Penetrating Keratoplasty for postgraduate students.

1. Penetrating
Keratoplasty
Dr. Jigyasa Sahu
Senior Resident
Guru Nanak Eye Centre
MAMC, New Delhi

2. ● Eduard Konrad Zirm performed the first successful full
thickness penetrating keratoplasty in a human in 1905, he
became the first person to perform a solid organ transplant.
● Ironically, he performed the surgery for one of the most
challenging indications in ophthalmology – bilateral alkali
burns .
● Vladomir Petrovich Filatov, a Russian ophthalmologist,
became known for his work on eye banking in the early 1900s.
He suggested using cadaver corneas as donor tissue and
developed a method to do so.He is also known as the father of
keratoplasty
HISTORY

4. Ocular Immune privilege!!

5. INDICATIONS OF KERATOPLASTY

7. Optical Keratoplasty
● The keratoplasty is performed with the main purpose of improving the visual acuity.
● Most common indication of penetrating keratoplasty (90 percent).
● The common indications of optical keratoplasty include :
○ aphakic bullous keratopathy
○ pseudophakic bullous keratopathy
○ Corneal opacities following infectious keratitis
○ trauma,
○ Graft failure
○ endothelial and stromal corneal dystrophies
○ corneal degenerations
○ congenital corneal opacities.
○ Very advanced keratoconus

8. Tectonic/Reconstructive Keratoplasty
● The prime purpose is to restore the altered corneal structure.
● This is required in :-
○ eyes with a thinning/ectasia in cornea,
○ corneal perforation or loss of corneal tissue,
○ pellucid marginal degeneration
○ corneal melting associated with autoimmune disorders,
○ corneal fistula
○ post-traumatic loss of corneal tissue.

9. Therapeutic Keratoplasty
● Mainly indicated in cases of infectious keratitis to eliminate
the infectious load in eyes with keratitis unresponsive to
specific antimicrobial therapy.
● Indications:
○ Severe corneal ulcer non responsive to maximal
medical therapy
○ Perforation >3mm
○ Descmatocele (impending perf) with infiltrates
● Prognosis!!

10. Cosmetic Keratoplasty
● Restore the normal appearance of the eye
● limited or no visual potential
● unsightly corneal scars or deposits
● not remain clear in all cases and long-term
medications are required
● availability of painted soft contact lenses, corneal
tattooing, enucleation or evisceration with a
skillfully prepared prosthesis

11. When not to do???

13. Preop history taking…...
Ocular injury,
infectious keratitis,
nutritional deficiencies,
history of previous surgery
collagen vascular disease
Stevens-Johnson S
Herpetic disease.
duration of corneal
opacity
Presence of amblyopia
Good vision prior to
opacity???
Prior infection
Ocular surgery
Any retinal
pathology

14. EXAMINATION
● Visual Acuity-[UCVA] , [BCVA].
● Contact lens corrected -irregular
astigmatism.
● projection of rays- retinal and optic
nerve function.
● small central scars- a stenopic slit
visual acuity after complete
pupillary dilatation.
● children -resistance to
Occlusion,Preferential looking test,
cardiff etc
Slit lamp biomicroscopy : rule out
lid pathology, lacrimal system
pathology might lead to later
failures
Tear film evaluation
Vision Gross ocular exam

15. Specific examination
Cornea: size, shape, extent and severity of corneal opacity, degree and extent of
vascularization, corneal sensation
Regrafts: prior donor size
Anterior segment : anterior synechia , how many clock hours involved
Lens: presence of cataract, aphakia and pseudophakia.
Aphakic may require anterior segment reconstruction including pupiloplasty,
anterior vitrectomy and ACIOL/SFIOL
IOP : MacKay Marg, pneumotonometer, scleral tonometer or Tono-pen..If not
available digital tonometry. Requirement of a prep trab???
Fundus : If not visible at all Bscan

16. Investigations
Refraction
Tear Film Status
Keratometry
Gonioscopy
Pachymetry
ASOCT for level of scarring
UBM (anterior segment evaluation)
Ultrasound

