Diseases of the iris - specialists and information

The middle layer of the eye consists of the iris, the ciliary body and the choroid. Diseases that affect the choroid include Iris inflammation (iritis) or the combined inflammation of the iris and ciliary body (iridocyclitis).

Below you will find further information and selected specialists for diseases of the iris.

Anatomy and structure of the middle membrane of the eye

The middle membrane of the eye is made up of

• The iris of the eye (iris)
• The ciliary body of the eye (corpus ciliare)
• The choroid of the eye (choroid)

Basically, the middle membrane of the eye is responsible for supplying the retina with nutrients. It is therefore also called the vascular membrane. The retina is part of the central nervous system. The tissue supplies the inner nerve cell layer.

The structure of the human eye @ bilderzwerg /AdobeStock

It also ensures that the eyes adapt to different distances (accommodation). By enlarging or reducing the pupil, it is possible to adapt to different light conditions (accommodation).

Inflammation of the middle skin of the eye is also known as uveitis. The subdivision of uveitis is based on:

• The affected sections of the middle membrane of the eye(iritis, uveal inflammation)
• The region of the eye (anterior, middle, posterior eye area)
• The cause (primary or secondary as a concomitant disease)

You should always have uveitis treated professionally, as it permanently impairs your vision.

The iris (iris)

The iris, which is covered with color pigments (melanin), is visible in front of the lens of the eye. Its coloration is the eye color of every person.

The pigmentation of the iris is not yet fixed at birth, but develops in the first year of life or later. A baby's eyes are almost always blue or gray at first.

The pupil is located in the center of the iris . It is a round hole that can be changed by the muscles of the iris.

This allows the eye to react to different light conditions. The iris therefore acts as a diaphragm in a camera.

Pupil reflex

We cannot consciously control the size of the pupil. Instead, it is controlled by the autonomic nervous system.

In stressful situations, in dark lighting conditions or when looking into the distance, the pupil dilates.

Conversely, the pupil diameter is reduced in bright light, when tired or when focusing on the near range.

The iris divides the area between the lens of the eye and the cornea into a posterior and anterior chamber.

Diseases of the iris

The middle part of the eye is sensitive and can quickly become inflamed if the immune system is weak.

Indications of iritis are

• Pain due to exposure to light
• A strong flow of tears
• A spasm of the eyelid with deterioration of vision

The inflammation of the iris can be either acute or chronic. As a rule, iritis is a concomitant disease of a rheumatologic disease. If the iris of the eye is inflamed, the ciliary body is usually also inflamed (cyclitis).

Iritis can have various causes, such as

• Various pathogens(Lyme disease - infection by ticks)
• Viral infection caused by influenza viruses

In the areas of inflammation, changes occur in the blood vessels of the iris. As a result, proteins or white blood cells can leak out of the anterior chamber of the eye.

This results in poorer visual performance. Inflammation of the iris can also lead to the secretion of fibrin and cells that block the drainage pathways of the aqueous humor. This can lead to adhesion of the cornea, iris and pupil.

The inflammation of the iris disrupts the aqueous humor circulation. As a result, the intraocular pressure rises (secondary glaucoma). In extreme cases, this can lead to blindness.

In albinism, the iris lacks pigmentation so that the back of the eye shows through. This leads to a reddish eye color. As the iris has a glare function, it cannot perform this function in albinism. The person affected feels blinded.

Most people with albinism have a lighter eye and hair color @ AnnaStills /AdobeStock

If the iris is not present at birth, experts call this aniridia. Defects in the iris of the eye are called colobomas.

The ciliary body (corpus ciliare)

The ciliary body (corpus ciliare) is part of the middle membrane of the eye. It is located between the iris and the choroid of the eye. It consists of the ciliary epithelium (membrane) and the ciliary muscle and surrounds the lens of the eye in a ring shape. It thus gives it support.

It is also involved in the production of aqueous humor for the eye chambers. The aqueous humor ensures a stable intraocular pressure.

During aqueous humor production, the epithelium first releases the fluid into the posterior chamber of the eye. From there, it can flow into the anterior chamber so that the cornea and lens are "washed around".

The anterior and posterior chambers of the eye contain around 125 microliters of aqueous humor. Production takes about one hour.

The ciliary body and the lens are connected by zonular fibers (suspensory ligaments). Tension on the fibers can cause the lens to contract or relax. Due to the flexible refractive power of the lens, it canfocus at distance and near.

Diseases of the ciliary body

The ciliary body is closely connected to the iris in an anatomical sense. Diseases therefore often occur in combination. Doctors call inflammation of both areas "iridocyclitis". If left untreated, it can lead to glaucoma or cataracts.

Eye pain and sensitivity to light can indicate inflammation of the ciliary body.

Other typical symptoms are

• Visual disturbances
• Color changes of the pupil
• Adhesions between the pupil and cornea

Inflammation of the ciliary body often has internal causes, such as

• Herpes viruses (human papillomaviruses)
• Various bacteria
• Corrosive chemicals
• Autoimmune diseases (rheumatic diseases)
• Concomitant disease in chronic intestinal inflammation
• Diseases of the connective tissue

The ciliary body can also be affected by tumors. The most common of these is malignant melanoma of the ciliary body. This is a life-threatening disease that requiresurgent ophthalmologic care. Ideally in an ophthalmo-oncology center.