Pupils of different sizes are observed in humans with certain ophthalmological and neurological diseases. In medicine, a symptom manifested by inequality in the size of the eye pupils is called anisocoria. This pathology is observed with damage to the sympathetic fibers of the eye associated with the muscle that dilates the pupil , or parasympathetic eye fibers belonging to the muscle responsible for the narrowing of the pupil.
Pupils of different sizes, causes of pathology
If anisocoria occurs as a result of an eye injury, in which the muscle narrowing the pupil is damaged, then immediately after the incident, the pupil initially narrows, but soon expands again, and ceases to respond to accommodation and light stimuli.
Pupils of different sizes sometimes cause inflammation of the iris, the so-called iritis.
All reactions of the pupil are reduced with angle-closure glaucoma as a result of ischemia of the iris. Glaucoma is accompanied by a noticeable acute pain in the eyeball, the patient's vision is gradually reduced.
If pupils of different sizes are more noticeable in bright light, then this is most likely a manifestation of parasympathetic innervation disorders. This disease causes pupil dilatation (mydriasis), and all its reactions also weaken. Most often, mydriasis is a consequence of damage to the oculomotor nerve, which is accompanied by divergent strabismus, restriction of the motor functions of the eyeball, ptosis and double vision.
Different pupils with anisocoria may be the result of a tumor or aneurysm, compressing the oculomotor nerve.
Parasympathetic denervation (pupils of different sizes) is due to infectious inflammation of the eyes or trauma in the orbit of the ciliary ganglion.
In this case, the pupil does not respond to light, but the delayed ability to accommodation (adaptation) is preserved.
Ady and Horner Syndromes
Adie’s syndrome is characterized by the fact that when moving away from the gaze, the pupil expands slowly, and this, in turn, disrupts accommodation, and visual acuity is lost . This syndrome is often observed in young women and is the cause of mydriasis in one eye.
If the anisocoria intensifies in the dark or when light is removed, then this is a manifestation of a simple anisocoria or Horner's syndrome.
This syndrome is accompanied by ptosis, facial anhydrosis (a violation of sweating) and narrowing of the pupil, and is often the result of a violation of the sympathetic innervation of the eyes. Pupils with Horner's syndrome react normally to accommodation and light.
The cause of Horner's syndrome is cancer of the upper part of the lung, damage to the trunk of the spinal cord or upper cervical spine. With Horner's syndrome, which arose with cancer of the upper part of the lung, weight loss of the small muscles of the hands, pains that extend to the medial surface of the hands are simultaneously observed.
Pupils of different sizes are due to squeezing of sympathetic fibers due to thyroid cancer, due to various surgical interventions, injuries, tumors, enlarged lymph nodes in the neck, with carotid artery thrombosis and for other reasons.
If the carotid artery exfoliates as a result of the injury, Horner's syndrome is accompanied by facial pain on the same side and cerebrovascular accident.
Horner's syndrome in children causes a neuroblastoma in the cervical or upper thoracic part.
With simple anisocoria (essential), quite often a small difference in the size of the pupils is diagnosed (no more than 0.5 mm).
A migraine attack sometimes causes unilateral mydriasis. Pupils of different sizes in this case are short-lived and the pupil reactions are completely preserved.
Different pupils are a serious reason to see a doctor, as they can be the result of serious illnesses.