SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
5] Penetrating Keratoplasty [PK]:
This procedure involves full thickness removal and replacement of a portion of
the cornea. The decision to perform a PK is made on the basis of poor
response to medications and the uveitis getting worse, imminent rupture into
the anterior chamber or unrelenting endophthalmitis or an anticipated poor
visual outcome. Donor corneal material is required [frozen or fresh equine
cornea]. A button of the infected cornea [6-8mm] is removed with a trephine.
A graft greater than 8mm has a greater chance of rejection. A partial
thickness trephine is done and the final piece removed with scissors.
Viscoelastic can be used to tapenade the iris from prolapsing. This does not
have to be removed again. The donor corneal button, 1mm larger, is
trephined from a donor cornea and placed into the recipient’s corneal wound
and sutured with 8/0 Vicryl. A conjunctival graft could be sutured over this
[optional]. A temporary tarsorrhaphy can be done to limit eyelid trauma to the
PK. Post operative medications’ are imperative and may be required for a
substantial period of time, and on average for 50 days. It is expected the
visual outcome can be as good as 75%.
4] Split-thickness Penetrating Keratoplasties [lamellar surgeries]
These procedures result in replacing only the diseased portion of the cornea
leaving normal tissue intact
A] Posterior Lamellar Keratoplasty [PLK]
A posterior lamellar keratoplasty [PLK] procedure can be performed when the deep
stromal abscess occupies the posterior cornea. This surgery involves lifting a
rectangular 2/3 corneal flap consisting of epithelium and anterior stroma directly
above the lesion and then trephining the affected abscess tissue out. A circular piece
of donor cornea is trimmed to remove the epithelium and sutured in place. This
piece has endothelium, Descemet’s membrane and posterior stroma. The flap is
then replaced and sutured down. This results in a strong two layer closure and less
scarring. This procedure is recommended for a DSA in the central cornea that is
<8mm in diameter and has a clear overlying anterior stroma. Postoperative
medications will include antibiotics, serum and Tacrolimus drops. Usually post
operative treatment is shorter at an average of 24 days and success rates of > 90%
can be expected.
B] Deep Lamellar Endothelial Keratoplasty [DLEK]
The final technique is the deep lamellar endothelial keratoplasty [DLEK]. This
technique is used where the deep stromal abscess is near the periphery of the
cornea and is 10mm or less in diameter. A flap of anterior cornea is lifted as for the
PLK and the abscess trephined out. A 2/3 deep limbal incision up to 23mm is made.
A stromal pocket is formed over the DSA. The flap is retracted and abscess removed
with a trephine and corneal scissors. A donor piece of cornea is then placed into the
space, positioned in place and often stabilised by injecting viscoelastic into the
anterior chamber. This together with the endothelial pump holds it in place. The
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