Irregular pupil size

Extended pupils (more than 5 mm in diameter) are called mydriasis.

Narrowed pupils (less than 2 mm in diameter) are called miosis.

[1], [2], [3]

Bilateral dilatation of pupils (mydriasis)

This phenomenon is observed:

1. As an innocuous benign feature in vegetatively labile sympathicotonic people.
2. In wearing contact lenses.
3. When the midbrain is affected.
4. As a result of a violation of the reaction to light (often with a deep coma).
5. Often with local or internal use of medications that cause mydriasis (also with the covert use of atropine drugs).

Pupils can expand with anxiety, fear, pain, hyperthyroidism, cardiac arrest, cerebral anoxia and sometimes with myopia. Pupils can also expand with muscle activity, loud sound and deep inspiration.

[4], [5]

Two-sided pathological narrowing of the pupils (miosis)

Two-sided miosis is observed:

1. As a benign feature (especially in the elderly) and sometimes with farsightedness.
2. As a normal reaction to the bright light in the room where the study is conducted.
3. When the bridge of the brain and the cerebellum is affected, a bilateral miosis is noted among other neurological symptoms and is often accompanied by a disturbance of consciousness (the pupils here become very small - the "pinpoint").
4. With topical application of drugs (pilocarpine in patients with glaucoma) or internal administration of drugs (morphine derivatives).
5. With syphilis, diabetes, with levodopa treatment.

Miosis can also occur during sleep, in deep coma, increased intracranial pressure with bilateral involvement of the fibers to m. Dilatator.

Difference in the size of pupils at rest (anisocoria)

Anisocoria indicates either a one-sided pathological enlargement or one-sided pathological narrowing of the pupil.

Unilateral pathologically dilated pupil

Possible reasons:

1. Oculomotor paralysis (accompanied by ptosis and often paralysis of the external eye muscles).
2. Eddie's syndrome usually has one-sided or predominantly one-sided manifestations (no pupillary reactions to light with a preserved response to tonic dilatation, often lacking tendon reflexes, mostly found in women, usually of a family nature).
3. Unilateral topical application of medications that cause mydriasis.
4. Ciliary ganglionitis.
5. One-sided lesion of anterior parts of the eye (often accompanied by an expansion of blood vessels, deformity of the pupil by synechiae).
6. Unilateral mydriasis with migraine (but also often miosis with Horner's syndrome, especially with a cluster headache).

Unilateral pathologically narrowed pupil

(possible reasons):

1. Horner's syndrome.
2. Unilateral topical application of myotic preparations.
3. Some unilateral local lesions of the anterior chamber of the eye (for example, with a foreign body in the cornea or intraocular).
4. Syphilis (rarely unilateral).
5. With irrigation of the III nerve.

"Benign central anisocoria":

The difference in the size of the pupils is rarely more than 1 mm, is more noticeable in poor light; the size of the smaller pupil often changes.

Violation of the shape and position of one or both pupils

Imbalances (oval or other deformities) are usually the result of eye disease and are observed when:

1. A congenital ectopic pupil, when the deformation is directed mainly up and out, is often accompanied by a lens dislocation and other eye anomalies
2. Irritate or partial absence of the iris, with synechiae and partial atrophy of the iris (for example, with dorsal dryness).

Among other disorders, pupil gippus (spontaneous, partially rhythmic contractions that may appear normal, but also occur in cataracts, multiple sclerosis, meningitis, contralateral vascular insults, or after recovery from paralysis of the oculomotor nerve).

Narrowed pupils on both sides with a normal or somewhat weakened reaction to light can occur in some people - as an individual feature; among healthy individuals as a normal reaction to intense lighting, traumatic subjects in front of the eyes, various menacing moments (protective reflex); in patients with a rough diabetic lesion of postganglionic sympathetic fibers reaching the dilator pupil; in patients with gliomas, ependymomas of the spinal cord, with the process in the region of the ciliospinal center; in patients with syringomyelia.

