Conjunctival degenerations.
Pinguecula
Definition: Harmless grayish yellow thickening of the conjunctival epithelium in the palpebral fissure.
Epidemiology: Pinguecula are the most frequently observed conjunctival changes.
Etiology: The harmless thickening of the conjunctiva is due to hyaline degeneration of the subepithelial collagen tissue. Advanced age and exposure to sun, wind, and dust foster the occurrence of the disorder.
Symptoms: Pingueculum does not cause any symptoms.
Diagnostic considerations: Inspection will reveal grayish yellow thickening at 3 o’clock and 9 o’clock on the limbus. The base of the triangular thickening (often located medially) will be parallel to the limbus of the cornea; the tip will be directed toward the angle of the eye
Treatment: No treatment is necessary. Occasionally a pinguecula may become inflamed, a condition called pingueculitis.
Pterygium
Definition: Triangular fold of conjunctiva that usually grows from the medial portion of the palpebral fissure toward the cornea.
Epidemiology: Pterygium is especially prevalent in southern countries due to increased exposure to intense sunlight & in elderly
Etiology: Histologically, a pterygium is identical to a pinguecula. However, it differs in that it can grow on to the cornea; the gray head of the pterygium will grow gradually toward the center of the cornea. This progression is presumably the result of a disorder of Bowman’s layer of the cornea, which provides the necessary growth substrate for the pterygium.
Symptoms and diagnostic considerations: A pterygium only produces symptoms when its head threatens the center of the cornea and with it the visual axis. Tensile forces acting on the cornea can cause severe corneal astigmatism. A steadily advancing pterygium that includes scarred conjunctival tissue can also gradually impair ocular motility; the patient will then experience double vision in abduction.
Treatment: only necessary when the pterygium produces the symptoms discussed above. Surgical removal is indicated in such cases.
Clinical course and prognosis: Pterygia tend to recur. Keratoplasty is indicated in such cases to replace the diseased Bowman’s layer with normal tissue. Otherwise the diseased Bowman’s layer will continue to provide a growth substrate for a recurrent pterygium.
Subconjunctival Hemorrhage
Extensive bleeding under the conjunctiva frequently occurs with conjunctival injuries (conjunctival laceration). Subconjunctival hemorrhaging will also often occur spontaneously in elderly patients (as a result of compromised vascular structures in arteriosclerosis), or it