Diathermic capsulotomy versus capsulorhexis: a biomechanical study.

PURPOSE

To compare the mechanical quality of a capsulotomy opening performed by diathermy with that made by capsulorhexis (tearing).

SETTING

Department of Ophthalmology, Vejle Hospital, Denmark.

METHODS

This study included 12 pairs of human cadaver eyes and 20 pairs of pig eyes. One in each pair was randomly selected for one capsulotomy technique. The capsulotomy edge was stretched in a materials testing machine until break; force and elongation values were continuously recorded.

RESULTS

In humans, the extensibility of the diathermic capsulotomy edge was approximately half that of the capsulorhexis edge (mean 38% +/- 4 [SD] versus 68% +/- 6), and the force required to break the edge was reduced by a factor of five (26 +/- 8 mN versus 134 +/- 36 mN).

CONCLUSION

The mechanical quality of the diathermic capsulotomy edge is significantly less than that of the capsulorhexis edge, which indicates that the diathermic capsulotomy edge would withstand less surgical manipulation.