The Cornea, Transplants and Specialized Cuts

The Cornea, Transplants and Specialized Cuts

Gregory Schmidt, BS, CEBTDirector of Tissue Preparation and Research

Iowa Lions Eye Bank

Layers of the Cornea

The Endothelium

Single layer of cells\Uniform in shape and density

Acts as a pumping mechanism

Cells do not proliferate Loss of cells results in enlargement/migration of neighboring cells

Trends and changes in eye banking occur to keep up with the advances in surgical techniques.

DSAEK – 2005 (North Carolina Eye Bank)IEK – 2006 (SightLife)DMEK/DMAEK – 2009 (Iowa Lions Eye Bank)

Surgical Trends

Penetrating Keratoplasty

Penetrating Keratoplasty ‐ LAK

Penetrating Keratoplasty – LAK Mushroom

Penetrating Keratoplasty – LAK Tophat

Penetrating Keratoplasty – LAK ZigZag

Amount of time to achieve BVA (3‐12 months) Greater surface area to promote stronger wound healing

Astigmatism

Penetrating Keratoplasty 

23,26921,970

21,620 21,422 20,954

18,22119,159

21,55523,049

24,987

1,116 1,5133,021

2,213 2,288

0

5,000

10,000

15,000

20,000

25,000

30,000

2009 2010 2011 2012 2013

EBAA Domestic Transplants by Type5‐year Data 2009‐2013

PKP EK Other

Surgical Trends

Endothelial Keratoplasty (EK)

EK ‐Microkeratome

EK ‐Microkeratome

DSAEK Graft

Visual recovery is shorter (2‐6 weeks) No induced astigmatism Refractive shift Small incision – stronger globe strength

Endothelial Keratoplasty

DMEK Grafts

Fast visual recovery No refractive shift Smaller incision 

DMEK Grafts

DMEK ‐Microkeratome

Where the bubble begins – DMEK/DMAEK Surgeon request for DMAEK prepared grafts Surgeon feedback Scrolls were tight

DMEK ‐Microkeratome

FS‐DMAEK

Surgeons shifted the request for DMEK tissue Comfort and improvements with the procedure Increase in request for eye bank prepared tissue

Surgeon Trend

0  1 1 

4 

9 

5 7 

5 

8 

4 

10  10 9 

11 10 

14 

17 

21 

0

5

10

15

20

25

How is the graft prepared? Peeled vs. Big bubble

Surgeon preference What’s best for the eye bank – peeled (91% success rate)

Surgeon Trend

DMEK ‐ Peeled

Images on Slit Lamp

Learning Curve Beyond the manual dexterity

Donor Selection Age Does the donor’s medical history influence outcomes?

No diabetic tissue – 97% success rate Consistency amongst preparation type Customized to the surgeon’s specific request

Designated graft size (8.0mm, 8.5mm, or 9.0mm) Specific peripheral markings – use of the “S” stamp

Better results/Improvements

What are we working on now?

Seahorse

Seahorse

Seahorse

For more information

Greg Schmidt, BS, CEBTIowa Lions Eye BankGregory‐Schmidt@uiowa.edu

Thank You

Questions?