Anatomy of the eye
Anatomy of the eye

How does the eye work?

The eye functions in the same way as the inner workings of a camera.

The front of the eye admits light rays through the cornea and the pupil (the middle of the iris that determines how much light enters the eye).

Next, the lens focuses that light through a clear gel-like substance—called the vitreous humor—onto the retina. The aqueous humor is in the front part of the eye in the anterior chamber. The retina is a thin layer of tissue that makes up the inner lining of the back of the eye.

The retina works like film in a camera, transforming light into images. It converts the light rays to impulses that travel along the optic nerve to the brain. The brain integrates the images sent from both eyes and interprets them as a single, three-dimensional image. This lets us perceive depth and distance.

If any of the parts of the eye become damaged, changes in eyesight can occur.

What is uveitis?

Uveitis is an inflammation of inner parts of the eye. The uvea consists of:

  • the iris (the colored portion of the eye)
  • the ciliary body (which produces fluid inside the eye and controls the movement of the lens)
  • the choroid (which lines the eyeball from the iris all the way around the eye)

Uveitis might also be known as iritis or iridocyclitis, depending on which part of the eye is affected by inflammation.

What causes uveitis in children and adolescents?

Uveitis can be caused by infection, injury or an autoimmune or inflammatory disease. However, many times an exact cause cannot be identified. This type is known as idiopathic, non-infectious uveitis.

What are the symptoms of uveitis in children and adolescents?

The symptoms of uveitis may not be obvious. Sometimes, children might complain of light bothering their eyes or blurred vision. Your child's eyes might look red or cloudy. However, these symptoms usually develop so slowly that permanent eye damage can occur before any visual difficulties are noticed.

In order to detect eye problems and prevent them from causing damage, your child needs frequent eye exams with a pediatric ophthalmologist.

Last reviewed by a Cleveland Clinic medical professional on 02/22/2019.


  • Expert knowledge and experience of healthcare providers at Cleveland Clinic
  • Angeles-Han ST, Rabinovich CE. Uveitis in children. Curr Opin Rheumatol. 2016;28(5):544-9.
  • American Academy of Ophthalmology. Pediatric Anterior Uveitis. Accessed 3/1/2019.
  • Parker DM, Angeles-han ST, Stanton AL, Holland GN. Chronic Anterior Uveitis in Children: Psychosocial Challenges for Patients and Their Families. Am J Ophthalmol. 2018;191:xvi-xxiv.

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