keratoplasty

1. Lamellar keratoplasty

2. REVIEW OF CORNEAL ANATOMY
 Cornea is composed of 6 layers
1. Epithelium -50 um
2. Bowman membrane – 8-12 um
3. Stroma - 478-500 um
4. Dua‘s layer - 6-15 um
5. Descemets membrane -3um
6. Endothelium - 5um

3. Lamellar keratoplasty
 Consists of replacement of diseased corneal tissue while retaining
normal tissue.
 Anterior lamellar keratoplasty (ALKP): ALKP is defined as varying
amounts of anterior corneal tissue replacement with retention of the
recipient Descemet’s membrane and endothelium.
 Posterior lamellar keratoplasty (PLKP): PLKP is defined as any corneal
lamellar procedure where the Descemet’s membrane and endothelium
are excised with or without host corneal stroma.

4. Lamellar keratoplasty
Anterior Posterior
Superficial ALK ~160
um
Deep ALK ~400-490 um
Mid ALK ~160-400 um
Descement Stripping Endothelial
keratoplasty /Descemets Stripping
Automated Endothelial Keratoplasty
Descement Membrane
Endothelial Keratoplasty.
Types

6. Need for lamellar
keratoplasty ???

7.  Penetrating keratoplasty is the most commonly performed corneal surgery and was the
only method available for about 100 years
Disadvantages of PK:
 High rate of immune rejection
 Unpredictable post operative astigmatism
 Long postoperative visual recovery
 Loose suture can induce epithelial breakdown , infection, vascularization
 Corneal wound following PK is fragile with poor tectonic strength.
 Inc. Risk of vitreous loss ,retinal detachment ,expulsive choroidal hmg.

8. DONOR TISSUE
Donor corneas are harvested from cadaveric donors preferably within 6-8
hours of death.
Corneal preservation:
• Can be transplanted immediately or preserved in an eye bank by
various preservation techniques for varying intervals.

9. Corneal preservation
short term-
moist chamber----1-2
days
•McCarey kaufman
medium-----2-4 days
•Intermediate term
Optisol/cornisol/eusol--
chondroitin sulphate
,dextran and
gentamicin(10-14 days)
•organ culture method
using eagle’s medium
for 30 days
Long term preservation
up to 1 year by
cryopreservation in
liquid nitrogen or in
glycerol-

10. Contraindications for corneal utilisation for transplant
• Death of unknown cause
• Death with neurologic disease of unestablished diagnosis
• Subacute sclerosing panencephalitis
• Progressive multifocal leukoencephalopathy
• Active meningitis or encephalitis
• Encephalopathy of unknown origin or progressive encephalopathy
• Active septicemia (bacteremia, fungemia, viremia, parasitemia)

11. • Active viral hepatitis
• Creutzfeldt-Jakob disease
• Congenital rubella
• Reye’s Syndrome
• Rabies
• Active miliary tuberculosis or tubercular meningitis
• Hepatitis B surface antigen positive donors
• HTLV-I or HTLV-II infection
• Hepatitis C Seropositive donors
• HIV seropositive donors

12. Recipient prognostic factors
Following host factors may adversely affect the prognosis of a corneal graft.
 Abnormalities of lids such as blepharitis, ectropion ,entropion and trichiasis .These
conditions should be addressed before surgery.
 Severe stromal vascularization ,absence of corneal sensation , extreme thinning at
proposed host graft junction and active corneal inflammation.
 Recurrent or progressive forms of conjunctival inflammation….atopic conjunctivitis and
cicatricial pemphigoid.
 Tear film dysfunction
 Anterior synechiae
 Uncontrolled glaucoma
 uveitis

13. Pre
operative
assessme
nt
Lid and adnexa
Tear fim,
Infection /
inflammation,
posterior segment ,
IOP
Slit lamp
examination, depth
of stroma involved,
corneal
vascularisation.
Anterior segment
OCT
Pachymetry

14. Anterior lamellar keratoplasty
INDICATIONS
Tectonic: for re-establishing structural integrity of the cornea
1. Pellucid marginal degeneration
2. Advanced terriens marginal degeneration
3. Descemetocele
4. Sterile moorens ulcer and other forms of peripheral corneal
melts
Optical: to enhance vision
1. Ectatic disorders
2. Scars
3. Dystrophies
4. Degenerations like salzmanns nodular degeneration , band keratopathy
5. Post refractive surgery complications.

