• Excessive exposure to outdoor condition such as ultraviolet radiation, drying and trauma from wind and dust has been proposed as the etiology of this conjunctival change

Clinical Features

  • Symptoms:
    • Often asymptomatic or only cosmetic
    • Rarely cause visual impairment
    • May cause serious threat to vision if it progresses to visual axis
  • Signs:
    • Raised triangular growth of bulbar conjunctiva which invades the cornea, and like a pinguecula is predominantly located nasally
    • Progression of pterygium may be very slowly over many years.


  • Routine ocular examination is suggested to determine whether the pterygium is active by the degree of the vascular injection in the bulk of tissue and growth of the leading edge encroaching on the visual axis.
  • Surgical removal is indicated if the lesion causes discomfort or local irritation, significant visual impairment, or restriction of lateral gaze.
  • Beta irradiation, mitomycin-C and free conjunctival autograft have all been used to reduce the recurrence rate.
  • Recurrence rate is high, especially in those countries with constant high exposure to ultraviolet radiation.
An extensive pterygia causes marked mechanical restriction of right abduction.