Great talk by Mark Terry regarding lamellar cornea transplant. Includes wonderful bibliography of must read articles. Insightful and on target.

1. Descemet Membrane Endothelial
Keratoplasty: A Simplified Technique to
Shorten the Learning Curve and Avoid
Complications
Senior Instructor: Mark A Terry MD
Course: 224
Sunday, October 16, 2016
11:30 AM - 12:30 PM
Room: S403A
Published: 8-7-16 9:45 PM
Join the conversation: #aao2016
© 2016 American Academy of Ophthalmology. All rights reserved.

2. AAO Annual Meeting 2016
Chicago
Descemet Membrane Endothelial Keratoplasty:
A Simplified Technique to Shorten the Learning Curve
and Avoid Complications
Course #224
October 16, 2016
11:30 AM –12:30 PM
Mark A. Terry, M.D.
Michael D. Straiko, M.D.
Paul M. Phillips, M.D.
Christopher Sales, M.D.

3. Recommended Reading List
1. Terry MA. Endothelial Keratoplasty: Why aren’t we all doing DMEK? Cornea 2012 (Editorial);
31(5): 469-71
2. Terry MA, Straiko MD, Veldman PV, Talajic JC, VanZyl C, Sales CS, Mayko ZM. A
standardized DMEK technique: Reducing complications using pre-stripped tissue, novel glass
injector, and sulfer hexafluoride (SF6) gas. Cornea 2015;34(8):845-52
3. Hamzaoglu EC, Straiko MD, Mayko Z, Sales C, Terry MA. DSAEK v DMEK: First 100 eyes of
each using a standardized technique at one institution. Ophthalmology, 2015. 122(11): p. 2193-9
4. Veldman, PB, Mayko Z, Sales CS, Stoeger C, Straiko MD, Terry MA. The S-stamp in Descemet
Membrane Endothelial Keratoplasty Safely Eliminates Upside-down Graft Implantation.
Ophthalmology, 2016. 123(1): p. 161-4.
5. Veldman PB, Dye PK, Holiman JD, Mayko ZM, Sales CS, Straiko MD, Stoeger CG, Terry MA.
Stamping an S on DMEK Donor Tissue to Prevent Upside-Down Grafts: Laboratory Validation
and Detailed Preparation Technique Description. Cornea, 2015. 34(9): p. 1175-8.
6. Veldman PB, Terry MA, Straiko MD. Evolving indications for Descemet’s stripping automated
endothelial keratoplasty. Curr Opin Ophthalmol 2014, 25:306-311
7. Van Zyl C, Terry MA. DMEK: The Grand Prix of corneal transplant surgery. Expert Rev.
Ophthalmol. 9(2), 89-98 (2014)
8. Sales CS, Straiko MD, Terry MA. Novel technique for re-bubbling DMEK grafts at the slit lamp
using IV extension tubing. Cornea 2016 35(4):582-5
9. Sales CS, Terry MA, Veldman PB, Mayko ZM, Straiko MD. The relationship between tissue
unscrolling time and endothelial cell loss. Cornea 2016 35(4):471-6

4. Descemet Membrane Endothelial Keratoplasty (DMEK): Step by Step
Mark A. Terry, M.D.
June 2013
Endothelial Keratoplasty has now evolved to the point where we can attain perfect anatomic
replacement of the diseased endothelium and Descemet’s membrane with healthy donor tissue. The
procedure of DMEK however requires a different surgical skill set than DSAEK surgery, and the
nuances of DMEK surgery can be important for success. This manuscript is created to ease the learning
curve of the novice DMEK surgeon, but should not be considered an adequate substitute for a “hands
on” DMEK course assisting an experienced DMEK surgeon at the operating microscope nor for the
insights gained in the DMEK in-vitro wet lab.
Pre-op considerations:
We routinely use DMEK for cases of Fuchs dystrophy and Pseudophakic Bullous Keratopathy (PBK)
which do not have any other complicating issues. Eyes with anterior chamber IOLs, filtering tubes,
trabeculectomy bleb, aphakia or extensive peripheral anterior synechiae are not good candidates for
DMEK and are better served with DSAEK. We have also found that eyes that have previously
undergone a posterior vitrectomy also are not easy to do with DMEK, due to the difficulty in shallowing
the anterior chamber for donor unscrolling. DMEK can be done in eyes with a prior failed PK, but this is
slightly more difficult than on a virgin cornea. The majority of cases of failed endothelium, however,
can be done with DMEK, either as a single procedure or as a combination of DMEK with
phacoemulsification cataract surgery.
DMEK Tissue Ordering:
One of the initial obstacles to the acceptance of the DMEK procedure was the worry that when the
surgeon was preparing the donor by stripping the Descemet’s membrane from the donor tissue that it
would tear or rip and the tissue would be destroyed, cancelling the case and still incurring a bill from the
eye bank. We are very fortunate that that obstacle has now been removed by the development of “pre-
stripped” tissue from the eye bank for use in DMEK. We obtain all of our pre-stripped tissue from the
Lions VisionGift (LVG) Eye Bank in Portland, Oregon, a leading eye bank in the Eye Bank Association
of America (EBAA). Tissue from a surgeon’s local eye bank can be shipped to LVG in Portland for pre-
stripping the day before scheduled DMEK surgery if the surgeons local eye bank does not provide this
service. LVG has shipped DMEK tissue as far as Hong Kong and Europe. It is expected that more and
more eye banks will offer pre-stripped tissue as DMEK becomes more common.
Pre-stripped DMEK tissue is 90% stripped by the skilled eye bank technician, leaving a hinge of
attachment of Descemet’s membrane to the peripheral posterior stroma. This allows the donor tissue to
remain attached and yet still be shipped in Optisol in the same plastic viewing chamber as standard
tissue. The location of the hinge is designated by a cut out “notch” in the scleral rim at that position.
Tissue is evaluated by slit lamp after the stripping, and pre and post stripping specular microscopy is
done. The diameter of the viable stripped tissue is noted and is usually at least 9.0 mm diameter.
The donor age influences the ease in which the donor Descemet can be unscrolled (older donors have
thicker Descemet’s membrane and become less tightly scrolled), and so choosing tissue with a donor
that is older than 50 years old is usually advisable. Younger donors can of course be used, but there is a
higher chance of getting tightly scrolling tissue.

