FUCH S DYSTROPHY & CATARACT SURGERY TREATMENT ALGORITHM ΙΟΑΝΝΙS Α. MALLIAS, MD, PHD Director of the Dept. of Ophthalmology, Mediterraneo Hospital, Glyfada, Athens, Greece Clinical Fellow in Cornea and external disease, Columbia University New York
Conflict of interests: None
What is Fuch s Endothelial Dystrophy Fuchs endothelial dystrophy is a non-inflammatory, sporadic or autosomal dominant, dystrophy involving the endothelial layer of the cornea. In Fuchs dystrophy the cornea begins to swell causing glare, halo, and reduced visual acuity. The damage to the cornea in Fuchs endothelial dystrophy can be so severe as to cause corneal blindness.
Fuch s Dystrophy Prevalence Fuchs dystrophy is often inherited in an autosomal dominant manner. The only risk factor for Fuchs dystrophy is an affected parent. If you have an affected parent there is at least a 50% chance of passing the gene on to your children. Fuchs dystrophy is rarely seen in people younger than 30 to 40 years of age, and seems to present slightly earlier in women.
Fuch s Dystrophy Stages In the early stages of Fuchs dystrophy loss of endothelial cells and small excrescences of Descemet s membrane can be seen and are called guttata. In very mild dystrophy, guttata can be seen on the corneal endothelium. The guttata are often more marked in the central cornea and will be bilateral, though one eye may be more severe than the other. Corneal Endothelium with Mild Fuch s Dystrophy
Fuch s Dystrophy Stages In more advanced Fuchs dystrophy a haze will develop in the corneal stroma. As the stroma thickens folds in the Descemet s membrane and endothelium will be visible. As endothelial cells are lost, the corneal edema worsens and fluid collects in the epithelium forming microcystic changes as well as large bullae in the epithelium. Corneal Endothelium with Mild-severe Fuch s Dystrophy
Fuch s Dystrophy Stages In more severe, long standing cases of Fuchs dystrophy, dense corneal edema and bullous keratopathy are seen. The corneal opacification can be severe enough to prevent visualization of the anterior segment structures as well as the endothelium. The chronic corneal edema will induce sub-epithelial fibrosis as well as corneal vascularization. Corneal endothelium with severe Fuch s Dystrophy
Clinical Signs of Fuch s Endothelial Dystrophy The most common signs of Fuchs' Dystrophy include: Guttata on Descemet's membrane (the guttata tend to be central and slowly become more prominent peripherally) Stromal edema Endothelial folds Epithelial microcysts Epithelial bullae Sub - epithelial fibrosis Stromal haze and scar formation Vascular ingrowth into the cornea
Symptoms of Fuch s Endothelial Dystrophy Some of the earliest symptoms of Fuchs endothelial dystrophy include: reduced contrast sensitivity mild reduction of visual acuity. Patients will often notice glare around a point source of light or have difficulty with nighttime driving. As the dystrophy often has a slow onset, patients may not even notice that their vision is reduced. Once fluid begins to collect in the stroma patients will start to notice fluctuation in vision, typically worse in the early AM and improving toward the end of the day.
Fuch s Endothelial Dystrophy Diagnosis The diagnosis of Fuchs endothelial dystrophy is clinical. The diagnosis is relatively easy in early disease as you can see the endothelial changes as well as mild corneal stromal edema. In severe cases where you cannot see the endothelium the diagnosis can be more challenging and the diagnosis may need to be based on the contra lateral eye or history.
Therapeutic Approach Medical treatment of Fuchs dystrophy begins once patients notice fluctuation in vision. The early treatment is usually in the form of hypertonic saline drops and/or ointments. Any activity that helps to evaporate fluid off the cornea will help shorten the time to visual recovery. This may include: o pointing car vents toward the face or blowing air by the eyes o using a hair dryer at arm s length. o Bandage contact lenses can also be quite helpful in management of painful ruptured bullae in more severe disease.
Therapeutic Approach As Fuchs dystrophy progresses its medical treatment may fail, at that point surgical management becomes necessary. The options for surgical management of Fuch s endothelial dystrophy is: Penetrating keratoplasty (PKP) Descemet s Stripping Automated Endothelial Keratoplasty (DSAEK) Descemet Membrane Endothelial Keratoplasty (DMEK)
PKP For the Treatment of Fuch s Endothelial Dystrophy Though the penetrating keratoplasty can be very successful, recovery can be relatively slow sometimes taking a year or more for full visual recovery. The advantage of a full thickness corneal transplant is that it can restore vision even in the most advanced stages of Fuchs dystrophy and other necessary intraocular surgery can be performed at the same time as the keratoplasty.
DSAEK For the Treatment of Fuch s Endothelial Dystrophy The most popular surgical procedure is currently named Descemet s Stripping Automated Endothelial Keratoplasty (DSAEK). In DSAEK only the endothelial layer is removed from the patients cornea and replaced by a thin strip of donor corneal stroma with attached, healthy, endothelial cells. This surgery can be performed through a much smaller incision than traditional penetrating keratoplasty. Once the cells are implanted into the eye they are held in place by an air bubble.
