Aniscoria is a condition, in which the pupils are of an unequal size. The pupils may tend to dilate and constrict. In reality, it is the iris that moves.  If the person has anisocoria, then the pupil tends to get larger and larger, thereby increasing the amount of light that enters the pupil. Anisocoria causes glaucoma, trauma to the eye or head, intracranial tumor or even infection of the membranes that surrounds the brain. It is also referred to as Physiological Anisocoria. It is a benign condition.

Anisocoria Symptoms

The only visible symptom of Anisocoria is unequal sizes of the pupil. Apart from this, you will not notice any visible symptoms of this disease. It is very important to get the eye infection examined by a doctor to verify that the symptoms are of the condition physiologic anisocoria.

Anisocoria Causes

The causes of anisocoria differ in seriousness from a normal condition to a physiologic one, or to one that is fatal.  When a patient is suffering from anisocoria, there is a fear of a serious condition, as in intracranial aneurysm, which often compels the clinicians to obtain numerous tests. If the iris is absent, then Anisocora is the result of a defect in the efferent nervous pathways that controls the pupil. Sometimes, Aniscoria may also be caused due to physical lesions or drugs, as these may disrupt the pathways. The causes of this disorder are explained in details below:

Parasympathetic Innervation failure

This causes dilation of the pupil, which causes t to react very sluggishly to direct light. There is another cause of isolated anisocoria, it can be caused due to the viral infection of the ciliary ganglion, which is an orbital structure receiving the parasympathetic component from the third cranial nerve.

Third Cranial Nerve damage

If the size of the pupil is abnormally large, it may indicate a damage to the outermotor nerve, which plays a prime role in controlling the movement of the eye.  If any problem occurs in the outermotor nerve, then it is known as the third cranial nerve damage. Due to this damage, the patient may undergo several difficulties. He may experience double vision, drooping eyelid or expanded pupil. It is a case that requires immediate attention.

Horner’s Syndrome

This syndrome also causes Anisocoria. In this syndrome, the affected pupil is smaller than the other one, and both the plans react briskly to light. The content of ptosis is mild.

Chemical Blockage

If by any chance, there is a contact between the parasympathetic chemicals, and the conjunctiva, it will lead to the deactivation of the iris sphincter muscle, and may result in the dilation of the pupil. It occurs mostly among the hospital personnel and all those people who are exposed to the atropine containing plants.

Adie’s  Pupil

This is another kind of anisocoria. It has similar symptoms which are already stated above. It is also caused due to the damage of cranial nerve. The nerve fibers get degenerated due to a viral infection. The symptoms of this disease are usually seen in case of women.

Iris Sphincter damage

Anisocoria is also caused due to the inflammation and trauma to the sphincter muscle. The shape of the pupil gets irregular, and when it is examined under magnification, you will be able to see signs of muscle damage.

Anisocoria Risk Factors

There are certain people who are more prone to anisocoria due to certain risk factors. Here are some of the risk factors:

Age – although there is no prediction for the occurrence of anisocoria, since anisocoria may occur at any age, but maximum cases of this condition have been reported at certain age.

Sex – No risk

Genetics or the Breed – There are certain breeds that are predisposed to the various causes of anisocoria.

Medical disorders – Anisocoria occurs mostly because of systemic illness. It may occur due to intrinsic eye problem or due to an underlying illness.

Environmental or Geographic factors – Anisocoria is more prevalent in some areas than the others due to the geographical and the environmental condition in that region. Therefore, these factors also play a major role in the occurrence of anisocoria.

Anisocoria in Infants

Anisocoeia is relatively more common in babies, although there is no particular age bar for this disease. But the babies who are born with different sized pupils may not have anisocoria. This can be a case of genetic disorder, and may not involve any anisocoria at all.

Intermittent Anisocoria

If the anisocoria is episodic, it may be intermittent. Simple anisocoria usually varies from week to week. Simple anisocoria is more frequent, and occurs in as many as 20% of the population. If therre are frequent and intermittent pasms, then a condition called the tadpole’s pupils can also result due to this condition.

Anisocoria Differential Diagnosis

This condition should be diagnosed in a proper manner, and for this, a number of tests needs to be performed. The differential diagnosis of this disease involves:

  • Adie’s Syndrome
  • Botulism
  • Alcohol intoxication
  • Cerebral Aneurysm
  • Brain tumor
  • Diabetes mellitus
  • Encephalitis
  • Herpes zoster
  • Injury on the iris
  • Iridocyclitis
  • Ischemia
  • Lead Poisoning
  • Intracranial Hemmorage
  • Multiple sclerosis
  • Retinal Disease
  • Tuberculosis
  • Trauma
  • Neoplastic
  • Ocular prosthesis
  • Syphilis
  • Tapes Dorsalis
  • Keratitis
  • Degenerative Neurologic disorder
  • Syringomyelia
  • Aniridia

Certain tests are recommended for the detection of this condition. It requires complete examination of the ophthalmic and neurologic area. After this, depending on the type of Anisocoria detected, the person has to undergo laboratory testing, electrodiagnostics, diagnostic imaging and pharmalogical testing. All these tests may be necessary so as to localize the underlining cause of the disease.

Once Anisocoria is confirmed, all exposure to the extrinsic pharmalogic agents should be ruled out. Succeeding this, a thorough ocular examination is necessary to identify the other intrinsic diseases of the eye. If neurological disorders are also suspected, then further actions may be taken, as prescribed by the doctor.

Anisocoria Treatment

This condition is a benign one, therefore you do not have to worry much. But it may lead to problems in vision and may be a cause of infection in the eye and other ophthalmic troubles. Therefore, when a person is diagnosed with this problem, he should be properly treated.

There are ceratin procedures that a person can follow for the treatment of this condition:

  • Specific therapies – The patient can go for certain iphthalmic therapies which hel to reduce the effects of this condition. It helps in curing this problem from the core.
  • Withdrawal of drugs – If the cause of miosis or mydriasis is an inadvertent application of topical agents, then it can be easily cured by the withdrawl of such drugs.
  • No required or available treatment – For idiopathic or isolated efferent mydriasis, a treatment procedure is not required. There is no treatment procedure available for iris sphincter atrophy or congenital malformations.
  • Maintain A healthy Lifestyle – To control anisocoria, it os very important to have a very healthy lifestyle. This helps to keep the immune system strong, and thereby controls the condition.

Though Anisocoria is not a fatal disease, yet when it occurs, it causes innumerable related problems. Therefore, seek medical help as soon as possible.

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