5. Recently, the eye bank has been able to place a dry ink “S” stamp on the Descemet’s portion of the
DMEK pre-stripped donor tissue. Validation studies by the eye bank have demonstrated only a 1% cell
loss from this “S” stamp on the tissue. We have found the mark of an “S” invaluable for determining the
proper orientation of the donor tissue before securing it with a gas bubble and it has eliminated the
adverse event of an upside down DMEK graft.
Like all tissue for transplantation, the donor tissue is removed from cold storage box at least 1 to 2 hours
prior to surgery to allow warming of the tissue to room temperature and allow the endothelium
metabolism to awaken. This serves the purpose of 1: having the chance of some endothelial pump
function soon after surgery and 2: to allow the antibiotics in the Optisol to work (they are antibiotics, not
antiseptics, and so require metabolic activity to be effective)
Pre-operative medications:
It is very important that the pupil be as small as possible for the insertion and unscrolling of the DMEK
tissue, and therefore I prefer not to use any cycloplegic drops for any DMEK case preoperatively, even
when cataract surgery is planned at the same time as the DMEK. Adequate dilation for the cataract
portion of the procedure can be accomplished with intraoperative epinephrine in the operating room. If
the surgeon must have better dilation for the patient, then a single drop of a very short acting mydriatic
(such as Mydriacyle) is recommended, and only if necessary. In addition, we avoid the use of non-
steroidal drops (such as Ocufen) to avoid persistent dilation effect.
If the eye already has a posterior chamber IOL in place, then use of a single dose of Pilocarpine 1% can
be useful to attain a small pupil, although it does make visualization of the stripping of recipient
Descemets and the creation of the peripheral iridotomy slightly more difficult.
Other preoperative drops such as antibiotics are according to the surgeon’s preference.
Anesthesia:
DMEK surgery is easiest in the first few cases with the patient under general anesthesia, as the stress
and frustration level of the novice DMEK surgeon can be high and it is always better when the patient
does not hear the surgeon curse!
DMEK surgery can be performed under retrobulbar/peribulbar injection anesthesia quite easily and this
is easiest on the patient. It does cause temporary pupillary dilation, which helps with some parts of the
case, but can make pupillary constriction slightly more difficult prior to tissue injection.
DMEK surgery can be performed under topical anesthesia, but this puts the responsibility on the surgeon
to get the case done more quickly and on the patient to be quite cooperative, especially during the
unscrolling of the tissue and the injection of the gas to secure the tissue. Topical anesthesia is not
recommended until the surgeon reaches a high level of comfort with the procedure.
Preparation of the Recipient Cornea:
The patient’s head is positioned to make sure that the eye is exactly facing up toward the ceiling. I
generally position the body in slight reverse Trendelenburg (feet down) incline to reduce the pressure on
the eye.
After anesthesia (see above), the eye is prepped and draped in the usual fashion and the lid speculum
placed. Care is taken to prevent pressure on the sclera and the globe by the lid speculum, and so I
usually place a 4X4 sponge pad beneath the handle of my Lieberman speculum to lift the separated lids
away from the globe.

