Lifespan of a corneal graft?

[PhilLer]

Dear All,

I'm 40 years old and I had a full thickness corneal graft on my right eyes close to 20 years ago. I was wondering how long can last my grafted cornea. It is thicker than a normal cornea (620 micrometers in the center of the cornea vs approximately 550 micrometers for a normal cornea) and the endothelial cell density is very low, around 650 cells/mm2 compared to around 2500 cell/mm2 for a normal cornea. As the number of endothelial cells decreases when time increases and their size decreases, I was wondering when my grafted cornea will swell and become not transparent any more (decompensation) due to the lack of endothelial cells (late endothelial fealure). I was also wondering, in the case of a second transplant, how my right cornea will react. If a transplant is necessary every 20 years or less, I should have many transplants during my life...

Thank you very much for your response,
best regards,
Phil

[Anne Klepacz]

If only we all had a crystal ball and could see into the future! There are studies which give average life spans for grafts (you probably saw my reply to the post about post graft queries on this page) but no one can predict what will happen to an individual graft. Partial (DALK) grafts which most people have these days are thought to have a longer life span. But even with full thickness (PK) grafts, individuals vary. I know several people with PK grafts that are between 30 and 40 years old and still going strong. In my case, my left eye needed at regraft after 28 years. My right eye (also a PK) is now 30 yrs old and, although the endothelial count is also low, the graft is still clear. So all I can do is to have it monitored regularly and cross my fingers that it will last a few more years yet! Although the prospect of more operations in the future doesn't fill me with joy, there are constant advances in surgical techniques which are heartening. In some cases where the endothelium is failing, it's now possible to do a partial graft of the endothelial layer where the recovery time is much quicker and the results are good. And who knows what other new discoveries there will be in the next few years.
I hope that helps.

[PhilLer]

Thanks a lot Anne for your quick and clear response!

[Green]

Survival rates of full thickness corneal grafts [Australian stats used by Moorfields]:

89% at 10 years post-op
49% at 20 years “
17% at 23 years “

Re-graft survival rates:

2nd graft – 53%
3rd graft – 33%

Survival rates for partial grafts [DALK] more commonly done now [which can’t be done to those who already have full thickness grafts] have substantially better survival rates. A French study demonstrated 50% of these grafts survive 49 years compared with less than 20 years for full-thickness grafts.

[FERNANDO]

Hi Phil,
As a newcomer to your country, I am amazed by the information you´ve gathered about your disease comparing with your Spanish counterparts. Thumbs up!
I agree with you that your endothelial counting is low but central pachymetry is almost what to expect in your case. My first understanding is cell counting instruments are designed for the average cornea and not for the sick ones. Something similar to topography, very lovely for regular corneas but with serious flaws for the irregular ones. My feeling, based on my experience, tends to under-calculate. Think that the measured area is small. I followed for many years corneas with very low density, and no decompensation found.
At this point, I would advise wearing contact lenses that are gentle with your cornea (if you are wearing) to avoid further endothelial damage and be observant for signs of corneal decompensations as rainbows around light upon awakening as a potential symptom of corneal oedema.
With the pass of years, you will need cataract surgery, as everybody needs luckily living enough time. As an intraocular surgery, this is a different story. That density is too low to expect a successful outcome (or maybe not). At this moment you will have to discuss with the surgeon what is the most feasible option; A double-procedure (cataract and keratoplasty at the same time), or one by the time. Every possible option will carry some advantages and disadvantages, for this reason, it will be worthy of a long discussion with the person on charge.

And just a quick note for Green. Yes, I agree that DALK cases have longer survival rates than PK. In DALK cases endothelial is not disturbed, but for instance, I have severe doubts about visual acuity outcomes between both groups. But I would love to review the Frech study and check how they figure it out the"49 yr " as the procedure is relatively new for that historical perspective.
Best regards

[PhilLer]

Hi Green and Fernando,

thank you sincerely for your replies!
The paper of Borderie et al. (2012)
"Long-term Results of Deep Anterior Lamellar versus Penetrating Keratoplasty"
Vincent M. Borderie, MD, PhD, Otman Sandali, MD, Julien Bullet, MD, Thomas Gaujoux, MD,
Olivier Touzeau, MD, PhD, Laurent Laroche, MD
Ophthalmology 2012;119:249–255

Objective: To compare deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in eyes
with corneal diseases not involving the corneal endothelium (keratoconus, scars after infectious keratitis, stromal
dystrophies, and trauma).
Design: Retrospective, comparative case series.
Participants: One hundred forty-two consecutive DALK (DALK group; big-bubble technique or manual
lamellar dissection using a slitlamp) and 142 matched PK (PK group).
Methods: Three models were used to describe the postoperative outcomes of the endothelial cell density.
A joint regression model was used to predict long-term graft survival. Visual acuity, ultrasound pachymetry,
specular microscopy, and optical coherence tomography (OCT) findings were recorded.
Main Outcome Measures: Postoperative endothelial cell loss and long-term predicted graft survival.
Results: The average 5-year postoperative endothelial cell loss was
22.3% in the DALK group and

50.1% in the PK group (P0.0001). The early- and late-phase annual rates of endothelial cell loss were
8.3%
and
3.9% per year, respectively, in the DALK group and
15.2% and
7.8% per year in the PK group
(P0.001; biphasic linear model). The median predicted graft survival was 49.0 years in the DALK group and 17.3
years in the PK group (P0.0001). The average visual acuity was lower in the manual dissection subgroup
compared with the PK group (average difference, 1.0 to 1.8 line) and with the big-bubble subgroup (average
difference, 2.2 to 2.5 lines). The average central corneal thickness at 12 months was 536
m in the PK group, 523

m in the big-bubble subgroup, and 562
m in the manual dissection subgroup (P0.001). The average
thickness of the residual recipient stroma measured by OCT was 8726
m in the manual dissection subgroup.
No correlation was found between this figure and logarithm of the minimal angle of resolution at any postoperative
time point (P0.05).
Conclusions: Long-term, model-predicted graft survival and endothelial densities are higher after DALK
than after PK. The big-bubble technique gives better results than manual dissection and PK. Compared with PK,
manual dissection provides higher survival of both the corneal endothelium and graft, but lower visual acuity.

The calculations of the average lifespan of corneal graft after DLAK and PK are based on predictions.

[PhilLer]

Where to find Borderie' paper:
https://pubmed.ncbi.nlm.nih.gov/22054997/