Clinical Article The Antimicrobial Effectiveness of a Mechanical Soft Lens Cleaning Device Maureen Boost, MSc, FIBMS, CIBiol, MIBiol, Robert Conway, BSc, MPhil, Evon Char Tsui Shan, and Cherie Ng Yuk Sim 7% investigation compared the effectiveness of digital rubbing with that of a mechanical cleaning device, the Clensatron 7OOCL. Soft contact knses were contaminated with bacteria and fungi, which are ocular pathogens in the presence of protein. The lenses were cleaned by the two methods. Cultures of the lenses were set up immediately and survivors enumerated. Du- plicate lenses were soaked overnight after ckaning in an all-in- one kns care solution and then cultured and survivors enumer- ated. The cleaning device was shown to be superior in reducing numbers present before disinfection. Subsequent to disinfection, there were no surviving organisms on lenses cleaned with the cleaning device but some survivors on lenses cleaned by finger rubbing. 7% cleaning device would appear useful, especially for patients with poor compliance with cleaning regimes. Keywords: Hydrogel contact lenses; mechanical cleaning; micro- bial contamination One of the most frequently reported problems drophilic lenses is that of deposits adhering to surfaces. The main sources of these deposits are with hy- the lens ?? Ocular secretions, ?? Tap water contaminants that may have been adsorbed by the lenses, ?? Eye drops, ?? Nicotine, Address reprint requests to Mrs. Maureen Boost, Senior Lec- turer, Department of Health Sciences, Hong Kong Polytechnic, Hung Horn, Kowloon, Hong Kong. Accepted for publication May 1994. 0 0 0 Oil and dirt from the fingers, Eye makeup, and Air-borne environmental pollutants such as chemical vapors, calcium, iron, and other insoluble metal salts.‘,’ The bulk of deposits, however, are mucoproteins from the tear liquid. While the lens is on the eye, the mucin in the tear fluid is adsorbed onto the surface of the lens in the same way that it is adsorbed onto the epithelium of the cornea. Mucin and other proteins of the tears such as lysozyme remain in their natural state when attached to the soft lens surface in the eye. Daily removal of the lens results in a gradual denaturing of the adsorbed proteins. This occurs very slowly when the lenses are stored in a “cold” disinfec- tion solution but more rapidly when they are boiled. The problem is worsened by lipid secretions from the meibo- mian glands, which can also bind to the lens surfaces, form- ing a lipoprotein film that is difficult to remove.’ These deposits can lead to Reduced lens comfort, Reduced visual performance, Reduced wearing time, Increased frequency of lens replacement, Increased chance of ocular complications, and Discontinuation of lens wear. 3 The surface film may serve as a growth medium for bac- teria and fungi and may actually protect microorganisms trapped within it. This increases the danger of microbial or viral contamination of the soft contact lens, with subse- quent infection of the eye.‘6 Surface deposits are often seen with the slit lamp and may take the form of roughness 0 1994 Butterworth-Heinemann ICLC, Vol. 21, July/August 1994 137