RESUMO
PURPOSE: To compare corneal endothelial bleb formation and disappearance processes between rigid gas-permeable (RGP) contact lenses and soft contact lenses (SCL) in the same class of oxygen transmissibility (Dk/L). METHODS: Experiments were conducted on 20 eyes of 10 nonwearers of contact lenses using six kinds of RGP lenses or soft lenses with hyper (A), high (B), and medium (C) classes of Dk/L. Each subject kept their eyes closed for 20 minutes after putting on each test lens. Starting just after eye opening, the subjects' eyes were examined for blebs every 5 minutes by specular microscopy, and percentage area of the blebs were calculated. For control, the same eyes were also examined without contact lens wear. RESULTS: The percentage area of the blebs just after eye opening was 1.2% for RGP-A, 1.7% for SCL-A, 5.1% for RGP-B, 4.7% for SCL-B, 6.9% for RGP-C, 8.6% for SCL-C, and 0.4% for the control. The difference from the control became insignificant in the bleb disappearance process just after eye opening for RGP-A and SCL-A, after 5 minutes for RGP-B and SCL-B, after 10 minutes for RGP-C, and after 30 minutes for SCL-C. CONCLUSIONS: Regarding bleb formation and disappearance, there was no difference in influence on the corneal endothelium between RGP lenses and soft lenses with similar Dk/L in the high and hyper classes. In the medium class, however, it was suggested that RGP lenses may have less of an impact on the corneal endothelium than soft lenses do.
