| Purpose:
|
| Tear microspheres (TMSs) also referred to as pre-corneal deposits, "lipid plugs" or "mucin balls", have been observed in low numbers with soft and RGP contact lens wear. We compared the incidence of TMSs between low DK (group IV) and high DK (group I) hydrogel lenses during extended wear. |
| Method: |
| 153 subjects were randomly assigned either the low DK 6N EW (n = 77) or the high DK 30N CW (n = 76) lenses bilaterally. TMSs were observed using a biomicroscope (16x) as small (10-50 m) spheres showing reversed illumination and trapped between the lens and the cornea. They were seen to be adherent to the cornea until soon after lens removal leaving small, fluorescein filled indentations. The number of TMSs was counted at baseline, one week, 1,3,6,9 and 12-month visits. |
| Results: |
| A significantly higher number of TMSs (p < 0.05) were found in the high DK lens wear group (mean for all visits, 14 26) compared to low DK (5 4) lenses at all visits except 12 month EW visit (p<0.05). No relationship could be found between TMSs and any adverse events. |
| Conclusions: |
| High DK lenses produced a higher incidence and number of TMSs, than the low DK lenses. We are investigating the hypothesis that they are lipid encapsulated mucin and proteinaceous material resulting from a "shearing" interaction between the lens, tear film and ocular surface which especially occurs with high DK lenses. This could be related to the higher lens modulus of elasticity or surface properties of the high DK materials. TMSs do not apparently cause any clinical adverse effects.
This research was supported in part by the Australian government via the Cooperative Research Centres program and CIBA Vision. |
| Download PDF of Poster: |
| |
 You will need Version 4 or later ofAdobe Acrobat Reader to view some documents on this site. You can get the latest version from the Adobe Home site. |
Posters