Commonest infection causing blindness in adult man -
Amongst the given options, only toxoplasmosis is a common cause of blindness.
"Toxoplasma infection is one of the most common latent infections of humans throughout the world".
"Almost all untreated congenially infected individuals will develop chorioretinal lesions by adulthood and about 50% will have severe visual impairment".
Toxocara
Plasmodium
Toxoplasma gondii
Tenia solium