LAMELLAR KERATOPLASTY DALK/ALK (MANUAL AND FEMTOSECONFD LASER)
Tuesday, January 18, 2022Introduction:
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
Deep Anterior Stromal Keratoplasty involves the replacement of the first 3 layers of the cornea (~90% of the volume), ie the epithelium, Bowmans membrane and stroma with similar layers from the donor. The original patients Duas layer, Descemets membrane and Endothelium are left intact.
This procedure requires advanced surgical skills, technique and experience which our Cornea Specialists are expert at. The procedure can successfully take care of scars that involve the first three layers of the cornea or conditions that affect the stroma alone such as keratoconus or other corneal ectasias such as Keratoglobus and Pellucid marginal degeneration or Terriens marginal degeneration as well as post LASIK ectasias.
The advantage of the procedure is that it is less invasive than a full thickness transplant and selectively replaced only the scarred cornea
How is it done?
A maximum of 80% of the existing corneal diameter can be removed- this is performed by a circular blade called a trephine (hand-held OR suction) or by a special Femtosecond laser. Suction trephines offer greater control on the depth of the cut than hand held trephines, whilst Femtosecond laser cuts offer the greatest accuracy in customizing the incision. A matching cut is made in the donor cornea as well so as to snugly fit into the area removed from the patients cornea..
OU Cornea Specialists will leave 5% or less of your original corneal thickness after ensuring that it is healthy in structure and functions and replace the rest with donor tissue.
The most commonly performed technique in DALK is using suction trephines- they are cost effective and offer great accuracy in planning the cuts in experienced hands. Our Cornea specialists have over 13 years of experience in this technique.
The femtoseconf laser technique although more recently introduced had definit advantages in precisely planning both the cuts and offers flexibility in making interlocking cuts thus potentially decreasing visual distortions. The interlock also offers greater area for healing thus reducing time taken for integration.
Subsequently sutures are placed along the graft-host junction, and can be selectively removed starting 3 months after surgery until about a year.
When is DALK advised as compared to Penetrating transplant?
All cases where the stroma is defective but the endothelium is healthy with a stable ocular surface can be considered for DALK.
What are the risks of DALK
1. Wound dehiscence
2. Graft rejection (less r/o endothelial rejection)
3. Suture related problems ( loose sutures, astigmatism, Infection
4. Intraoperative perforation- conversion to PKP
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 DALK?
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
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