17. Eye banking
Death to enucleation time : ideal 6 hrs (6-8 hrs)
Storage media
Moist chamber- 48 hrs
MK - upto 4 days
Cornisol - upto 7- 10 days (14 days????)
Organ culture - upto 35 days
Cryo - upto 1 year

19. PREOPERATIVE PREPARATION
● Infection Control: treatment of blepharitis
● Decrease in Corneal Neovascularization: preoperative steroids, electrocautery,
argon laser photocoagulation and adrenaline soaked sponges.
● Intraocular Pressure Control: A good hypotony should be achieved
preoperatively by means of intravenous mannitol, digital massage or a Honan
balloon. It decreases posterior pressure during open sky phase of surgery and
the risk of vitreous loss and choroidal hemorrhage.
● Pupillary Management: pilocarpine - phakic PK ; Tropac P - PK with cataract

20. Steps
❏ Painting and Draping
❏ Exposure and Insertion of Lid-speculum
❏ TREPHINATION OF DONOR CORNEA
❏ Graft Host Disparity: Most corneal surgeons use
a 0.5 mm oversized graft for their routine cases.
In keratoconus- 0.25 mm to compensate for the
associated myopia.
❏ Use of hand-held trephines
❏ Using the corneal endothelial punch systems
(Cottingham punch, Barron vacuum donor corneal
punch, IOWA PK Press corneal punch and
Rothman-Gilbard corneal punch.
❏ Non-mechanical Laser Trephination- excimer
laser

22. MARKING THE HOST CORNEA
● Centration
● Radial marking

23. Trephining host cornea
● 7 to 8 mm in routine cases.
● Larger in keratoconus
● Cornea thoroughly dried before trephining.
● Rotated between the thumb and the forefinger maintaining a downward
pressure.(80%)
● Full thickness cut is generally avoided- damage to iris, lens, sudden AC collapse
● MVR entry (guarded) followed by cutting with corneo scleral scissors
Small grafts - inc astig
Less rejection
chances
large grafts - decrease astig
inc rejection
chances

25. Suturing of donor cornea
anterior chamber of the host is filled with a viscoelastic
4 cardinal sutures

26. Suturing techniques
● Single Interrupted Suturing Technique
● Combined Continuous and Interrupted Suturing (CCIS) Technique
● Single Continuous Suturing Technique
○ Torque : rotates the corneal graft counterclockwise by 0.7 +/- 0.1 mm at the wound or 11 degrees;
○ Antitorque : the antitorque pattern rotates the corneal graft clockwise by 0.7 +/- 0.1 mm at the wound
or 11 degrees;
○ no torque : the bites of which form an isosceles triangle, produces no rotational effect.
● Double Continuous Suturing Technique

28. ● Interrupted sutures are recommended in infants and children, highly
vascularized corneas and in therapeutic keratoplasty.
● advantage of selective suture removal
● The needle should pass anterior to the Descemet’s membrane. The suture
length should be about 2 mm, 1 mm on each side.
● Full-thickness suture should not be put as these cause more endothelial trauma
and aqueous may leak through the suture tracts postoperatively.
● bury the knots on the donor cornea as, if buried on the recipient side, they may
stimulate vascularization.

29. POSTOPERATIVE MEDS
● Antibiotics -fortified in TPK
● Corticosteroids - oral in high risk cases, young patients, suspect high
inflammation
○ Not until 1-2 weeks atleast in therapeutic cases
● Antiglaucoma Medications-
■ Pre-existing glaucoma
■ Penetrating keratoplasty combined with
○ Cataract surgery
○ Vitrectomies
○ Lysis of synechiae
○ Use of large amounts of hyaluronate
○ Anterior segment reconstruction
● Cycloplegics - cautiously, risk of urets zavalia!
● Lubricants - preservative free

30. Postop follow up
1st month - every 2 weeks 2nd month - every 4 weeks
3-12 months - every 6 weeks 1-2 yr - 6-12 weeks till all sutures
removed

32. Graft in Ocular surface diseases
● Toxic topical medication and preservatives may have an adverse effect on epithelial wound
healing
● Abnormalities of the tear film from decreased aqueous secretion, rapid evaporation, mucin
deficiency, blepharitis, poor lid position or movement and lagophthalmos can influence epithelial
healing and wound healing.
● Aberrant lashes (trichiasis) should be eliminated
● Blepharitis, whether from local or systemic disease, such as rosacea, must be controlled with lid
hygiene
● lateral tarsorrhaphy or lateral canthal sling procedures for lagophthalmos, punctal plugs.
● Unpreserved solutions should be used to minimize epithelial toxicity.

