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8/20/2014 - PowerPoint PPT Presentation

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Plasma Knife versus Conventional Scissors for In-situ Excision of Donor Corneoscleral button for the purpose of Penetrating Keratoplasty. Ashutosh Agarwal 1 , Radhika Tandon 1 , Namrata Sharma 1 , Jeewan S. Titiyal 1 , Rasik B. Vajpayee 1,2

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Plasma Knife versus Conventional Scissors for In-situ Excision of Donor Corneoscleral buttonfor the purpose of Penetrating Keratoplasty

Ashutosh Agarwal1, Radhika Tandon1, Namrata Sharma1, Jeewan S. Titiyal1, Rasik B. Vajpayee1,2

1Department of Ophthalmology, All India Institute Medical Sciences, New Delhi, India;

2Centre for Eye Research, University of Melbourne, Melbourne, Australia

The authors have no financial interest in the subject matter of this poster.



In India

Prevalence of corneal blindness is approximately 6.8 million of which about 1 million are bilaterally blind and 40,000 fresh cases are added every year.

Nearly 3.5 million good quality cornea donors are required, quite challenging with an annual meagre collection of 20,000 eyes.

Rajesh Sinha, Namrata Sharma et al .Corneal Blindness—Present Status I CATARACT & REFRACTIVE SURGERY TODAY ,OCTOBER 2005: 59-64

Major obstacles include ineffective procurement of donated corneas as also failure to successfully convince the potential donors.

Tandon et al.. Factors Affecting Eye Donation From Postmortem Cases in tertiary Care Hospital (Cornea 2004;23:597–601)

In situ excision of donor cornea (compared to conventional Whole Globe Enucleation)) is a

newer technique (last one decade)

swift and precise extraction with least damage to endothelium

prolific in enhancing the quality and utilization of donor corneas by reducing death preservation time




review of literature contd
Plasma Knife


Safe, quick, atraumatic

By tissue ablation

Resistance free (minimum tissue traction)

No tactile sensation of making incision

Tip does not adhere to tissue

Lower frequency and power compared to laser

Application in a wide range of ocular surgeries

Plasma Knife can produce sharp cuts in the cornea while

minimal tissue damage seen beyond edges of the incision

Peponis et al ,Fugo Blade in Corneal Surgery ;Cornea 2006;25;206-208

Review of Literature (contd…)



aims and objectives
Aims and Objectives
  • Systematic comparative prospective evaluation of two techniques of harvesting donor cornea by in-situ method with respect to:
    • Donor tissue microbiological contamination
    • Corneal endothelium in the donor and also the recipient following transplantation
    • Graft infection
    • Graft outcome in the recipient at three months
  • Donor selection
    • YES
      • Age <60 years
      • DPT < 6 hours
    • NO
      • Aphakia / Pseudophakia
      • Putting on ventilator for long time (>72hrs)
      • Hypotension
  • Recipient Selection
    • Non-vascularized corneal opacity
  • Written consent from legal next of kin



Eyes were systematically randomized (Right/Left) for both type (Plasma Knife or Corneoscleral Scissors) and sequence of extraction.

The eye cleaned externally with povidone iodine 10% for 3 mins

Irrigation of conjunctival sac with saline

Povidone 10% instilled in conjunctival sac and washed off with saline

The eye cleaned and draped

1st limbal swab for culture

Gatifloxacin 0.3% eye drops instilled





After doing 360° peritomy, a scleral incision made (in conventional method) with surgical blade 3mm from limbus taking care not to enter the choroid

Corneoscleral rim excised using curved corneal scissors/ or Plasma Knife

Careful separation of cornea from underlying tissue care not to damage endothelium

Second swab taken(S2)

Eyes put in McKarey Kauffman (MK) medium (transferred to eye bank)

A transparent plastic cap put over the eye




  • Comparative evaluation done for 2 techniques of in-situ excision i.e. Plasma Knife assisted versus conventional scissors
    • Preoperative Evaluation
    • Donor tissue microbiological contamination (before and after excision)
    • Evaluation and grading of donor cornea on Slit Lamp
  • Post operative follow up of graft recipients
    • Post-op. corneal endothelial status
    • Graft status at 3 months in terms of Central Corneal Thickness, Graft Clarity and Spectacle Corrected Visual Acuity
    • Any associated complications like graft infection/ graft failure etc.



results donor evaluation
RESULTS: Donor Evaluation

FET=Fischer Exact Test, MWT=Mann Witney Test, CST=Chi Square Test

results recipient evaluation
RESULTS: Recipient Evaluation

FET=Fischer Exact Test, MWT=Mann Witney Test, CST=Chi Square Test

  • Plasma knife is a safe and effective equipment for in-situ extraction of donor corneoscleral rim.