Mydriasis and miosis refer to opposite conditions of pupil size: mydriasis is pupil dilation, while miosis is pupil constriction.
Here's a breakdown:
Understanding Mydriasis and Miosis
To fully understand the difference, it's crucial to know what these terms describe:
- Mydriasis: Refers to the dilation (enlargement) of the pupil.
- Miosis: Refers to the constriction (shrinking) of the pupil.
Mydriasis vs. Miosis: A Detailed Comparison
| Feature | Mydriasis | Miosis |
|---|---|---|
| Pupil Size | Dilated (enlarged) | Constricted (shrunken) |
| Mechanism | Contraction of the iris dilator muscle or relaxation of the iris sphincter muscle. | Contraction of the iris sphincter muscle or relaxation of the iris dilator muscle. |
| Common Causes | Medications, recreational drugs, eye drops, injury, illness, bright light. | Medications, eye drops, nerve damage, bright light, opioid use. |
According to research, pupil constriction (miosis) can either be stimulated by contraction of the iris sphincter or by relaxation of the iris dilator. On the other hand, pupil dilation (mydriasis) can either be stimulated by contraction of the iris dilator or by relaxation of the iris sphincter.
