Materiales de alto Dk para compensación de irregularidades corneales. Dk/l de sistemas piggybackprimeros resultados.

Résumé

Purpose: Evaluate how selecting the material of a hydrophilic contact lens (HCL) and rigid gas permeable contact lens (RGP) influence the achievement of the appropriate physiological respect of the piggy-back systems. Material and methods: Six HCL, with premeabilities among 8.5 and 140 barrer, were combined with a PMMA contact lens impermeable to gas (24-189 barrer). With a polarographic probe coupled to a permeometer, transmissibility measures were obtained registering five measures for each piggyback system. Results: The PMMA lens showed the lowest permeability. All the remaining combinations showed a significant effect on the permeability to gas of the piggyback system. Conclusion: PMMA lenses are not adequate for piggyback systems. For the compensation of corneal irregularities, keratoconus or keratoplasty with risk of corneal neovascularization, only combinations of HCL and high permeability RGP should be used.