Application of the holmium:YAG laser for refractive surgery III

We update the continued progress of laser thermokeratoplasty (LTK) clinical trials being conducted in the U.S. for the treatment of hyperopia and hyperopic astigmatism. Data from the Phase II hyperopia investigations on 25 patients and from Phase I astigmatism trials on 30 patients is reviewed. From the hyperopia Phase IIa study, the near uncorrected visual acuity of 13 patients for whom complete follow-up results are available at 1 year shows that all 13 patients gained 2 or more lines of visual acuity (Ave. gain 3.5 lines), which indicates a significant improvement in near vision. A survey given to these hyperopia patients finds 8% could read without glasses preoperatively versus 58.3% at 1 year post-operatively. The preoperative uncorrected visual acuity of those patients treated for astigmatism in the Phase I trial showed 2 out of 30 patients or 6.7% seeing better than 20/40 versus 10 out of 27 patients or 37% at one year post-op. The one year data in both studies indicates that after an initial period of partial regression of effect, the residual correction remains relatively stable between 6 months and 1 year. Continued follow-up will be carried out to see if the corrections remain stable beyond 1 year.

[1]  Daniel S. Durrie,et al.  Application of the holmium:YAG laser for refractive surgery , 1992, Photonics West - Lasers and Applications in Science and Engineering.