11. OCULAR EVALUATION
⢠Ocular history
⢠Visual acuity
⢠Detailed examination:
Underlying pathology
IOP
Vascularization
Tear film status
Presence of cataract
Need for IOL exchange
B-scan
13. PREOPERATIVE PREPARATION
⢠ANTI INFECTIVE AGENTS:PRE OP ANTIBIOTICS
TREATMENT OF BLEPHARITIS
5% POVIDINE IODINE SOLUTION
ď§ IOP CONTROL: PRE-OP MANNITOL
HONANâS BALLOON COMPRESSION AT 30 MM HG
GOOD LID EXTRA OCULAR AKINESIA.
ď§ ANESTHESIA : PERIBULBAR ANESTHETIA WITH OR WITHOUT LID
BLOCK
GENERAL ANAESTHESIA FOR PAEDIATRIC CASES
APPREHENSIVE PATIENTS
MENTAL IMPAIRMENT
ď§ PUPIL DILATATION: PUPIL CONSTRICTION WITH 2% PILOCARPINE
PUPIL DILATATION WITH MYDRIATICS WHEN CATARACT
SURGERY IS PLANNED
16. DONOR TREPHINATION
⢠Trephination of the donor button should
preferably be performed from the epithelial
side using an artificial anterior chamber
with a large central opening
⢠Punching the donor from the endothelial
side results in an undercut at the level of
Descemetâs membrane with convergent cut
angles
17.
18. HOST TREPHINATION
⢠Horizontal positioning of limbal plane is
indispensable
⢠Flieringa ring is only necessary in aphakic
eyes
⢠The higher the intraocular pressure
(iatrogenic!) the more divergent are the
cut angles to be expected
19. Combination of donor trephined from the
endothelial side (convergent cut angle) and mechanically
trephined recipient (divergent cut angle) results
in a triangular-shaped tissue deficit at the level of
Descemetâs membrane which has to be compensated
by suture tension resulting in central flattening
20. ⢠graft size has to be judged by the microsurgeon
individually in every single case
before recipient trephination to achieve the
best compromise between immunologic
purposes and optical quality
Ď donor trephination from the endothelial
side results in a smaller donor button than
trephine size and convergent cut angles
(âundercutâ)
Ď recipient trephination results in larger
openings than trephine size and divergent
cut angles
Ď this discrepancy makes a donor âoversizeâ
of âĽ0.25 mm necessary
Ď same size grafts are feasible
if the donor is
created by means of an artificial
anterior
chamber from the epithelial
side
Ď
undersizing the graft for simultaneous
21.
22. Hessburg-Barron suction trephine.
A Recipient trephine with cross-hairs for
centration;
B Donor trephination is performed from the
endothelial
side
23. GRAFT
⢠A good optical performance
requires a larger graft, whereas a low rate of
immunologic graft reactions tends to be seen
with smaller grafts.
24. TRIPLE PROCEDURE
⢠Comprises of grafting+extraction of cataract+IOL
implantation.
⢠PEARL:
⢠Cataract should be removed regardless of the stage as
later it will progress & then it can cause damage to the
corneal endothelium.
⢠Vitreous can be removed with vannazs or wide bore
canula.(host âgraft junction should be free of vitreous)
⢠IOL insertion-routine insertion if not then the lens can be
sutured to the iris or to the sclera.
25. MEDIUM FOR CORNEAL PRESERVATION
⢠Short term storage
⢠Intermediate storage
⢠Long term storage
26. SHORT TERM STORAGE
Method:
⢠Moist chamber method:
when globe is preserved
at 4âc with saline
humidification for upto 48
hrs.
Endothelial viability
depends on:
⢠Enucleation within 6 hours of
death.
⢠Cool enviornment
maintainence until enucleation
⢠Maintaining 4âC
⢠Careful slit lamp examination
28. McCAREY âKAUFMAN MEDIUM
ORIGINAL
⢠TC199
⢠5% Dextran
⢠Bicarbonate buffer
⢠Penicillin&streptomycin(100uni
t/ml) later substituted by
gentamycin in conc of 50-
200Âľg/mi
MODIFIED
⢠Added phenol red as a pH
indicator
⢠Osmolarity -290mOsm/kg
⢠pH is 7.4
⢠k/as modified MK medium
⢠Cornea can be stored at 4âC
upto 4 days
29. LONG TERM STORAGE
ORGAN CULTURE
⢠DONOR CORNEA UPTO 35
DAYS
⢠NO REMARKABLE LOSS OF
ENDOTHELIAL CELLS .
CRYOPRESERVATION
⢠ONLY TRUE
PRESERVATION
⢠CAPELLA & KAUFMAN
⢠Corneoscleral rimâin a series of soln
of dimethyl sulfoxide(DMSO)
upto 7.5%.---placed for 10minsâ
upto -80âC & subsequently stored at -
160âC indefinitely.
