پذیرش اینترنتی

DALK

چهار شنبه 29 فروردین 1397
بازدید: 1186

deep anterior lamellar keratoplasty (DALK)

Why would I need a corneal transplant?

The cornea is a window of transparent tissue at the front of the eyeball. It allows light to pass into the eye and provides focus so that images can be seen. Various diseases or injury can make the cornea either cloudy or out of shape. This prevents thenormal passage of light and affects vision.

The cornea has threelayers (thin outer and inner layers and a thick middle layer). In some diseases, only the middle layer or part of the middle layer is affected (see picture below).DALK is a moderntechnique whereby the outer two layers of the cornea are removed and replaced with the outer twolayers from a donor cornea to give a partial-thickness transplant.

 

Benefits of deep anterior lamellar keratoplasty(DALK)

Improved vision

Approximately 75% of transplant recipientsfor this surgeryhave good enough vision to drive legally, although they usuallyneed glasses or contact lenses or sometimes further surgery for best results.It can take up to 18 months until the full improvement in vision isseen.

Risks of deep anterior lamellar keratoplasty (DALK)

Rare but serious complications

Corneal transplant rejection

A corneal transplant may be rejected by your immune system. This happens in less than 10% of DALK recipients in the first two years after transplantation and can cause graft failure. However, it can often be reversed if anti-rejection medication is started promptly.

Graft failure

When a graft fails, your cornea becomes cloudy again and your vision becomes blurred.

Glaucoma

This can usually be controlled by eyedrops,but occasionally requires surgery and may harm your sight.

Cataract

This can be removed surgically.

Conversion to penetrating keratoplasty occasionally, it is not possible to perform a partial thickness transplant and a full-thickness transplant must be performed instead (penetrating keratoplasty).

Possible advantages of DALK over full-thickness graft

Possible disadvantages of DALK over full-thickness graft

DALK recipients have a slightly lower chance of achieving 6/6 (excellent) vision than recipients of full-thickness grafts.

About the operation

The operation is performed under general anaesthetic, and takes about one hour. A central partial thickness 8mm button of your cornea is removed and a similar-sized button of the donor cornea is stitched in with tiny stitches. These cannot be felt or seen. After the operation you will usually be examined by the surgical team after the surgery and can generally go home the same day.You will be seen again within one week in the outpatient clinic and regularly thereafter. (Approximately six visits in the first year).

We generally recommend that you take two weeks off work but please discuss your individual circumstances with your doctor.You will need to use anti-rejection eyedrops for at least six months and indefinitely in some cases. Individual stitches may be removed from three months after the operation,but complete stitch removal is not performed until at least one year after the procedure.

What if my transplant fails?

A failed transplant can be replaced in a procedure known as a regraft. However, the risk of further rejection and failure increases each time for second and subsequent regrafts.Corneal transplant rejection needs urgent treatment, as this can lead to failure of the transplant and loss of vision.

Symptoms of rejection are:

If you experience any of these symptoms, you should come immediately to our 24-hour emergency department.

 


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