PTERYGIUM (pterygium; grech, pterygion wing; synonym alate pleva) — the triangular fold of a conjunctiva of an eyeglobe accruing on a cornea in the horizontal direction with internal less often from the outer side within a palpebral fissure.
Distinguish true and false P.
the True PTERYGIUM
the True PTERYGIUM — a disease of preferential mature and advanced age; usually develops at people, living and working in unfavorable conditions. when the conjunctiva constantly is exposed to irritation wind, dust, a dry air with harmful impurity, etc. In the southern countries and in the southern areas of the Soviet Union P. meets more often than in middle latitudes.
False, or cicatricial, the PTERYGIUM
False, or cicatricial, the PTERYGIUM (pseudo-pterygium) represents a reinforced fold of a conjunctiva (see); it develops as a result of a cicatricial union of a conjunctiva with a cornea after burns, injuries, inflammatory processes in to a cornea (see), operative measures concerning her tumors. Unlike true P. the pseudo-pterygium can have different situation depending on localization of damage. The progressing growth is not characteristic of it.
Part P. located on a cornea carries the name of a head, the place of transition from a conjunctiva to a cornea — necks, and the part lying on a conjunctiva — bodies. P.'s head grows into a cornea, destroying a front boundary plate (a boumenova a cover) and surface layers of a stroma. Ahead of P.'s head the strip of opacification of a cornea is defined gray color. The biomicroscopy allows to establish that this opacification consists of the separate centers going to deep layers of a cornea. In tissue of a body of P. numerous vessels are visible. At morfol. a research P. dystrophic changes in its connective tissue basis are defined.
P.'s growth usually slow and does not influence in the beginning function of sight, causing only cosmetic defect. In process of P.'s advance to a pupil visual acuity worsens, and at achievement of an optical zone of a cornea there occurs its considerable decrease.
Treatment only operational. Items of the small sizes delete by the method offered by Arlt: delete a head and P.'s body, and a conjunctiva over a naked sclera sew (fig. 1). At the big sizes P. removal of the considerable site of a conjunctiva can lead to its undesirable shortening. In such cases it is more preferable to move the separated P. to a section of a conjunctiva on Demarr's (fig. 2) way. At recurrent P. change of a donor cornea to the place of a remote head of P. is shown (see. Keratoplasty ).
Bibliography: Volokhovskaya 3. Item, Gratsianskaya E. A. and Karanov K. S. About dystrophy of a connective tissue basis of a pterygium, Vestn. of-talmas., No. 4, page 52, 1981; The Multivolume guide to eye diseases, under the editorship of V. N. Arkhangelsky, t. 5, page 30, M., 1960; The Guide to eye surgery, under the editorship of M. L. Krasnov, page 117, M., 1976; Rumyantseva A. F. Eye surgery, page 209, Kiev, 1957.
O. V. Grusha.