DIATHERMIC CAPSULOTOMY VERSUS CAPSULORHEXIS - A BIOMECHANICAL STUDY

Purpose: To compare the mechanical quality of a capsulotomy opening pe rformed by diathermy with that made by capsulorhexis (tearing). Settin g: Department of Ophthalmology, Vejle Hospital, Denmark. Methods: This study included 12 pairs of human cadaver eyes and 20 pairs of pig eye s. One in each pair was randomly selected for one capsulotomy techniqu e. The capsulotomy edge was stretched in a materials testing machine u ntil break; force and elongation values were continuously recorded. Re sults: 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). Conclu sion: The mechanical quality of the diathermic capsulotomy edge is sig nificantly less than that of the capsulorhexis edge, which indicates t hat the diathermic capsulotomy edge would withstand less surgical mani pulation.