30. SUTURING TECHNIQUES
⢠Suture material
⢠Suture technique (interrupted,
single running, double
running, combinations)
⢠Length of stitch
⢠Depth of stitch
⢠Angle of stitch towards graft-
host apposition
⢠Suture tension
⢠âDepth disparityâ
31. Correct position of second cardinal
suture (arrow) is facilitated by orientation
tooth
(donor) and corresponding notch (host)
32.
33. SURGICAL OUTCOMES
GROUP 1
⢠EXCELLENT
PROGNOSIS
>90%
KERATOCONUS
CENTRAL/PARACENTRAL
CORNEAL SCARS
STROMAL DYSTROPHY
GROUP 2
⢠VERY GOOD
PROGNOSIS
EXPECTED SUCCESS
RATE OF 80-90 %
APHAKIC/PâPHAKIC CORNEAL
ODEMA & BULLOUS
KERATOPATHY
INACTIVE HERPETIC KERATITIS
MACULAR STROMAL DYSTROPHY
34. GROUP 3
⢠FAIR PROGNOSIS-
SUCCESS RATE 50 TO
80%
Active microbial /herpetic keratitis
Mild chemical injury
Moderate keratoconjunctivitis sicca
GROUP 4
⢠POOR PROGNOSIS-
<50%
⢠Severe chemical injury
⢠Radiation injury
⢠Stevenâs johnson syndrome
⢠Multiple failed grafts
35. COMPLICATIONS
INTRAOPERATIVE
⢠SCLERAL PERFORATION
⢠Trephination related
⢠Retained descement
membrane
⢠Endothelial damage
⢠Intraocular hemmorhage
⢠Vitreous loss
POSTOPERATIVE
⢠Wound leak
Persistent epithelial defect
Post op inflammation
Suture related
Raised IOP
Ant synechiae formation
LATE:
Post PK astigmatism
Graft rejection
Post pk glaucoma
36.
37. GRAFT REJECTION
⢠Time : rarely within 1st month but it can be till 20 years
post PK
⢠These rejections takes 4 clinical forms
⢠EPITHELIAL REJECTION:in this immune responseâ
donor epithelium-lymphocytes causes elevated linear
epithelial ridgeâcentipetally
The rejection has been reported at the rate of 10% of
patients experiencing rejection
Usually seen in the post op period (1-13 months)
38.
39. SUBEPITHELIAL REJECTION
⢠They may present as subepithelial infiltrates
⢠Alone they may cause no symptoms
⢠Lymphocytes direction is unknown
⢠Can be seen in broad,tangential light
⢠These leave no sequelae if treated
⢠But it may presage the more severe endothelial graft rejection
⢠STROMAL REJECTION:
⢠This is uncommon
⢠If present can present as neovascularization
⢠In very prolonged bouts the stroma can become necrotic
40. ENDOTHELIAL REJECTION
⢠THE MOST COMMON TYPE
⢠8%-37%
⢠loss of significant NUMBER OF ENDOTHELIAL CELLS
LEADS TO GRAFT REJECTION
⢠inflammatory cells seen in anterior chamber.
⢠endothelium lostâstroma thickensâepithelium
odematous
⢠pts have--- photophobia,redness,irritation,halos around
light.
41. TREATMENT
⢠Frequent steroid instillation
⢠Dexamethasone 0.1%
⢠Prednisolone0.1%
⢠Periocular injection of
triamcinolone acetonide for
severe rejection or non
compliant patient.
⢠PREVENTION
⢠Early attention to loosening
sutures
⢠Use of
cyclosporine,tacrolimus,mycop
henolate.
42. o preservative-free topical steroids hourly for 24 hours are the mainstay of
therapy. the frequency is reduced gradually over several weeks. steroid
ointment can be used at bedtime as the regimen is tapered. high-risk
patients can be maintained on the highest tolerated topical dose (e.g.
prednisolone acetate 1% four times daily)
â topical cycloplegia (e.g. homatropine 2% or atropine 1% OD or BD daily).
â topical ciclosporin 0.05% to 2% may be of benefit, but the onset of action is
delayed.
â systemic steroids oral prednisolone 1 mg/kg/day for 1â2 weeks with
subsequent tapering; if given within 8 days of onset IV methylprednisolone 500
mg daily for up to 3 days may be particularly effective, suppressing rejection
and reducing the risk of further episodes.
â subconjunctival steroid injection (e.g. 0.5 ml of 4 mg/ml dexamethasone).
43. KERATOPROSTHESIS
Group 1
⢠With good blink rate
⢠Wet eye
⢠BOSTON Type 1 K Pro
Group 2
⢠Significant conjunctival
scarring
⢠Dry eye & exposure
⢠Alpha cor
keratoprosthesis