Adult worms migrating across the conjunctivae of the eyes can be removed surgically. They are first immobilized using a solution of 10% cocaine that is dropped into the eye, and the worm is then directly excised. The worm may still cause some edema in the conjunctiva and eye lid. Surgical removal is also used when worms are crossing the bridge of the nose.
Above: Surgical removal of adult worm from eye; Below: structure of DEC
DEC is a microfilaricidal, and it also can slowly kill adult worms. It is effective but risky due to its penetration of the blood brain barrier. Possible side effects are retinal hemorrhage and fatal encephalitis. A standard dosage is 2 mg/kg body weight, three times a day for 21 days.
Treatment of heavily infected patients should begin at low dosage and steroid and antihistamine cover should be provided for the first 2 to 3 days.
Pregnant women should not be treated until after delivery (From http://mednet3.who.int/eml...).
Structure of Ivermectin
Ivermectin is another effective microfilaricidal drug with a slower onset than DEC, and side effects tend to be mild, usually manifested as pruritis. Fatal interactions can occur, however, in patients being treated for onchocerciasis as well, including coma and other neurological complications. An experimentally effective dosage consisting of a 200 micrograms/kg every 3 months for two years resulted in significant reduction of microfilaremia (Ranque et al., 1996 as relayed in Markell et al)