mydriasis
Very lowTechnical/Medical
Definition
Meaning
Abnormal dilation of the pupil of the eye.
A state where the pupil is enlarged beyond its normal size, which can be physiological (in dim light), pharmacological (caused by drugs), or pathological (due to injury or disease). In neurological contexts, it can indicate specific brainstem activity or trauma.
Linguistics
Semantic Notes
The term is almost exclusively used in medical, pharmacological, and optometric contexts. It refers to a specific clinical sign, not a symptom a patient would typically report. Its antonym is 'miosis' (pupil constriction).
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or spelling. Pronunciation differences follow general UK/US patterns.
Connotations
None beyond the technical medical meaning.
Frequency
Equally rare in both varieties, confined to specialist fields.
Vocabulary
Collocations
Grammar
Valency Patterns
The patient presented with mydriasis.The drug induced mydriasis.Mydriasis was caused by the head injury.The condition is characterised by mydriasis.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None. The word is strictly technical.”
Usage
Context Usage
Business
Not used.
Academic
Used in medical, pharmacological, and neuroscience research papers and textbooks.
Everyday
Extremely unlikely to be used or understood by the general public.
Technical
Core term in ophthalmology, neurology, emergency medicine, and toxicology to describe a clinical finding.
Examples
By Part of Speech
verb
British English
- The agent will mydriatise the pupil for the examination.
American English
- The agent will mydriatize the pupil for the exam.
adverb
British English
- The pupil reacted mydriatically to the stimulus.
American English
- The pupil reacted mydriatically to the stimulus.
adjective
British English
- The mydriatic effect of the drops was pronounced.
American English
- The mydriatic effect of the drops was pronounced.
Examples
By CEFR Level
- The doctor said the pupil was very big.
- Some eye drops make your pupils get bigger.
- The medication can cause temporary dilation of the pupils.
- The neurologist noted a unilateral mydriasis, which suggested possible intracranial pressure.
Learning
Memory Aids
Mnemonic
Think: 'MY eye DILATES in a CRISIS' (sounds like 'my-driasis').
Conceptual Metaphor
The pupil as a camera aperture that can be widened (mydriasis) or narrowed (miosis).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'миоз' (miosis, the opposite condition).
- The Russian medical term is 'мидриаз' (midriaz), a direct cognate, so pronunciation and spelling are similar.
Common Mistakes
- Misspelling as 'mydrasis' or 'mydraisis'.
- Using it to describe normal pupil changes in dim light without a pathological/drug-induced context.
- Pronouncing the first syllable as 'mee' (like 'me') instead of 'mi' or 'my'.
Practice
Quiz
What is the direct antonym of 'mydriasis'?
FAQ
Frequently Asked Questions
No. It can be a normal physiological response to low light, or an intended effect of eye drops used for retinal examination.
It is not recommended, as it is a highly technical medical term. Most people would say 'dilated pupils' or 'large pupils' instead.
It can be caused by head trauma, stroke, brain tumor, increased intracranial pressure, or damage to the eye's nerves (e.g., from glaucoma).
Yes, though very rare. 'To mydriatize' (US) or 'to mydriatise' (UK) means to induce mydriasis. The adjective 'mydriatic' (as in 'mydriatic drugs') is more common.