Eyeworld

EW FEATURE 38 Corneal lamellar surgical procedures April 2015 • Penetrating keratoplasty still has a role in corneal transplant practice because not all patients are candidates for lamellar procedures. • The major challenges with full- thickness transplants are the delay in visual recovery, broken or infected sutures, high postoperative astigmatism, and late-onset traumatic graft ruptures. • Results from the Cornea Donor Study showed that donor age is not an important factor in graft survival. • Femtosecond laser-assisted transplant procedures may offer clinical benefits in the future. by Lauren Lipuma EyeWorld Staff Writer is also an issue, largely because it is dependent on the healing process of the patient as much as the skill of the surgeon, he added. Dr. Mannis finds that patients who have had a PK in 1 eye and DSEK in the other almost routinely prefer the DSEK eye, even if the 2 eyes have comparable visual acuity. A potentially devastating com- plication following PK is traumatic graft rupture, according to Dr. Lee. "[It] is a particularly devastating complication that I see several times S ince the first successful penetrating keratoplasty (PK) was performed in 1905, corneal transplan- tation has become one of the most commonly performed tissue transplant procedures. With the development of surgical mi- croscopes, microfilament sutures, a standardized eye banking system, and anti-rejection medications, the technique has evolved into a highly sophisticated and effective proce- dure for treating diseased corneas. Lamellar transplant procedures have further revolutionized corneal care, allowing eye surgeons to spot treat diseased layers of the cornea while sparing the healthy layers of tissue. With these techniques, sur- geons can offer faster visual recovery and alleviate many of the side effects associated with full-thickness grafts. Although partial-thickness pro- cedures have shifted the treatment paradigm in corneal transplantation, penetrating keratoplasty still has a role to play in corneal practice, and experts agree that it should still be a part of a corneal surgeon's arma- mentarium. The rise of endothelial keratoplasty The development of endothelial keratoplasty (EK) procedures— Descemet's stripping endothelial keratoplasty (DSEK) and Descemet's membrane endothelial keratoplasty (DMEK)—has contracted the role of PK in the last 2 decades. "Almost three-fourths of the corneal transplants I perform now are endothelial keratoplasty proce- dures with an increasing number of these becoming [DMEK]," said Barry Lee, MD, Eye Consultants of Atlan- ta. "However, [DSEK] remains the most common type of keratoplasty I perform." "For essentially any problem that's isolated to the endothelium, DSEK or DMEK are clearly superior procedures," said Mark Mannis, MD, professor and chair of UC Davis Eye Center, Sacramento, Calif. "They provide much more rapid visual re- habilitation, are safer for the patient, and the incidence of rejection is much lower." "Most surgeons in the U.S. and around the world find that DSEK— and those who are doing DMEK— is a better procedure all around for the appropriate patients," said Christopher Rapuano, MD, director of the cornea service, Wills Eye Hospital, Philadelphia. Although PK is no longer the first choice procedure in cases of pure endothelial disease, specialists agree that it should still be a part of a corneal surgeon's repertoire. There is still a large percentage of patients with pan-corneal disease—disease spanning the entire thickness of the cornea—who are not candidates for a lamellar procedure. That includes patients who have coexisting Fuchs' dystrophy and keratoconus, those who have had long-standing Fuchs' and scarring due to the years of swell- ing, full-thickness scars, perforated or infected ulcers, and bacterial or fungal keratitis that threatens the integrity of the eye. Additionally, eyes with PKs performed 20–30 years ago often develop severe astigma- tism from wound ectasia. When these PKs eventually fail, repeat PKs may do a better job than EKs in improving astigmatism and reducing the patient's dependence on rigid contact lenses. Challenges with PK The biggest challenges with PK remain the delay in visual recovery and the complications associated with full-thickness sutures. These include broken or infected sutures, high postoperative astigmatism, and late-onset traumatic graft ruptures. "There's no question that en- dothelial keratoplasties have much more rapid visual rehabilitation, and overall, the quality of their vision is better than with penetrating kerato- plasty," Dr. Mannis said. DSEK patients usually reach their visual goals in 1–3 months, whereas PK patients reach their visu- al goal at 6–12 months. The shorter visual recovery time with DSEK is a huge advantage, especially for an el- derly patient, Dr. Mannis said. High postop corneal astigmatism after PK Penetrating keratoplasty in the era of lamellar surgery The torque-antitorque suture technique in penetrating keratoplasty compresses the wound, allowing for optimal wound healing. Corneal graft rupture after a traumatic injury is a particularly devastating complication of penetrating keratoplasty. Source: Barry Lee, MD AT A GLANCE

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