Lamellar keratoplasty

LAMELLAR
KERATOPLASTY
DR. SUBHRA SARITA BEHERA
JUNIOR RESIDENT, 2ND YEAR

EVOLUTION OF LAMELLAR
KERATOPLASTY
1886
Von hippel-
1st lamellar
1998
Dr Melles
DALK
2003 Dr
price
DSEK,
DSAEK
2006 -Dr
Melles
DMEK

Why lamellar keratoplasty??
Unpredictable post op
astigmatism
Loose suture can induce
epithelial breakdown,
ulceration, infection,
vascularisation .
Long post operative visual
recovery
Dramatic shift in corneal
topography can occur
following suture removal
resulting in irregular
astigmatism
corneal wound relatively
fragile, with poor tectonic
strength, making eye
susceptible to minor
even several years
surgery
Increased risk of all open
procedure like RD,
choroidal haemorrage.

ANATOMY
LAYERS THICKNESS(µm) COMPOSITION
Epithelium 50 Stratified
squamous
Bowman’s
membrane
8-14 Compact layer of
unorganized
collagen fiber
Stroma 500 Orderly arranged
collagen lamellae
with keratocyte
Dua’s layer 10-15 Consists of typ 1
collagen
Descemet’s
membrane
10-12 Consist of
basement
membrane
Endothelium 5 Single layer of
simple squamous
epithelium

surgical anatomy of stroma
Collagen
fibrils in
Ant. 1/3 Post 2/3
Orientation to
corneal
surface
oblique parallel
arrangement Branching
present
lamella
interweave
Less loosely
placed
 Thickness of
stroma- 478-500
microns
 The deeper in
the stroma the
surgeon is, the
easier it is to
dissect between
the lamellae
 i.e Easier to do
LK, The deeper
we go

Classification
LAMELLAR KERATOPLASTY
ANTERIOR LAMELLAR KERATOPLASTY
Superficial
anterior
lamellar
keratoplasty
(SALK)
Deep anterior
lamellar
keratoplasty
(DALK)
POSTERIOR LAMELLAR KERATOPLASTY
Descemet’s
stripping
endothelial
keratoplasty
(DSEK)
(DSAEK)
Descemet
membrane
endothelial
keratoplasty
(DMEK)
Deep lamellar
endothelial
keratoplasty
(DLEK)

 ADVANTAGE
I. Non-penetrating
surgery
II. Reduced risk of
endothelial graft
rejection
III. Does not require good
endothelial quality
donor tissue
IV. Technically achieves a
stronger corneal wound
V. Suture related
astigmatism is lesser
 DISADVANTAGE
I. Technically more demanding
and time consuming
II. Suboptimal visual acuity
compared to PK due to
 Interface problems
 Lamellar dissection
regularity
 Residual scarring

Optical ALK- for visual
rehabilitation
Congenital dermoid Post chem. scar Post trauma scar
Healed SPKS Band keratopathy Salzmann nodule

Tectonic ALK- for re-establishing
structural integrity of the cornea
Mooren’s ulcer
Pellucid marginal
degeneration
Terrin’s marginal degeneration

Therapeutic – to eliminate corneal
infection
optical + tectonic ALK
MICROBIAL KERATITIS

ANTERIOR LAMELLAR
KERATOPLASTY
Superficial Anterior
Lamellar Keratoplasty
(SALK)
 anterior 30 to 50% of
cornea
 stroma-to-stroma
interfaces can degrade
visual acuity over time
Deep Anterior
Lamellar Keratoplasty
(DALK)
 corneal stroma is
completely excised up to
DM
 stroma-to-DM interface
provides higher quality
vision

Preoperativ
e
assessment
Slit lamp: depth
of stroma
involved
Lid and
adnexa, tear
film,infection/i
nflammation,
posterior
segment, IOP,
general
systemic exam
Pachymetry
Anterior
segment
OCT

Surgical technique
Globe exposure
Host cornea marking: optical axis is marked using gentian violet
marking pen.
Stained 8 or 12 prong radial marker used to aid in suture
placement
Sizing & trephination: size of opacity measured with measuring
caliper
Trephine is preset to requisite depth in accordance with depth of
stromal involvement
Partial thickness trephination of host cornea is done
Stromal dissection:
Manual or automated

MANUAL DISSECTION
 CLOSED DISSECTION-
After desired depth trephination, stromal pocket is made with
paufique knife at incision site
Introduce lamellar dissector through the pocket while lifting
up the anterior lip of the flap
Dissection continued by gentle side to side movement and
parallel to posterior stroma
Smoother preparation but no direct visualisation possible