15. Cntd……
 Therapeutic
1. Resistant corneal infections
2. Dermoids and some tumor inflammatory masses
 Cosmetic
1. Corneal opacity which can be excised and replaced with lamellar corneal
button

16. Anterior Lamellar Keratoplasty : surgical
technique
 Direct open dissection ~Anwar
 Dissection with intrastromal air injection ~Archilla and Deep
 Dissection with hydro delamination ~ Sugita and Kondo
 Dissection with MELLE’S technique.
 Dissection with Anwar’s big bubble technique
 Dissection with double big bubble technique
 Microkeratome-assisted lamellar Keratoplasty

17. Anwar bubble technique
 Fastest and safest way of baring Descemet’s membrane in which air is used to
separate the deepest stroma from Descemet’s membrane.
 The technique involves trephining the anterior host corneal surface with a
Hessburg barron suction trephine to a depth of 400 um

18.  27/30G needle attached to air filled syringe is bent by 30-40 degree
 Needle inserted deep into stroma at 80% depth through trephination groove near the 12 O clock
position and advanced to paracentral region.

19.  Once the tip is in the desired position, the plunger is depressed and air is
injected with some force. The cornea whitens, with an irregular outline,
where air enters the stroma .

21.  Stop injecting air as soon as either the bubble forms or it is apparent by the
irregular white outline spreading outward that the bubble will not form
 The procedure can be repeated once or twice in clear regions of cornea.
 If the bubble fails to appear and no clear cornea is left for safe insertion
of the needle, perform an anterior keratectomy (at least half corneal
thickness) and inject balanced salt solution into the stroma until it is semi
translucent .

23.  Once the bubble forms, Anterior keratectomy is performed
 The depth of the keratectomy should not comprise all stromal layers. If the
big-bubble collapses prematurely at this early stage, inserting a spatula into
the pre Descemet plane may be impossible because of the inability to find an
opening through the stroma.
 Perform a paracentesis and drain the aqueous to soften the globe

28. Contraindication
 corneal disorders with pre existing breaks in Descemet’s membrane, or when
deep stromal scars involve this membrane.
 Among the corneal dystrophies, macular dystrophy may be a relative
contraindication to the big-bubble technique because of the increased
fragility of Descemet’s membrane in this disease, causing the membrane to
be more prone to tearing when air is injected forcefully.

29. Melles technique: air guided deep stromal dissection
Anterior chamber aqueous completely
replaced with air bubble
Half depth scleral incision 5mm in width , 1-2 mm
away from limbus
Sclero corneal tunnel dissected extending 1mm in clear cornea
Beveled spatula inserted and gradually advanced into stroma until mirror reflex
of the tip of spatula narrows to a fine line indicating corneal depth of about 95%

30. Spatula advanced over 360 degree
Air bubble partially evacuated and
descement membrane kept away from
stroma using ocular viscoelastic devices
Trephination

31. Double big bubble technique
 Partial trephination
 Paracentesis just posterior to limbus at 11 o clock
 First bubble : air injected in AC
 Second bubble: 27/3O G needle attached to air
filled syringe , with bevel facing down, used to
inject air in corneal stroma
 End point sudden peripheral movement of air
bubble in AC

32. Automated lamellar therapeutic
keratoplasty
 Allows quick and easy lamellar dissection with great precision
and excellent optical properties.
 The procedure is carried out using a microkeratome and an
artificial anterior chamber
 Range of microkeratome heads varying from 130 to 450um
permit excision of opacities involving anterior , middle and
posterior corneal stroma.
 Donor lamella is prepared using artificial anterior chamber and
graft is sutured under tension using 16 interrupted 10/0 sutures

33. Femtosecond Laser assisted keratoplasty- FLAK
 Femtosecond surgical lasers used for LASIK surgery employ near infra red pulses to
cut tissue with minimal collateral damage.
 It has been programmed to create anterior lamellar interfaces and peripheral
trephinations of desired depth and diameters.
 Peripheral trephination requires higher energy than lamellar incisions and for DALK
energy levels are further increased and spot size set closer to overcome the laser
scatter caused by additional thickness of stroma.
 Donor cornea is also trephined in similar fashion.

