Scanning Electron Microscopy Findings With Energy-Dispersive X-ray Investigations of Cosmetically Tinted Contact Lenses.

Cosmetically tinted contact lenses (Cos-CLs), including colored corrective lenses, are widely available to the public and are especially popular among teenage girls and younger women in Pacific Asians. Although the sale of Cos-CLs is regulated by prescription in most Western countries, they can be easily purchased without a prescription in other countries. In such regions, young wearers use Cos-CLs with little or no supervision from professional eye care providers. Many of those wearers are uninformed about appropriate lens use and care, including proper hygiene practices for handling and storage. Therefore, we may see an increasing trend in corneal disorders related to the unregulated use of Cos-CLs.1–5 Lens materials and surfaces play an important role in the adherence of bacteria to the lens surface6–9 and are also believed to influence the manifestation of microbial keratitis related to contact lens (CL) wear.7–9 Given the potential role of Cos-CLs in microbial infections, a better understanding of the nature of the tinted surfaces in such lenses is desirable. Additionally, if colorants, which are printed, dot-matrix patterned tint on the anterior/posterior lens surfaces, potentially induce changes in corneal epithelial cells,10,11 the elements of those colorants should be fully published; however, this information is mostly unknown, or the characteristics including the manufacturing methods used for colorants are unclear in the information provided on the Internet. In the article reported by Begley and Waggoner,12 nodular deposits on soft CLs were investigated using scanning electron microscopy with energy-dispersive x-ray analysis (SEM-EDX). The results provide a breakthrough for analysis of CL surface and indicated that most CL deposits contained calcium. The aim of this study was to use SEM-EDX to observe the surfaces of several commercially available Cos-CLs and to analyze the chemical elements in the colorants used in those lenses.