Open dissection
 Here the edge of the separated anterior lamellar tissue
is held retracted with the help of forceps during the
dissection enabling direct visualization of the area of
separation.
AUTOMATED LAMELLAR KERATOPLASTY-
 Microkeratome used Allows for superior smooth
surface
 Not suitable for thin & irregular corneas as in
advanced keratoconus
Indications:
 Stromal lesions limited to anterior stromal layers
 Moderate keratoconus
 Post PRK haze

In DALK
 Entire corneal stroma is removed baring the Descemet’s
membrane .
Adv –
 elimination of the graft host stromal interface, scarring,
irregularity
 Various methodes used to seprate DM from stroma-
1. Air dissection- ANWAR BIG BUBBLE TECHNIQUE most commonly
used
2. Viscodissection –
3. Hydrodelamination –saline solution is used

DONOR CORNEA
 The donor tissue is prepared by
punching an appropriate sized CS
button with a trephine.
 Trypan blue can be used to stain
the endothelium to improve
visualization in order to facilitate
the removal to DM and
endothelium from donor tissue.
 Donor tissue is then sutured with
host tissue using 10-0 nylon sutures
in a contineuos or interrupted
fashion.

INTRAOP COMPLICATION
 Descemet membrane perforation-
 Microperforation –self sealing or inject air to AC
 Large perforation from rim to rim- suture (10-0 nylon)it with
donor stroma. If not possible convert it to PK
 Pseudoanterior chamber-
 Due to occult break
 Due to retained visco
 Treatment-
 Shallow double chamber-self limiting, resolve in few week,
long standing one required surgical intervention by injecting
air to AC
 Irregular lamellar bed-
 Causes astigmatism, significant interface haze
 Can be avoided by big bubble technique or automated
microkeratome assisted anterior lamellar keratoplasty

 Graft-host malapposition/edge irregularity-
 due to improper sizing of tissue
 Adopt hemi-automated anterior lamellar procedure in
which the trephine is used to cut grafts of appropriate
size after the donor automated cuts on the donor cornea
and the host corneal lamellar dissection is performed
manually.
 Interface debris-
 due to fibers, bleeding
 Wash thoroughly after procedure

POST OP COMPLICATION
 Persistent epithelial defect
 Infection: Graft infection due to various causes such as
suture related, lid adnexal abnormalities, poor ocular
surface, prolonged topical steroid, poor hygiene
 Recurrence of the primary pathology- ex HSV, corneal
dystrophy
 Graft Rejection- less common
 Graft vascularization-can be seen in ocular surface
pathologies such as trachomatous keratopathy,
chemical burns and Stevens-Johnson syndrome.

POSTERIOR LAMELLAR
KERATOPLASTY (PLK)
Replacement of diseased posterior corneal layers
& endothelium with donor corneal tissue while
the host corneal stroma is retained.
IDEAL GOAL: obtain smooth surface topography
Predictable & stable corneal power
Tectonically stable globe
Safety from injury & infection

Indications
Fuchs
Endothelial
Dystrophy
Aphakic/Pseu
dophakic
Bullous
Keratopathy
Failed Graft
Iridocorneal
Endothelial
Syndrome
DM Breaks
Hereditary
Endothelial
Dystrophy

DEEP LAMELLAR ENDOTHELIAL
KERATOPLSTY (DLEK)
 It is a surgical method of endothelial replacement that
is performed through a limbal scleral incision that
leave the surface of the recipient cornea untouched.

INSTRUMENTS
AAC Diamond knife Crescent blade
Straight devers dissector Cindy scissor Trephine

Surgical procedure
Marking of host cornea
5mm scleral incision with diamond knife, 350 micron depth,
5mm temporal to limbus
Sclero corneal tunnel by cresent knife, 75% depth into clear
cornea
Straight devers dissector – to initiate from deep lamellar
stromal pocket
Dissect upto mid pupillary zone

A curved dissector is used to complete the stromal dissection
Enter AC with diamond knife at scler ocorneal tunnel
Healon inserted to AC
Cindy scissor used to dissect posterior stroma, DM, endothelium
Dissected tissue removed
Placed upon cornea to check its uniformity and smooth interface

Preparation of donor tissue
CS button is placed on AAC with epithelium side up
Suction trephine is used to achive 70% of depth
Cresent knife is used to dissect it
Then cs button is placed on a punch with
endothelium side up
a/c to host size punch is made

Healon is removed from AC
Graft is folded and inserted into AC
It made flatten inside the AC
Sclerocorneal tunnel then sutured with 3 interrupted suture
Air bubble is injected to ac to fix the graft in place

