Pupillary Margin

The pupillary margin is the inner edge of the iris, formed by pigment ectodermal epithelium, resembling the peculiar pigment necklace. It is better pronounced in the miosis state, thereby it is beneficial to carry out biomicroscopic examination with constricted pupils, using a bright light source. To obtain the reliable data in dynamics, it is necessary to conduct the following measurements with the similar pupils diameter.

The pupillary margin is developed from the anterior part of the embryonal eye sac of the fetus. Usually it looks like a beautiful velvety rim of dark-brown or black color. The average dimensions of the pupillary margin is 0.2 - 0.8 mm (i.e. 1.7-6/7 % of iris diameter), depending on the form. Its configuration is individual for every person, nevertheless, it is possible to distinguish 6 main types of pupillary margin:

The first two types (uniformly thickened and uniformly granular) are considered to be the indicator of relatively good states of the pigment metabolism of a person, reflecting the state of the immune system. The other 4 types take place in certain pathological states. For example, aureole-like form can be found in patients with diffuse changes in stomach, such as sub-atrophic and atrophic gastritis. Thin form takes place in exhaustive chronic diseases, cancer. Some authors call uniformly thinned pupillary margin 'neurasthenic (asthenic) ring', associating this sign with the increased sensitivity, weakness, and the state of constant excitation.

During a person's life, the progressive 'melting' of the pigment takes place because the content of melanin in the organism is decreasing. The width of the normal margin is reduced approximately twice from 2-d till 7-th decades. This rule does not work in case of thin and non-uniform pupillary margin. Besides changes of form, chromatic changes should also be distinguished, including decoloration from the outside, which points to the exhaustion of the immune and anti-tumor resistance. According to the data of R.Schnabel, the partial defect of the pupillary margin in the upper sector is indicative of the dysfunction of the central nervous system, excessive sensitivity of brain, and an inherited predisposition to the vascular cerebral disturbances. The most detailed studies of the morphological and clinical features of the pupillary margin were carried out by I.Angerer. He considered that pupillary margin reflects the state of the neuronal control in the organism, being the peculiar product of the neurons metabolism. The author described 21 types of pupillary margin. The state of pupillary margin is the indicator of the parasympathetic nervous system activity. In case of moderately pronounced margin, parasympathetic activity is normal. In case of the thin margin – reduced, and in case of thick and wide - increased.

Sample Course Level

Besides the mentioned pathology, it is necessary to know the ophthalmologic symptoms of specific disease processes regarding the pigment margin of pupil.

In iridocyclitis, mostly chronic ones, small whitish, semi-transparent fluffy clods with the round shape, resembling cotton wool, can be observed at the pupillary edge. They are called efflorescence. Such formations are situated on the surface of the non-changed pigment epithelium, and are friably connected with the tissue and thereby can move to the other areas of iris. Usually there are no reactions on such formations from the surrounding tissues. The lifetime of efflorescence is different - from several days to more than a month. In most cases, they resolve completely. In the case of a focal type of the tuberculous iridocyclitis, the specific eruption (tubercles) can be found not only in the area of the lesser arterial circle, but also in the area of the pupillary edge. They have a grayish-yellow color and distinct borders. The absence of the vessels in the tubercle is the typical symptom. Sedimentation of sebaceous precipitates on the posterior surface of the cornea often accompanies such symptoms. Papules near the pupillary edge of the iris - small knots of the reddish-yellow color - take place in syphilitic iridocyclitis, observed in the secondary period of syphilis. Contrary to the tubercle, all the papule is pierced with the blood vessels and more often is situated in the area of the autonomous wreath. Papules are resolved completely.

Pigment cysts of the pupillary margin can be found after long-term administration of the miotic drugs. The dimensions of cysts are 0.1 - 1 mm, their amount - up to 10 and more. The pigment cyst protrudes to the pupil gap, and at biomicroscopic examination looks like the small round formation of dark-brown color with velvety surface. Involution of cysts can be very slow (up to 1 year).