A Comparative Study of the Effect of Hydrogen Peroxide and Polyhexamethylene Biguanide Contact Lens Solutions on Pseudomonas aeruginosa, in vitro.

Contact lens cases contaminated with Pseudomonas aeruginosa are a major risk factor in ocular infections. A comparative study of the effect of 0.6% hydrogen peroxide and 0.0005% polyhexamethlylene biguanide on Pseudomonas aerugunosa isolated from three different sources, and cultured on nutrient agar plates and one drop of the undiluted disinfectant. Result showed that the 0.6% hydrogen peroxide had a wider diameter of zone of inhibition (466+1.00mm)than polyhexamethylene biguanide (335 + 5.00mm) indicating better disinfectant activity. This difference was significant using the Z-test at 0.05 level of significance (p>0.05). Furthermore, the diameters of the zones of inhibition decreased with serial dilution of the disinfectants. The minimum inhibitory concentration of hydrogen peroxide was 6x107 while that of polyhexamethylene biguanide was 5x10 -8 or 12 times a more effective disinfectant. Hydrogen peroxide is a very effective contact lens disinfectant solution in order to avoid possible pseudomonas infection of the eye.Key words: Contact lens, disinfectant Pseudomonas aeruginosa, ocular infection