Answer:
The correct option is : a. Acanthamoeba keratitis
Step-by-step explanation:
Acanthamoeba keratitis is the infection of the cornea of the eye. This infection is caused by the protozoa Acanthamoeba and can lead to permanent blindness. This disease is very difficult to treat by using conventional medications.
The common medication used in the treatment of this infection is a combination of polyhexamethylene biguanide (0.02% to 0.06% drops) and chlorhexidine (0.02 to 0.2% drops).