The many diverse theories put forward to explain the pathogenesis of pterygia testify to the fact that their aetiology has as yet not been adequately explained. In recent years ultraviolet irradiation (Cameron, I962; Elliot, I966; Peckar, I972) and microtrauma (Kubik, 1975) have been suggested as being major environmental predisposing factors. One theory is that tear film abnormalities cause local drying of the cornea and conjunctiva which in turn predisposes to these new growths (Barraquer, I965; Elliot, I966; Mackie, I97I; Greer, I972; Paton, 1975). Elliot (I966) stated that the sequence was ultraviolet light causing drying and that this was followed by the pterygium. These theories have been supported by studies of geographical distribution (Cameron, I962)-pterygia appearing to occur more frequently in hot, dry climates-and by clinical and biochemical studies of the tear film (Mackie, I97I). Our study was undertaken to investigate the correlation between the occurrence of pterygia and the 'dry eye'.
Material and methodsBoth the patients with pterygia and the controls were drawn from Bantus living in Johannesburg, South Africa (latitude 26°S), an industrial urban area with more than 250 sunny days a year. This area is within the latitudes 300 N and S where the incidence of pterygia is regarded as being highest (Cameron, I962).Forty-three patients with unilateral and eight with bilateral pterygia (59 eyes) and 23 normal subjects (46 eyes) aged between 44 and 79 years of both sexes were studied. The patients presented with one of three complaints: cosmetic, optical, or those due to secondary infection. No age or sex differences were found.As the 'dry eye' is defined as being either a quantitative or qualitative dysfunction of the tear film (Dohlman, 1971), we submitted all our patients and controls to Schirmer's tests and fluorescein break up time tests. The Schirmer's test was used to determine the quantitative tear formation. I2 mm wetting or more on the 5 x 30 mm strip of N' 41 Whatman filter paper after five minutes was considered to be nonnal (Moses, 1970).The fluorescein break up time test was used to measure the quality of the tear film (Girard and Moore,
La gale est une dermatose infectieuse transmise par l'ectoparasite Sarcoptes scabiei var. hominis. Elle reste encore fréquente et affecte les patients indépendamment de leur niveau socio-économique et de l'hygiène. Le diagnostic est essentiellement clinique. Un prurit généralisé à recrudescence nocturne et des manifestations cutanées de topographie particulière sont hautement évocateurs. La présentation clinique varie avec l'âge. Le diagnostic précoce est impératif pour limiter la transmission. Les traitements individuels et familiaux font appel aux traitements topiques (perméthrine ; benzoate de benzyle). L'ivermectine orale est indiquée en cas d'épidémie institutionnelle (homes, hôpitaux et prisons). Pour espérer un contrôle durable de l'infection, de nouvelles méthodes diagnostiques et des thérapeutiques simples, précises, efficaces et peu coûteuses sont nécessaires.
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