[Computerized corneal topography in treatment of high grade astigmatism after perforating keratoplasty].

BACKGROUND

High astigmatism is the most frequent complication of penetrating keratoplasty for keratoconus. The postoperative use of corneal topography enables the surgeon to analyse the surface geometry of the graft and consequently to reduce in controlled steps the postoperative astigmatism.

PATIENTS AND

METHODS

Based on the measurements of corneal topography 13 patients underwent selective sutures removal and/or arcuate keratotomy to reduce high postoperative astigmatism (> 3 dpt). In 7 cases only selective sutures removal was applied. 5 patients underwent sutures removal combined with arcuate keratotomy and in one case only arcuate keratotomy was performed.

RESULTS

The mean astigmatism after perf. keratoplasty was 8.2 dpt (Min. 3.0-Max 19.0). After selected sutures removal or arcuate keratotomy the mean astigmatism was 4.7 dpt (Min. 0-Max. 6.5). The mean reduction corresponds to 4.7 dpt. In no cases we observed an increase in astigmatism after selective sutures removal.

CONCLUSION

The measurement of corneal topography after penetrating keratoplasty enables us to better analyse and recognize the tissue forces responsible for high astigmatism and consequently to selectively reduce it.