Pre-Descemet's endothelial keratoplasty

PDEK graft is transplanted so far for adult patients who have lost vision due to endothelial decompensation meaning the Endothelium is not working.

Once the type 1 BB is formed in the centre, it is gradually enlarged to maximum size which is about 8 mm.

Following this, the bubble is pierced with a trephine or knife (Fig 2B) and the graft is dissected meticulously.

The dissected PDEK graft is then placed in a storage medium till the recipient (patient) is ready for transplantation.

Descemet's membrane along with endothelium in the patient is removed mechanically by reverse Sinskey hook by controlled stripping on the endothelial side[citation needed] (Fig 3A-C).

[citation needed] Normal human lens is placed inside a capsular bag by nature.

To overcome this problem, the technique of glued IOL was introduced by Prof Amar Agarwal in 2007, December for lens implantation in eyes with the absent or deficient capsular bag.9,10 Here 2 scleral flaps about 180 degrees apart are made and the IOL is inserted through the corneal incision (Fig 3).

After making the sclerotomy below the flaps, the haptics are externalized and tucked in a scleral tunnel at the point of exit.

Gabor Scharioth and Pavilidis in 2006 reported the scleral tuck and intrascleral haptic fixation of a posterior chamber Intra ocular lens (PC IOL).

Because type 1 BB is formed easily in young corneas, this is an added advantage in PDEK which can be performed in infant donors.

Our preliminary results on Infant donor PDEK have been excellent and we expect to do more research on the functional differences in the young donors.7 Post operatively these patients are given topical steroids and antibiotics for 1 month.

Post operative anterior segment optical coherence tomography may be performed for assessing the anatomical success of the technique.

Minimal interface opacification, less refractive shift and reduced topographic changes are the extra benefits of PDEK.

In the last one and half year, many patients have been benefitted by PDEK surgery.1,6,7 Early visual recovery and less post operative inflammation is the main advantage.

Young donor eyes seemed to have made a huge difference in the visual quality and functional outcome.

There are additional research studies in progress to elucidate the regenerating capacity of the endothelial cells in vivo.

Fig 1 : Photograph shows the normal layers of the cornea from front to back (Epithelium, Bowman's layer, Stroma, Predescemet's layer, Descemet's membrane and Endothelium).
Fig 2 : Pre-Descemet's endothelial keratoplasty (PDEK). A, B: A 30 gauge needle is introduced into the centre of the cornea and air is injected. A big bubble is formed in the donor cornea on the endothelial side and it is pierced with Knife. C, D: Graft is stained or coloured by Trypan blue dye and dissected out.
Fig 3 : Graft injection into the host bed in combined PDEK with glued IOL. A: A central Big bubble formed in the donor cornea by pushing air into the cornea B,C: Flaps are made in the white sclera, IOL is inserted into the eye and the arms or haptics of the IOL is pulled out of the eye and attached to the white sclera in a tunnel and then glue is applied. The patient's damaged posterior part of cornea (descemet's membrane with endothelium) peeled manually. D: PDEK graft pushed into the eye under saline and opened. Endoilluminator or external light source is used to confirm the orientation of the graft. E, F: Donor graft is attached to the host stroma by air injection below the graft without sutures.
Fig 4 : Pre Descemets Endothelial Keratoplasty - the latest technique of corneal eye transplantation Photograph of a patient with corneal haziness due to endothelial damage with lens displaced before surgery (left) and the same patient after 6 months of PDEK with glued IOL surgery (Right). Note the white cornea is becoming clear (right). (Below) Anterior segment optical coherence tomography scan showing good adhesion of the graft on the inner side of cornea.
Fig 5 : Pre Descemets Endothelial Keratoplasty in young donor. In this 25 micron from a young or infant donor eye is transplanted into an adult and makes the adult eye see. On the left note the adult eye before Pre Descemets Endothelial Keratoplasty surgery . The eye is white and patient cannot see. On the right is same patient after Pre Descemets Endothelial Keratoplasty surgery using a young donors 25 micron corneal tissue . Note the clear eye and patient can see the last line on the vision testing.