Fungal flora of the conjunctival sac in healthy and diseased eyes.

IN the past 13 years there has been a notable increase in the number of reports of cases of ocular mycosis, a large proportion of which originate in North America (Haggerty and Zimmerman, 1958; Mikami and Stemmermann, 1958; Chick and Conant, 1962). The increase has apparently been associated with the increasing use of topical corticosteroids and wide-spectrum antibiotics (Hogan, Thygeson, and Kimura, 1954; Suie and Havener, 1963; McLean, 1963). There is experimental evidence for the enhancement of the effects of fungus infection by corticosteroids (Mankowski and Littleton, 1954; Ley, 1956; Hirose, Yoshioka, Abe, Kanemitsu, and Kiya, 1957; Agarwal, Malik, Mohan, and Khosla, 1963), and possibly also by wide-spectrum antibiotics (Tanaka, 1952; Seligmann, 1952, 1953; Ley, 1956). It seems certain that corticosteroids increase the virulence of species that are recognized pathogens, and some authors believe that they will allow species normally regarded as commensals to behave pathogenically (Agarwal and others, 1963; Suie and Havener, 1963). In the United Kingdom no similar increase has been reported in the incidence of ocular mycosis, yet the use of topical corticosteroids and antibiotics in ophthalmology is probably as frequent here as in North America or Japan. For this apparent discrepancy, which prompted the present investigation, there may be several reasons: (a) There may be a difference in the pathogenicity of the fungal flora to which the population is exposed in the United Kingdom as compared with other parts of the world, perhaps because of a difference in the range of species to which the population is exposed in each region. If this is the case, the use of topical corticosteroids may be less conducive to ocular mycosis here than in, for example, North America. Since no studies of the mycotic flora of the eye appear to have been published from the United Kingdom, the point cannot yet be decided. (b) It may be that the frequency of diagnosis of ocular mycosis in the United Kingdom has, in fact, increased, but has not been reflected by a corresponding increase of cases reported in the literature. This seems unlikely. (c) Possibly the diagnosis rate is lower in the United Kingdom than elsewhere. "Antibiotic-resistant" ocular infections due to fungi may well go unrecognized (Barsky, 1959).