Pigmentary glaucoma

The most important pigment contained in biological tissues and responsible for skin color is melanin. The pigment layer contained in the eye absorbs excess light not used by the retina during the visual act. It is located between the retina and the vascular membrane of the eye (pigment epithelium).

The iris, which functions as a diaphragm, also contains a pigment that absorbs light. The largest amount of melanin is normally found in the posterior leaf of the iris. Melanin, found in the anterior leaf of the iris, determines the color of the eyes: from blue (with a small amount of pigment) to dark (with a large amount of pigment).

Pigment lumps can be deposited on the surface of the eye structures (this is called dispersion syndrome). This condition in some cases contributes to increased intraocular pressure and the development of pigment glaucoma.

Most often, pigment deposition is observed on those surfaces of the eye that are constantly washed by aqueous humor, for example, on the back surface of the cornea, forming the so-called Krukenberg spindle.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ]

Symptoms of pigmentary glaucoma

Pigment dispersion syndrome is characterized by a specific eye structure: a deep anterior chamber, a wide angle. Myopic refraction is often observed with this pigment syndrome. The iris has a concave shape with a backward slope, due to which the iris contacts the zonules. This leads to mechanical erasure of the pigment from its back surface and the formation of defects in the form of rays. A particularly large amount of pigment accumulates in the trabecular network, which can lead to the development of pigment glaucoma. In a patient with pigment dispersion syndrome, when blinking (with the corresponding eye structure), aqueous humor is squeezed out of the posterior chamber into the anterior chamber, which leads to an increase in pressure in it. The reverse flow of aqueous humor is no longer possible, since the iris, which acts as a valve, is pressed against the lens.

Pigment syndrome is more common in men and is accompanied by myopia. The age of patients is 20-50 years. In older people, the syndrome is less common. This is explained by the fact that with age, the lens increases in thickness and moves the iris forward from the zonules. With age, accommodation weakens and melanin reserves decrease.

In pigmentary glaucoma, pigmentation of the anterior chamber angle is observed. This glaucoma can take a severe course, especially with pronounced fluctuations in intraocular pressure.

Treatment of pigment glaucoma

In most cases, surgery is necessary.

Peripheral laser iridotomy is also used, which reduces the pressure difference between the anterior and posterior chambers and thus prevents the peripheral part of the iris from deviating backward.