FUCHES UVEITIES:

ochromic iridocyclitis, is

Fuchs’ heterochromic uveitis (FHU), sometimes known as Fuchs’ heter

a chronic (longstanding), relatively mild form of uveitis of unknown cause. . FHU is usually a

unilateral disease (affecting one eye) but in about 15% of patients both eyes are involved. FHU

typically presents as a chronic uveitis with change in the color of one eye compared to the other

(a phenomenon referred to as “heterochromia,” hence the name). FHU is commonly associated

with the development of a cataract and/or glaucoma.

History

FHU has been described in the medical literature since at least the 19

th

 century. The first

definitive characterizations and studies occurred in the beginning of the 20

th

 century by Professor

Earnest Fuchs from Vienna. Since then, many other ophthalmologists have added to our

knowledge of this condition.

Course of the disease

Many patients with FHU have no symptoms for many years. During that time, the eye shows

mild signs of inflammation if examined, but the patient may not notice pain or redness. ..

However patients may seek medical attention because of decreased vision, ‘floaters’ or a change

in the color of one eye. FHU may also be discovered during routine eye examination.

Patients with FHU may experience periods of relative inactivity of their disease alternating with

periods of activity and increased symptoms. In particular, patients tend to notice vitreous

opacities and floaters when their vitreous detaches from the surrounding retina, a condition

called posterior vitreous detachment (PVD). Once a PVD has occurred, the vitreous becomesvery mobile and its motion inside the globe casts shadows on the retina, perceived as "floaters".

Diagnosis and testing:

There is no laboratory test that can make the diagnosis of FHU. Rather, the clinical diagnosis is

based on the findings of a mild chronic uveitis in association with other characteristic changes in

the eye, including flattening and thinning of the iris which may sometimes, but not always, cause

heterochromia (Figure 1). If there is heterochromia, the affected eye may be lighter or darker

than the healthy eye. Other useful signs are the presence of inflammatory cells on the back

surface of the cornea (keratic precipitates). In FHU these keratic precipitates are distinct in their

appearance and distribution. Other types of uveitis may need to be ruled out, which is usually

done by careful history and the performance of laboratory testing.

Treatment:

Unlike most uveitis syndromes, FHU does not usually respond to corticosteroid treatment. Most

uveitis specialists avoid the long-term use of corticosteroids in FHU.

There are two conditions which may require medical and/or surgical treatment in FHU.

1. Cataract.  This  typically  presents  as  a  gradual  blurring  of  vision,  possibly

associated with glare while driving at night and difficulty reading. Cataract is

diagnosed on examination by an ophthalmologist. Cataracts may be removed

surgically  when  they  become  bothersome  to  the  patient  and  impair

performance of one’s activities of daily living.

2. Glaucoma. In most  cases, glaucoma does not  cause  symptoms in the  early

stages, and is only detectable by  examination. However, if undetected and

untreated,  glaucoma  causes  gradual  damage  to  the  optic  nerve  with

irreversible  loss  of  peripheral  (side)  vision.  Patients  with  FHU  should

therefore  be  examined  periodically  even  if they  notice  no  new symptoms.

Once  detected,  glaucoma  can  be  treated  medically  with  eye  drops  and

occasionally pills. Some patients require glaucoma surgery in order to control

the pressure inside their eyes and prevent visual field loss.