Introduction:
Another name for iridodonesis is tremulous iris. Iridodonesis or tremulous iris causes tremors of the eyes that are passive and abnormal. With the movement of an eye, movement of the eye membrane occurs, resulting in the wobble of the eye. This condition is mainly seen when the support of the iris is lost. It can be due to the absence of the lens or the accumulation of vitreous humor in the eye. Sometimes this condition paralyzes the iris also.
What Is the Basic Structure of the Iris?
The location of the iris is the posterior region of the cornea (outer layer of the eye). The iris is made up of three layers:
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Endothelium.
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Stroma.
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Epithelium.
In front of the lens, the iris has a small circular opening called the pupil. In the eyes, blood flows from the front to the back in the choroidal veins (veins of the eyes that carry blood). The iris is 12 millimeters in diameter. It regulates the amount of light that enters, and light separates the iris into two chambers, anterior and posterior chambers. The nervous supply of the iris is by the oculomotor nerve.
What Is the Function of the Iris?
The iris is the colored part of the eye. The identity of the iris is unique, just like the person's fingerprints. It is one reason to use eye scanners for security purposes. The means of security are through eye scanners. In light perception, the pupil changes size so the retina can receive the optimal light level. That is why pupils are more constricted on bright days and dilate in lower or dim light. It is the eye's protective mechanism to allow the entrance of proper light because too low can affect the person's vision.
What Is the Basic Anatomy of the Ciliary Body?
The structure of the ciliary body comprises two parts:
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First, an extension of the iris is a circular muscle forming a ring.
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The ciliary epithelium's presence produces aqueous humor in the eye's anterior chamber.
The ciliary zonule is a band of fibers that helps to attach the ciliary body to the lens. It is made up of two layers: the first one is a thin layer, and the second one is a thicker layer. These layers form the ligament of the lens that provides support and stability to the lens or eyes. Loosening these fibers leads to the partial dislocation of the lens, known as ectopia lentis, resulting in iridodonesis. In Marfan's syndrome, this weakened ciliary zonule leads to lens subluxation. Therefore, iridodonesis is considered a hallmark of Marfan's syndrome.
What Are the Different Causes of Iridodonesis?
Iridodonesis can occur due to the following reasons:
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Cataract: In cataracts with aging, clouding of the lens is seen. It is progressive damage to the eyes. In the course of the disease, it can also cause iridodonesis.
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Lens Subluxation: Partially displaced lens is known as lens subluxation. It may occur due to trauma or systemic disease. It can cause iridodonesis.
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Marfan Syndrome: It is an inherited disorder that affects the body's connective tissue. There is a problem in the development of the connective tissue required for bones, muscles, and organs of the body. For example, Iridodonesis is seen when it involves the eyes.
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Increase Intraocular Pressure: Disorders that raise intraocular blood pressure can cause iridodonesis.
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Corneal Diseases: Corneal disease is a serious condition that can even cause blindness. Some corneal diseases can also cause iridodonesis.
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Eye Injury: It displaces the eye's holding tissue, leading to iridodonesis.
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Glaucoma: Glaucoma of the eyes leads to increased eye pressure, which can cause iridodonesis.
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Intraocular Lymphoma: Intraocular lymphoma leads to detachment in the retina of the eyes. It can also cause painless, blurring of vision.
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Iatrogenic: Some iatrogenic causes or intraoperative complications can also cause it.
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Corneal Edema: It is inflammation of the outermost layer of the eyes. Some injuries or infections can cause corneal edema, which can cause iridodonesis.
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Congenital Ectopia: It occurs due to trauma, ocular diseases, and systemic diseases. In some cases, the lens is detached, leading to the presence of error from birth.
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Nearsightedness: Sometimes, it is seen in healthy people who are nearsighted people. In such a person, very slight wave movements of the iris are seen.
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Agitated Movement: Sometimes, a vibration or agitated movement of the iris can be due to the partial dislocation of the lens or the absence of a lens.
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Metabolic Disorders: Iridodonesis has also been seen in some metabolic disorders in young persons with ischemic stroke.
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Retinal Detachment: It is also seen in retinal detachment and hydrophthalmos (fluid-filled eyes) cases.
What Are the Symptoms of Iridodonesis?
Iridodonesis does not have any specific symptoms rather than a common symptom, just like many conditions.
How to Make a Diagnosis of Iridodonesis?
No specific diagnosis is required. An observer from the outside can notice the visible vibration with the naked eye, and a slit lamp is used for evaluation and examination. However, in some instances, some tests are done further to find out the cause.
What Is the Treatment of Iridodonesis?
Iridodonesis mainly occurs due to lens subluxation, so treating lens subluxation is necessary. Surgical approaches help reduce the tremulousness of the iris. When the genetics of patients is the reason, there is no cure. Iridodonesis usually does not show symptoms. So sometimes, it is left untreated when it occurs alone without complication.
Treatment options for lens instability are:
Medical Therapy: Latanoprost drops can be used every 12 hours, and it helps in maintaining or reducing the risk of anterior luxation.
Lens Removal Surgery: It is done with or without the placement of an intraocular lens implant to stop the vibrational moment.
Conclusion
Iridodonesis or tremulous iris causes tremors of the eyes. These tremors are passive and abnormal. It can be due to the ligament's detachment, which helps hold eyes together. It can be due to some underlying reason or can be due to some trauma that leads to detachment. Its diagnosis is easy. Usually, it does not cause any complications and also does not require specific treatment.
