ISSN 2398-2977      

Cornea: penetrating keratoplasty - transplantation

pequis
Contributor(s):

Tim Knott

Johana Premont

Synonym(s): PK, Keratoplasty


Introduction

  • Full thickness corneal transplantation of homologous tissue to restore full thickness corneal integrity.
  • To provide tectonic, structural support to a deeper corneal defect.

Uses

  • Full thickness removal of deep stromal lesions, such as stromal abscess, wound repair and preserving structural globe integrity by transplanting fresh or frozen homologous tissue.
  • Fresh homologous donor corneal tissue provides improved corneal clarity due to grafting of viable endothelium.
  • Cryopreserved homologous donor corneal graft provides tectonic structural support. Graft rejection occurs via corneal vascularization and edema. This may result in more rapid healing and lower dehiscence.
  • Ideally used for defects up to 6-8 mm in diameter.

Advantages

  • Strong structural support for full thickness lesions.
  • Fresh corneal tissue improves corneal clarity due to transplantation of the endothelium (in contrast to cryopreserved corneal tissue).

Disadvantages

  • Logistical difficulty in obtaining fresh corneal donor tissue at the time it is needed.
  • Prolonged surgical, anesthesia and healing times.
  • No blood supply provided.
  • Graft rejection by secondary vascularization and edema leads to increased corneal scarring when using cryopreserved corneal tissue.
  • Most technically challenging procedure.
  • Penetration of the anterior chamber results in more pronounced uveitis, and increased risk of hemorrhage, intraocular infection, anterior and posterior synechiae, graft dehiscence, especially in grafts larger than 8 mm diameter, during healing process.

Requirements

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Preparation

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Procedure

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Aftercare

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Outcomes

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Prognosis

  • If technically correct and the disease process is controlled, the majority of corneal lesions will heal with the above techniques.
  • Scars will form at the ulcer site.
  • Intraocular synechiae   Eye: anterior synechia - post-corneal penetration  may interfere with pupillary movement.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • de Linde Henriksen M et al (2013) Equine deep stromal abscesses (51 cases - 2004-2009) - Part 1: the clinical aspects with attention to the duration of the corneal disease, treatment history, clinical appearance, and microbiology results. Vet Ophthal 17Suppl 1, 6-13 PubMed.
  • de Linde Henriksen M et al (2013) Equine deep stromal abscesses (51 cases - 2004-2009) - PART 2: the histopathology and immunohistochemical aspect with attention to the histopathologic diagnosis, vascular response, and infectious agents. Vet Ophthal 17Suppl 1, 14-22 PubMed.
  • Makra Z, Tuboly T & Bodo G (2013) Penetrating keratoplasty and graft rejection in eight horses. Acta Vet Hung 61 (2), 160-174 PubMed.
  • Martins B C et al (2013) Light microscopic evaluation and scanning electron microscopic analysis of horse eyes following deep anterior lamellar keratectomy. Vet Ophthal 16Suppl 1, 42-51 PubMed.
  • Henriksen Mde L et al (2012) Visual outcome after corneal transplantation for corneal perforation and iris prolapse in 37 horses: 1998-2010. Equine Vet J Suppl (43), 115-119 PubMed.
  • Brooks D E (2010) Targeted lamellar keratoplasty in the horse: a paradigm shift in equine corneal transplantation. Equine Vet J Suppl (37), 24-30 PubMed.
  • Plummer C E et al (2009) The use of amniotic membrane transplantation for ocular surface reconstruction: a review and series of 58 equine clinical cases (2002-2008). Vet Ophthal 12Suppl 1, 17-24 PubMed.
  • Brooks D E et al (2008) Corneal transplantation for inflammatory keratopathies in the horse: Visual outcome in 206 cases (1993-2007). Vet Ophthal 11 (2), 123-133 PubMed.
  • Ollivier F J et al (2006) Amniotic membrane transplantation for corneal surface reconstruction after excision of corneolimbal squamous cell carcinomas in nine horses. Vet Ophthal (6), 404-413 PubMed.
  • Brooks D E (2005) Penetrating keratoplasty, deep lamellar endothelial keratoplasty, and posterior lamellar keratoplasty in the horse. Clin Tech Equine Pract (1), 37-49 VetMedResource.
  • Denis H M (2004) Equine corneal surgery and transplantation. Vet Clin North Am Equine Pract 20 (2), 361-380, vi-vii VetMedResource.

Other sources of information

  • Clode A & Matthews A (2011) Diseases and Surgery of the Cornea. In: Equine Ophthalmology. 2nd edn. Ed: Gilger B C. Elsevier Saunders, Maryland Heights, MO. pp 181-266

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