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SUMMARY The microbial flora of 738 patients with acute bacterial conjunctivitis, corneal ulceration, blepharitis, dacryocystitis, and discharging sockets has been investigated. Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae were the main pathogens isolated. Str. viridans was associated with conjunctivitis in patients aged under 1 year. Moraxella sp.was isolated on only one occasion. Overall, 40% of specimens were associated with Staph.

SUMMARY The concentrations of tear lysozyme, lactoferrin, ceruloplasmin, IgA, and IgG have been estimated in patients with dry eyes at the same time as semiquantitative bacterial culture was performed of the conjunctivae and lids. Staphylococcal isolations were quantified and biotyped. There was no increased conjunctival colonisation by any particular biotype of Staphylococcus aureus or Staph. epidermidis, and similar numbers of conjunctivae were sterile as in controls (33%); neither were any pathogens such as pneumococci or haemophili isolated. We consider that the conjunctiva of the dry eye, without the lacrimal secretion components of lysozyme and lactoferrin, has an alternative protective antibacterial mechanism which is derived from serum proteins via chronically inflamed vessels.The dry eye is often considered to be infected with staphylococci,' partly because they are easy to culture from the lids and conjunctivae2 and partly because of reduced amounts of tear lysozyme being present. However, the normal eye is usually colonised with certain types of staphylococci, so that commensals need to be distinguished from those with a pathogenic role. Different subtypes of staphylococci have recently been investigated in both normal persons and patients with chronic blepharitis by a semiquantitative culture technique.3 Certain biotypes of staphylococci were shown to exist in large numbers on normal lids and conjunctivae while only 33% of normal conjunctivae sampled were sterile. This same technique has now been used to culture organisms from patients with either keratoconjunctivitis sicca or 'questionably dry' eyes in order to investigate how the bacterial flora differs in these patients from that of normal persons and whether it relates to altered concentrations of lysozyme, lactoferrin, ceruloplasmin, or immunoglobulins found in their tears. Patients and methodsResults from 66 normal volunteers, aged 20-80 and previously described,34 have been compared with those from patients. Both groups were sampled for tear proteins and microbial culture over the same period by identical techniques. Both eyes were sampled of six patients with well established keratoconjunctivitis sicca, as were both eyes of 13 patients who were considered 'questionably dry' and who also had reduced levels of tear lysozyme and lactoferrin.The bacteriological sampling technique has been described previously3 together with the simple BairdParker scheme used to subdivide Staphylococcus epidermidis isolates into five biotypes. The enzymelinked immunosorbent assay (ELISA) method developed to measure the concentration of the various tear proteins has also been given,3 as well as the effect of age on normal levels.4 This has allowed us to compare the tear protein concentrations for each patient with expected normal values for that age. Results TEAR PROTEIN PROFILESIn the sicca patients both tear lysozyme and lactoferrin concentrations were more than 2 standard deviations below the mean of normal persons (p<0O05), while the ceruloplasmin concentration...

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