ENDOTHELIAL KERATOPLASTY –DMEK DSEK DSAEK

Introduction:

The Cornea which is a glass like dome shaped structure present in the front part of the eye is composed of 6 layers each having different cell types and structure as well as function. With advancements in transplantation techniques, it is now possible to selectively replace the dysfunctional layers alone rather than the entire cornea. This is called a lamellar transplant. This not only reduces the chances of rejection of the graft but also reduces the need for post op medications and hastens visual recovery. Our Cornea Specialists are experienced in all types of lamellar corneal transplants

If the Endothelium is dysfunctional selective replacement of the same can be done and is categorized into DSEK DSAEK or DMEK

Our Cornea specialist use extremely thin donor tissue and replace the dysfunctional endothelium alone. This technique of selective endothelial keratoplastyreduces the size of the cut (incision) number of sutures, healing time and most importantly the risk of rejection since the antigenic load is much lesser to begin with. 

In DSEK the donor tissue is manually dissected using special dissectors after fixing the donor cornea on an artificial anterior chamber. This separates the descemets membrane and some stroma and Duas layer from the rest of the cornea.

In DSAEK the same procedure is done using a motorized microkeratome blade that can cut at a precise depth (~350microns) 

In DMEK the entire procedure is diiferent where the skilled corneal specialist removes only the Descemets membrane of the donor by a special non touch technique taking no stroma along

How does the Donor Cornea attach ?

Once the donor graft is ready (Either by manual/microkeratome /DMEK) a similar sized defect (or larger) is created in the patients endothelium. The graft is then transferred inside the eye by special instruments (glides/ injectors). The graft if folded or scrolled in unfolded in the correct orientation and then pushed up against the patients’ cornea using an air bubble. During surgery the air bubble fully replaces any fluid inside the eye- at the end of surgery some of it is partially burped out. This remnant air bubble is allowed to remain in the patients’ eye for a few days as it provides a force to enable the new cell layer to attach itself to the patients’ cornea. 

Why is it done?

Any problem affecting the corneal endothelium that renders it incapable of performing its basic function of keeping the cornea in a dehydrated state warrants an endothelial transplant. These include post-surgical bullous keratopathy, endothelial dystrophies (such as Fuchs corneal dystrophy and posterior polymorphous corneal dystrophy), ICE syndrome, and other causes of corneal endothelial dysfunction. Most commonly in India our Cornea specialists find that there is dysfunctional endothelium due to complicated cataract surgery.

Benefits of selective Endothelial replacement

Endothelial Keratoplasty offers the most rapid visual rehabilitation as compared to other techniques.Once the new layer has attached itself to the patients’ cornea, it starts working gradually to remove the fluid that has collected in the patients’ stroma. This along with the fact that there are very few sutures used in the technique allows a rapid visual recovery as compared to full thickness transplants. Additionally steroids can be discontinued as early as 1 year after the procedure thus also reducing risk of steroid induced glaucoma and cataract. 

ABOUT GRAFT REJECTION 

Any Organ when transplanted is at a risk of being rejected by the host. This risk although least of all in the case of Cornea is atill a major threat to the graft. Patients must watch out for

R: Redness (unusual redness of the eye)

S: Sensitivity (increase in light sensitivity)

V: Vision (sudden change in vision clarity)

P: Pain (increase in eye pain)

Early diagnosis of an episode of rejection is useful as it can be successfully reversed with special medications

Other complications such as Infection in the graft, recurrence of the primary problem, secondary Glaucoma, suture related problems may arise and can be appropriately managed if found in the patient.

What is the post-operative care after Endothelial Keratoplasty?

GENERAL INSTRUCTIONS

1. Some redness discomfort and minimal watering are natural after any eye surgery.

2. In case of irritation/pain on application of eye drops –stop immediately and consult your eye doctor

3. Prolonged/indiscriminate use of any medication may cause damage to the eyes/optic  nerve/infections which may lead to irreversible blindness-PLEASE STOP YOUR MEDICATIONS AS GIVEN IN THE SCHEDULE AND DO NOT DISCONTINUE ANY MEDICATION WITHOUT CONSULTATION AS WELL

4. Keep the medicines in a cool and dry place protected from sunlight

5. Keep the cap of the bottle in a clean place, replace and tighten the screw  after every use 

6. Don’t touch/clean the nozzle of the bottle

7. Clean hands and dry them before application of drops

8. Pull the lower lid and apply 1 or 2 drops of the medicine

9. Close the eyes completely for atleast 5 minutes after application

10. Between applications of two eye medications, give a gap of 10 minutes at least.

11. Clean the eyes twice a day with sterile wipes or clean dry kerchief/ Ear buds soaked in antibiotic eye drops.

OR

You can boil water, soak cotton bolls in it, squeeze them and use to clean the eye/s

12. You can eat normal food/Diabetic diet as usual. 

13. Take all previous medicines as per your physician/Diabetologist/cardiologist etc

14. No Head bath for a week-you can take a bath from below your shoulders

15. Avoid TV/Screens etc for 1 week- after that you can watch the same as usual

16. Wear the protective glasses given to you after surgery at all times in the day. At night use the green colour shield as protection

17. No lifting of heavy weights/excessive exercise/weights/gym etc for 3 months

18. You can sleep on your back or on the side opposite the side of surgery. 

19. Do not bend repeatedly (for prayer or work ) for a month

20. Pranayam/light Yogasanas  can be safely resumed after a week of surgery( avoid kumbhak)

21. Avoid crowded places(malls/temples/etc) and long journeys for atleast 1 month

22. Travelling by flight after routine cataract surgery is permitted –discuss with your doctor if needed.

23. In case of any of the following please contact us immediately:-

1. Sudden loss of vision

2. Sudden development of Intense redness/pain/watering more than before

3. Discomfort with lights

4. Sudden appearance of whiteness in eye

Risks & Complication:

Because less tissue is transplanted, there is a lower risk of allograft rejection and less long-term reliance on topical steroids compared with other types of keratoplasty.

Because of thinness, fragility, and its characteristic scrolling properties (with the endothelium facing outward), the donor tissue can be difficult to handle and contribute to technical difficulties with DMEK  procedure.  There is a higher risk of graft edge lifts compared with DSAEK, sometimes requiring a re-bubble procedure.

The biggest challenge with DMEK is the preparation of the donor tissue. 

However our Cornea specialists are skilled in all three techniques and can fashion a very thin graft even with the manual technique hence our outcomes are superior.