MedGen

Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. [from HPO]

A form of filariasis, caused by the parasitic worm <i> Onchocerca volvulus</i>, transmitted by the black fly. The infection can either be asymptomatic or manifest as an ocular disease (river blindness) with itchy eyes, erythema, photophobia, onchodermatitis or onchocercal skin disease (classified into acute papular, chronic papular, lichenified, atrophic, and depigmentated) and onchocercomas (over bony prominences). Other classic clinical manifestations are ichthyosis-like lesions (''lizard skin'') and ''hanging groin'', which may be associated with lymphadenopathy. [from ORDO]

Infections caused by nematode larvae which never develop into the adult stage and migrate through various body tissues. They commonly infect the skin, eyes, and viscera in humans. Ancylostoma brasiliensis causes cutaneous larva migrans. Toxocara causes visceral larva migrans. [from MONDO]

A parasitic infection characterized by the infestation with worms, mainly in the intestine. [from NCI]

A parasitic disease caused by tissue-invasive, vector-borne nematodes which can be found anywhere in the human body and that are transmitted to humans through the bite of an infected mosquito or fly or by consumption of unsafe drinking water and which, depending on the subtype can manifest with lymphedema, dermatitis, subcutaneous edema and eye involvement. The disorder is a major public health problem in many tropical and subtropical countries. Six subtypes have been described in the literature: lymphatic filariasis, onchocerciasis, loiasis, mansonelliasis, dirofilariasis and dracunculiasis caused by <i>Wuchereria bancrofti</i> and filarioidea of the genus <i>Brugia</i>; <i>Onchocerca volvulus</i>; <i>Loa loa</i>; <i>Mansonella</i>; <i>Dirofilaria</i>; and <i>Dracunculus medinensis</i>, respectively. Tropical eosinophilia is considered a frequent manifestation. [from ORDO]