6. I sit temporally for nearly all my ophthalmic surgery and the description of surgical approach below
reflects that orientation. (However, any surgeon seated position is possible and is entirely a surgeon
preference)
A calipers set at 3.0 mm is used to mark the clear corneal limbus at the 180 degree meridian for the main
wound and this is marked with a marking pen in the epithelium. Two additional ink marks are made in
the superior and the inferior temporal limbal cornea to mark the paracentesis sites.
A stab incision paracentesis with a 1 mm diamond keratome is made at the two sites and the chamber is
filled with cohesive viscoelastic (Healon). The central surface of the cornea is marked with an 8.0 mm
circle indentation and this is marked with multiple spots of marking pen ink. A reverse Terry-Sinskey
hook is used to strip Descemet’s membrane, making sure to score exactly along the template circular
mark so a full 8.0 mm area is bared of Descemets. Care is taken to make sure that the stripped area does
NOT overlap the posterior entrance wound of the paracentesis or the main wound, so that the subsequent
graft does not overlap the entry points.
The chamber is filled again with Healon to pressurize the eye and the main wound is created. A guarded
diamond knife is set for 300 microns and a vertical 3.0 mm incision is placed at the temporal limbus
where previously marked. A 3.0 mm (or smaller) diamond or steel microkeratome is placed through the
vertical main incision edge and used to create a beveled entrance wound with about 1.5 mm of length
before entry into the anterior chamber. The stripped Descemets is removed.
The inferior peripheral iridotomy is then performed:
Healon is used to fill the chamber and also some is put beneath the posterior iris inferiorly. Care is also
taken to sweep the posterior iris to make sure that there are no posterior synechiae which would impede
pupillary constriction or movement.
A 30 guage short needle is then bent with a needle driver. The sharp tip is bent anteriorly and the hub is
bent to provide a convenient angle of entry. The needle tip is placed through the superior paracentesis
site and passed through the pupil, walked along the posterior iris inferiorly, and then pressed upward
against the far peripheral iris tissue. At the same time, a straight Sinskey hook is placed through the
inferior paracentesis site, into the anterior chamber and anterior to the iris. The hook is then used to
scrape down on the location of the needle tip that is tenting up the iris tissue in the inferior periphery.
Once the tip of the needle perforates the iris from behind, this creates a hole where the Sinskey hook tip
can then be placed and using the needle and the hook, the small iridotomy hole can be stretched wide
open. This is liberally done to about a 2 mm hole, as the P.I. will tend to become a slit opening by the
next am. I will usually also use intraocular scissors to also cut the peripheral base of the P.I. further, to
be absolutely sure that the P.I. remains patent.
Prior to removing the Healon, I then check to make sure that my tissue injector device tip will fit snugly
into the main 3.0 mm wound. We use a modified Jones Tube (designed by Mike Straiko, MD of Devers
Eye Institute) which is FDA approved for human use and is used off-label. This glass tube (part number
80000-DMEK) is made by Gunther Weiss Scientific Glassblowing Co., Inc.in Portland, Oregon and
contact information is: 503 644-4056 and info@guntherweiss.com) (price in 2013: $95.00). Most of
the time, the incision needs to be opened with an angled blade to 3.2 or 3.5 mm in order for the tip to fit
snugly into the anterior chamber.
Once the main wound is the proper size, the irrigation/aspiration tip is used to remove ALL of the
Healon. This only takes 15 or 30 seconds, as cohesive Healon does NOT coat surfaces and comes out
quickly.
At this point it is VERY IMPORTANT to make the pupil as small as possible. We inject Miochol (short
acting) initially and will also “stroke” the iris surface to bring the pupil down to at least 3 mm in size,

7. but preferably smaller. If the pupil will not come down after this, then we also will add Miostat (long
acting). A small pupil will cause less problems and damage to your donor tissue during the injection and
unscrolling process.
The IOP of the recipient is left normal or slightly soft using BSS injections and attention is turned to the
donor table.
Preparation of the Recipient in eyes undergoing concurrent Cataract Surgery with DMEK
Cataract surgery can be safely performed at the same time as DMEK with a few minor changes from the
above steps.
Once again, we do NOT use cycloplegics at any time prior or during the triple procedure surgery, as we
want the pupil to be as small as possible for the DMEK portion of the procedure. If the pt has a pupil
that cannot be dilated with intraocular epinephrine, then use of a mild short acting mydriatic (mydriacyl)
can be used preoperatively.
We do not use NSAIDs such as Ocufen to prolong the dilation when also doing DMEK.
We make sure that there are NO dilation agents (epinephrine) in the irrigating bottles when doing phaco
and DMEK, as this can inadvertantly cause dilation later in the procedure.
For phaco at the time of DMEK, we inject “Sugarcaine” (intraocular epinephrine and lidocaine) into the
anterior chamber after the paracentesis incisions are made and BEFORE the Healon is injected. This
dilation will last at least 20 minutes and ample time for doing the phaco.
We use the main wound for the phaco and the insertion of the IOL, before it is enlarged to accept the tip
of the insertion device.
The P.I. is made after the IOL is inserted into the bag.
The Descemet’s is stripped after the phaco and the P.I. are done.
Every effort is made to get the pupil as small as possible using Miochol or Miostat and iris stroking.
The rest of the recipient preparation is done the same as detailed for standard DMEK.
Preparation of the Recipient in eyes that are Phakic and we leave the crystalline lens in place with
DMEK
In young patients (ie: less than 50 years old) that are phakic and do not have a cataract, DMEK can be
safely performed. There are only slight variations:
Preoperatively, the phakic eye is given 1% pilocarpine drops (2 sets)
I use AIR to fill the chamber after the paracentesis incisions are made and do the stripping of
Descemet’s under air. This is more difficult than using Healon, but I have found it difficult to get all the
Healon out without iris prolapse and worry of lens damage during the I/A portion of the procedure.
The P.I. cannot be made with the 30 guage needle through the pupil without damaging the crystalline
lens, so in phakic eyes, I make a vertical paracentesis incision at 6 o’clock far limbus, pick up the
anterior iris stromal tissue with a capsularhexis forceps, pull the iris base up through the paracentesis,
and cut a small hole with scissors. This creates a small peripheral iridectomy. Care must be taken to
insure that there is pigment in the tissue excised so that the P.I. is known to be patent.
The remainder of the DMEK operation is exactly as described for DMEK in eyes with an IOL.
Preparation of the Donor Tissue:

