Eye banking &Keratoplasty

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EYE BANKING AND KERATOPLASTY

• BY DR. ANITA
• PG 2nd year
• DEPT. OF OPHTHALMOLOGY

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EYE BANK
EYE BANKING

• An Eye Bank is a non-profit community
  organization which deals with the collection,
  storage, distribution of cornea for the purpose
  of corneal grafting, research supply of the
  other eye tissues for the other purposes.
• A medical director, an eye bank manager, eye bank
  technicians and grief counselors manage the day-
  to-day affairs of an eye bank.

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• The functions of eye banks are
• Educate the public about eye donation and eye
  banking
• Carrying out eye donations.
• Preserving, processing and evaluating the donor
  corneas
• carrying out serological tests of eye donors
  blood sample.
• Distributing donor corneas to corneal surgeons
  according to waiting list.
• Initiating Hospital Cornea Retrieval Programme in
  neighbouring hospitals.

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LEGAL ASPECTS OF ORGAN DONATION

• Under the Transplantation of Human Organ Act,
  1994
• The qualification of doctors permitted to perform
  enucleation (surgical eye removal) has been
  reduced from MS (Ophth.) to MBBS.
• Eye donation in India is always decided by the
  donors surviving relatives and not by the actual
  donor,
• Enucleation doctors always have to legally obtain
  a written consent from the relatives of the
  deceased before they actually remove the eyes.

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WHAT IS EYE DONATION?

• Eyes should be donated within 6-8 hrs. of death.
• Total removal time is about 15-20 minutes.
• Nobody is charged for making eye donation.
• The only cost to encounter is one local telephone
  call.

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STEPS OF EYE DONATION

• Donor selection
• Tissue retrieval
• Corneal examination
• Tissue transportation
• Storage of corneal tissue
• Distribution

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WHO CAN DONATE EYES?

• Any gender can donate eyes
• All religions endorse the practice of eye
  donation
• Willing donation of ones own eye during life
• Eyes from medico legal post mortem cases
• Eyes from unclaimed bodies
• A good donor cornea
• Healthy cornea
• Removal of cornea soon after death(within 6 hrs)

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DONOR SELECTION

• 1. AGE no influence of age on transplant
  outcome
• Lower limit 2 yrs to myopic shift after
  keratoplasty

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Medical history review

• Eye banks must have consistent policies for the
  examination and documentation of donors
  available
• medical records,
• medical history
• cause of death
• medications
• laboratory reports

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• Serology testing
• Preparation of donor
• povidone iodine 1-5 for 1-2 min
• Good stream of balanced saline

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• Legal consent taken from next of kin
• Consented donor meets medical and social history
  screening criteria
• Physical assessment reveals no contraindication
  to donation
• Acquisition of donor tissue can be carried out

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Contraindication for the use of donor tissue for
keratoplasty

• Death of unknown cause
• Death from central nervous system disease of
  unestablished diagnosis
• Creutzfelt-Jacob disease or a risk factor
• Subacute sclerosing panencephalitis
• Progressive multifocal leukoencephalopathy
• Congenital rubella
• Reyes syndrome
• Active viral hepatitis

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WHO CANT DONATEEYES
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• Active leukemias
• Active disseminated lymphomas
• High risk for HIV infection
• Hepatis B surface antigen positive
• HTLV-1 or HTLV-2 infection
• Hepatitis C seroposive donors
• Retinoblastoma, malignant tumor of the anterior
  ocular segment
• Active ocular inflammation
• Congenital or acquired disorders of the eye
• Prior intraocular surgery or anterior segment
  surgery

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TISSUE RETRIVAL

• enucleation by
  in- situ corneo-scleral i.e. surgical removal of
  the whole eye excision( globe is
  retained in the orbit)

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CORNEAL EVALUATION

• Examination of the corneas in situ
• A simple penlight examination
• Epithelial defects (drying, erosion, sloughing)
• Corneal edema with associated haze
• Abnormal corneal shape
• Blood or cloudiness in the anterior chamber
• Corneal scars or infiltrates, arcus senilis, and
  any sign of conjunctivitis or discharge.

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The slit-lamp examination

• Low power higher power
• Whole eyes can be examined within the container
  used for the retrival
• Excised cornea from the bottom of the storage
  vial
• Cornea should be allowed to reach the room
  temperture

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Methods of endothelial evaluation

• Specular microscopy Mostly used by eye banks
  using hypothermic storage of corneo-scleral
  buttons.
• Other methods
• Phase contrast microscopy
• Transmitted light microscopy
• Critical density 300-500 cells/mm3
• Functional cell density1500-2000cells/mm3

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Storage methods

• Short term method
• Moist chamber technique
• Whole globe is preserved at 40 C temp. with
  saline humidification for upto 48 hours.
• Simple, cheap, easily transportable, and
  requires minimum manipulation

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Intermediate term method

• Mc-Kaufman(MK) medium can preserve cornea upto
  4 days at 40C temp.
• Chondroitin sulphate enriched media
• dexol medium
• Lysol medium
• Optisol medium it contain dextran and
  chondroitin sulphate which enhances corneal
  dehydration during storage and the cornea can be
  preserved for 14 days.