DSAEK For the Treatment of Fuch s Endothelial Dystrophy Using this technique a minimum of corneal sutures are necessary and suture-induced astigmatism is minimized. Once the transplanted cells are in place, the patients cornea will be cleared of any excess fluid. Recovery after DSAEK is much more rapid than after a full thickness corneal transplant, with patients recovering vision after just a few months. An additional advantage to DSAEK is the smaller incision size which keeps the eye much more resistant to damage in the event of ocular trauma. DSAEK surgery has a very small rejection rate, about 2%
DSAEK VIDEO
What is DMEK? Descemet s membrane endothelial keratoplasty (DMEK) is a partial thickness cornea transplant where the host Descemet membrane and endothelium are replaced by donor DM and endothelium. Graft rejection rates ranged from 1.4-5% with a mean of 3.7% in a large multicenter series. Allograft rejection in DMEK seems to have a slower onset and immune response than DSAEK or PK and can present different clinically. Another series demonstrated a 0.7% rejection rate after DMEK compared with historical control groups of DSAEK (9%) and PK (17%)
DMEK VIDEO
DMEK Vs DSAEK DMEK has been shown to have superior visual outcomes when compared to DSAEK. In multiple studies where patients had DSAEK in one eye and DMEK in the fellow eye, significantly better visual acuity and preference were reported in the DMEK eye. However, some studies suggest that DSAEK visual outcomes can be improved by ultra-thin tissue. Though recovery is slower with ultra-thin DSAEK versus DMEK, final visual outcomes at 1 year are comparable. If the ultra-thin DSAEK technique continues to improve, the ease and reliability of it may decrease the utilization of DMEK. DMEK also has a lower immunologic rejection rate and has the advantage of using a smaller incision (2.8 mm) than DSAEK (5 mm).
DSAEK Vs DMEK Donor preparation and transplant surgery are technically easier with DSAEK. DSAEK is a more versatile procedure than DMEK, and is preferred in some complex cases. Although eye banks now can pre-strip tissue for DMEK, some surgeons perform the entire stripping in the operating room, which carries the risk of destroying tissue at time of surgery. There are higher rates of re-bubbling and primary graft failure in DMEK compared to DSAEK.
Fuch s Endothelial Dystrophy and Cataract Surgery Patients with early stages of Fuch s Endothelial Dystrophy are advised to proceed in cataract surgery when the crystalline lens is still relatively soft, so as to have the fewer possible loss of endothelial cells during surgery. Patients with medium to severe Fuch s Endothelial Dystrophy are advised to proceed in cataract surgery when it s time, combined with DSAEK surgery, on the same day. Patients with very severe Fuch s Endothelial Dystrophy and corneal opacification are advised to proceed on cataract surgery combined with a penetrating keratoplasty.
Tips & Pearls If a patient has Fuch s dystrophy and cataract, you should proceed in cataract surgery using hydrophobic intraocular lens (IOL), in order to avoid a chance for IOL opacification from the air bubble if he/she needs DSAEK on the same day or later.
Tips & Pearls There are studies 1,2 indicating that the hyperopic shift that occurs after DSAEK surgery should be taken into consideration when calculating the IOL that is going to be implanted (simultaneously or later). 1:Relationship between Hyperopic Shift after DSAEK and Corneal Anterior Curvature, Posterior Curvature, and Thickness, William Bradley Wainright; Ryan McNabb; Alan Carlson; Terry Kim; Natalie A Afshari; Anthony N Kuo, ARVO Annual Meeting Abstract April 2014, April 2014, Volume 55, Issue 13 2:Effect of the shape of the endothelial graft on the refractive results after Descemet's stripping with automated endothelial keratoplasty, Esquenazi S1, Rand W, Can J Ophthalmol. 2009 Oct;44(5):557-61. doi: 10.3129/i09-087.
Tips & Pearls Smoking 1 has been associated with a higher risk of presenting with Fuch s dystrophy according to studies. It is advisable that patients should be informed about the role of smoking in Fuch s dystrophy progressing. 1:Association of Smoking and Other Risk Factors With Fuchs' Endothelial Corneal Dystrophy Severity and Corneal Thickness, Xiaolin Zhang,1 Robert P. Igo, Jr,2 Jeremy Fondran,2 V. Vinod Mootha,3 Matt Oliva,4 Kristin Hammersmith,5 Alan Sugar,6 Jonathan H. Lass,1,2 and Sudha K. Iyengar1,2, for the Fuchs' Genetics Multi-Center Study Group, Invest Ophthalmol Vis Sci. 2013 Aug; 54(8): 5829 5835. Published online 2013 Aug 27. doi: 10.1167/iovs.13-11918
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