33. Grafts in prexisting glaucoma
Topical prostaglandin analogues are controversial.
Dorzolamide may affect the donor endothelial function and result in prolonged graft
edema and should be avoided postkeratoplasty.
Systemic carbonic anhydrase inhibitors- caution in old patients

34. Graft in inflammed eyes
systemic as well as intensive topical immunosuppression.
Tight control of the systemic disease is necessary to maximize graft survival and
should be undertaken in conjunction with a rheumatologist or immunologist.

35. Graft in infected eyes
Send button for culture
Sensitivity report
No steroids for atleast 1-2 weeks
Start with low potency steroids

36. Regrafts
● Two approaches can be taken to prevent immune mediated rejection and ultimately failure in
high-risk corneal transplantation:
• Suppression of the host immune response.
• Making the donor tissue less antigenic: pretreatment with ultraviolet B irradiation and
the use of anti CD4 receptor antibodies.
● Corticosteroids
● Cyclosporine A (4-5mg/kg)
● Azathioprine (50-100mg/day)
● Mycophenolate Mofetil (2-3 gm/day)
● Tacrolimus (0.03% ointment)

37. Complications of PK
❖ Preop:
➢ Poor anesthesia and positive vitreous pressure
❖ Intraop:
➢ Scleral Perforation during application of fixation sutures or bridle suture
➢ Improper Trephination :Reversed host and donor trephines (tight sutures/inc IOP)
➢ Eccentric Host Trephination (use sharp trephine; might have to change to a larger
trephine)
➢ Irregular/Oval Trephination
➢ Retained Descemet’s Membrane (thick and edematous cornea seen in cases of congenital
hereditary endothelial dystrophy and interstitial keratitis; Failure to grasp the iris is a
conclusive sign of presence of retained Descemet’s membrane)
➢ Damaged Donor Button
➢ Inversion of the Graft
➢ Excessive Bleeding (cautery, adr soaked sponge)

38. ❖ ..
➢ Injury to Iris-lens Diaphragm : zonular dialysis, lens tilt
➢ Posterior Capsular Tear and Vitreous Prolapse
➢ Suture Related Complications (final assessment of such sutures should be made after the
reformation of anterior chamber; The second suture is the most important) .
➢ Iris Incarceration (inject viscoelastic to push away)
➢ Suprachoroidal Hemorrhage (0.47 to 3.3 percent; most dreaded complication) Various
risk factors involved are pre-existing glaucoma, hypertension, high myopia, inflammation,
sudden cough, previous surgery, previous traction and Valsalva maneuver, excess
retrobulbar block).
■ Mx: inf temp sclerotomy
■ Iv mannitol
■ Quick donor suturing with 8-0 nylon

39. Postop complications
● Early-
○ Shallow Anterior Chamber and Wound Leak : seidels, microleak?, pad bandage/BCL, resuturing
req?
○ Iris Incarceration (hypotony/leak)
○ Wound Dehiscence
○ Suture-Related Problems : loose sutures, suture infiltrates, vasc sutures

41. Mx of Persistent epi defect in graft
❏ Eye patching
❏ Bandage soft contact lens
❏ temporary tarsorrhaphy
❏ Autologous serum
❏ Amniotic membrane transplantation
❏ recombinant epidermal growth factor and
fibronectin

42. Primary Graft Failure
Corneal grafts that have gross corneal edema with large broad folds immediately after keratoplasty and
which is not preceded by a period of clear cornea is called primary graft failure.
➔ Prolonged death-enucleation time
➔ Poor donor endothelial count
➔ Aphakic and pseudophakic donor
➔ Elderly donor
➔ Inadequate preservation
❏ Mx: proper donor selection, good preservation and by avoiding endothelial injury during donor
processing and during the surgery.
❏ Observed for 3-4 weeks for the signs of graft clearing before proceeding with the second surgery.

