This document discusses different types of keratoplasty procedures including penetrating keratoplasty, lamellar keratoplasty, and Descemet stripping endothelial keratoplasty. Penetrating keratoplasty involves replacing the entire diseased cornea and is used for conditions involving all corneal layers. Lamellar keratoplasty replaces only partial layers of the cornea. Deep anterior lamellar keratoplasty removes tissue to the level of Descemet's membrane while Descemet stripping endothelial keratoplasty only replaces the diseased endothelium and Descemet's membrane through a small incision.

1. KERATOPLASTY
- Dr. Narang

2. Keratoplasty/corneal grafting /
corneal transplantation
• Definition: It is an operation in which the patient's diseased
cornea is replaced by the donor's healthy clear cornea.
Types:
• 1. Penetrating keratoplasty (full-thickness grafting)
• 2. Lamellar keratoplasty (partial-thickness grafting) -anterior
or posterior lamellar

3. • Indications:
• Optical ,i.e., to improve vision - corneal opacity, bullous
keratopathy, corneal dystrophies, advanced keratoconus.
• Therapeutic, i.e., to replace inflamed cornea not responding
to conventional therapy
• Tectonic graft, i.e., to restore integrity of eyeball in eyes with
severe structural changes such as severe thinning with
descemetocele.
• Cosmetic, i.e., to improve the appearance of the eye.

4. Donor tissue :
• removed as early as possible (12–24 hours of death).
• Corneas from infants (3 years and under) are rarely used -
surgical, refractive and rejection problems.
• It should be stored under sterile conditions.
• Evaluation –medical history review and donor blood screening
to exclude contraindications, and microscopic examination of
the cornea including endothelial cell count determination

5. Methods of corneal preservation
• Short-term storage (up to 2 days) -The whole globe is
preserved at 40C in a moist chamber.
• Intermediate storage (up to 2 weeks) -McCarey-Kaufman
(MK) medium and various chondroitin sulfate enriched media
such as optisol medium used.
• Long-term storage (up to 35 days) -It is done by organ culture
method.

6. Contraindications to ocular
tissue donation
• Death of unknown cause.
• Certain systemic infections such as HIV, viral hepatitis, syphilis,
congenital rubella, tuberculosis, septicaemia and active
malaria.
• Prior high-risk behavior for HIV and hepatitis.
• infectious diseases of the CNS.
• Receipt of a transplanted organ.
• Most hematological malignancies.
• Ocular disease such as inflammation and malignancies (e.g.
retinoblastoma) and corneal refractive surgery.

7. Host factors may adversely affect
the prognosis:
• Severe stromal vascularization, extreme thinning at the
proposed host-graft junction and active corneal inflammation.
• Abnormalities of the eyelids (blepharitis, ectropion, entropion
and trichiasis).
• Recurrent or progressive forms of conjunctival inflammation.
• Tear film dysfunction.
• Anterior synechiae.
• Uncontrolled glaucoma.
• Uveitis.

8. Penetrating keratoplasty
• most commonly performed corneal transplantation
procedure.
INDICATIONS INCLUDE:
• Disease involving all layers of the cornea.
• Specific common indications: keratoconus, pseudophakic
bullous keratopathy, Fuchs endothelial and other dystrophies.

9. Technique:
• Determination of graft size:
- by trial placement of trephines with different diameters or by
measurement with a calliper.
- An ideal size is 7.5 mm.
- grafts smaller than this may give rise to high astigmatism.
- Grafts of diameter 8.5 mm or more are prone to postoperative
anterior synechiae formation, vascularization and increased
intraocular pressure.

10. • Excision of donor corneal button -The donor corneal button
should be trephined 0.25 mm larger than the recipient, taking
care not to damage the endothelium.
- to facilitate watertight closure, minimize postoperative
flattening and reduce the possibility of postoperative
glaucoma.

11. • Excision of recipient corneal button - care should be taken,
not to damage the iris and lens.
- Recipient trephining can be performed freehand or with
suction trephine systems which stabilize the globe and ensure
that the angle of trephination is perpendicular to the surface.

12. • Suturing of corneal graft into the host bed is done with either
continuous or interrupted 10-0 nylon sutures.

13. Postoperative management:
• Topical steroids are used to decrease the risk of
immunological graft rejection.
• Other immunosuppressants –azathioprine, ciclosporin may be
rarely used in high-risk for prevention of rejection.
• Mydriatics - if uveitis persists.
• Monitoring of IOP is performed during the early postoperative
period.
• Removal of sutures when the graft-host junction has healed.
This is usually after 12–18 months.
• Rigid contact lenses -to optimize visual acuity in eyes with
astigmatism.

14. Postoperative complications:
• Early complications: persistent epithelial defects, irritation by
protruding sutures, wound leak, flat anterior chamber, iris
prolapse, uveitis, elevation of intraocular pressure, microbial
keratitis and endophthalmitis .
• Late: astigmatism, recurrence of initial disease process, late
wound separation, retro-corneal membrane formation,
glaucoma and cystoid macular oedema.

15. Superficial lamellar keratoplasty
• This involves partial thickness excision of the corneal
epithelium and stroma.
• endothelium and part of the deep stroma are left behind.
Indications:
• Opacification of the superficial one-third of the corneal
stroma.
• Marginal corneal thinning or infiltration as in recurrent
pterygium, marginal degeneration.
• Localized thinning or descemetocele formation.

16. Deep anterior lamellar keratoplasty
• Opaque corneal tissue is removed almost to the level of
Descemet membrane.
• decreased risk of rejection because the endothelium, a major
target for rejection, is not transplanted.
Indications:
• Disease involving the anterior 95% of corneal thickness with a
normal endothelium and absence of breaks or scars in
Descemet membrane .
• Chronic inflammatory disease such as atopic
keratoconjunctivitis which carries an increased risk of graft
rejection.

17. Descemetstripping endothelialkeratoplasty
• It involves removal only of diseased endothelium along with
Descemet membrane, through a corneoscleral or corneal
incision.
• Folded donor tissue is introduced through the same small
(about 5 mm) incision.
Indications:
• include endothelial disease such as pseudophakic bullous
keratopathy.