8. The operating microscope MUST be used to prepare and load the donor tissue. These steps cannot safely
be done using just the naked eye…even by pre-presbyopic surgeons.
The donor table should include:
-- 7.75 mm donor trephine punch that enables the surgeon to look down the bore of the trephine during
the punch process to ensure that the edges of the trephine do not include damaged tissue edges from the
pre-stripping. We have used trephines from Katena (Hessburg/Barron trephine) and also from Moria.
-- 3.0 cc syringe with a Luer lock tip
-- 14 French gastric tubing (and a very heavy drape scissors to cut it)
-- Vision Blue (trypan blue)
-- tying forceps
-- A shallow container filled with BSS (like a petri dish or the cap of a jar)
-- Multiple miracell sponges
-- 5 cc syringe filled with BSS and with a 27 guage cannula
-- the Straiko modified Jones Glass Tube used for loading and injecting the DMEK tissue
The donor cornea-scleral tissue cap is picked up from the viewing chamber with forceps and placed
endothelial side up onto the donor table. Trypan blue (Vision Blue/ DORC, The Netherlands) is dripped
onto the surface of the endo, left in place for 1 minute then gently wicked off (with a miracyl sponge) at
the scleral edge of the donor that is directly OPPOSITE the scleral notch placed by the eye bank. This
insures that as the vision blue is wicked off, the pre-stripped donor Descemet’s membrane will lie flat
along the edges on the underlying posterior stroma. If it does not, re-float the Descemets and wick the
fluid again until folds along the edges are gone.
The tissue is mounted onto the punch block (endothelial side up) and suction applied to the block to
secure the tissue for trephination.
The trephine punch is then lowered very slowly onto the block until the trephine edge meets the
endothelium. Gentle pressure and even tapping are done to the trephine to cut through the donor
Descemets and into the underlying stroma, but care is taken to NOT trephine all the way through the
entire cornea. The trephine is then carefully removed.
The tying forceps are then used to remove the Descemets that is peripheral to the trephination cut. Great
care must be taken not to pull this tissue away too quickly, because even the sharpest trephine will
sometimes cut 300 degrees, but not 360 degrees of Descemets tissue! If you find that there is a segment
that is not cut through by the trephine, then we have used a diamond knife (or 75 beaver blade) to hand
cut the Descemets in the areas that the trephine did not cut. Alternatively, the trephine can be re-
mounted and used to cut again, if there are extensive areas not cut originally.
Rather than discard it, I use that peripheral Descemets donor tissue to later test my injector. So I place
segments of peripheral donor Descemets into a petri dish (or cap) filled with BSS on the donor table.
The trephined donor tissue is then covered with BSS. The tying forceps are used to gently pick up the
edge of the tissue that is OPPOSITE the scleral notch placed by the eye bank, as this edge is OPPOSITE
the hinge of the pre-stripped tissue. Under the BSS, the edge is lifted up until the final hinge area and
then lifted out of the BSS, and it immediately scrolls in air. The well of the donor corneal-scleral tissue
is then filled with Vision Blue (trypan blue) and the donor Descemets is then gently lowered back into
the well. More Vision Blue is placed on top of the tissue so it is submerged in Vision Blue. The tissue is
left to stain in place for at least 3 minutes to get a dark stain. (There is no damage to the tissue if it stains
for even 3 hours).
These methods of handling the donor tissue insures that the tissue transplanted is only touched once
along the edge during the entire transplant surgery.

9. Construction of the insertion device is as follows:
The 14 French Gastric Tubing is used as a connecting junction between the glass Jones tube and the 3 cc
syringe. You only need 15 mm of it, so there is more than enough!
Cut a middle section of tubing for a length of 15 mm or so. Wet the inside with BSS. Connect the tubing
into the Luer lock of the 3 cc syringe. Connect the other end over the proximal tip of the modified Jones
tube. Make sure both ends are tightly bound. Suction up 2.5 cc of BSS from the petri dish and inject it
back. Make sure the junctions are water tight.
Testing the Jones Tube prior to use as an injector:
Remember the NASA space program in the early days?? Before they sent an astronaut into space, they
sent a monkey into space first to make sure all systems work as expected, with no glitches…I like to do
the same with my DMEK surgery. I call those peripheral pieces of donor Descemets that we previously
saved my “space monkeys”.
Take the Jones tube with 2.0 cc of BSS, submerge the tip into that petri dish of BSS with the space
monkeys, and placing the tip bevel up, suction a space monkey into the tip of the Jones tube and note
how much suction effort it took to bring the space monkey into the tip. You want to suction the space
monkey far enough into the tip that it floats into the flared out portion of the tip. Mike Straiko designed
the modified Jones tube so that the flared out portion of the tube would create a Bernulli effect, slowing
down the tissue as it was aspirated from a constricted high flow area to a larger, low flow area. This
protects the tissue from being sucked up all the way into the syringe. After loading the space monkey,
shake the tube and syringe in your hand to demonstrate to yourself that the tissue stays loaded and the
system is sound. Then put the tip back in the petri dish of BSS and inject the space monkey back into the
dish to get a feel for how much syringe pressure it takes and to see that the tissue can easily be injected.
Repeat all this with space monkeys until you feel comfortable that your system is foolproof.
Loading the Donor Descemets: REMEMBER – THE DONOR SCROLL HAS ENDOTHELIUM ON
THE OUTSIDE SURFACE OF THE SCROLL
Before loading the actual tissue we are transplanting, we need to dilute the solution that is staining it.
Take the BSS syringe and cannula and irrigate the well where the tissue is staining. (ie: the well is the
donor cornea-scleral cap sitting in the donor punch) Use a miracell sponge to wick off some of the
Vision Blue in the well. TAKE GREAT CARE NOT TO WICK OFF FLUID TOO QUICKLY OR THE
TISSUE WILL END UP ON THE SPONGE. Continue irrigating and wicking, slowly diluting the well
of fluid until the tissue is easily seen as a dark blue scroll sitting in nearly clear fluid. Fill the well
completely with BSS. Take the Jones tube tip and place it bevel up into the well, directly next to the
edge of the donor scroll, or even with the tip of the bevel beneath it. Gently aspirate the tissue into the
tip of the Jones tube. If you are aspirating and the fluid is coming but not the tissue, fill the well again
with BSS to get the tissue to “float” and try aspirating again. Get the tissue into the flared portion of the
Jones tube and inspect it to see (if possible) which way it is curling up. Bring the loaded tube and
microscope over to the patient.
Injection of the donor Descemet’s membrane into the Anterior Chamber:
The recipient eye should be normal or low IOP and the pupil should be small prior to inserting the tip of
the Jones glass tube into the main wound.
If possible, inspect the tissue in the Jones Tube to determine which side of the tube allows the tissue to
be face up upon injection. Face up for the tissue is where the tissue scrolls toward you with the double
scroll formation best with the scroll edge on either side facing anteriorly, “hugging” you.

