Abstract
Purpose :
The present study proposes to evaluate the technological viability of ultraviolet light as an alternative for CL sterilization, and its potential in social technology development.
Methods :
This experimental study was approved by the Research Ethics Committee of UNIFESP (9042310815), carried out in the Advanced Center of Ocular Surface (CASO), Department of Ophthalmology and Visual Sciences/UNIFESP, with partnership of the Central Laboratory of São Paulo Hospital. Sterile gelatinous lenses were contaminated with Pseudomonas aeruginosa (PSA) or Staphylococcus epidermidis (SEP) strains at 105 and 102 UFC/mL. After lenses contamination, the CLs were treated according to the groups (n = 9): a) Cleaning solution (CS): CLs sanitized with standard cleaning solution according to the product orientation; b) Ultraviolet light C (UVC): CLs sterilized in UVC laminar flow; d) Positive control (CT): CLs contaminated without treatment, e) Negative control (CTN): virgin lenses without any manipulation. After the treatments, lenses were incubated in BHI nutritive medium (brain heart Infusion) at 37°C, with daily observations, for 72 hours. Media that presented turbidity were seeded in blood agar, incubated at 37°C for 24 hours for further identification of the microorganism by Maldi-tof.
Results :
There was no bacterial growth in the negative control group, whereas, as expected, in the CLs of the positive control group, the bacteria SEP or PSA used in the CL contaminations were present.
It was observed that both, cleaning solution and UVC treatments, were 100% effective in the contact lenses decontamination with PSA at both concentrations (105 and 102 UFC/mL). On the other hand, cleaning solution was effective in 89% decontaminating of the lenses with SEP (105 and 102 UFC/mL). The UVC light decontaminated 100% of LCs with SEP at 102 UFC/mL, but only 56% at the highest concentration of the bacterium (105 UFC/mL).
Conclusions :
The UVC light still has doubts about its potential for decontamination of contact lenses with high concentration of SEP, although a concentration of the bacteria studied was very high and not found in the CLs of users. More studies have been carried out to verify the effectiveness of UVC light for contact lens sterilization.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.