Irregualar astimatism:

has anyone had their cornea removed and not replaced? What was the outcome?

Has anyone had a corneal transplant, then re-ablated? What was the outcome?

Sorry, no disrespect intended, but I just have to ask...

Why on earth would anyone undergo the misery and lengthy healing time of a corneal transplant only to re-ablate the new, healthy cornea?

I am assuming that the original poster might be asking the question because of very irregular astigmatism, not permitting visual rehab with a contact lens. OP-is this the reason you are asking?

Beagle,

I had my cornea replace in an attempt to fix the severe irregular astigmatism that resulted from a dislocated flap. this is a procedure refer to as a "Lamellar graft".

I still ended up with irregular astigmatism, but this was treated with 2 PRK procedures that provided me with better vision.

Yes- indeed I have heard that a two step PRK is sometimes done. I know of quite a few offices that do Lasik atop the graft...with the reasoning being the cornea is now "thick enough"......
Perhaps I should have read many of your posts- but may I ask- did the PRK help significantly?

Beagle,

Yes it helped significantly. I am correctable (at times) to 20/20 during the day, but the night vision is still not good, but better than it was prior to the PRK procedures.

I will tell you though, that I had a very extensive follow-up care, and that I was on steriods for over two years to control corneal haze.

They will tout that in "theory" that the PRK procedure can help, but my guess is that they really have no statistics over the long range. I probably know more about eyes then the average person, and could tell when I needed medical treatment. If you are not personally akin to this you could end up with less than the quality results.

Although I had good results I personally know of very few doctors that have any long term experience with this type of treatment.

Good luck.

Agreed- I would want the doc practically to live around the block at this point if I were to have prk. Am I right to call this a 2 step prk?

quote:

Originally posted by Barbara B:
Beagle,

I had my cornea replace in an attempt to fix the severe irregular astigmatism that resulted from a dislocated flap. this is a procedure refer to as a "Lamellar graft".

I still ended up with irregular astigmatism, but this was treated with 2 PRK procedures that provided me with better vision.

I was thinking LASIK after the transplant, but perhaps you might answer a question no one has.

Your response suggests that the irregular astigmatism was not in your flap since you received a new one with the transplant, suggesting that the irreg. was on the bed.

The question no one has ever answered adequately, where is irregular astigmatism?

Is it on the surface of the cornea? within the cornea? the bed? could be any of the above or in combo?

What explanation have been given re. yours?

StarEyed,

Irregular astigmatism is a layman's term for the visual aberrations which result from a cornea which has an irregular surface after having surgery. The doctors who contribute to SurgicalEyes generally use the term "higher order aberrations" or HOAs when refererring to this problem.

Someone who has had a corneal transplant or lamellar graft frequently has significant visual aberrations, as do folks who have had RK or LASIK.

Dry eyes can make the aberrations worse. Soft contact lenses do little to help, but wearing rigid gas permeable (RGP) contact leses or scleral lenses (which are larger and much more expensive) can help. These lenses simulate a smooth corneal surface, because a layer of tears is held between the lens and the cornea. They can be very comfortable to wear - I find mine better than any soft lens I wore before having LASIK - but it can be difficult to get used to them at first.

Good luck,

Lynne

quote:

Originally posted by StarEyed:

The question no one has ever answered adequately, where is irregular astigmatism? Is it on the surface of the cornea? within the cornea? the bed? could be any of the above or in combo?

Irregular astigmatism, as Lynne pointed out, is often described as higher order aberrations which are basically defined as optical errors that can not be corrected with spectacles. Most irregular astigmatism manifests on the corneal surface but can be generated from irregular thickening of the epithelium, from the flap not conforming evenly over the bed, or from the shape of the ablation itself.

None of these problems are mutually exclusive. You have epithelial sloughing which is suggestive of irregular epithelial thickening. But some of your irregular astigmatism may be due to the flap being incongruent with the bed and may also be further complicated by oblate contouring of the bed (the shape of the ablation).

The irregular astigmastism was on the replaced flap. It is extremely difficult to cut a new flap that would be exactly the same thickness and shape as the flap that was removed. that was the intent of the surgery. However, I ended up with irregular astigmatism, which was improved with 2 PRK procedures. I still have irregular astigmatism in this eye, however, it is only noticeable in dimmer light when my pupil is more dialated. Night vision is still no good.

I'm not sure why one would perform LASIK after a corneal transplant or lamellar graft. PRK makes more sense to me, but I am not a doctor.