10. Insert the tip of the Jones tube, bevel down, into the main wound so that the tip is over the pupil then
rotate the tube if necessary so that the tissue will be injected scroll sides up. Inject slowly with short
bursts of fluid if necessary to get the tissue to move. Once the tissue is in the chamber, it is sometimes
helpful to give short bursts of fluid to allow the tissue scroll to orient perpendicular to the tip to have a
harder time coming back into the tip or out the wound. To remove the injector tip, release fluid from the
paracentesis site with a cannula held with your other hand. DO NOT REMOVE THE INJECTOR TIP
UNLESS THE ANTERIOR CHAMBER IS NEARLY EVACUATED AND THE EYE IS VERY
SOFT. If the chamber is well formed and the IOP is high, then the tissue will follow the tip out of the
wound. To remove the tip, place the cannula on the cornea just central to the wound and slowly remove
the tip while depressing with the cannula on the anterior corneal surface so that the wound closes as the
tip is removed. This will trap the tissue in the anterior chamber. Once the tip is removed, immediately
place one interrupted 10-0 nylon suture in the wound to close it. Now the “dance” begins to unroll the
tissue and center it for placement.
Determining if the tissue is right side up (scrolling up) or upside down (scrolling down):
Before anything else is done, it is paramount to know the orientation of the tissue and because the tissue
is so thin, it is sometimes hard to tell immediately. Remember, the tissue will always scroll with the
endothelium on the OUTSIDE, so if the scrolls are facing anteriorly, then the tissue is correct, if
posterior, then the tissue is upside down. After injection into the AC and suturing of the wound, the
chamber is shallow or flat. I will usually inject a burst of fluid through the paracentesis and then watch
how the tissue reacts to the deepening of the chamber. The tissue can “swirl” around and then settle with
a curling of the edges in the deepened chamber. That movement is a dynamic way of watching how the
tissue curls, and often that is enough to know if the scrolling is anteriorly (correct) or posteriorly
(incorrect). If there is doubt, repeat the irrigation and tissue movement until you are sure. Another useful
but more invasive method of determining orientation is to use the Mountsouri sign described by Gerrit
Melles. This sign is demonstrated in his excellent published technique paper (ARCH OPHTHALMOL/VOL
129 (NO. 1), JAN 2011)
and also in my accompanying lecture slides. Basically, if the tissue it correctly
oriented (scrolls up), then a silver spatula placed into the AC between the two scrolls edges will be
silver, but when passed to left or right, the spatula passes below the edge of the scroll and is tinted blue
by the overlying scroll edge of tissue. This demonstrates that he tissue is correct. If the tissue is upside
down (scroll edges down) then that same silver spatula when passed from left to right will stay silver,
because the scrolls are facing downward and do not obstruct or tint the spatula which is above them.
Finally, another way to determine the orientation is by using a mounted or hand-held penlight slit beam.
This can be passed across the chamber with the lights out and if there are two scroll reflections then the
tissue is right side up, if one reflection, then it is upside down. Once you are sure that the tissue is “right
side up”, then the tissue is centered and opened with a shallow chamber.
Unrolling the tissue and centering it: The Yoeruek Tap Technique
The key to unrolling the tissue is to be able to have a very shallow chamber and to use short taps on the
surface of the cornea to generate fluid waves that push the scrolls open. The surgeon’s non-dominant
hand is used at the same time to put intermittant gentle digital pressure on the sclera (about 4 mm from
the limbus), as this can provide changes in chamber depth that will allow an unscrolled edge to “catch”
from the shallow chamber and remain unscrolled. The Yoeruek tap technique is well described in his
original article published in 2013 in Cornea (Yoeruek, et al: Cornea 2013; 32:370-73).
Centering of the tissue is done either before or after unscrolling. Centering is accomplished by having a
shallow chamber and then applying short “golf stroke” taps to the limbus near the decentered graft edge
to create fluid waves that bump the tissue along the surface of the iris until it is centered. Unlike

