Study On The Effect Of PM_2.5 On Contact Lens And Its Adhesion To Contact Lens And Chemical Composition

Objective:To observe the influence of atmospheric particulate matter PM_2.5 on the contact lens and analyze its adhesion to the contact lens and its chemical composition,so as to provide experimental basis for further study on the influence of PM_2.5.5 on the eye surface of the contact lens,and advance the improvement of the contact lens material and haze prevention treatment.Methods:A total of 36 contact lenses,including rigid gas permeable?RGP?and soft?SCL?lenses,was investigated.RGP?n=12?and SCL?n=12??experimental group?lenses were incubated in a PM_2.5 solution for24 h,after which PM_2.5-treated RGP?n=6?and SCL?n=6?lenses were further washed for 1 h in phosphate-buffered saline?PBS?.The remaining6 RGPCL and 6 SCL were used as the control group,incubated in PBS and oscillated at room temperature for 25 h.The oxygen permeability and refractive index of the contact lenses were measured by polarography and refractive index before and after treatment to evaluate the effect of atmospheric particulate matter PM_2.5 on contact lenses.Field emission scanning electron microscope?FESEM?was used to observe the attachment of PM_2.5.5 on the surface of contact lenses.The morphology and chemical composition of PM_2.5 on contact lens were analyzed by X-ray energy spectrum analyzer to provide a basis for haze prevention on the surface of contact lens and ocular surface.Results:The oxygen permeability and refractive index of contact lens in each group were detected by polarography and refraction apparatus,and no significant difference was found between the experimental group and the control group?p<0.05?.Average sizes PM_2.5 particles deposited on RGP and SCL contact lens surfaces after immersion in the PM_2.5solution were 3.192±1.637 and 2.158±1.187/100?m²,respectively.On RGP lens surfaces,we observed both large?>2.5?m diameter?and small(PM_2.5)particles,the diameter of PM_2.5 was 2.060±0.56?m,and these are almost compact,circular and dense.On SCL lens surfaces,PM_2.5 particles were deposited in diffuse patterns,primarily along the honeycomb-shaped border and the diameter of PM_2.5 was 1.359±1.056?m,and these are fine,uniform,loose and irregular in shape.No PM_2.5 particles were found in the central hole of SCL lens surfaces.Washing in PBS removed the larger PM particles from RGP lens surfaces,but left copious amounts of PM_2.5 particles,the count approximately was5.123±1.267/100?m².In contrast,nearly all PM particles were removed from SCL surfaces after PBS washing and the difference before and after washing was statistically significant?p<0.05?.Field emission scanning electron microscope?FESEM?and X-ray energy spectrum shows that the main components of PM_2.5 particles were carbon compounds,sulfates and nitrates,as well as a small amount of metal components.Conclusions:Deposition PM_2.5 particles on contact lens surfaces varies according to lens material.PM_2.5 particles deposited on SCL,but not RGP,surfaces were able to be removed by washing in PBS and did not appear to alter OP and RI of either lens type.