Holmium laser thermal keratoplasty for hyperopia and astigmatism after photorefractive keratectomy

To report results of holmium laser thermal keratoplasty used to treat induced hyperopia and induced, as well as pre-existing astigmatism after photorefractive keratectomy.

Sixteen eyes of 16 patients were included in this study. Contact holmium laser (Technomed Holmium 25) was used in 7 patients to correct hyperopia (8 spots at 8 or 9 mm) and in 9 patients to correct astigmatism (4 spots at 7, 8, or 9 mm). Follow-up evaluation was done after at least 6 months. The effectiveness, stability, and safety of the procedure were investigated.

Spherical correction was ineffective (1.00 D or less) when applied at the 9-mm diameter treatment zone. Spherical correction applied at the 8-mm diameter treatment zone was ineffective in 1 eye. Three eyes achieved 1.00 to 2.00 D change, but 2 of these eyes showed an induced astigmatic change as well. Correction of astigmatism at the 7-mm diameter treatment zone resulted in a 0 to 4.00 D cylinder component change. Treatment at the 8-mm diameter treatment zone showed a 0 to 1.50 D effect and at the 9-mm treatment zone, 0.25 to 1.50 D. All eyes that achieved significant improvement (1.00 D or more change in cylinder component) showed significant overcorrection in the first postoperative phase. There were no sight threatening complications.

Holmium laser thermal keratoplasty can be useful for the treatment of overcorrection and induced as well as pre-existing astigmatism after photorefractive keratectomy. However, predictability is low and astigmatism can be induced with the attempted spherical correction.