Ocular manifestations of onchocerciasis in a rain forest area of west Africa.
The epidemiology and natural history of onchocerciasis and its ocular complications in rain forest areas are poorly understood. The present study was conducted on a rubber plantation in a hyperendemic area in the rain forest of Liberia, West Africa, where 800 persons were examined. The prevalence of infection was 84% overall 29% had intraocular microfilariae, and 2.4% were blind in one or both eyes. Onchocerciasis was the cause of all binocular blindness and one-third of all visual impairment. Over half of the visual impairment caused by onchocerciasis was due to posterior segment diseases. Chorioretinal changes were present in 75% of people, and included intraretinal pigment clumping in 52% and retinal pigment epithelium atrophy in 32%. Atrophy of the retinal pigment epithelium was associated with increasing age and severity of infection. Intraretinal pigment was strongly associated with anterior uveitis. There was a strong correlation between uveitis and the inflammatory chorioretinal sequelae: retinitis, intraretinal pigment, subretinal fibrosis, and optic neuropathy. These findings indicate that considerable visual impairment associated with rain forest onchocerciasis is common and is due largely to chorioretinal disease.
Newland
H S
HS
Dana Center for Preventive Ophthalmology, Wilmer Institute, Johns Hopkins University, Baltimore, Maryland.
White
A T
AT
Greene
B M
BM
Murphy
R P
RP
Taylor
H R
HR
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000818:Animals; D000869:Anterior Eye Segment / Q000469:parasitology; D001766:Blindness / Q000209:etiology; D002648:Child; D002825:Chorioretinitis / Q000209:etiology; D005260:Female; D006801:Humans; D007988:Liberia / Q000453:epidemiology; D008297:Male; D008842:Microfilariae / Q000302:isolation & purification; D008875:Middle Aged; D015827:Onchocerciasis, Ocular / Q000150:complications* / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology; D009902:Optic Neuritis / Q000209:etiology; D010857:Pigment Epithelium of Eye / Q000473:pathology; D012168:Retinal Pigments; D012307:Risk Factors; D012737:Sex Factors; D014606:Uveitis, Anterior / Q000209:etiology / Q000473:pathology; D014786:Vision Disorders / Q000209:etiology*
D012168:Retinal Pigments