AFM in mode Peak Force applied to the study of un-worn contact lenses

Abstract

Contact lenses (CLs) are of common use and the biocompatibility, topography and mechanical properties of the used materials are of major importance. The objective of this contribution is to apply the AFM in mode Peak Force to obtain surface topography and mechanical characteristics of un-worn CLs of different materials. One material of hydrogel, two of siloxane-hydrogel and one of rigid gas permeable, were used in the There is no significant influence of the environment, water or saline solution, on the measured properties.

Characterization of surface roughness of new nanophotonic soft contact lenses using lacunarity and AFM method

“…Also, as it is mentioned before, fullerene unlike its derivates, fullerol and methformin hydroxylate fullerene, does not dissolve in water and certain solvents. Topographic analysis in this study dealing with the hydrogel SCL type was comparable with values reported in the literature [53][54][55][56][57]. The inhomogeneity may originate as a consequence of processing, showing that some parts of surface had polymers with altered conformation states, thereby expressing different intermolecular interactions.…”

AFM in peak force mode applied to worn siloxane-hydrogel contact lenses

“…The characteristics of un-worn P and AO CLs were studied in a previous work [12], and they are summarized in Table 1 for the case of being immersed in saline solution. Figure 1 shows the AFM topographic images of several worn CLs, corresponding to several subjects, for both Si-H CL types.…”

“…For the topographic analysis, four parameters have been used [20]: mean roughness (Ra), root-mean-square roughness (RMS or Rq), skewness (Rsk) and kurtosis (Rku). More details were reported in reference [12].…”

“…Adhesion, Adh, or adhesion force, is a measure of the binding interaction between two material surfaces as a result of intermolecular forces. More details were reported in reference [12].…”

“…In a previous paper [12] the applicability of the Peak Force mode of AFM to study un-worn CL was proved. Thus, the main goal of this paper is to obtain the adhesion and the Young modulus of two worn Si-H CL made of different materials using the Peak Force mode, and to compare these values.…”