11. DSAEK, sweeping along the surface of the cornea along the entire length of the donor tissue does not
help to center it.
Another way to move the tissue and also to help unfold an edge is to create short bursts of fluid release
from the anterior chamber through the paracentesis site nearest the edge that you want to uncurl. This
can be done using a cannula through the paracentesis site and “flicking” the site open while quickly
removing the cannula. While removing AC fluid through the main wound can also help center tissue or
uncurl edges, great care is taken at this site of fluid removal, as the tissue can expel through an opened
main wound quite quickly and easily.
A surgical movie is worth a million words and for a superb teaching video on tips for DMEK
surgery, I recommend Dr Mike Straiko’s video available on YOUTUBE accessed by:
http://www.youtube.com/watch?v=NuC7ZjHGICc
Injection of air or gas (20% concentration of SF6) to secure graft in place:
Because the DMEK graft tends to have graft edge separation inferiorly at about post-operative day #4 or
5, we feel that the DMEK graft needs a longer time of bubble support than DSAEK tissue. Therefore,
we have transitioned to using only SF6 gas for the retained bubble for DMEK surgery. This gas bubble
resolves in 6 to 8 days, giving longer lasting support and reducing our re-bubble rate to less than 10%
for DMEK surgery.
With the graft now fully uncurled and flat on the iris surface in a very shallow chamber, a 3 cc syringe
filled with a 20% concentration of SF6 gas is used to put the tissue up against the recipient corneal bed.
The 27 guage cannula is placed through the paracentesis, onto the iris surface, and hugging the iris, the
tip moved centrally beneath the donor tissue all the way to the central pupil (or even slightly beyond
center). Great care is taken not to inject the gas bubble too soon or the tissue will be displaced and
folded. Once in the central pupil, the gas is SLOWLY injected, as this allows the edges of the graft to
flatten out as they are pushed up by the expanding bubble onto the posterior surface. With the graft now
in position the chamber is filled with gas.
All the edges of the graft must be completely flat with no folding of the edges anywhere. Any “flat
edge” of the circular tissue must be investigated for graft edge folding onto itself. If this is seen, the edge
MUST be corrected or postoperatively, there is a greater risk of detachment. Melles has described
“bubble bumping” to correct this problem. Basically, the gas bubble is reduced in size to about the
diameter of the tissue. The eye is then rotated TOWARD the edge of concern. This moves the bubble
proximally away from the edge and the folded edge is now with only fluid around it. A few taps of the
surface of the cornea and the edge will unfold. When this is seen to occur, the eye is righted and the
bubble now covers the edge, locking it into proper unfolded position.
A final check of the graft should show clean round edges, good centration, and no folds. I usually will
do a final sweeping with the Cindy Sweeper for 30 seconds over the entire surface of the cornea with a
soft eye with the AC filled with gas to insure that there is no gross interface fluid and to also smooth out
any visible microfolds in the central or peripheral graft.
Final Check and Gas Bubble:
When the tissue is in position, with all edges clean and round and no folds, the chamber is filled
completely with gas to an elevated IOP for a couple of minutes then the IOP is normalized with gas
release through a paracentesis site to a normal IOP. After 5 to 10 minutes, the gas bubble is reduced with

12. injection of BSS through the paracentesis site so that a gas fill of about 90% is achieved and the inferior
peripheral iridotomy is uncovered, or will be uncovered in the seated position. The iris plateau should be
flat, the chamber deep, and the IOP normal at the end of the case.
If topical or general anesthesia was used for the case, only a Fox shield is placed on the eye and the
patient is started on antibiotic and steroid drops every two hours while awake immediately and then seen
the next day.
If retrobulbar or peribulbar anesthesia is used, then the eye is dressed with a collagen shield soaked in
antibiotic and steroid, the lid closed and lightly patched, and the patient keeps the patch on until seen the
next day.
Post-operative instructions:
The patient is instructed to lie supine (“with your nose facing the ceiling”) as much as possible, allowing
20 minutes for bathroom or meal breaks or if their back is hurting. They are allowed to sleep in whatever
position is comfortable.
We do not take the patch off an hour after surgery to check the IOP, as we trust our inferior P.I. will
prevent pupillary block, but we do tell the patient to call us if they have extreme pain or nausea.
The usual positioning schedule for the patient with SF6 gas bubble is as follows:
--Supine as much as possible for day of surgery and also Post op day 1
--Supine for two hours, up for two hour, supine for two hours, up for two hours, etc while awake for
Post op days 2, 3 and 4
--Supine for one hour in the morning and one hour in the evening with hyperextension of the neck or
with looking behind them in order to get the remaining bubble to come in contact with the inferior graft
for Post op days 5, 6, and 7.
Patients are seen on Post op day 1, 6 and 14 and then seen at 1, 3, 6 and 12 months post op. Patient with
graft edges that are separating or with more edema of the recipient cornea may be seen more frequently.
The Melles group has shown that if there is 30% or less of the graft with interface fluid at the one week
postop visit, that 100% of these grafts will be attached and with good function at 6 months post op. (Yeh
et al: Ophthalmology 2013; 120:240-45) Therefore, not every graft edge separation needs to be re-
bubbled.
Medications instructions are begun after the patient is seen in clinic and are as follows:
Prednisolone 1%: one drop every two hours while awake for first week, then 4 times a day for 3 months,
then 3 times a day for 3 months, then 2 times a day for 3 months, then once a day for three months. We
usually try to get the patient off steroids at one year. There is some evidence that DMEK grafts may
need much less steroids after 6 months than PK or DSAEK grafts, but controlled studies are pending.
Antibiotic drops: 4 times a day for one week then stop
Glaucoma drops: If used pre-operatively, used postoperatively.
Monitoring of the DMEK graft:

