Why Surgeons Are Switching to the I-II Marking for DMEK and DSEK

November 13, 2025

For years, the S-stamp has been the go-to orientation marking, but it’s not perfect. That’s why we strongly recommend trying the I-II marking for your next surgery and here’s why.

What Makes I-II Different?

• Less Ink, Less Risk: The I-II marking uses significantly less ink, reducing potential endothelial cell damage.
• Peripheral Placement: Keeps markings out of the visual axis.
• Quick Orientation: The linear marks appear sooner during unfolding, saving time and reducing stress.

 

Anterior	Posterior	Actual Posterior Image

 

Our Chief Medical Director, Matthew Giegengack, M.D., explains why he made the switch:

“I’ve been exclusively using the I-II marker for my DMEK and DSEK surgeries for several years now. The I-II mark is more peripheral, which feels better to me. The ink probably does have some endothelial toxicity, and the I-II mark is substantially smaller than the S mark.

But the biggest reason? When you’re unfolding tissue, the I-II marks come into view quicker than the S mark. Sometimes the S mark is hidden in the fold, and you can’t see it until the graft is almost fully unfolded. With I-II, I know the orientation right away, and that makes the unfolding process much easier.”

 

Want to Try It?

Switching is simple. Just let your customer advocate know or email tissue@corneagen.com. And if you’re looking for tips, videos, or surgical pearls, check out our resource library at corneagen.com.