PDEK

introduction

What is PDEK?

Pre Descemets Endothelial Keratoplasty is a partial thickness corneal transplant. The diseased endothelial cells are removed from the patient’s eye and selectively replaced with a new layer of endothelial cells which are taken from the donated eye. The endothelial cells are the healthy cells lining the back of the cornea which pump fluid from the cornea to prevent the cornea swelling. The normal endothelial count is 2000 – 3000 cells/mm2. When the cells decrease in number < 500 cells/mm2, corneal decompensation occurs, clarity of the cornea reduces and eventually the vision becomes cloudy.

How is the surgery performed?

The surgery is usually performed under local anaesthesia. Through a small corneal incision (opening), the endothelium is removed from the patient’s eye and a disc of donor endothelium is inserted in the patient’s eye which is placed in position with the help of an air bubble. A few stitches may be taken which will be removed 3-4 weeks after the surgery. The patient needs to lie down flat for a few hours post surgery for proper attachment of the graft. The air bubble usually gets absorbed in 48 hours but may take longer.

 

What are the indications of PDEK?

  • Fuch’s endothelial dystrophy
  • Pseudophakic bullous keratopathy
  • Aphakic bullous keratopathy
  • ICE syndrome
  • Endothelial dysfunction secondary to glaucoma

 

What are the advantages over full thickness penetrating Keratoplasty?

  • Few sutures required as compared to penetrating keratoplasty.
  • Suture induced astigmatism is avoided
  • Suture related complications are avoided
  • Greater stability
  • Faster visual rehabilitation
  • The graft can be obtained from any age group of the donated eyes
  • Chances of rejection are less

 

What are the complications of PDEK?

  • Graft detachment/ dislocation
  • Recurrent epithelial erosions
  • Cataract formation
  • Glaucoma
  • Graft rejection
  • Graft failure

 

What is rejection?

The donor eye is genetically different from the patient’s body, due to which the patient’s body tries to fight against it. This is called corneal graft rejection. 

 

What are the symptoms of rejection?

The symptoms are : Redness, Sensitivity to light, Vision drop, Pain (RSVP). Along with sticky discharge and foreign body sensation.
Report to your Ophthalmologist as soon as possible if any of the above symptoms show up post surgery.


How do I prevent graft rejection?

  • In order to prevent rejection, a list of anti-rejection medications will be prescribed by your doctor, which should be used religiously.
  • You should have an adequate supply of eyedrops at home so that a single dose is not missed.
  • Do not stop any medication without consulting your Ophthalmologist.
  • In case any of the above symptoms of rejection occur, meet your Ophthalmologist immediately. It can often be reversed if anti-rejection medications are started promptly. It should also be noted that rejection can occur at anytime in the years to come.
  • Review regularly to check for vision, intraocular pressure, graft condition and retinal assessment.

 

What are the risk factors for rejection?

  • Vascularisation over the cornea
  • Pre-existing inflammation
  • Corneal transplant done more than 2 times
  • Pre-existing glaucoma

 

What is graft failure?

When the corneal rejection has not been promptly treated or does not respond to anti- rejection medication, graft failure has occurred. It can be managed by replacing the graft. 

 

Written by: Dr. Preethi Naveen – Chairman, Education Committee

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