Index
We are talking about a symptom that produces tremors in the ocular iris.
In some instances, they are pretty 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 period; it comes from the Latin: iris and done from the Greek: ονεo, which means to shake from one side.
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 comprises 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 eye’s ciliary body is drained through the vortex vein.
The iris is a 12mm diameter structure that regulates the amount of light that enters the eye and separates it into the anterior and posterior chambers.
Branches of the autonomic nervous system control the iris.
Therefore, parasympathetic stimulation, delivered by the oculomotor nerve, will constrict the pupil, while sympathetic stimulation, originating from the superior cervical ganglion, will 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. Interestingly, 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 is 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 light level.
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 more prominent (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 an aperture 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.
Albinism ocular
It is a genetic condition that causes pigmentation abnormalities.
Uveal disorders
The uvea is the eye’s middle layer 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, 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 direction 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.
In the absence of trauma, Iridodonesis 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
An outside observer makes the vibrations visible to the naked eye and is evaluated by slit-lamp examination.
