Natural fat in external eye. Vital-stained by Sudan III powder.

Examination of 113 eyes vital-stained by Sudan powder revealed that fat on the skin of outer canthus may pass onto the precorneal film (in 68%), and that the most reliable staining is obtained by application on the bulbar conjunctiva below the limbus corneae at 6 o'clock. In 41%, the precorneal film had stained drops or foam, with a tendency towards an increase among pathological cases (infectious conjunctivitis and blepharitis). An increased amount of fat was found in the mucous thread of eyes affected with infectious conjunctivitis and lagophthalmos. In a small number of pathological cases fat was also detected on cornea, bulbar conjunctiva, and inferior fornix. The fatty layer on the lower lid margin was stained more frequently and more intensely than that on the superior. The secretion of the meibomian glands was stained in no more than a scant one half of the glands (on an average 44%), independently of age, sex, site, and diagnosis.