Complications of intrastromal corneal ring segment implantation using a femtosecond laser for channel creation: a survey of 850 eyes with keratoconus

PURPOSE

To report complications after the implantation of intrastromal corneal ring segments (Keraring; Mediphacos, Belo Horizonte, Brazil) in keratoconic eyes using a femtosecond laser (IntraLase; Advanced Medical Optics, Santa Ana, California, USA) for channel creation.

METHODS

Retrospective chart review of 531 patients (850 eyes) who underwent Keraring insertion using a femtosecond laser for channel creation. Intraoperative and postoperative complications were recorded.

RESULTS

Intraoperatively, there were 22 (2.7%) cases of incomplete channel formation. The rest of the intraoperative complications were galvo lag error (system malfunction) [five eyes (0.6%)], endothelial perforation [five eyes (0.6%)] and incorrect entry of the channel [two eyes (0.2%)]. Postoperatively, there were 11 (1.3%) cases of segment migration, two (0.2%) cases of corneal melting and one (0.1%) case of mild infection. The overall complication rate was 5.7% (49 cases out of 850 eyes).

CONCLUSION

In this study, intracorneal ring segment implantation using a femtosecond laser for channel creation was related to a number of complications. The most common complications were incomplete channel creation (intraoperatively) and segment migration (postoperatively).

Customized pachymetric guided epithelial debridement for corneal collagen cross linking

Backround

We describe a modified method for deepitheliazation prior to corneal cross linking (CXL). The technique may overcome the current corneal pachymetric limitation parameter (over 400 microns) that is necessary for the safety of the procedure without affecting the overall benefits.

Methods

In a series of two patients, with inferior topographic steepening and regional thinning (less than 400 microns corresponding to the area of corneal steepening), CXL after customized epithelial removal was performed.

Results

There were no intra- or postoperative adverse events seen by the nine month follow up examination. Stabilization of the corneal ectasia was observed up to nine months post-costumized pachymetric-guided epithelial removal.

Conclusion

The technique of customized pachymetric-guided epithelial removal is easy to perform and may overcome the limitations of the preoperative corneal pachymetry expanding the application of the procedure in patients with regional corneal thinning.

Ablationsprofile in der kornealen refraktiven Laserchirurgie

The predictability and quality of results in corneal refractive laser surgery are determined by a number of factors. Here, the calculation and choice of the ablation profile represent central elements. Our growing knowledge about the physical and optical properties of the eye in recent years has led to the development of different strategies in the generation of ablation profiles. This review describes the currently used ablation profiles with their advantages and disadvantages and provides an outlook on future methods for the calculation of ablation profiles.