HYDRATION OF HIGH WATER NON-IONIC SOFT LENSES DURING HYDROGEN PEROXIDE DISINFECTION

Title HYDRATION OF HIGH WATER NON-IONIC SOFT LENSES DURING HYDROGEN PEROXIDE DISINFECTION
Author, Co-Author Russell Lowe, Richard Lindsay, Noel Brennan, Michael Harris, JD
Topic
Year
1992
Day
Sunday
Program Number
1:15 pm
Room
Great Hall North
Affiliation
Abstract Hydrogen peroxide produces substantial hydration changes in ionic, high water, hydrogel contact lens materials. With a number of new non-ionic hydrogel materials recently released onto the market, it is topical to consider the influence of hydrogen peroxide on the parameters of these lenses. We measured the water content (hydration) of a set of high water, non-ionic soft contact lenses during brief and overnight two-step hydrogen peroxide disinfection (Omnicare, Allergan). The contact lenses evaluated were Calendar (Barnes-Hind), Cristelle (Essilor), Excelens (Ciba Vision), Lunelle (Essilor), Igel 67% (Igel), Gelflex EWII (Gelflex), Menicon Soft 72 (Menicon) and Weicon CE (Ciba Vision). The water content of each soft lens was measured with a refractometer before disinfection, after disinfection and after neutralization. Two different disinfection/neutralization cycles were investigated: (i) 20 min disinfection followed by 10 min neutralization (ii) overnight (approx.9h) disinfection followed by 20 min neutralization. During both disinfection cycles the lenses showed small decreases in percentage water content (1.4, 11.0 and 1.6, 11.1 respectively). A partial return to pre-disinfection water content was observed following the 20 min neutralization period but not after the 10 min neutralization (0.5, 11.0 and -0.2, 10.9 respectively). The individual materials showed variation with respect to their susceptibility to hydrogen peroxide disinfection. However, the amount of dehydration for a given material was comparable for the brief and overnight cycles (r=0.75 for the disinfection component and r=0.95 following neutralization). Despite the consistency of the water content changes during disinfection, the extent of dehydration is unlikely to pose clinically significant problems. The implication is that prescribing non-ionic, high water content lenses with a hydrogen peroxide lens care system is acceptable.
Affiliation of Co-Authors
Outline