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ULY CLINIC

ULY CLINIC

12 Septemba 2025, 00:34:48

Miosis

Miosis
Miosis
Miosis

Miosis is the constriction of the pupil due to contraction of the sphincter muscle in the iris. It occurs normally as a response to bright light, during the accommodation reflex, after administration of miotic agents, and as part of the natural aging process (pupil size gradually decreases from adolescence to about age 60). Miosis can also result from ocular or neurologic disorders, trauma, or systemic drug use.

A rare form — Argyll Robertson pupil — is often associated with tabes dorsalis or other neurologic disorders. These pupils are usually bilateral, small (“pinpoint”), irregular, fail to dilate with mydriatics, and do not react to light but do constrict with accommodation.


History and Physical Examination

  • Ask the patient about ocular symptoms, including onset, duration, and intensity.

  • Inquire about trauma, systemic diseases, and drug use (topical or systemic).

  • Perform a thorough eye examination:

    • Test visual acuity with and without correction.

    • Compare pupil size, color, shape, reaction to light, accommodation, and consensual reflex.

    • Examine the eyes for additional signs such as conjunctival injection, nystagmus, or ptosis.

    • Evaluate extraocular muscle function using the six cardinal fields of gaze.


Medical causes

Cause

Typical Presentation / Findings

Cerebrovascular arteriosclerosis

Usually unilateral miosis; visual blurring, slurred speech, aphasia, memory loss, vertigo, headache

Cluster headache

Ipsilateral miosis, tearing, conjunctival injection, ptosis, facial flushing, sweating, bradycardia, nasal stuffiness, restlessness

Corneal foreign body

Miosis in affected eye, pain, foreign body sensation, photophobia, tearing, slight vision loss

Corneal ulcer

Moderate eye pain, visual blurring, diffuse conjunctival injection, miosis in affected eye

Horner’s syndrome

Ipsilateral moderate miosis, ptosis, enophthalmos, anhidrosis, sluggish pupillary reflex, vascular headache; congenital cases show lighter iris

Hyphema

Miosis following blunt trauma, moderate pain, blurred vision, conjunctival injection, slight eyelid swelling

Iritis (acute)

Constricted pupil, decreased pupillary reflex, severe eye pain, photophobia, visual blurring, conjunctival injection, pus in anterior chamber

Neuropathy

Argyll Robertson pupils in diabetic or alcoholic neuropathy; sensory disturbances, muscle weakness, hypotension, incontinence

Parry-Romberg syndrome

Facial hemiatrophy, miosis, sluggish pupillary reflexes, ptosis, nystagmus, differing iris colors

Pontine hemorrhage

Bilateral miosis, rapid coma onset, paralysis, decerebrate posture, absent doll’s eye sign, positive Babinski

Uveitis

Anterior: miosis, moderate/severe eye pain, photophobia, conjunctival injection, pus possible; Posterior: gradual onset, visual floaters, blurred vision, distorted pupil shape


Other causes

  • Chemical burns: Can produce miosis with pain, conjunctival injection, inability to open the eye, visual blurring, blistering.

  • Drugs: Topical (acetylcholine, carbachol, pilocarpine) or systemic (opiates, barbiturates, cholinergics, clonidine overdose, reserpine) agents may induce miosis.

  • Deep anesthesia may also cause pupil constriction.


Special considerations

  • Reassure the patient to reduce fear and anxiety about ocular findings.

  • Explain the diagnostic tests, which may include ophthalmologic and neurologic evaluations.


Patient counseling

  • Demonstrate proper eye drop administration.

  • Advise on measures to relieve eye pain or discomfort.


Pediatric pointers

  • Neonatal miosis is common due to sleepiness.

  • Congenital microcoria: rare autosomal dominant condition with bilateral pupils <2 mm and absent dilator muscle.


References

  1. Dexl AK, Seyeddain O, Riha W, Hohensinn M, Hitzl W, Grabner G. Reading performance after implantation of a small-aperture corneal inlay for the surgical correction of presbyopia: Two-year follow-up. J Cataract Refract Surg. 2011;37(3):525–531.

  2. Epstein RL, Gurgos MA. Presbyopia treatment by monocular peripheral presbyLASIK. J Refract Surg. 2009;25(6):516–523.

  3. Gerstenblith AT, Rabinowitz MP. The Wills Eye Manual. Philadelphia, PA: Lippincott Williams & Wilkins; 2012.

  4. Huang JJ, Gaudio PA. Ocular Inflammatory Disease and Uveitis Manual: Diagnosis and Treatment. Philadelphia, PA: Lippincott Williams & Wilkins; 2010.

  5. Roy FH. Ocular Differential Diagnosis. Clayton, Panama: Jaypee–Highlights Medical Publishers, Inc.; 2012.

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