EyeWorld Asia-Pacific March 2020 Issue

CORNEA 44 EWAP MARCH 2020 Drs. Terry, Colby, and Chamberlain said cataract surgery would be staged after DMEK, DSEK, or Descemet’s stripping only (DSO), the corneal procedure depending on the patient’s situation and the surgeon’s capabilities. “We are increasingly doing DMEK surgery first in patients who present with Fuchs and waiting to do the cataract,” Dr. Chamberlain said. “This step normalizes the cornea and creates a more predictive refractive outcome when cataract surgery is done.” The benefit of a combined cataract and corneal procedure is time, expense, and saved endothelial cells. “You always worry about doing phaco [later] with an endothelial keratoplasty graft. Are you going to damage some of those endothelial cells that you transplanted?” Dr. Colby said. If irregular astigmatism cannot be corrected or if Fuchs is not being addressed with endothelial keratoplasty or DSO, Dr. Chamberlain said he would choose a monofocal lens. Dr. Chamberlain cited analysis of a randomized, controlled patient population of DMEK and DSEK patients that found the cornea flattened or lost power in two- thirds of cases and steepened or gained power in the remaining third. “Granted, these shifts are small but can be enough to create greater than 1 D of refractive surprise. For this reason, when combining cases, I typically use monofocal lenses,” Do Hyung Lee, MD Professor, Inje University, Ilsan Paik Hospital 2240 Daewha, Ilson, Kyong, Kyunggyi, South Korea eyedr0823@hotmail.com ASIA-PACIFIC PERSPECTIVES I read the article with much interest. I agree that irregular astigmatism associated with Fuchs has been devalued despite its possible cause for decreased vision. However, irregular astigmatism is usually associated with cornea swelling due to advanced Fuchs. We should not overlook abnormal cornea with irregular astigmatism which is not Fuchs but accompanied by irregular cornea due to corneal pathology or tight lid. The paper by Sun et al., 1 had suggested new classification of Fuchs based on tomography and it is useful to determine the combined or the staged surgery of cataract and keratoplasty. I agree that endothelial transplantation is needed prior to cataract surgery before corneal edema becomes significant to ensure good visual quality. However, based on my experience, not only medical knowledge but also non-medical factors such as epidemiology, history, and culture should be considered to make a final decision on the surgical procedures. In the United States, Fuchs is the most common cause of corneal transplantation (22%) followed by corneal edema after cataract surgery (12%). 2 However, infectious keratitis (22.0%) is the most common cause of keratoplasty followed by trauma (21.0%) and bullous keratoplasty (13.8%), and Fuchs (1.0%) as twelfth cause in South Korea. 3 Similar findings are observed in Japan: bullous keratoplasty (54.9%), corneal opacity (13.7%), keratoconus (7%), and Fuchs (less than 1.5%). 4 Also, there are active infection (33.13%), bullous keratopathy (13.57%), keratitis (10.78%), and Fuchs (2.05%) in India. 5 Even when the patient understands the disease course of Fuchs and necessity of cornea surgery, it is very difficult to decide on keratoplasty for less significant corneal edema. Recently, endothelial transplantation including DSAEK and DMEK has become more popular in managing bullous keratopathy. However, penetrating keratoplasty is still a common procedure in treating Fuchs in Asian countries. The reason why donor cornea is not sufficient is that the patients miss the adequate time of endothelial transplantation. Additional donor preparation is needed to perform endothelial transplantation and this can become an economic burden especially for precut donor corneas from an eye bank. In terms of refraction and visual quality, endothelial transplantation following cataract surgery is recommended. Considering the expense and saved endothelium, a combined surgery is another option. In reality, performing cataract surgery should be the first option to consider as soon as possible in Fuchs before cornea edema develops. Not overemphasizing that cataract surgery itself does not harm corneal endothelium. In case of cornea edema in Fuchs, I prefer a combined surgery instead of staged operations because Fuchs with cornea edema is usually already accompanied by significant cataract. References 1. Sun SY, et al. Determining Subclinical Edema in Fuchs Endothelial Corneal Dystrophy: Revised Classification using Scheimpflug Tomography for Preoperative Assessment. Ophthalmology. 2019;126:195–204. 2. Park CY, et al. Keratoplasty in the United States: A 10-Year Review from 2005 through 2014. Ophthalmology . 2015;122:2432–42. 3. Choi S, et al. Epidemiologic Studies of Keratoplasty in Korea. J Korean Ophthalmol Soc . 2006;47:538–47. 4. Nishino T, et al. Changing indications and surgical techniques for keratoplasty during a 16-year period (2003–2018) at a tertiary referral hospital in Japan. Clin Ophthalmol . 2019(6);13:1499–1509. 4. Sharma N, et al. Procurement, storage and utilization trends of eye banks in India. Indian J Ophthalmol. 2019;67(7):1056-1059. Editors’ note: Dr. Lee declared no relevant financial interests.