Eyeworld

EW FEATURE 72 World Cornea Congress highlights September 2015 by Lauren Lipuma EyeWorld Staff Writer AT A GLANCE • Peter's anomaly and sclerocornea are outdated terms; congenital corneal opacities are better described as primary and secondary corneal diseases. • If a corneal opacity is central or eccentric, optical iridectomy in the area of the clear cornea is an alternative to penetrating keratoplasty. • Specialists have reclassified corneal dystrophies into 4 groups based on corneal anatomy, incorporating new genetic and histopathologic information about these conditions. • Genetic testing for corneal dystrophies is useful during preop testing for refractive surgery. clarity, but in children with congen- ital opacities, graft clarity does not necessarily translate into functional vision. A better measure of success, Dr. Nischal said, is how well postop vision allows a child to continue developing. "We know in pediatrics that if you give children vision that goes from hand movements to counting "If you have congenital glauco- ma and a corneal opacity, if I said to you that the way to treat that was to do a corneal graft, you would think I was mad, and you would be right," Dr. Nischal said in his presentation. "But there are conditions inside the eye affecting the lens that give you a corneal opacity, and we do a corneal transplant and expect it to work. That is equally mad." Physicians usually measure a transplant's success by graft Corneal opacities in newborns that are not due to glaucoma are often lumped together under the headings of "Peter's anomaly" or "sclerocornea," but these terms don't really make sense, Dr. Nischal said, because they don't communi- cate a specific sign or a disease. In addition, with the advent of anterior segment imaging, it became apparent that Peter's anomaly and sclerocornea were describing many types of opacities that don't orig- inate in the cornea. One example is primary aphakia, where the lens fails to form and this causes corneal opacification secondary to a primary lens failure. "It doesn't make any sense to call it sclerocornea because the prob- lem is not the sclera or the cornea," Dr. Nischal said in his presentation. "To label this as sclerocornea doesn't impart the gravity of the intraocular complications you're about to deal with." Dr. Nischal suggests naming congenital opacities as primary and secondary corneal diseases, where primary corneal diseases are devel- opmental anomalies of the cornea itself and secondary corneal diseases are those that originate elsewhere but have corneal symptoms. He and other ophthalmologists who treat these conditions hope to establish an international consensus on this classification system in the near future. Choosing the best treatment for each child Congenital corneal opacities are usually treated with penetrating keratoplasty, but if the opacity doesn't affect the entire cornea, there is another option. "If the opacity is central or eccentric, you can do an optical iridectomy by cutting out the iris in the area of the clear cornea," Dr. Nischal said in an interview with EyeWorld. "If, however, the cornea is completely opaque, there is no other option than a corneal transplant." Determining whether the opac- ity is primary or secondary could help physicians predict how success- ful a transplant will be. Patients with secondary corneal opacities often have a poor prognosis and their grafts frequently fail—because the problem is not the cornea. New approaches for managing corneal opacities and dystrophies Specialists present alternatives to traditional ways of classifying, diagnosing, and treating corneal disease P hysicians have historically described congenital cor- neal opacities and corneal dystrophies in terms of the patient's clinical presenta- tion. But recently, as new methods such as anterior segment imaging and DNA sequencing have deep- ened our understanding of these conditions, they have shown that traditional classification systems are woefully inadequate. During the "Dystrophies, Degenerations, and Genetics" ses- sion at World Cornea Congress VII, several cornea specialists described how they have used new technolo- gies to create superior classification systems for corneal disease that could lead to better diagnostic testing, more effective treatments, and improved visual outcomes. Getting rid of outdated terminology Ken Nischal, MD, FRCOphth, professor of ophthalmology, Univer- sity of Pittsburgh Medical Center, Pittsburgh, highlighted the short- comings of the terms physicians use to describe congenital corneal opacities. continued on page 74 Subtle corneal opacities in an individual with granular corneal dystrophy type II (GCD type II, a TGFBI corneal dystrophy). As the opacities are not characteristic of GCD type II, genetic analysis is the only means of making an accurate diagnosis to determine candidacy for refractive surgery. Failure to identify and exclude individuals with GCD type II as candidates for refractive surgery may result in a significant exacerbation of the corneal deposits, as seen here. Source: Anthony Aldave, MD

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