A manual of the principles and practice of ophthalmic medicine and surgery / by T. Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891
Date:
1847
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Licence: Public Domain Mark

Credit: A manual of the principles and practice of ophthalmic medicine and surgery / by T. Wharton Jones. Source: Wellcome Collection.

    498/620 (page 456)
    PTERYGIUM. 2323. Pterygium has its seat generally on the nasal side of the eye, in which case its base corresponds to, and is in- corporated with, the semilunar fold, but that it is not in its • nature an extension of that fold of conjunctiva is proved by the circumstance, that pterygium sometimes occurs on the temporal side, and even, though more rarely, on the upper or lower side of the eye. 2324. Moreover, in many cases, if not in all, the disease appears to begin by the formation of what ultimately forms its apex, close to the edge of the cornea, before any thicken- ing or unnatural vascularity of the conjunctiva is ob- servable. 2325. The disease is of consequence only when it impli- cates the conjunctiva cornea? so far that the vascularity and thickening extend to the middle of the cornea, and obstruct the pupil. 2326. Both the nasal and temporal sides of the same eye are sometimes the seat of pterygium. Cases have even been met with in which pteiygium existed not only on the nasal and temporal, but also on the upper and lower sides of the same eye. 2327. Two degrees of pterygium are met with, viz., ptery- gium tenue vel membranosum and pterygium crassum vel musculosum• the former thin and semi-transparent, the latter thick and fleshy-looking. 2328. Causes.—Nothing certain has been made out on this head. The subjects of it are generally old persons. It sometimes takes its origin in chronic inflammation of the conjunctiva. The affection has been most frequently met with in labourers whose work exposed them to the entrance of mortar and stone dust into the eye, and in persons who have been long resident in hot climates. Dr. Mackenzie mentions that he has seen a particle of gunpowder, which had been lodged for years under the conjunctiva, at last cause pterygium. 2329. Diagnosis.—Partial mediate symblepliaron is apt to be confounded with pterygium. Indeed, many of the cases which have been described and delineated as examples of superior and inferior pterygium, appear to be examples ra- ther of partial mediate symblepliaron. 2330. Prognosis.—The morbid state of the conjunctiva under consideration, is not disposed to disappear spontane- ously, but it may remain stationary or be long before it