43. Graft infection
● The incidence of microbial keratitis in
corneal grafts ranges from 1.76 to 4.9
percent in western countries.
● Developing countries- 11.9 percent.
● Loose suture, PED risk factors
● Close follow-up and any loose suture must
be removed as soon
● scrapings are obtained for smear and
culture-sensitivity

44. Late Postoperative complications

45. Infectious Crystalline Keratopathy
★ Chronic, progressive corneal infection occurring mostly in the anterior
lamella of the grafts without any clinically evident stromal
inflammation.
★ Crystalline branching opacities in the anterior and mid stroma due to
intralamellar aggregates of gram-positive cocci occurring several
months following penetrating keratoplasty

46. ★ Characteristic lesions are associated with persistent
epithelial defect, use of topical corticosteroids, herpes
simplex keratitis and contact lens use.
★ Streptococcus viridans. Rarely other organisms such as
Staphylococcus, Enterococcus, Hemophilus, fungal species
like Candida.
Mx
Intensive fortified
antibiotic
Concentrated
vancomycin and cefazolin
(both 50 mg/ml) most
commonly

47. Urrets-Zavalia Syndrome
❖ Permanent fixed dilated pupil after penetrating keratoplasty in patients
❖ unresponsive to miotics.
❖ etiology is unknown, severe iris ischemia, as demonstrated by anterior
segment fluorescein angiography and use of strong mydriatics
❖ Peripherally painted contact lens
❖ Try prevention..

48. Epithelial ingrowth
❖ Predisposing factors
➢ Poorly healed wound
➢ Fistulous tract
➢ Wound dehiscence with iris
incarceration
➢ Trauma
➢ Previous intraocular surgery
progresses over the posterior surface of cornea,
anterior chamber angle and the iris in a sheet like
fashion. Ingrowth over the posterior surface of
cornea results in endothelial dysfunction, corneal
edema and hazy graft.
Fibrous ingrowth
❖ known as retrocorneal membrane is a gray
or white fibrous collagenous tissue invading
between Descemet’s membrane and
endothelial cell layer.
REGRAFT

50. Recurrence of Original Recipient Disorder
Stromal dystrophies
–Granular-upto 100 percent at 4 years
–Macular-5.2 percent
–Lattice-48 percent
• Reis-Buckler’s dystrophy
• Central crystalline dystrophy
• Posterior polymorphous dystrophy.

51. Corneal Graft Rejection
Graft failure is divided into two groups: primary (or early) and secondary (or late)
failure.
PRIMARY
● never clears, remaining
thickened postoperatively
● is usually due to poor eye
banking or surgical trauma with
damage to the endothelial
surface.
SECONDARY
● Functioned well in the immediate
postoperative period (at least 2 weeks).
● Unless specifically stated graft failure
refers to secondary graft failure.

52. Graft failure is due to any cause of endothelial cell loss to such as aphakia, older
style anterior chamber intraocular lenses, uncontrolled intraocular pressure or
ongoing inflammation.
The commonest cause of secondary graft failure is an immune mediated process
termed allogenic graft rejection.
Not all episodes of allogenic graft rejection however, progress to secondary graft
failure. Some resolve with endothelial function returning and stromal edema
improving.

53. Types of graft rejection
Close Differential!! - recurrence of HSV keratitis in graft
HSV progresses from host to graft/ at GHJ, has focal
inv, no khodadaust line

54. Post keratoplasty astigmatism

55. Post keratoplasty Glaucoma

56. Paediatric keratoplasties
● Staged
● EUA required
● Ideal surgery at 8-12 weeks of age.
● bilateral opacity, the first eye is also done between
2-3 months of age.

57. ADVANCES IN PENETRATING
KERATOPLASTY

58. Femto assisted keratoplasty
★ IntraLase Enabled Keratoplasty
★ The IEK software enables the femtosecond laser to perform three-cut segments:
a posterior side cut, a lamellar cut and an anterior side cut.
○ a top-hat pattern (larger diameter cut posteriorly)
○ mushroom pattern (larger diameter cut anteriorly)
○ zigzag
○ Christmas tree pattern, tongue and groove

59. Bioengineered corneas