TABLE 2.
NONABLATIVE SYSTEMS FOR HYPEROPIA CORRECTION
| DESCRIPTION | CONDUCTIVE KERATOPLASTY | SUNRISE HYPERION NONCONTACT LASER THERMAL KERATOPLASTY (LTK) | CONTINUOUS-WAVE DIODE LASER THERMOKERATOPLASTY (DTK) |
|---|---|---|---|
| Manufacturer | Refractec, Inc, Irvine, California | Sunrise Technologies, Fremont, California | Rodenstock; ProLaser Medical Systems, Inc, Dusseldorf, Germany |
| Approval status | FDA approved for 0.75 D to 3.00 D of spherical hyperopia | FDA approved for 0.75 D to 2.50 D of spherical hyperopia | Open Investigational Device Exemption |
| Type of device/energy delivery | Radiofrequency energy, 350 kHz, contact probe | Ho:YAG laser, pulsed 226 to 258 mJ, 5 Hz, noncontact | Continuous-wave diode laser, contact device |
| Wavelength | Not applicable | 2.1 μm | 1.87 μm |
| Temperature during treatment | Highest at center of cylinder | Highest on corneal surface | Radial and axial temperature gradient |
| Radial (side-to-side) temperature gradient | Radial and axial temperature gradient | ||
| No axial (surface to bottom) temperature gradient | |||
| Consistent thermal effect along the probe | |||
| Treatment depth | 80% of corneal depth, based on porcine histology | Wider on surface than in deep stroma | Not available |
| Footprint | Cylindrical | Conical | Conical |
| Number of spots | 8, 16, 24, or 32 | 16 to 32 | In development |
| Nomogram adjustment to increase effect | Increase number of treatment spots | Increase laser energy/temperature | Increase number of treatment spots |