Study finds, Factors Affecting Microbial Contamination on th
The results of this study demonstrates that Smart Touch Technology packaging, which is designed to reduce and simplify contact lens handling before insertion, is effective in reducing the frequency of bacterial contamination of the back surface of contact lenses after short-term wear.

The purpose of this study was to investigate the effect of lens packaging type, chelating agent, and finger contamination on microbial contamination on the back surface of worn soft contact lenses.

25 subjects completed each contralateral lens wear comparison in this randomized study: Smart Touch Technology versus conventional blister packaging for:
(1)Silicone hydrogel lenses with ethylenediaminetetraacetic acid (EDTA) and
(2)Hydrogel lenses without EDTA in the packaging, and
(3)Silicone hydrogel lenses without EDTA versus hydrogel lenses with EDTA both in Smart Touch Technology packaging.

Participants washed hands, underwent finger swabs, and inserted the lenses. After 45 minutes, lenses were removed aseptically and the posterior lens surfaces cultured.

Results:
--38 subjects participated in this study. Overall, the level of back surface contamination was low for both lens materials, ranging from 0 to 43 colony-forming unit (CFU)/lens for the silicone hydrogel and 0 to 17 CFU/lens for the hydrogel lenses.

--The proportion of lenses with zero back surface contamination ranged from 16 to 64% for silicone hydrogel lenses and 28 to 64% for hydrogel lenses.

--Contact lenses from conventional packaging containing EDTA had 3.38 times increased risk of contamination being present compared with lenses from Smart Touch packaging with EDTA.

--Contact lenses from conventional packaging without EDTA had 3.4 times increased risk of contamination being present compared with Smart Touch packaging without EDTA, and silicone hydrogel lenses had a 6.28 times increased risk of contamination being present compared with hydrogels.

--The median (interquartile range) number of bacteria isolated from fingers used to perform lens insertion after handwashing but before lens insertion was not significantly different between the silicone hydrogel and hydrogel lenses.

--Finger contamination was not significantly associated with lens contamination in the presence or absence of EDTA.

Finally, Smart Touch Technology packaging was successful in lowering the percentage of compromised lenses. Despite the fact that silicone hydrogel lenses were more likely to be contaminated, the presence of EDTA counteracted this. Contamination of the fingers was not linked to contamination of the lenses.

Source: https://journals.lww.com/optvissci/Fulltext/2021/05000/Factors_Affecting_Microbial_Contamination_on_the.14.aspx
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