13. An OCT that can show the entire diameter of the graft is invaluable in assessing the postoperative edge
position of the DMEK graft. On the first day post-op the gas bubble is usually covering the pupil and
filling 60 or 70% of the chamber and the inferior P.I. is cleared and the vision is H.M. with the gas over
the pupil.
The edges of the graft should all be attached with no interface fluid and most importantly, the overlying
stroma should be clearer than what you usually see with DSAEK.
If the recipient stroma is very edematous throughout the grafted area, beware that the tissue is either not
functioning well or is upside down (the endothelium is anterior, against the stroma). This type of patient
I will see two days later and repeat the OCT. By then, the stoma will either be clearer, showing the graft
is now functioning, or the stroma will be diffusely still edematous and the OCT will show an inferior
edge which is starting to detach. Look closely at the edge of detachment on the OCT. If the edge of
detachment is curling anteriorly, toward the cornea, then the graft is correctly oriented (“correct side
up”) and you can watch the graft or add more air or position the patient to have the gas bubble better
cover the inferior graft. These corneas will clear over time. If the edge of detachment is curling
posteriorly, away from the cornea, toward the anterior chamber, then the graft is “upside down” and no
amount of re-bubbling or positioning will help. We will then schedule the patient for either a repeat
DMEK or DSAEK the next week.
For routine cases of DMEK we get an OCT pre-op, one day, one week, one month and 6 months after
surgery. Small edge lifts on OCT that are not visually significant are watched and will always resolve
with either peripheral recipient endothelium filling in the gap or the edge re-attaching (usually the
former). Edge lifts with greater than 30% of the grafted area exposed are re-bubbled.
Frequently
Asked
Questions
About
DMEK
1.Do
you
deliberately
strip
the
host
DM
larger
than
the
graft
diameter
or
smaller
as
in
DSAEK?
I
always
strip
an
8
mm
recipient
and
punch
out
a
7.50
to
7.75
mm
graft.
What
I
find
is
that
the
graft
will
always
punch
out
slightly
larger
than
the
trephine
size
chosen
because
the
tissue
is
like
a
bedsheet
that
is
not
pulled
tight
so
you
cut
out
excess
than
the
trephine
diameter
2.What
is
your
air
fill
protocol
after
you
have
the
graft
positioned?
Once
graft
unfolded
and
centered
on
iris
surface
in
a
VERY
shallow,
nearly
flat
chamber,
I
inject
a
20%
concentration
of
SF6
gas
to
a
complete
air
fill.
I
then
pressurize
the
chamber
with
gas
to
about
30
or
40
mm
Hg,
use
the
Cindy
sweeper
to
sweep
corneal
surface
from
the
center
to
peripheral
edge
of
graft
for
a
minute
to
make
sure
graft
is
smooth
without
wrinkles,
and
it
seems
to
also
get
out
some
microscopic
interface
fluid
by
OCT.
Then
I
leave
filled
with
gas
for
another
5
minutes
before
releasing
some
gas
with
injection
of
BSS,
leaving
a
90%
gas
fill
and
a
normalized
IOP.
We
never
inject
air
anymore.

14. 2.
PI
or
no
PI?
ALWAYS
need
an
inferior
P.I.
And
ALWAYS
make
sure
it
is
patent.
We
do
the
P.I.
at
the
time
of
surgery
with
the
30
guage
needle
through
the
pupil
technique
that
Mike
Straiko
showed
on
his
YOUTUBE
video
3.
Are
you
still
recommending
20%
SF6
instead
of
air?
If
so,
what
%
fill
do
you
aim
to
leave?
20%
SF6
and
leave
a
90%
fill
so
that
when
pt
sits
up,
the
inferior
P.I.
is
uncovered.
4.
What
is
your
post
op
review
schedule?
I
do
NOT
see
the
pt
until
the
next
morning
or
afternoon
and
leave
the
patch
on
until
then.
They
call
me
if
they
have
severe
pain
(hasn't
happened
with
P.I
and
SF6)
I
then
see
them:
POD
#1,
6,
14,
and
30.
If
the
cornea
is
unduly
swollen
and
I'm
worried
about
the
graft
on
day
1,
then
I
will
see
them
on
POD
3.
The
gas
bubble
is
usually
still
present
enough
to
give
some
support
on
POD
4
through
7
so
during
that
time
I
have
the
pt
give
me
an
hour
in
the
am
and
an
hour
in
the
pm
lying
flat
with
neck
hyperextended
or
looking
behind
them
while
flat
so
the
gas
bubble
will
cover
the
inferior
edge
of
graft
where
a
detachment
is
most
likely
to
start.
5.
If
a
partial
detachment,
do
you
always
rebubble?
Melles
group
had
a
great
article
in
Ophthalmology
this
year
(2013)
that
showed
that
if
30%
or
less
of
the
graft
is
detached
at
1
week
after
surgery,
ALL
the
grafts
with
this
status
were
fully
attached
and
functional
3
months
after
surgery,
so
we
use
that
data
as
a
guide
of
when
to
re-­‐bubble.
If
there
is
an
area
of
detachment
into
the
visual
axis,
I
watch
those
pts
more
closely,
but
only
re-­‐bubble
if
detachment
is
getting
worse.
6.
If
a
total
detachment,
do
you
rebubble
or
replace
the
graft?
If
a
total
detachment,
the
graft
is
clear
and
floating
in
the
AC
and
the
recipient
cornea
is
fully
swollen
and
cloudy.
I
don't
know
of
any
way
to
re-­‐attach
this
invisible
totally
detached
graft,
so
we
always
replace
it.
If
the
pt
is
willing,
then
we
do
another
DMEK,
but
if
the
pt
appears
"tired"
and
disappointed
with
this
"new"
technique
(and
especially
if
they
have
had
a
successful
DSAEK
in
the
other
eye),
then
we
replace
the
DMEK
with
a
DSAEK.

