A prospective, randomized, double-blind comparison of 5 % against 1.25 % povidone-iodine solution in preoperative antisepsis for strabismus surgery in young children.

Endophthalmitis after strabismus surgery in young children leads to blindness
and loss of the affected eye. It is caused by conjunctival bacteria. PI
solutions between 1% and 5% reduce the number of bacteria on the conjunctiva.
The concentration used varies widely among clinics, from 1% to 5%. In vitro
studies have shown that PI is paradoxically more effective at lower
concentration, but in cataract surgery in elderly, 1% PI has been shown to be
less effective than 5% PI. Dilution by tear fluid or binding of PI to proteins
in tear fluid may lower its effectiveness. Since endophthalmitis after
strabismus surgery especially affects young children and the bacterial flora of
the conjunctiva in children is different from that in adults, the cataract PI
study should be repeated in young children operated for strabismus.

To compare the efficacy of 5 % vs. 1.25 % povidone-iodine (PI) as preoperative
antiseptic prior to strabismus surgery in children as a prophylaxis of
endophthalmitis. Given the low rate of endophthalmitis the conjunctival
bacterial flora rate is used as surrogate marker to determine the effectiveness
of topical PI in reducing or eliminating bacteria from the ocular surface at
the time of the surgery.

The study is a multi-centre, prospective, randomized-controlled,
parallel-groups, assessor-blind (microbiological assessments),
investigator-initiated trial.

Diluted PI, 1.25% or 5%, will be prepared in a sterile fashion, and distributed
in single-use dispensers. These will be coded for randomization. Before
initiation of surgery, children randomized to the 5% PI group will have their
conjunctival fornices irrigated with 5 ml PI 5%. Children randomized to the
1.25% PI group will have their conjunctival fornices irrigated with 5 ml PI
1.25%. Conjunctiva cultures for aerobic and anaerobic bacteria will be obtained
(1) after general anaestheasia has been established, (2) 5-10 min after PI
irrigation, (3) after reattachment of the eye muscles and (4) after closing the
conjunctiva with sutures.

Risks are limited to the act of taking the four bacterial cultures, as both
1.25% PI and 5% PI are approved preoperative antiseptic applications of PI and
both are used, rather indiscriminately, by the university departments of
ophthalmology participating in the study.