35. Tuck in lamellar keratoplasty
 Involves central lamellar keratoplasty with intrastromal tucking of the peripheral
flange.
 Safe and effective technique for management of peripheral corneal ectasias such as
pellucid marginal degeneration , keratoglobus and those after Keratoplasty

37. PREPERATION OF GRAFT FOR ALK
PROCEDURE
Peeling of descemet’s membrane and endothelium
Corneo scleral rim mounted on an artificial chamber
Donor corneal button of 0.25 -0.5 mm larger than the
recipient is used to avoid wound tension

38. Post operative medication
 Topical fluoro quinolone qid for 2-3 weeks
 Topical steroids
 Lubricating eye drops As needed.
 Follow closely until completion of epithelial healing (usually 3-4 days)
 Postoperative visits at 2 to 3 weeks, 2 to 3 months, 6 months, and 1 year
 Removal of sutures generally at 6 to 12 months.
 The sutures can be left longer if astigmatism is low; with high astigmatism,
which may occur after keratoconus and ectasia we should not be tempted to
remove sutures too early.

39. Complications
Intraoperative complications
Perforation and ruptures of descemets membrane :
 MC complication encountered during DALK .Approx. 10-30% of cases.
 Young keratoconus patients and patients with deep stromal scars
following infection and inflammation are at increased risk.
 Can occur in different surgical steps like trephination, stromal
dissection and can also occur while suturing a graft.

40. Management of descemets membrane
tear
 Anterior chamber pressure must be lowered so that break does not exend to the rim of
donor bed.
 Once a DM break is identified ,a different approach should be used to remove
remaining stroma.
 If DM break occurs during trephination , then a suture can be used to close the tear
and DALK can be attempted from a different clock position
 If tear is longer than 2 to 3 cock hours ,converting to PKP is advised.

41.  Irregular lamellar bed
 causes astigmatism, significant interface haze
 Can be avoided by big bubble technique or automated microkeratome
assisted anterior lamellar keratoplasty.
 Interface debris
 Due to fibres , bleeding
 wash thoroughly after procedure

42. Post operative complication
 Pseudo anterior chamber
• Due to occult break
• Due to retained visco
• Rx
• Self limiting , long standing --- injecting air into AC
 Pupillary block and fixed dilated pupil
 Persistent epithelial defect.
 Infection
 Graft rejection
 Graft vascularization

43. POSTERIOR LAMELLAR KERATOPLASTY /Endothelial
keratoplasty
 Removal of diseased recipient endothelium and replacing it with healthy donor
corneal endothelium
 Melles et al first described this technique which involved large limbal incision and
deep lamellar corneal dissection
 2000: Dr Terry modified by small incision and renamed the procedure as “deep
lamellar endothelial keratoplasty”
 2004: Next evolution by Mellis was substitution of patient dissection with descemets
stripping and “descemets stripping endo keratoplasty “ term was coined.
 2006:Gorovoy introduced the use of microkeratome and thus bringing about DSEAK

44. Goals of endothelial keratoplasty
 Healthy donor endothelium that resolves all edema.
 Smooth surface topography without significant change in
astigmatism from preoperative to postoperative status.
 Tectonically stable globe.
 Optically pure cornea.

45. ENDOTHELIAL KERATOPLASTY VS PKP
 EK procedure preserve normal topography to allow faster visual
recovery.
 Astigmatism after DLEK surgery was about 1.63 +-0.97 D in contrast to
4 to 6D after standard PKP
 Endothelial cell loss from preoperative donor was about 54% after 5
yrs in DLEK and DSEK patients. In PKP IT WAS 69 %
 Less immunological rejection rates than PK.PK>DSEK>DMEK.
 Tectonically stable globe.
 No suture related complication.

