Trabecular meshwork pigmentation

Introduction The trabecular mesh pigmentation is a manifestation of clinical diagnosis of pigmented glaucoma. Pigmentary glaucoma (pigmentary glaucoma) is a secondary open angle glaucoma caused by pigmentation in the anterior segment of the eye.

Cause

Important risk factors affecting the occurrence and development of PDS are: young people, men, myopia and white people. The harm of PG to society is caused by the age at which people start their careers, which has a great impact on society and families.

In Western society, PG accounts for 1% to 1.5% of the total number of glaucoma. PDS generally occurs in young people. The age of onset is 20 to 45 years old, but the proportion of men and women with PDS is also the same in the elderly. However, PG is more common in men, and the ratio of men to women is about 3:1. The age of onset of female PD patients is about 10 years later than that of men, with an average age of 46 to 53 years and an average of 34 to 46 years for men. PDS is more common than imagined.

For PDS, myopia is a risk factor. It has been found that the higher the degree of myopia, the younger the age at which glaucoma optic disc damage occurs. The depth of the iris cornea angle was also asymmetrical in patients with a significant asymmetry in the anterior chamber.

Whites are more likely to suffer from this disease, and rare people of color are rare in the East. There have also been reports of cases of PG in black and white mixed-race families and blackened albino.

Most PDS/PG cases are sporadic and have little family history. Shortly after the abnormal pigmentation in the anterior chamber was reported, the family with the Krukenberg shuttle was also reported. It was not until the 1980s that PDS could be autosomal dominant in the family disease PDS, and the gene associated with this syndrome was located at the end of the long arm of chromosome 7 (7q35-q36). The gene mapping associated with this disease is the first step in the isolation of this gene. The characteristics of the gene will help to elucidate the patho biochemical characteristics of PDS. Other special conditions, such as large eyeballs, large corneas can also be associated with PDS/PG. However, there is no risk of developing PDS after congenital glaucoma has become larger.

an examination

Related inspection

Fundus examination

Mainly based on the signs and intraocular pressure of PDS, glaucoma visual field and optic disc changes by transillumination examination to see the mid-circumference iris spoke-like translucent area, the most characteristic. In addition, slit lamp examination showed Krukenberg fusiform pigmentation on the posterior wall of the cornea. The anterior chamber was deep, the iris was posterior and pigmented. After the expansion, the pigmentation of the posterior surface of the lens near the equator was observed. The iris keratoscopy is a wide angle of the anterior and a dense pigmentation zone on the trabecular. With iris signs and some other signs, it can be diagnosed as PDS; if accompanied by pathological high intraocular pressure glaucoma vision and optic disc changes, you can diagnose PG.

Differential diagnosis

1. Iris pigmentation loss: There are no other diseases associated with Iris sporadic transillumination defects in PDS/PG. Patients with congenital glaucoma, occasionally visible transillumination defects near the attachment of the iris at the periphery, but not spoke-like. Occasionally, patients with exfoliation syndrome have pigment spreads, and the position of the transillumination defect is mostly at the edge of the pupil, or it is scattered throughout the iris. Irregular iris pigmentation is lost due to trauma or surgery causing damage to the posterior surface of the iris. Patients with post-irisal loss of pigment due to severe uveitis also have regional plaque loss, but not peripheral spoke-like defects. Occasionally there may be a marble pattern transillumination defect in a normal eye, but it is quite different from the PDS/PG change.

2. Uveitis: If small pigment particles float in the aqueous water, they are mistaken for white blood cells and are misdiagnosed as uveitis. To make the right judgment, it is necessary to notice the typical signs of PDS and lack other symptoms of uveitis, such as conjunctival hyperemia, KP, and post-iris adhesion. Pigment loss on the posterior surface of the iris in patients with PDS Although phagocytic cells can move forward into the iris matrix, they do not provoke an inflammatory response. Herpes zoster keratitis can cause atrophy of the fan-shaped iris, and herpes simplex keratitis can cause extensive iris atrophy. Neither had a PDS-like iris transillumination defect.

3. Increased trabecular mesh pigmentation: In addition to PDS/PG, abnormal pigmentation can also occur in other syndrome eyes. The pigmentation associated with exfoliation syndrome can cause the trabecular meshwork to become black. In many of these cases, the pigment is mixed with the exfoliating material to form an irregular, hemp-like pigment band. A typical Krukenberg shuttle is not developed. Typical capsular exfoliation aids in proper diagnosis.

Patients with peripheral iris or ciliary body cysts occasionally have moderate pigmentation on the trabecular meshwork, but there is no typical Krukenberg shuttle. Diagnostics by means of observing the characteristic diurnal defects of the peripheral iris PDS. The diagnosis of the subarachnoid cyst should be performed using dilated keratomileusis under dilated conditions. In both cases, there was no pigmentation on the posterior surface of the periphery of the lens.

4. Anterior and posterior melanoma: iris, ciliary body or posterior melanoma (if the anterior membrane of the vitreous is ruptured) can be accompanied by pigmentation. Pigmented neoplastic cells or pigmented phagocytic cells can cause considerable darkening of the anterior and posterior chambers. However, there is a lack of typical symptoms of PDS/PG: there is no Krukenberg shuttle, and there is no transillumination defect. It is easy to find the primary tumor. Inflammation of the posterior surface of the iris occasionally has a moderate amount of pigment release, often clustered in the lower corner of the anterior corner, accompanied by inflammation.

5. Others: PG can sometimes be caused after implantation of the posterior chamber intraocular lens. At this time, the posterior chamber IOL and the iris with abnormal position are in contact with the iris for a long time after surgery, and the friction leads to pigment release.

6. Exfoliation syndrome: mechanical friction between the peripheral lens and the iris around the pupil in pigmented glaucoma, similar to pigmented glaucoma, iris transillumination defect Krukenberg shuttle, trabecular pigmentation and elevated intraocular pressure, but the following conditions are easy to do Identification: more common in the elderly over 160 years old, rare in the age of 40 years old; 250% of patients are unilateral, no gender, refractive error (myopia) tendency; 3 transillumination defects are common in the pupillary margin and the surrounding iris is rare In the mid-week iris, the trabecular mesh pigmentation is not as dense as the pigmented glaucoma (usually grade 2); the most distinguishing feature is the gray-white dandruff-like particles or flakes of the pupillary margin, and the gray pseudo-sex on the peripheral lens anterior capsule. Exfoliate the substance. It has been reported that both diseases can coexist.

Mainly based on the signs and intraocular pressure of PDS, glaucoma visual field and optic disc changes by transillumination examination to see the mid-circumference iris spoke-like translucent area, the most characteristic. In addition, slit lamp examination showed Krukenberg fusiform pigmentation on the posterior wall of the cornea. The anterior chamber was deep, the iris was posterior and pigmented. After the expansion, the pigmentation of the posterior surface of the lens near the equator was observed. The iris keratoscopy is a wide angle of the anterior and a dense pigmentation zone on the trabecular. With iris signs and some other signs, it can be diagnosed as PDS; if accompanied by pathological high intraocular pressure glaucoma vision and optic disc changes, you can diagnose PG.

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