A Preliminary Study of Silicone Hydrogel Lens Material and Care Solution Bioincompatibilities

Abstract

Use of an objective quantitative physiological method suggests that significant differences in lens solution bioincompatibilities occur that mirror corneal staining data relative to corneal compromise.

Dendritic immune cell densities in the central cornea associated with soft contact lens types and lens care solution types: a pilot study

“…In acute studies (2-hour studies)20,21 and in a longer-term (1-month) study,22 silicone hydrogel lenses that were conditioned with PHMB-preserved solutions resulted in excessive corneal staining, while silicone hydrogel lenses conditioned with peroxide solutions or PQ/MAPD solutions resulted in minimal corneal staining. Similarly, silicone hydrogel lenses in combination with PHMB solutions have been found to induce fluorescein penetration through the cornea at a rate ratio that was significantly higher than the rate ratio associated with PQ/MAPD solution and silicone hydrogel lenses 23. Laboratory and clinical studies have indicated that silicone hydrogel lenses absorbed biocides (like PHMB and alexidine) during soaking,24–26 and then released the biocides into the eye during lens wear 27.…”

Effects of Lens-Care Solutions on Hydrogel Lens Performance

“…Even though this study found a correlation between the increased corneal staining and corneal epithelial permeability noted with RevitaLens, it is important to delineate the difference between corneal staining and corneal epithelial permeability because there is still conflicting evidence regarding their relationship and their implications on ocular health. 18,19,47 Epithelial barrier function evaluated by fluorometry measures the amount of fluorescein that penetrates through the epithelium and remains after all excess fluorescein is washed. 16 There are multiple proposed explanations of epithelial corneal staining visualized with sodium fluorescein, namely, (1) fluorescein pooling in areas of epithelial erosions, (2) paracellular movement of fluorescein due to damaged tight junctions, (3) transcellular diffusion due to damaged surface glycocalyx followed by movement through gap junctions, (4) solution-induced corneal staining, and (5) preservativeassociated transient hyperfluorescence.…”

“…7 Manufacturer-provided lens cases were used with each solution to reflect real-world use and to minimize binding of preservatives to cases. 19 Staff members prepared the study lenses while wearing sterile nitrile gloves to minimize contamination during lens handling. Subjects wore the contact lens and were exposed to each solution for 2 hours.…”

“…Previous clinical studies have demonstrated that certain formulations among the older generation of multipurpose solutions can have a greater impact on corneal epithelial permeability, but similar investigations on the newer generation of multipurpose solutions (Biotrue, Opti-Free PureMoist, RevitaLens, and Clear Care) have not been done. 18,19 Currently, there has been only one in vitro study on newer multipurpose solutions using cultured human corneal epithelial cells, which found that Biotrue had the least impact on cell viability and epithelial barrier function. 20 Nevertheless, in vitro models are unable to simulate the complex system involving interactions among various ocular-surface parameters; therefore, an in vivo study is warranted.…”

Safety Assessment of Fatty Acid Amidopropyl Dimethylamines as Used in Cosmetics

“…Myristamidopropyl dimethylamine is used as a biocide in contact lens disinfecting solution (concentration reported to be *0.0005%) and may have uses as a broad-spectrum therapeutic antimicrobial for keratitis and for surgical prophylaxis. [25][26][27][28][29][30] Toxicokinetics Absorption, Distribution, Metabolism, and Excretion…”