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Effect of trephine tilt on corneal button dimensions
American Journal of Ophthalmology
|June 15, 1986
Summary
Trephine tilt during corneal transplantation may not significantly impact wound shape or size, challenging the assumption that tilting causes wound disparity and postkeratoplasty astigmatism.
Area of Science:
- Ophthalmology
- Corneal Surgery
- Biomedical Engineering
Background:
- Wound disparity, a mismatch in donor corneal button and recipient wound size/shape, is linked to postkeratoplasty astigmatism.
- Tilting a hand-held trephine is hypothesized to create oval wounds and contribute to wound disparity.
Purpose of the Study:
- To investigate the quantitative contribution of trephine tilt to wound size and shape irregularities in corneal transplantation.
Main Methods:
- Eyebank eyes were subjected to hand trephination at varying tilt angles (0-25 degrees).
- The endothelial edges of the resulting corneal buttons were analyzed using the photogrammetric index method to assess shape and symmetry.
Main Results:
- All analyzed buttons exhibited significant deviations from theoretical circularity and symmetry.
- Button ovality and asymmetry were comparable across tilt angles from 0 to 15 degrees.
- Maximum ovality was observed at 20 and 25 degrees, but ovality and asymmetry did not correlate with the degree of tilt.
Conclusions:
- Trephine tilt angle does not appear to be the sole determinant of wound shape or disparity.
- Irregularly shaped corneal wounds can result even without intentional trephine tilting, suggesting other factors influence wound geometry.