How the eye works
Although it might not seem possible, a disease that affects the
joints can sometimes also affect the eyes.
Children with juvenile idiopathic (formerly called rheumatoid)
arthritis (JIA) can develop eye problems either as a result of the disease
itself or, rarely, as a side effect of some medicines.
This information will help you learn more about how JIA might
affect your child's eyes.
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, the pupil (the middle of the iris that
determines how much light enters the eye), and a transparent fluid known as the
aqueous humor in the anterior chamber.
Next, the lens focuses that light through a clear gel-like substance called the vitreous humor, onto the retina. 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, allowing us to perceive
depth and distance.
If any of the parts of the eye become damaged, changes in eyesight can occur.
What are some common eye problems that might affect children with JIA?
Uveitis is the most common eye problem that can develop in
children with JIA. 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) and
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.
If the inflammation is not detected and treated early, scarring
and vision problems can occur. Glaucoma, cataracts, and permanent visual damage
(including blindness) are all complications that could result from severe uveitis.
Uveitis can occur up to one year before, at the same time as, or
up to 15 years after JIA is diagnosed. It can also occur several years after JIA
is in remission (the disease is not active).
The severity of the child's joint disease does not determine how
serious the uveitis might be. However, eye problems are more common in children
with oligoarthritis (less than five joints with arthritis in the first 6 months
of disease). Eye problems are also more likely if your child has a positive
blood test for antinuclear antibodies (ANA). They are most likely to occur in
female toddlers.