15. Surgical Instrument List
Glass injector
14G tubing
3ml syringe
Scissors
Punch/ block with syringe attached (7.5-8.0mm)
1 tryphan blue syringe
2 Healon or Provisc
2 tying forceps
1 fine-toothed forceps
1 needle holder
1 Sinskey hook
1 Utrata forceps
1 8mm corneal marker
1 tissue marker
1 10/0 nylon
1 Vannas scissors
2 3ml syringes with cannulas - air & BSS
3 blades - 15 degree, crescent, 3.0mm keratome
1 bottle of BSS
Additional syringe & needle to pressurize globe

16. Resource Links
DMEK Tips and Tricks
http://www.youtube.com/watch?v=NuC7ZjHGICc
This is a video a corneal transplant technique for endothelial dysfunction such as
Fuch's corneal dystrophy. The video emphasizes tips and techniques for unfolding and
positioning a DMEK graft. It features clips from numerous surgeries. The surgeries are
being performed by Dr. Michael Straiko at Devers Eye Institute / Legacy Good
Samaritan Hospital. The type of transplant in this video is a DMEK (Descemet's
Membrane Endothelial Keratoplasty). In this type of transplant only the dysfunctional
inner layers of the cornea are replaced. This technique allows for a safer surgery and a
more rapid recovery than conventional transplants. In this video Dr Straiko is using a
novel injector system to insert the tissue ad providing some pearls on unfolding a
difficult DMEK graft.
DMEK Surgery Using a Modified Alcon B Cartridge
http://www.youtube.com/watch?v=SmJcZM3M9rk
This is a video of a corneal transplant for Fuch's corneal dystrophy. The surgery is
being performed by Dr. Michael Straiko at Devers Eye Institute / Legacy Good
Samaritan Hospital. The type of transplant in this video is a DMEK (Descemet's
Membrane Endothelial Keratoplasty). In this type of transplant only the dysfunctional
inner layers of the cornea are replaced. This technique allows for a safer surgery and a
more rapid recovery than conventional transplants. This is the latest iteration of
endothelial keratoplasty. In this video Dr Straiko is using a novel injector system to
insert the tissue ad providing some pearls on unfolding a difficult DMEK graft.

17. DMEK Corneal Transplant Using a No-Touch “Tap-Technique”
http://www.youtube.com/watch?v=nxPtifLyE2E
This is a video of a corneal transplant for Fuch's corneal dystrophy. The surgery is
being performed by Dr. Michael Straiko at Devers Eye Institute / Legacy Good
Samaritan Hospital. The type of transplant in this video is a DMEK (Descemet's
Membrane Endothelial Keratoplasty). In this type of transplant only the dysfunctional
inner layers of the cornea are replaced. This technique allows for a safer surgery and a
more rapid recovery than conventional transplants. This is the latest iteration of
endothelial keratoplasty.
DMEK Injectors 1
http://www.youtube.com/watch?v=HuJ-DHMwtgE
This is a video of a corneal transplant for Fuch's corneal dystrophy. The surgery is
being performed by Dr. Michael Straiko at Devers Eye Institute / Legacy Good
Samaritan Hospital. The type of transplant in this video is a DMEK (Descemet's
Membrane Endothelial Keratoplasty). In this type of transplant only the dysfunctional
inner layers of the cornea are replaced. This technique allows for a safer surgery and a
more rapid recovery than conventional transplants.
Lions VisionGift Prepared DMEK Graft
http://www.youtube.com/watch?v=aNcF9ndXmiY
Dr. Mike Straiko performs a DMEK transplant utilizing tissue prepared by Lions
VisionGift.

18. Contact Information
Devers Eye Institute
1040 NW 22nd Ave., Suite 200
Portland, OR 97210
Zachary Mayko
Research and Training Questions
ZMayko@deverseye.org
Phone: (503) 413-8377
Fax: (503) 413-6937
Mark A. Terry, MD
mterry@deverseye.org
Phone: (503) 413-6223
Michael D. Straiko, MD
mike.straiko@gmail.com
phone: (503) 413-8202
Lions VisionGift
2201 SE 11th Avenue
Portland, Or 97214-5303
Eligibility Specialist & Distribution Manager
Jameson Clover, CEBT
jameson@visiongift.org
Phone: (503) 808-7012