Fuchs’ (fooks) endothelial dystrophy is a problem that affects the corneal endothelium’s smoothness and its pumping function.
Endothelial cells in individuals with Fuchs’ are intermixed with abnormal cobblestone-like bumps called guttata, which disrupt the smooth inner surface of the cornea. The formation of an increasing number of guttata in the center of the cornea, where they have the greatest effect on vision, is a hallmark of Fuchs’. A moderate to severe concentration of guttata can blur vision, reduce contrast, and cause glare symptoms by causing light to scatter in a manner that is similar to, but not as pronounced as, the frosted glass etched into shower doors for privacy. Blurry vision and a reduction in the quality of your vision caused by corneal guttata make up the first phase of disease progression of Fuchs’ – well before you develop corneal swelling.
Fuchs’ patients eventually lose so many endothelial cells that there is not enough pumping function to oppose the cornea’s natural tendency to absorb fluid. The result is swelling of the cornea, which causes your vision to become blurrier. In its early stages, corneal swelling blurs your vision in the morning and not as much in the evening, but eventually the swelling worsens to the point that your vision remains blurry throughout the day. Blurrier vision caused by corneal swelling makes up the second phase of disease progression of Fuchs’.
Longstanding corneal swelling causes the superficial layers of the cornea to become permanently scarred, and if severe, it can also cause painful blistering. Scarring further blurs your vision, sometimes permanently. Scarring and pain make up the final phase of disease progression of Fuchs’.
Fuchs’ dystrophy can be a distressing diagnosis, but, thankfully, it is not a medical emergency. Most individuals with Fuchs’ are unaware that they have the condition until they are about 40-50 years of age because the disease does not typically interfere with visual function in the first few decades of life.
Most patients with symptomatic Fuchs’ first notice that colors look washed-out and that bright lights cause them to experience glare. Patients with these symptoms typically have early stages of the disease (i.e. guttata with or without early corneal swelling). Recognizing these symptoms and seeking specialized care during the early stages of Fuchs’ helps ensure that you receive appropriate treatment before your corneas have become permanently damaged from more advanced stages of the disease (i.e., scarring from longstanding corneal swelling).
Corneal scarring is the one factor that imparts a degree of urgency to deciding when to have a DMEK corneal transplant. In general, corneal scarring limits vision, but it can sometimes improve after surgery. Undergoing DMEK surgery before your corneas have significantly scarred gives you the best chance of having good vision after the procedure.
The potential for DMEK surgery to provide rapid and complete visual rehabilitation has enabled ophthalmologists to offer surgical treatment at earlier stages of Fuchs’ compared to when full-thickness corneal transplant surgery was the standard-of-care for endothelial disease. In the age of DMEK, it is no longer the norm to wait until you have developed severe corneal swelling or scarring before having surgery. Earlier stages of Fuchs’, if visually significant, are reason enough to proceed with DMEK surgery. But, as you might expect, “visually significant” can mean very different things to different individuals based on what their daily activities involve and how well they are coping with a reduction in visual function.
Not renewing your driver’s license because you failed the vision test is a stark example of when most patients would begin considering surgical intervention for Fuchs’. But in my experience, the majority of patients with Fuchs’ (with or without cataracts) fall into a much more nuanced gray zone.
For many patients with Fuchs’, life has become more difficult or less enjoyable because of their disease, but they have managed to adapt to and/or accept whatever limitations Fuchs’ has imposed on them. For example, a patient with moderate guttata and mild swelling might avoid driving at night because she feels uneasy about it, but not to the point of cancelling appointments. The same patient might have difficulty spotting the golf ball, but still manage to play the occasional round if she’s with friends.
For the vast majority of patients in the “gray zone,” odds are good that a DMEK corneal transplant performed by an experienced surgeon will improve or resolve their symptoms. But the decision to have DMEK surgery is nevertheless emotionally daunting because the potential improvements in vision and quality of life provided by the procedure as well as its risks are relatively abstract. By comparison, whatever compromises have been made to one’s life because of Fuchs’ are concrete and, despite not being ideal, are at least a known quantity.
Helping patients to vicariously experience what DMEK surgery and recovery are like and, more importantly, how life can improve afterwards is an invaluable contribution of the Fuchs’ Friends online forum to patients with Fuchs’. Fuchs’ Friends helps bridge the gap of patients’ uncertainty, which is a tremendous benefit for both surgeons and patients alike.
In summary, deferring a corneal transplant until visual symptoms affect your daily activities remains a good guidepost for when to consider surgery, but you don’t have to wait until you are incapacitated to consider having a DMEK corneal transplant. You should consider having DMEK surgery once your visual symptoms significantly affect your quality of life – at whatever stage of Fuchs’ that might be. When weighing whether to have DMEK surgery, remember: your surgeon can tell you how the disease is affecting your corneas, but only you know how it is affecting your happiness, which can be just as important. For the most part, the timing is up to you, but you should have surgery before your corneas develop significant scarring to maximize your chances of enjoying good vision after a DMEK corneal transplant.
When is the right time to undergo cataract surgery with Fuchs’ Dystrophy?
If you have Fuchs’ dystrophy, your decision to have cataract surgery is complicated and should be discussed with a doctor who specializes in your condition. Your decision to have cataract surgery will likely not just be a decision about cataracts, but also a decision about Fuchs’, which can usher in the potential to fully rehabilitate your vision with a DMEK corneal transplant.
If your disease is not advanced, cataract surgery alone can sometimes improve the visual symptoms caused by Fuchs’ without eliminating them, but it can also make them worse by causing irreversible damage to your endothelial cells. Special precautions should be taken during cataract surgery in individuals with Fuchs’, but if the damage caused by the surgery is still too great, a subsequent DMEK corneal transplant may be required.
It is usually not possible for individuals with Fuchs’ to altogether avoid cataract surgery in their lifetime, even if a DMEK corneal transplant is performed without preceding cataract surgery. Many patients over the age of 50 who have a DMEK corneal transplant prior to having cataract surgery will need cataract surgery anyway within a few years. Having cataract surgery after DMEK surgery, although possible, is also not the preferred order of operations for preserving the health of transplanted endothelial cells.
The ideal approach is either to combine cataract surgery with DMEK corneal transplant surgery in one procedure or to plan for a two-stage procedure in which the cataract surgery is performed first and the DMEK surgery is performed second, a few days or weeks afterwards. Most patients and surgeons prefer one of these options because addressing both the cataract and Fuchs’ provides the best possible chance of restoring clear, vivid vision
Christopher S. Sales, MD, MPH is an Assistant Professor of Ophthalmology at Weill Cornell Medical College in New York, NY, and an Assistant Medical Director at the Lions VisionGift Eye Bank in Portland, OR.
He completed residency training at Stanford University in Palo Alto, CA, and Fellowship training with Drs. Mark Terry and Mike Straiko at the Devers Eye Institute in Portland, OR.
