- There is no direct evidence in the provided studies that alcohol causes mydriasis (dilated pupils) 2.
- However, methanol, a type of alcohol, has been shown to cause fixed, dilated pupils in cases of methanol-induced vision loss 3, 4.
- Other substances, such as tricyclic antidepressants (TCAs), typical antipsychotics, and selective serotonin reuptake inhibitors (SSRIs), have been associated with mydriasis 5.
- The dilated pupil can present a significant challenge to the clinician, and a complete history and physical examination is sufficient to make an accurate diagnosis in most cases 6.
Related Ocular Effects
- Methanol consumption can lead to severe vision loss or death, with symptoms including fixed, dilated pupils and optic atrophy 3, 4.
- Psychotropic medications can induce numerous and diverse unwanted ocular effects, including mydriasis, angle-closure glaucoma, and retinopathy 5.
- Acute alcohol intoxication can cause a range of symptoms, including impaired coordination, unstable gait, nystagmus, and stupor or coma, but mydriasis is not specifically mentioned as a symptom 2.