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Anatomy of cornea

• The cornea is the refractive surface of the eye
  and constitutes up to 1/6 of the entire eyeball.
• It has 5 layers
• The epithelium
• Bowmans layer
• The stroma
• Descemets membrane
• endothelium

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Anatomy of cornea
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KERATOPLASTY

• INTRODUCTION
• Keratoplasty is the corneal transplant procedure
  in which diseased host corneal tissue is excised
  and replaced with healthy donor cornea.
• Either full thickness of the cornea or a part of
  it may be transplanted.
• Objectives
• Establish clear corneal visual axis
• Minimize refractive error
• Provide tectonic support
• Alleviate pain
• Eliminate infection

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Indication

• Optical to improve visual acuity
• Corneal scars
• Corneal dystrophy/degenerations
• Congenital corneal opacities
• Keratoconus

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Indication

• Tectonic and reconstructive
• Restoration of altered corneal structure
• corneal perforations/thinning
• Therapeutic
• Tissue substitution for corneal diseases
• Non healing corneal ulcer(infectious keratitis)
• Cosmetic
• To improve the appearance of eye

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Types of keratoplasty

• Penetrating keratoplasty full thickness
  replacement of entire cornea
• Lamellar keratoplasty partial thickness
  replacement of only part of the cornea
• superficial lamellar keratoplasty
• Deep lamellar endothelial keratoplasty
• Endothelial keartoplaty a variation in which
  only the endothelium layer is replaced
• Type of surgery chosen according to corneas
  condition

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Penetrating keratoplasty

• Full thickness replacement of diseased tissue
  with healthy donor cornea
• Indications
• Pathology involving whole cornea
• Full thickness scars
• Perforation of cornea
• Herpetic scars
• Vascularized scars
• keratoconus

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Penetrating keratoplasty (PK)

• Surgical indication for PK
• Optical a healthy, clear donor cornea is used to
  replace an opaque, cloudy, or distorted cornea in
  an attempt to improve vision
• Pseudophakic bullous keratopathy
• Keratoconus
• Regraft secondary to allograft
  rejection
• Regraft unrelated to allograft
  rejection
• Keratoglobus
• Degeneretions
• Dystrophies
• Scars
• Aphakic bullous keratopathy
• Congenital opacities
• Chemical injuries

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• Tectonic
• Descemetocele
• Corneal stromal thinning
• Corneal perforation
• Therapeutic infection may be due to bacteria,
  virus, parasite,or other cause
• Cosmetic to improve appearance of the patient

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Procedure for PK
PREOPERATIVE PREPARATION
ANESTHESIA
SURGICAL PREPARATION
TREPHINATION OF DONOR CORNEA
TREPHINATION OF RECIPIENT CORNEA
SUTURING OF DONOR CORNEA
POSTOPERTIVE TREATMENT
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Preoperative evaluation

• Ocular history
• Visual acuity
• Detailed examination underlying pathology
• IOP
• Vascularization
• Tear film status
• Presence of cataract
• Need for IOL exchange
• B-Scan

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Donor tissue preparation

• The donor cornea is trephined from endothelial or
  epithelial surface. For epithelial surface
  trephination, an artificial anterior chamber is
  required.
• 2 types of trephines are- suctionless trephines
  and suction trephines.
• A cutting block and artificial anterior chamber
  may also be used for corneal disc preparation.
• Graft size 7.5 mm

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Trephination of donor cornea

• Endothelial punch system
• Hessberg barron vaccum trephine less AC collapse
  distortion
• Sharper, deeper more perpendicular cut

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Hanna trephine laser trephine

• Donor cornea encased within an artificial chamber
• Corneal trephination from epithelial surface

• Femtosecond excimer laser
• No mechanical distortion
• Perpendicular congruent edges

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Trephination of recipient cornea
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Recipient dissection
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Suturing of donor cornea

• Placement of donor cornea on recipient
• Anterior chamber filled with viscoelastics
• Donor cornea brought into field of microscope
  with a graft holder
• Suturing of recipient cornea with 10-0 nylon
  suture -
• - place 4 cardinal suture first at 900
  interval
• - first suture at 12 oclock, 2nd at 6
  oclock followed at
• 3 oclock and 9 oclock

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Postoperative management

• Topical steroids To decrese the risk of
  immunological graft reaction.
• Immunosuppressants azathioprine,ciclosprin may
  be used in high risk for prevention of rejection.
• Mydriatics if uveitis persist.
• Monitoring of IOP is performed during the early
  postoperative period.
• Removal of sutures when the graft-host junction
  has healed.
• Rigid contact lenses- to optimize visual acuity
  in eyes with astigmatism

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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 endopthalmitis.
• Late astigmatism, recurrence of intial disease
  process, late wound separation, retro-corneal
  membrane formation, glaucoma and cystoid macular
  oedema