DESCEMET STRIPPING ENDOTHELIAL
KERATOPLASTY(DSEK)/DESCEMET’S MEMBRANE
STRIPPING AUTOMATED ENDOTHELIAL
KERATOPLASTY (DSAEK)
DSEK/DSAEK It is a method of posterior lamellar
keratoplasty in which the recipient bed is prepared by
stripping off the recipient’s Descemet's membrane.
Technique was popularized by Gerrit Melles in 2003

Donor cornea preparation
MANUALLY WITH
ARTIFICIAL
ANTERIOR
CHAMBER
AUTOMATED
MICROKERATOME

DSAEK
 Donor cornea preparation

Methods of insertion of donor
lenticule
Taco fold technique
Donor tissue folded into 60:40
Insertion using non coapting
forceps
Busin glide
Catridge
Tan’s endoglide

DSEK VS DSAEK
 risk of donor tissue
perforation
 does not yield a smooth
anterior surface of the
donor posterior lamella
 More time consuming
 Visual recovery is slower
 Adhesion of the posterior
lamellar lenticule is better
due to the greater tissue
thickness and irregular
anterior surface
 Donor lenticule dislocation
is lesser
 Microkeratome dissection
reduces the risk of donor
tissue perforation
 yields a posterior donor
lamellar of superior optical
quality
 Less time consuming
 Visual recovery is more
rapid
 Adhesion of the posterior
lamellar lenticule is not as
easy as in DSEK, as the
donor posterior stromal
lenticule is thinner and has a
smooth anterior surface
 Donor lenticule dislocation
is more

DESCEMET MEMBRANE
ENDOTHELIAL KERATOPLASTY
(DMEK)
 Transplantation of isolated donor endothelium and
Descemet’s membrane.
 Steps – Isolation of donor DM and endothelium ,
recipient descematorrhexis followed by donor
insertion and positioning
 Donor preparation :DM isolated by direct peeling or
by injection of air to create a Big Bubble
 Donor tissue over 40 years of age is preferred
 Insertion – glass pipette or IOL catridge and injector,
through 2.8mm corneal incision—unwrapping--air fill

COMPLICATION
 INTRAOP-Inversion of the donor lenticule
 POST OP-
 Increased handling of the posterior stromal donor tissue
 Postoperative dislocation of the posterior lamellar disc
 Air bubble tamponade- result in postoperative pupillary
block and secondary angle closure glaucoma.
 Primary graft failure-
 Posterior graft dislocation
 Endothelial graft rejection
 Iatrogenic glaucoma

Reduction of interface haze
Less incidence of graft dislocation
Larger donor surface provides more viable endothelial cells
Shorter visual recovery as total corneal thickness remains same
Less strong host graft apposition at interface allows easier removal of
failed/rejected donor lenticle
DMEK

Disadvantages
 difficult graft
preparation
 challenging nature
of surgery
 Inability to harvest
grafts from young
donor corneas

SURGICAL OUT COME
 Visual acuity-6/9 to 6/18 with DSEK
DMEK has faster and better visual recovery
DMEK – 6/9 or better vision
 Refractive results- mean hyperopic shift of 0.75 to 1.5D
due to changes in posterior corneal curvature and
increase in thickness in DSEK
 DMEK– 0.25 to 0.50 D hyperopic shift
 Endothelial cell loss- at 6months- 18-35 % , 54% at
5years
 Graft survival-55-100% in various studies

RECENT ADVANCES
FEMTOSECOND LASER DSAEK •
 This laser is used to create flaps in LASIK and can be used
to perform keratoplasty with different shapes of stromal
cut.
 The laser uses an infrared wavelength (1053nm) to deliver
closely spaced, 3 microns spots that can be focused to a
preset depth to photodisrupt the tissue within the corneal
stroma.
 Femtosecond laser is used to create a dissection plane on
the donor cornea mounted on artificial anterior chamber.
 Offers a potential advantage over microkeratome with
regards to
 better sizing of the posterior lenticule.
 Obtains a smooth surface and precise stromal cuts

Sutureless corneal adhesion
 Bioadhesive (Fibrin glue)- Kaufman et al successfully
used fibrin glue in small series of lamellar keratoplasty
 Photochemical keratodesmos is method of producing
sutureless adhesion by applying a photosensitizer to
wound surfaces followed by low energy laser
irradiation. Laser promotes cross linkage between
collagen molecules to produce tight seal without
thermal damage

Lamellar keratoplasty

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