46. PRINCIPLES

47. DSAEK/DSEK INDICATIONS
 ENDOTHELIAL DYSFUNCTION WITH NO SCARRING OF ANTERIOR CORNEAL
LAYERS
• Fuchs Endothelial dystrophy
• Pseudophakic and aphakic bullous keratopathy
• Endothelial failure of an existing PK
• Irido corneal endothelial syndrome
• Congenital hereditary endothelial dystrophy

48. DSEK VS DSAEK
DSEK DSAEK
Manual dissection, inc risk of donor tissue
perforation.
Microtome dissection reduces risk of
donor tissue perforation.
Does not yield a smooth ant. Surface of
donor posterior lamella
Posterior donor lamella of superior quality
Better adhesion Adhesion not as easy as in DSEK
Donor lenticule dislocation lesser dislocation more
More time consuming Less time consuming
Visual recovery slower visual recovery is more rapid

49. DSEAK /DSEK surgical technique
Terry unfolding technique
 Creation of 5mm scleral tunnel
 The descemets membrane is scored and stripped using
reverse Terry sinsky hook under healon : Descemetorhexis
The precut donor epithelium is marked centrally and with
microkeratome surface cut.(epithelial side down in artificial
chamber)

50.  INSERTION OF DONOR LENTICULE :
 The pre cut donor tissue is marked centrally and tissue is folded in a 40/60
underfolded taco
 Charlie II non coapting forceps are used to insert the graft in AC.

51.  BSS is injected to partially unfold the graft f/b air injection
beneath endothelium for complete unfolding.
 Anterior chamber tamponade: The cornea is compressed with the
air in AC to centre the graft and milk fluid out of interface.
 Air fill only for 7 to 10 minutes f/b partial removal , in order to
prevent any undue increase in IOP

52. OTHER TECHNIQUES OF INSERTI0N OF
DSEAK GRAFT
 A suture pull through delivery
 Use of an insertion device
Busin glide
Tan endoglide
Endoserter

54. COMPLICATIONS
GRAFT DISLOCATION :
 significant separation of graft from the recipient posterior stroma
 Most commonly in the first postoperative week
Rx
 intra cameral air injection and repositioning
REBUBBLING
PRIMARY GRAFT FAILURE:
 When DSEAK surgery fails in deturgescence of cornea within 6 weeks post
operatively
 Almost always induced by surgical trauma

55.  REJECTION:
 HOST IMMUNOLOGICAL REACTION
 Mean rate is approx. 10%
 Long term continuance of low dose steroid to prevent rejection.
 ELEVATED IOP
 INFECTIOUS KERATITIS
 ENDOPHTHALMITIS

56. DMEK
 Donor descemets membrane and endothelial cells are transplanted and no
stromal tissue Is transferred.
 No interface --- better visual acuity

57. Advantages
 Less surgical trauma to recipient Eye
 Near normal restoration of anatomy of grafted cornea
 Faster and near complete visual rehablitation
 Less strong host graft apposition At interface allows easier removal of failed/
rejected donor lenticule.

58. DMEK: Graft insertion and positioning
 Recipient eye is prepared by marking the epithelium with the trephine to
indicate the planned graft diameter, scoring DM just inside this mark and
removing descemets membrane from within the scored area.
 Inserting scroll of donor descemet membrane and endothelium into recipients
eye Using intraocular lens inserter.

59. DMEK: Limitations
 Steep learning curve
 Difficulties in handling thin and friable DM
 Higher rates of primary graft failure and donor tissue wastage then DSEK.
 donor age > 50 yrs --- easy removal of DM

60. Pre descemets endothelial keratoplasty- PDEK
 PDEK tissue scrolled less and was easier to handle and unscroll in eye as
compared to DMEK tissue.
 the donor endothelial graft in DSEK has 100-150 microns of posterior stroma
,while PDEK graft is much thinner.
 Visual outcomes are similar to DMEK grafts.
 Endothelial cell loss in donor tissue is less.
 Relatively new procedure, graft failure rates and long term outcomes are yet
to b published.

61. Recent advances
Bio engineered corneas
 Descement stripping only
 in 2015, worlds first artificial bioengineered cornea was approved by
CFDA to be applied clinically as a substitute for human cornea in
lamellar keratoplasty.
 ACORNEA is made using tissue engineering technique on porcine
cornea to preserve collagen architecture of the corneal matrix so
that it can quickly integrate with patients corneal tissue.
 Human corneal endothelial cell culture

62. Thank you