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Lamellar keratoplasty

• Similar to PK but only a part of thickness of
  cornea is grafted.
• 1.Superficial Lamellar keratoplasty
• Partial thickness excision of the corneal
  epithelium and stroma.
• Endothelium and part of the deep stroma are left
  behind.
• INDICATIONS
• Superficial 1/3 stromal corneal opacity, granular
  dystrophy
• Marginal corneal thinning or infiltration as in
  recurrent pterygium, marginal degeneration
• Localised thinning or descemetocele formation

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2.Deep anterior lamellar keratoplasty

• Opaque corneal tissue is removed almost to the
  level of Descemet membrane
• 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
  keratoconjuctivitis.
• During DALK, the surgeon injects air to lift off
  and separate the thin outside and thick middle
  layer of cornea and removal of ant. Corneal
  layer( leaving the endothelium and Descemets
  membrane behind)

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Endothelial Keratoplasty

• REPLACES ONLY THE INNERMOST LAYER OF THE CORNEA
  (ENDOTHELIUM) AND LEAVES THE OVERLYING HEALTHY
  CORNEAL TISSUE INTACT.
• - THE SURGEON MAKES A TINY INCISION BY TREPHINE
  OR FEMTOSECOND LASER AND PLACES A THIN DISC OF
  DONOR TISSUE CONTAINING A HEALTHY
• ENDOTHELIAL CELL LAYER ON THE BACK SURFACE OF THE
  CORNEA , AN AIR BUBBLE IS USED TO POSITION THE
  NEW ENDOTHELIAL LAYER INTO PLACE , THE SMALL
  INCISION IS SELF-SEALING AND TYPICALLY NO SUTURES
  ARE REQUIRED.

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DESCEMENT STRIPPING ENDOTHELIAL KERATOPLASY(DSEK)

• This technique combine stripping off endothelium
  and Descemet membrane, through a corneo-scleral
  or corneal incision.
• INDICATIONS
• Pseudophakic bullous keratopathy

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DSEK

• THIS TECHNIQUE COMBINES STRIPPING OFF THE
  DYSFUNCTIONAL ENDOTHELIUM FROM THE HOST CORNEA
  WITH MICRODISSECTION OF THE DONOR TISSUE.
• - IN THIS TYPE PATIENT'S ENDOTHELIUM IS REPLACED
  WITH A TRANSPLANTED DISC OF POSTERIOR
  STROMA/DESCEMET'S MEMBRANE/ENDOTHELIUM.
• - SURGEON REMOVES THE ENDOTHELIUM ( ONE CELL
  THICK) AND THE DESCEMET MEMBRANE JUST ABOVE IT.
  THEN HE REPLACES THEM WITH A DONATED
• ENDOTHELIUM AND DESCEMET MEMBRANE STILL ATTACHED
  TO THE STROMA .
• -THIS REDUCES OCULAR SURFACE COMPLICATIONS
  GENERALLY COMPARED TO PENETRATING KERATOPLASTY.

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DSEK surgical techinque
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a) DLEK, b)DSEK
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DESCEMENTS MEMBRANE ENDOTHELIAL KERATOPLATY
(DMEK)

• DMEK is further variation on ( DSEK), in which
  immune- mediated rejection is reduced by
  transplanting bare endothelium and Descemets
  membrane without stroma.
• Donor tissue thin and fragile, so difficult
  procedure but healing is quicker.

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Before injecting DMEK tissue into anterior chamber

• Descemetorhexis with no loose tags of Descemet
  membrane or stroma
• Patent inferior peripheral iridotomy
• Main incision widened to accommodate the Straiko
  injector and form a watertight seal
• Evacuation of all viscoelastic from the anterior
  chamber and the injector
• Pupil smaller than 3 mm, constricted

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Complication of keratoplasty

• Early complications-
• Persistent epithelial defect(gt2 weeks in
  duration) symptoms are as for corneal abrasion
  pain- redness- tearing- sensitivity to light-
  blureed vision- may be a/w headache
• Irritation by protruding sutures
• Iris prolapse through operative wound
• Keratitis or endophtalmitis- sight threatening
  complication
• Uveitis
• Flat anterior chamber
• Elevated intraocular pressure

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Late complications

• -Astigmatism
• -Glaucoma
• -Late wound separation and suture related
  problems
• -Cystoid macular edema
• Graft rejection complications
• Early graft rejection
• Occurs by the first operative day
• There is a cloudy cornea
• this is usually due to defective donor
  endothelium or trauma

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Cont.

• Late graft rejection
• Sign of rejection eye pain, redness, photophobia,
  cloudy vision.
• Occurs within the first 6 months or year
• Red eye, corneal clouding uveitis, a/w decreased
  visual acuity
• Rejection line
• Usually due to immunological graft rejection

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PROGNOSIS

• POOR PROGNOSIS IS NOTED IN PATIENTS WITH
• 1-ADDITIONAL CORNEAL PROBLEMS SUCH AS
  VASCULARISATION OR PERIPHERAL THINNING.
• 2- ASSOCIATED OCULAR DISEASE SUCH AS HERPES,
  ACTIVE INFLAMMATION OR UNCONTROLLED GLAUCOMA.

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POSTOPERATIVE CARE
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THANK YOU