instrument insider
Kershner LRI Marker (Rhein Medical)

Even after a perfect cataract extraction with perfect IOL power selection, about 20% of patients have enough astigmatism to limit their uncorrected visual acuity. In these cases, I perform a corneal relaxing incision. The Kershner Marker is a useful part of this procedure.

Next, I apply the dye to the teeth of the Kershner Marker, which has a convenient axis alignment indicator on the top; I apply this to the previously marked steep axis of the cornea. The cross hatch pattern is easier to incise to the correct length than a curvilinear mark.

Each incision can correct about a diopter of astigmatism (less in the vertical axis).

Not all corneas are the same size, so it would be helpful if Rhein made another marker 1 mm larger in diameter. With this one reservation, I find the Kershner Marker a very handy tool.

Reviewed by Dr. Lloyd Taustine, who is in private practice in Louisville, Ky. Dr. Taustine is also a clinical associate professor in the University of Louisville School of Medicine's Department of Ophthalmology.