Penetrating keratoplasty in ophthalmology

PENETRATING KERATOPLASTY

KERATOPLASTY• An operation in which diseased corneal

tissue is replaced by donor corneal tissue.

CLASSIFICATION

• Penetrating Keratoplasty

• Lamellar Keratoplasty

– Anterior Lamellar (DALK)

– Posterior Lamellar (DSAEK)

INDICATIONS1.OPTICAL - To restore vision

2.TECTONIC / RECONSTRUCTIVE - To restore integrity

3.THERAPEUTIC -To eradicate disease

4.COSMETIC -To improve

appearance

TECTONIC / RECONSTRUCTIVE

OPTICAL INDICATIONS

THERAPEUTIC

To pain in PBKTo visualize fundus

COSMETIC unsightly corneal scars/deposits

CONTRAINDICATIONS• Advanced Dry eye

• Anterior staphyloma

• Severe cases of SJ syndrome

• Grade 4 chemical burns

• Ocular cicatrical pemphigoid

RELATIVE C/I• Multiple graft failure

• RD with PR inaccurate

• severely scarred cornea with AS trauma/infection in 1 eye with other eye 6/6

• central corneal opacity with peripheral clear area

DONOR SELECTION

• CONTRA INDICATIONS

• prion d/s :Jacob - Creutzfeld syndrome

: PPLE

• infections : AIDS,Septicemia,Syphilis,Viral hepatitis

• malignancy :HL,PCV,leukemia,lymphoma,myeloma

• intrinsic eye d/s :KC,KG

• intra ocular sx : LASIK,PRK,RK

• death of unknown cause

• H/O & EXAMINATION

• MEDICAL H/O

– cause of death

– past medical h/o

– time of death

– donor identification details

– lab reports

• SEROLOGY TESTING

– HIV,HBAg,HEP C +/- syphilis

• ENUCLEATION,INSITU EXCISION,CORNEOSCLERAL RIM SECTIONING

EVALUATION OF DONOR CORNEA• Gross insitu examination

– Intactness of globe

• Slit Lamp Examination

– Shape and size of cornea

– Epithelial haze ,defects,Abrasions

– Any Stromal opacities ,oedema

– Microcystic oedema

– Descemet’s fold /Breaks

– Condition of anterior chamber

• ENDOTHELIAL MICROSCOPY

– critical count :300 -500 cells/mm²

– eye bank cut off:1500-2200 cells/mm²

– r/o polymegatheism,pleomorphism,guttae

– r/o inflammatory cells,bacteria

• SPECULAR MICROSCOPY- usually after placement in storage media in room temp- cell density,size,uniformity of size of cell

• LIGHT MICROSCOPY– phase contrast /transmitted light microscopy + intra vital

staining of endothelial layer by trypan blue.– evaluates after storage & close to time of transplantation

RECRUITMENT OF DONOR TISSUE• tissue removed within 6 hours after death.

• Cornea can be stored in :

• SHORT TERM (UPTO 96 HOURS)

– Whole Globe preserved in moist chamber(48hrs

– McCarey-Kaufman media

• INTERMEDIATE TERM (UPTO 2 WKS)

– Optisol/Dexsol/Ksol Corneal storage

• ORGAN CULTURE (UPTO 35 DAYS)

• LONG TERM (UPTO 1 YEARS)

– cryopreservation

PROCEDURE FOR PK • Preoperative preparation

• Anesthesia

• Surgical preparation

• Trephination of Donor cornea

• Trephination of Recipient cornea

• Suturing of Donor cornea

• Post operative treatment

PREOPERATIVE EVALUATION OF RECIPIENT

• Ocular history

• General history

• Visual acuity

• Gross ocular examination

• Slit lamp biomicroscopy– conjunctiva & cornea

– AC & iris

– lens

• Intraocular pressure

• Fundus evaluation

INVESTIGATIONS• Refraction • tear film assesment• Keratometry• Gonioscopy• Pachymetry• Specular & confocal microscopy • Laser interferometry • Videokeratography• orbscan & pentacam• USG• electrophysiological tests

– ERG– pattern VEP

ANAESTHESIA

Sx PREPERATION

PREPARATION OF DONOR CORNEA

TREPHINATION OF DONOR CORNEA

TREPHINATION OF RECIPIENT CORNEA

• Marking centration on host cornea

• Trephination done either by hand held, suction & automated trephines

DIFFERENT TYPES OF FLAPS• Top Hat Shape -Provides large endothelial surface

transplantation

• zig-zag shape- Hermetic wound seal Angled edge provides smooth transition between host and donor

• Mushroom Shape- Preserves host endothelium

SUTURING OF DONOR CORNEA • AC formed - viscoelastic

• 10-O nylon & 11-0 mersilene.

• Cardinal sutures - 4 in number– 1st suture :12 o’ Clock

– 2nd suture : 6 o’ clock

– 3rd & 4th :90 ⁰ to 1st & 2nd

• Suture depth : 90%

• Equidistant bites – 16 interrupted//20-24 single running

• Bury knots on donor side /recipient cornea.

• Check wound leak. -

TYPE OF SUTURING• interrupted

• combined interrupted & continuous

• single continuous sutures

• double continuous sutures

NO ROTATIONAL EFFECT. CLOCKWISE ROTATION OF GRAFT BY 0.7+/- 1MM //11⁰

BITES FORM ISOSCELES TRIANGLE

• COUNTER CLOCKWISE ROTATION OF GRAFT 0.7+/- 1MM//11⁰

INTRA OP REGIME

• Subconjunctival injections of gentamycin ( 40mg in 1 ml ) + dexamethasone ( 4 mg in 1 ml)

• Pad & bandage for 24 hrs.

POST OP REGIME • Assess Visual acuity

• Degree of pain ,Wound leak, pupil shape, corneal epithelial status, anterior chamber, IOP, early signs of infection & endophalmitis

• Medication:- Topical antibiotics & steroids + Lubricants + cycloplegic.

• TOPICAL ANTIBIOTICS • 0.3% oflox/ciplox• infectious kertitis:fortified tobramycin /cephazolin• fungal keratitis :5% natamycin• herpetic keratitis: po acivir 400mgx 5 tx3 wks

• SYSTEMIC AB• ciplox 500-750 mg

• STEROID• 1% pred acetate/0.1% dexa-topical • 1mg/kg/d prednisolone :po

• ANTI GLAUCOMA• cat /VR Sx/synechiolysis/AS reconstruction//glaucoma

• CYCLOPLEGICS• 1% tropicamide/cyclo:pain & inflammation

• LUBRICANTS• preservative free

EXPECTED OUTCOMES POST PK