What Is Fuchs' Heterochromic Iridocyclitis?

Heterochromic iridocyclitis (HI) is a chronic non-granulomatous iridocyclitis that mainly affects one eye. Also known as Fuchs syndrome. The onset of this disease is insidious, and the inflammation is slight. Star-shaped KP (sediment) and iris depigmentation often appear in the diffuse distribution of the cornea or in the pupil area, and are prone to concurrent cataracts and secondary glaucoma.

Basic Information

English name: heterochromic iridocyclitis
Visiting department: Ophthalmology
Multiple groups: Young men
Common locations: eye

Common causes: Unclear etiology, may be abnormal development; neurological, genetic, immune factors
Common symptoms: Long course, slight inflammation, diffuse KP (sediment), iris depigmentation, etc. diffusely distributed in the cornea or in the pupil area

Causes of heterochromic iridocyclitis

The cause of the disease is unclear, and the following are currently possible:

Developmental abnormality

During the fetal period or at the beginning of life, there are certain factors that inhibit the normal development of the uveal membrane and cause iris heterochromia. Causes persistent but very slight inflammation, gradually appearing KP, aqueous turbidity, vitreous opacity, and iris atrophy, followed by lens metabolic disorders or difficulty in drainage of aqueous humor, concurrent cataracts or secondary glaucoma.

2. Neurological factors

HI is related to the blockage of the sympathetic nerve pathway that governs the eye, which induces nutritional defects, thereby inhibiting the formation of melanin particles. At the same time, this factor can also increase the iris vascular permeability and the subsequent protein leakage, aqueous turbidity, and release of inflammatory mediators.

3. Genetic factors

HLA-related genetic factors may play a role.

4. Immune factors

Plasma cells and lymphocytes are present in the aqueous humor of the patient, and inflammation may be caused by the immune response.

Clinical manifestations of heterochromic iridocyclitis

The course is long, the inflammation is mild, and it is slow and undulating. KP is characteristic, with small white dots or stars, which are diffusely distributed. KPs are not fused, and sometimes there are fiber-like filaments connected, and the appearance of the filaments is often exuded like floc. KP can disappear and repeat itself. Tynddall phenomenon is mostly negative, a few weakly positive, and some are positive. For example, compared with healthy eyes, the iris color of diseased eyes is lighter than that of healthy eyes. This characteristic change is caused by atrophy of anterior iris, stroma and pigment epithelium. Mild heterochromia is not easily identifiable, and severe cases have a velvety appearance with occasional blood vessel exposure. Iris atrophy begins in the anterior stratum, then the stroma, and finally the pigment epithelium. A strong light beam from a slit lamp was used to enter the back of the iris from the pupil, and when worm-like light was transmitted on the iris surface, it was suggested that the pigment epithelium had also collapsed.

At the beginning of the course of the disease, the pupil is smaller than the healthy side. In the later stage, the pupil is often irregularly enlarged, which indicates that the pupil sphincter is damaged. Koeppe nodules and Busacca nodules can also be encountered, but no post-iris adhesions occur. Increased iris ciliary body vascular permeability or neovascularization, damage to the blood-aqueous barrier, such as intravenous injection of sodium fluorescein, examination with a slit lamp microscope and cobalt blue filter, visible iris fluorescence leakage and no perfusion Area.

Heterochromic iridocyclitis examination

1. Aqueous aqueous cell count and gamma globulin

Peripheral blood soluble IL-2 receptor levels are elevated, patients have systemic lymphocyte activation, and circulating immune complex (CIC) levels can be determined.

2. Pathological examination

In iris specimens, non-specific chronic iris inflammation such as lymphocytes, plasma cell infiltration, and Russell bodies can be found under light microscope.

Slit lamp examination revealed characteristic KP, anterior chamber flashes, and discoloration of iris depigmented nodules, but no post-iris adhesions occurred.

3. Other auxiliary inspections

Including abnormalities of fluorescein iris angiography, abnormal angle of the room, ultrasound biomicroscopy.

Diagnosis of heterochromic iridocyclitis

Mainly based on the following clinical characteristics:

1. Most cases of monocular disease, long and undulating course, vision is not affected before complications occur;

2. The iris color of the sick eye is lighter than that of the healthy side;

3. There are obvious characteristic KP, Tyndall phenomenon is negative or weakly positive, no ciliary congestion or extremely slight, and no inflammation and irritation symptoms such as pain and photophobia;

4. Diffuse iris atrophy;

5. Post-iris adhesions do not occur.

Differential diagnosis of heterochromic iridocyclitis

1. Iris heterochromia caused by sympathetic nerve damage

In addition to monochromatic iris without signs of inflammation of the ciliary body of the horn, Horner syndrome also has signs such as drooping of the eyelid, invagination of the eyeball, shrinking of the pupil, and no sweating of the affected skin. (Trauma, surgery, Pancoast mass, etc.) are generally easy to distinguish.

Parry-Romberg syndrome is rare, and it is also monocular. The eye lesions are basically the same as HI, except for KP, which can be identified by the presence of progressive muscle atrophy in the affected side.

2. Simple iris heterochromia

It is abnormal iris development, no inflammation, and more eyes.

3. Other reasons

Diffuse iris atrophy caused by chronic iris ciliary inflammation can be seen in pigment KP, pigmentation of the anterior capsule of the lens, post-iris adhesion and so on.

Hemochromic iridocyclitis complications

Complicated cataract is the most common complication of HI. Occurs later in the course of the disease. In some cases, secondary open-angle glaucoma may occur later.

Heterochromic iridocyclitis treatment

Iridocyclitis

Generally, no treatment is needed, but glucocorticoid eye drops can be given for eye treatment when obvious anterior chamber flashes and more anterior chamber inflammatory cells appear.

2. Concurrent cataract

Most patients have better tolerance to surgery. The indications for surgery are complicated cataracts that significantly affect the patient's vision. KP and anterior chamber flashes are generally not contraindications for surgery. Glucocorticoid and non-steroidal anti-inflammatory eye drops were given before and after the operation.

3. Secondary glaucoma

Most of the secondary glaucoma of Fuchs syndrome can be controlled with drugs, so patients should first choose drug treatment. Those with uncontrollable intraocular pressure can perform different anti-glaucoma surgery according to the specific conditions of the patient.

Prognosis of heterochromic iridocyclitis

The prognosis of patients is generally good. The prognosis mainly depends on the effectiveness of cataract surgery and whether glaucoma is effectively controlled.