Do SSRIs change your pupils?

October 10, 2025 •

4 min read

According to the Centers for Disease Control and Prevention, over 13% of American adults use antidepressants, with Selective Serotonin Reuptake Inhibitors (SSRIs) being the most commonly prescribed type. For many taking this medication, a notable side effect is the potential for pupil dilation, raising the question: Do SSRIs change your pupils?.

Quick Summary

SSRIs can cause mydriasis, or pupil dilation, due to increased serotonin affecting eye muscles. This effect can lead to light sensitivity and blurry vision, and, in susceptible individuals, it can increase the risk of acute angle-closure glaucoma.

Key Points

Mydriasis is a known side effect: SSRIs can cause pupils to dilate due to increased serotonin activity in the eye's iris muscles.
Associated visual symptoms: Pupil dilation can lead to light sensitivity (photophobia) and blurry vision, especially when focusing on nearby objects.
Risk of acute angle-closure glaucoma: In susceptible individuals with narrow drainage angles, the pupil dilation can trigger a sudden increase in eye pressure, which is a medical emergency.
Other ocular side effects: Users may also experience dry eye syndrome, as some SSRIs can affect tear production.
Risk factors matter: The risk of serious eye complications can depend on pre-existing conditions, age, and dosage of the medication.
Prompt medical attention is vital: Severe eye pain, vision changes with headache, or seeing halos around lights require immediate evaluation.

The Link Between SSRIs and Pupil Dilation

Yes, SSRIs can indeed cause changes to your pupils, most notably leading to mydriasis, which is the medical term for pupil dilation. While not everyone experiences this side effect, it is a documented occurrence for many individuals taking these medications. The mechanism behind this ocular change is linked directly to how SSRIs function within the body.

The Role of Serotonin in Pupillary Response

SSRIs work by increasing the concentration of serotonin in the brain's synaptic clefts by inhibiting its reuptake. However, serotonin receptors are not confined to the brain; they are also found in various ocular structures, including the iris and the ciliary body. The iris contains two main muscles that control pupil size: the pupillary sphincter muscle, which constricts the pupil, and the radial dilator muscle, which dilates it. Increased serotonin levels, through their interaction with specific serotonin receptors (like the 5-HT7 receptor), can cause the pupillary sphincter muscle to relax, leading to pupil dilation.

Common Ocular Side Effects Associated with SSRIs

Beyond just dilated pupils, the serotonergic and other related actions of SSRIs can manifest in several other eye-related side effects. While most are mild and reversible, others can signal a more serious underlying issue.

Light Sensitivity (Photophobia): With larger pupils, more light enters the eye, which can cause discomfort and heightened sensitivity to bright light. This is one of the most common complaints associated with SSRI-induced mydriasis.
Blurred Vision: The changes in pupil size and the potential effect on the eye's ciliary muscles can impair accommodation, making it difficult to focus, especially on near objects.
Dry Eye Syndrome: Some SSRIs have been linked to a reduction in tear production, possibly due to anticholinergic effects, leading to symptoms like burning, itching, and redness.
Acute Angle-Closure Glaucoma (AACG): This is a rare but serious complication. In individuals with a naturally narrow drainage angle in their eye, pupil dilation can cause the angle to close completely. This blocks the outflow of aqueous humor, leading to a rapid and dangerous increase in intraocular pressure. Symptoms include severe eye pain, blurred vision, seeing halos around lights, headache, nausea, and vomiting. This is a medical emergency that requires immediate treatment.

Comparing Antidepressants and Ocular Side Effects

It is important to note that the risk and type of ocular side effects can vary across different classes of antidepressants. While SSRIs are generally associated with a lower risk profile than older generations of medication, understanding the differences is key for patient management.


Feature	SSRIs	SNRIs	TCAs	MAOIs
Mechanism	Inhibit serotonin reuptake	Inhibit serotonin & norepinephrine reuptake	Block serotonin, norepinephrine, and acetylcholine	Inhibit breakdown of serotonin, norepinephrine, dopamine
Pupil Dilation	Yes, via serotonergic effects	Yes, similar to SSRIs	Yes, via anticholinergic effects	Yes, can occur
Dry Eye	Possible, generally mild	Possible, generally mild	Common, often moderate to severe due to anticholinergic action	Yes, possible
Glaucoma Risk	Elevated risk for AACG in susceptible individuals	Elevated risk for AACG in susceptible individuals	Elevated risk for AACG	Risk related to hypertensive crises
Blurred Vision	Possible, related to pupillary and ciliary muscle effects	Possible, related to pupillary and ciliary muscle effects	Common, linked to anticholinergic effects	Possible, related to eye movement disturbances

When to Consult a Doctor

While many SSRI users experience mild or no ocular side effects, certain symptoms warrant immediate medical attention. If you experience severe eye pain, sudden onset of blurred vision, headache, nausea, or see halos around lights, call a doctor immediately, as these could be signs of acute angle-closure glaucoma. For less severe symptoms like light sensitivity or dry eyes, it is still important to discuss them with your prescribing physician and an eye care professional. There may be options for managing symptoms, such as lubricating eye drops for dry eyes or tinted glasses for photophobia. A thorough eye exam can also determine if you have narrow angles that put you at higher risk for glaucoma.

Conclusion

Selective serotonin reuptake inhibitors can and do change pupils, causing mydriasis in some individuals. This is a direct result of increased serotonin levels affecting eye muscles. Although often mild, the potential for complications like acute angle-closure glaucoma exists, particularly for those with pre-existing risk factors. Open communication with your healthcare provider and regular eye monitoring are essential to safely manage any potential ocular side effects while continuing your mental health treatment. Awareness of the symptoms of more serious conditions can help ensure timely intervention and protect your vision.

For more information on the wide range of effects antidepressants can have on your vision, the American Academy of Ophthalmology offers comprehensive resources on eye health and medication side effects. Link: https://www.aao.org/eye-health/diseases/antidepressants-eye-side-effects

Frequently Asked Questions

SSRIs increase serotonin levels throughout the body, including in the eye's iris where specific serotonin receptors are located. This rise in serotonin can relax the pupillary sphincter muscle, leading to mydriasis, or pupil dilation.

For most people, pupil dilation from SSRIs is a mild and manageable side effect. However, in individuals with narrow anterior chamber angles, it can be a risk factor for a serious condition called acute angle-closure glaucoma.

Yes, for individuals with narrow eye drainage angles, the pupil dilation caused by SSRIs can increase the risk of an acute angle-closure glaucoma attack. It is important to inform your doctor if you have a history of glaucoma or have been told you have narrow angles.

Symptoms of AACG, which requires immediate medical attention, include severe eye pain, sudden blurred vision, seeing colored halos around lights, headache, nausea, and vomiting.

Generally, ocular side effects, including pupil dilation, tend to subside as the body adjusts to the medication or after discontinuation. However, you should never stop an antidepressant abruptly without consulting your doctor.

While the potential for pupil dilation is a recognized side effect across the SSRI class, not all individuals experience it. The effect can also vary by the specific medication, dosage, and individual patient factors.

To manage light sensitivity (photophobia) resulting from dilated pupils, some individuals find relief by wearing sunglasses, even in moderately lit environments, or using tinted lenses.