Characteristics, Behaviors, and Awareness of Contact Lens Wearers Purchasing Lenses Over the Internet.

OBJECTIVES: To describe the characteristics and hygiene habits of contact lens (CL) wearers who acquire CLs over the Internet, as well as their awareness of modifiable risk factors (RFs). METHODS: A web-based survey was conducted among clients of an online CL sales platform during 6 months. Demographic data, CL hygiene-related awareness, and compliance were collected and analyzed. RESULTS: The questionnaire was completed by 1,264 CL wearers: the average age was 40.8 years; most were women (71.1%), had myopia (76.4%), and wore monthly disposable CLs (63.6%). The frequency of eye examination was significantly lower among those buying the CL exclusively online (15.8% vs. 6.6%, P<0.001) and those who had begun CL use on their own (17.5% vs. 8.8%, P<0.001). Initiation to CL wear without the intervention of an eye care practitioner was more frequent in wearers with less experience. Common risk behaviors included water exposure (68.1% in swimming and 64.9% in the shower), use of the case (61.9%) and CL (65.1%) beyond the recommended replacement time, and reuse of the maintenance solution (31.9%). Ignorance of recommended hygiene increased the probability of risky behavior. CONCLUSION: There were no differences in compliance or awareness of risks between those purchasing exclusively online and other CL wearers. However, the growing frequency of self-taught initiation in CL wear among less-experienced online customers and online exclusive purchase was associated with a decrease in eye examination frequency and therefore worse compliance and increased risks. This finding underlines the importance of publicizing correct hygiene habits by all possible means so as to increase compliance.

The conformity of a soft contact lens on the eye.

An axisymmetric elastic shell deformation model has been created to predict the conformity of a soft contact lens when pressed against the eye. Regions of contact and gap may be predicted, and the nonuniform reaction pressure between the lens and eye may also be found. This is important for issues like abrasion and comfort. Bending, membrane and transverse shear loads within the lens are also computed. Commercial soft contact lenses and a representative eye shape are used for the examples. We find that the uniformity of loading against the eye is strongly affected by the degree to which the lens is shaped to fit the eye, and relatively unaffected by the thickness of the lens.