Narrowed pupils from both sides with a sharply weakened or absent reaction to light can occur in conditions accompanied by trophotropic shifts (during sleep, digestion, with moderate arterial hypotension, vagotonia); with neurological diseases (shell processes, encephalitis, brain tumors, syphilis, Argyle Robertson's syndrome); at psychogenic and mental diseases (hysteria, epileptic dementia, depression, imbecility); with intraorbital diseases (glaucoma, increased blood pressure in the vessels of the iris in elderly people); when poisoning opium, morphine, bromine, aniline, alcohol, nicotine; with uremic coma.

The dilated pupils on both sides with the preservation of pupillary response to light can occur in the following cases: for conditions and diseases accompanied by ergotropic shifts (thyrotoxicosis, arterial hypertension, eclampsia of pregnant women, febrile conditions, acute inflammation, increased attention, danger); as a characteristic feature of vegetatively labile individuals, sympathetics; at the same pathological conditions as the narrowed pupils with normal reaction to light, only at earlier stages, stages of diseases, ie, at the stage of irritation of the sympathetic pathways leading to the pupil (diabetes mellitus, syringomyelia, gliomas, ependymoma of the spinal cord) ; in people who use contact lenses.

Extended pupils with a lack or a sharply weakened reaction to light are met during poisoning with atropine, cocaine; fungi, plants containing cholinolytic poisons; quinine, carbon monoxide; when using mydriatic (including drugs, at least partially containing atropine); with botulism; gross lesions of the midbrain.

Anisocoria is the inequality of the pupils of the right and left eyes. The dilatation of the pupil on one side and the preservation of the reaction to light can be observed with the Purfur du Ptie syndrome (pupil dilatation, exophthalmos, lagophthalmus), irritation of sympathetic pathways to the pupil by abnormal processes in the neck region, local action of sympathomimetic agents (when instilled into the eye), migraine, cluster syndrome. Irritation of sympathetic pupillary tracts on the one hand leads to the dilatation of the pupil of the same name.

Expansion of the pupil on the one hand with the lack or weakening of the reaction to light can be observed with the syndrome of Adi, one-sided lesion of the oculomotor nerve, post-traumatic iridoplegia, diphtheria (lesion of the ciliary nerves). The reason is paresis or paralysis of the pupil sphincter due to a break in the parasympathetic pupillary tract in the ciliary knot or distal.

The narrowing of the pupil on one side and the preservation of the reaction to light are most common in Horner's syndrome. This syndrome occurs when the lateral sections of the bridge, the medulla oblongata, as well as in the defeat of the ciliospinal center and the corresponding pre- and postganglionic sympathetic fibers (alternating syndromes Babinsky-Najotte, Sestana-Schene, Wallenberg-Zakharchenko, Villary, Pankosta, Dejerin-Klumpke, Murphy, Nuffziger, Romberg, Godfredsen).

The narrowing of the pupil on one side with a sharply weakened reaction to light or its absence is found in the pathology of the ciliary unit (Charlene syndrome: pain in the inner corner of the eye socket, rhinorrhea, keratitis herpetic, lachrymation), local effects of cholinomimetics, combination of Horner's syndrome with intraocular pathology on the same side (glaucoma). The reason for this is the irritation of parasympathetic pupillary fibers on one side, leading to a spasm of the pupil sphincter of the same name.

The perfect symmetry is not inherent in the organism: a small difference in the size of the pupils is quite common. Almost a quarter of the normal population has a clinically perceptible (0.4 mm or more) anisocoria. This phenomenon becomes more pronounced with age; This degree of anisocoria occurs in 1/5 of persons under 17 years of age and in 1/3 of persons over 60 years of age. Anisocoria occurs, which decreases in bright light. It is not a sign of any disease and is called "simple anisocoria."

Hippus - rapidly changing constrictions and dilatations of the pupil, independent of external stimulation, can occur in healthy people, but also in cataracts, multiple sclerosis, meningitis, cerebral strokes, narcolepsy, and restoration of the suffered cranial nerve III.

[6], [7]