الفهرس 
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Abstract
The prophylactic role of topical antibiotics, administered prior to cataract extraction is still the subject of dispute.
Leopold in 1972 claimed that the surgical field can not be completely sterilized, and the use of topical antibiotics may lead to the alteration of the local conjunctival flora, permitting the development of pathogens which flourish because competitive organisms have been inhibited.
Allen and Mangiaracine in 1974 stated that the elimination, reduction or suppression of indogenous ocular flora may significantly reduce the occurrence of postoperative infection.
Postoperative infections, especially endophthalmitis are serious complications of intraocular surgery. The aetiological agents of postoperative infections are often introduced intraocularly from patient’s own normal eyelid and conjunctival bacterial flora during surgical manipulation. To minimize the risk of postoperative infections prophylactic topical antibiotics are usually administered prior to intraocular surgery. (Baum, 1976).
To ensure protection from both Gram—positive and gram- negative micro-organisms, a broad—spectrum antibiotic such as gentamicin, erythrormycin or a combination of bacitracin and polymyxin, are frequently used in prophylaxis. The choice of topical prophylactic antibiotic should be based on its efficacy against the causative agent, its low toxicity, low risk of systemic sensitization and reasonable cost. (Taylor et al., 1988).
Most of the studies of the incidence of endophthalmitis following cataract surgery were performed over two decades ago; even then its incidence was low, being of the order of 1.30% (Starr, 1983).
Jankins in 1990 stated that the use of antibiotics prophylaxis can therefore be justified only an account of poor visual outcome of intraocular infection. The low incidence of infection has necessitated that clinical trials on the prophylactic use of antibiotics in cataract surgery be performed over many years, with vast number of
patients, in which it is almost impossible to keep other variables constant, such as advances in surgical technique. Reported therapeutic regimens have varied widely, not only in the choice of antibiotic but also in the route and timing of administration in relation to surgery.
Thus Allen and Mangiaracine in 1964 reported an incidence of endophthalmitis of 0.75% in 660 patients operated on without prophylactic antibiotics. While Kolicer et al. in 1967 reported an incidence of 1.42% in 494 patients given no prophylactic antibiotics compared with 0.21* in 480 patients given subconjunctival penicillin and streptomycin. But Christy and Lall in 1987 did not find any superiority of subconjunctival antibiotics on topical antibiotics.
AIM OF THE WORK
Evaluation of necessity of antibiotics routine in cataract surgery.