Table 1. Characteristics of the contact lenses.
FDA Group I: non-ionic, low water (<50% H2O); FDA Group 2: non-ionic, high water (>50% H2O); and FDA Group 4: ionic, high water (>50% H2O)).
| FDA group | Ion charge | Water content (%) | Diameter (mm) | Basic curve (mm) | United States adopted name (USAN) | Manufacturer | |
|---|---|---|---|---|---|---|---|
| Pure Vision | I | Non-ionic | 24 | 14.0 | 8.6 | Lotrafilcon A | Bausch&Lomb |
| Softens 38 | I | Non-ionic | 38 | 14.0 | 8.7 | Polymacon | Bausch&Lomb |
| Softens Toric | II | Non-ionic | 64 | 14.5 | 8.5 | Alphafilcon A | Bausch&Lomb |
| Acuve 2 | IV | Ionic | 58 | 14.0 | 8.7 | Etafilcon A | Johnson&Johnson |
Notes.
a
Because the physicochemical properties of CLs from FDA Group 3 (ionic/low water) are similar to FDA Group 4, that CLs were not included in this study.