gerami d seitzman

To determine if there is a difference in the quantity of microbial flora of the conjunctiva in individuals practicing head submersion (“dunk”) versus no head submersion(“no-dunk”) during hot tub use.

In this double-blind randomized clinical trial, healthy volunteers aged ≥ 18 years were recruited. Participants were randomized to head submersion versus no head submersion during a 15-minute hot tub soak. Study personnel,masked to the dunkor no-dunk group assignment,obtained conjunctival cultures before and immediately after hot tub use. De-identified specimens were submitted to the clinical microbiology laboratory for culture and analysis. The main outcome measure was the difference in the quantity of organisms cultured from the conjunctiva beforeand after hot tub exposure, as determined usinga defined ordinal scale.A two-tailed Student’s t-test was performed to compare the total microbial colony counts between the two arms. Simpson’s diversity was used to measure the changes in organism diversity between the arms.

Of 36 enrolled subjects, 19 were randomly assigned to thedunkand 17 were assigned to the no-dunk groups. Water samples obtained from all hot tubs wereculture negative. Eleven of 19 eyes (58%) from the dunkgroup and eight of 17 eyes (47%) from the no-dunkgroup had negative conjunctivalbacterial cultures before and after hot tub exposure. However, six of 19 eyes (32%) and four of 17 eyes (24%) of the dunkand no-dunkgroups, respectively, were culture-positiveafter,but not beforehot tub exposure. The quantity of organisms before and after hot tub exposure was notsignificantlydifferentbetween the two arms (P=0.12). However, the dunk grouponly showed a small increase in the quantity of organisms afterascompared to beforehot tub use(P=0.03). None of the samples from subjects or hot tubs were culture-positive for Acanthamoeba.

Head submersion in a public hot tubsduring a 15-minute soak does not appear to change conjunctival flora,as determinedby culture plate yield, this does not eliminate the association between hot tub use and devastating and painful corneal blindness. Therefore, our recommendation is to remove contact lenses prior to hot tub use, avoid head submersion in a hot tub, and urgently seek ophthalmological help if any eye pain and/or decrease in vision is experienced after hot tub use.