Descemet’s Stripping Only (DSO)

We are constantly evaluating new approaches for treating Fuchs dystrophy, and far, the DMEK procedure we helped pioneer remains the gold standard. With DMEK we remove the central corneal endothelium and Descemet’s membrane and implant healthy donor tissue, which has normal endothelial cells and a clear Descemet’s membrane without guttae.  It provides rapid and reliable visual recovery within 2 days to one month after surgery with minimal risk of immunologic graft rejection (<1% with appropriate use of eye drops).[reference]  Also, we have optimized the postop eye drop regimen to prevent graft rejection to minimize any risk of side effects.

A surgical alternative to DMEK is called Descemet’s Stripping Only (DSO).With DSO we remove a smaller area of the central unhealthy endothelium and Descemet’s Membrane and do not implant any donor tissue.  We then wait to see if the surrounding endothelial cells migrate from the periphery to recover the central area.  
 

Click here to view a DSO brochure.

Compared with DMEK, DSO has 2 possible benefits. First, since we are not using any donor tissue, there is no immune response to foreign tissue, 0% risk of rejection, and no need to use eye drops long term to prevent rejection.
 
On the other hand DSO is limited in terms of how much unhealthy tissue can be removed. Typically we remove an area only ¼ as large as the area treated with DMEK. If we try to treat a larger area with DSO, the cornea may remain thick and hazy for months on end or never fully clear. Patients have told us they are satisfied with the vision they get using the smaller 4-mm area of treatment with DSO. But we wonder if they just notice some visual improvement with the central guttae removed without realizing how much better it could be if we treated a wider 8-mm area with DMEK. We know from laser refractive surgery (LASIK or PRK) that a small treatment zone causes patients to have significant glare and halos at night.  We also know that the intraocular lenses used in cataract surgery do not perform well when the clear optical zone is only a 4-mm diameter. Typically, clear zones of 6-mm diameter or more are needed to avoid glare and halos.    
 
Another limitation of DSO is the time to corneal clearing. With DSO the eye goes through at least a 2 to 4 week time period of corneal edema with blurred vision and light sensitivity. With DMEK some people may take a month to clear, but 3 out of 4 clear within days, allowing the second eye to be treated one week after the first eye. So individuals who may be on a tight schedule for getting both eyes done because offamily issues, insurance, or work, should consider DMEK over DSO.  Many of our Fuchs’ dystrophy patients initially tell us they only need one eye treated because their other eye is doing fine.  But after DMEK, they realize the “good” eye was not as good as they thought, and then they want to have the second treated as soon as possible to eliminate glare and haze. 
 
Since guttae generally begin forming in the central portion of the cornea and then increase peripherally, DSO is primarily an option for patients in the early stages of Fuchs’ dystrophy. Patients can be rescued with DMEK if the cornea fails to fully clear or if visual recovery is not satisfactory after DSO.



The corneal endothelial cells are attached to a thin membrane called Descemet’s membrane. In Fuchs’ dystrophy, abnormal deposits called “guttae” accumulate on Descemet’s membrane.  These guttae are like water drops on a windshield (guttae mean raindrops in Latin).  They distort the light coming into the cornea and also cause glare and halos and must be removed to improve vision.


A healthy endothelium compared to a diseased endothelium.

 Your surgeon will determine if you may be a candidate for DSO, or whether DMEK is more fitting. This is an example of when it’s best to seek evaluation as soon as you observe changes in your vison, as you may have more treatment options at that time.
 
In summary, we look forward to continuing research to assure the cornea will reliably clear within a month or sooner with DSO and are actively conducting studies to optimize this treatment option for Fuchs’ dystrophy patients.  Two small studies found that the use of a “Rock Inhibitor” eye drop available outside the USA seemed to help the cornea clear faster and more reliably by helping the cells migrate and possibly regenerate.⁷
  
If you would like to learn more about DSO and determine if you are a candidate to have the surgery and/or be in a study, please call 317-814-2996.

We hope the ROCK inhibitors will prove successful in speeding up the recovery of DSO, but studies are needed to get a good idea of how successful it is in a large group of patients, that is why we are conducting studies on DSO.
 
Looking ahead, cell culture techniques are improving, and someday we may be able to harvest your blood cells and reprogram them to become corneal endothelial cells.  But until we can either do that or use medications to get your peripheral corneal endothelial cells to reliably heal the central cornea in less than a month, we will continue to recommend DMEK as the optimal treatment option for most patients with Fuchs’ dystrophy who are not able to face a potentially long recovery with DSO.  Currently the best candidates for DSO are those whose guttae are primarily located in the central 4 to 5mm of the cornea.
We certainly live in an exciting time with new developments occurring continually around the world. So stay tuned!

References:

1. Bleyen et al. Spontaneous corneal clearing after Descemet’s stripping.Ophthalmology 2013l120:215.
2. Arbelaez et al. Long-term follow-up and complications of stripping descemet membrane without placement of graft in eyes with Fuchs endothelial dystrophy.Cornea 2014 33:1295-1299 (our study)
3. Koenig SB. Planned Descemetorhexis Without Endothelial Keratoplasty in Eyes With Fuchs Corneal Endothelial Dystrophy. Cornea 2015;34:1149-51.
4. Baydoun et al. Repeat Descemet membrane endothelial keratoplasty after complicated primary Descemet membrane endothelial keratoplasty.Ophthalmology 2015; 122:8-16.
5. Cirkovic et al. Clinical and ultrastructural characteristics of graft failure in DMEK: 1-year results after repeat DMEK. Cornea 2015; 34:11-7
6. Price et al. Repeat Descemet Membrane Endothelial Keratoplasty: Secondary Grafts with Early Intervention Are Comparable with Fellow-Eye Primary Grafts.Ophthalmology 2015;122:1639-44.
7. Moloney et al. Descemetorhexis Without Grafting for Fuchs Endothelial Dystrophy-Supplementation With Topical Ripasudil. Cornea 2017;36:642-648.