Iridodonesis: Definition, Causes, Symptoms, Diagnosis and Treatment

We are talking about a symptom that produces tremors in the ocular iris.

In certain cases, they are quite pronounced and follow a dislocation of the lens, wounds and contusions of the eye , or a considerable softening of the vitreous body.

The term originated in irido, it comes from the Latin: iris and doneo from the Greek: ονεo, which means to shake from one side to the other.

The iris

The iris is located in the posterior region of the cornea and appears as a root of the ciliary body.

Histologically, the iris is composed of three different layers: endothelium, stroma, and epithelium.

The iris makes a small circular opening in front of the lens, called the pupil.

Each ciliary body contains a ciliary process, which in turn has a fibrovascular nucleus that appears to be continuous with the stroma of the ciliary body.

Blood flows from the anterior to the posterior choroidal veins. All the blood from the ciliary body of the eye is drained through the vortex vein.

The iris is a 12mm diameter structure that works to regulate the amount of light that enters the eye and also separates it into the anterior and posterior chambers.

The iris is controlled by branches of the autonomic nervous system.

Therefore, parasympathetic stimulation, delivered by the oculomotor nerve, will constrict the pupil, while sympathetic stimulation, originating from the superior cervical ganglion, will act to dilate the pupil.

Iris layers

The iris can be divided into four layers:

  • The leading edge layer.
  • The stroma and sphincter muscle.
  • The anterior epithelium and the dilator muscle.
  • The posterior epithelium.

Iris function

The iris is located behind the cornea and is commonly described as the colored part of the eye. An interesting fact about the iris is that we all have a unique one, just like our fingerprints.

And one reason why they can be used as a means of security through eye scanners.

The middle portion of the iris has an opening, called the pupil, that helps regulate the amount of light that passes through the retina. It is analogous in action to the diaphragm of a camera.

The pupil changes in size so that the retina receives the optimal level of light.

This is why, on a bright day, you will notice that the pupils are more constricted. However, in low-light environments, the pupils will appear much larger (or dilated).

It is the eyes’ way of ensuring that only the proper amount of light enters the eye. Too much or too little can affect vision. Also, excessive sun exposure can cause irreversible eye damage. Even the eyes can be burned by the sun.

Associated diseases

Iris coloboma

It is a hereditary malformation of the iris that is characterized by a cleft due to the lack of development of the iris.

Aniridia

It is a rare hereditary condition of the iris that is usually bilateral and hereditary, it is, a partial or total absence of the iris.

Albinismo ocular

It is a genetic condition that causes pigmentation abnormalities.

Uveal disorders

The uvea is the middle layer of the eye and consists of three parts: iris, ciliary body, and choroid.

Some disorders of the uvea include uveitis (an inflammation of the uvea), neovascularization, benign and malignant uveal tumors, iridodialysis, iridodonesis, and heterochromia.

Iridodonesis

Iridodonesis or tremulous iris is an abnormal and passive tremor of the iris.
This membrane wobbles when an eye movement occurs.

This condition appears when the iris has lost support due to the absence of the lens, or when the vitreous humor is abnormally liquid or the iris is completely paralyzed.

Causes of iridodonesis

It is sometimes seen in healthy or nearsighted people. The wave movements of the iris are very slight.

This vibration or agitated movement of the iris with the movement of the eye, can be due to a subluxation of the lens, the incomplete or partial dislocation of the lens; or by aphakia, the absence of a lens.

Iridodonesis, in the absence of trauma, should guide the specialist in the search for a metabolic etiology in young subjects with ischemic stroke.

It is also seen in cases of hydrophthalmia and retinal detachment.

The iridodonesis, coincides many times with nystagmus.

Symptoms of iridodonesis

Iridodonesis is therefore nothing other than a common symptom in many conditions and no exclusive treatment can be applied to it.

Diagnosis of iridodonesis

The vibrations are visible to the naked eye by an outside observer and are evaluated by slit lamp examination.

Treatment of iridodonesis

Treatment for iridodonesis will depend on the cause that causes it.