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治疗儿童角膜混浊的新方法
Two different keratoprostheses offer fewer risks than penetrating keratoplasty
Mar 1, 2007
By: Lynda Charters
Ophthalmology Times
Dr. Gearinger
Las Vegas—Implantation of a keratoprosthesis for pediatric corneal opacity seems to be a promising option for optical rehabilitation. One keratoprosthesis (Boston KPro, Massachusetts Eye and Ear Infirmary) is well tolerated in children and may offer an alternative to penetrating keratoplasty (PKP), which is associated with several potential complications, Matthew D. Gearinger, MD, said at the American Academy of Ophthalmology annual meeting.
PKP performed in children can be a high-risk procedure with the potential for serious complications, making the use of a keratoprosthesis more reasonable.
"Penetrating keratoplasty carries a high risk of allograft rejection, a prolonged period of irregular astigmatism that can lead to refractive amblyopia, trauma, and other unhygienic practices that children engage in more often than adults," explained Dr. Gearinger, assistant professor of ophthalmology, University of Rochester Eye Institute, Rochester, NY.
The advantages of using a keratoprosthesis, he pointed out, include a low risk of allograft rejection, less risk of the development of irregular astigmatism, and more rapid optical rehabilitation that leads to improved treatment of amblyopia. Possible complications associated with a keratoprosthesis are extrusion of the device and the development of retroprosthetic membranes.
Two different devices
Figure 1 This keratoprosthesis (Boston KPro, Massachusetts Eye and Ear Infirmary) is an alternative to penetrating keratoplasty and is well tolerated in children. (Figure courtesy of Matthew D. Gearinger, MD)
Dr. Gearinger and colleagues use both the aforementioned keratoprosthesis and a newer one (Alpha Cor, Addition Technology). He described the former as a nut and bolt that is carried by a donor corneal skirt. The latter is an intralamellar disc with a biointergradable rim.
A retrospective study of the keratoprostheses included 17 children (22 eyes) who ranged in age from 4 weeks to 12 years. All patients had congenital or acquired corneal opacities resulting from Peter's anomaly (13 patients), glaucoma with corneal scarring (six patients), spontaneous perforation (two patients), and sclerocornea (one patient). Twelve eyes had had multiple previous grafts. The mean follow-up after implantation of the keratoprosthesis was about 10 months.
When using the Boston KPro, he explained, an 8-mm central trephination is performed in the host. An 8.75-mm donor corneal button with a 3-mm central aperture is made, and the keratoprosthesis is assembled on the donor tissue and held in place with 16 interrupted sutures. A large bandage contact lens is placed over the top.
When using the Alpha Cor, a partial-depth intralamellar dissection of the cornea is performed with trephination of the posterior lamella. The keratoprosthesis is inserted into the pocket and sutured in place. Three months later, a second procedure is performed to trephinate the anterior cornea.
Children who received the keratoprostheses were assessed for corneal clarity in the visual axis and retention of the devices. Of the 22 eyes, 20 eyes received a Boston KPro and two received an Alpha Cor, one of which was later replaced with a Boston KPro.
"The visual axis was clear in all the eyes that received a Boston keratoprosthesis," Dr. Gearinger reported. "Five eyes developed membranes that were cleared with a YAG capsulotomy in two eyes and with a surgical membranectomy in three eyes. All of the Boston keratoprostheses were retained without extrusion.
"A traumatic extrusion occurred in one patient who received an Alpha Cor, and a penetrating keratoplasty was performed at another institution," he added. "The second patient who received an Alpha Cor had a spontaneous extrusion and then underwent a conversion to the Boston KPro."
Regarding the visual results, most patients were too young to have quantitative visual acuity, Dr. Gearinger said. In the seven patients who were aged more than 4 years, the vision ranged from 20/30 to near light perception in the case of one patient who had a retinal detachment. All infants who were too young to have their vision checked were fixating and following with the operated eye. Many patients had dense deprivation amblyopia or other causes of decreased vision.
No intraoperative complications developed during implantation of the keratoprostheses, he said.
"Implantation of a keratoprosthesis offers early optical rehabilitation in children with corneal opacities. It is our procedure of choice at this time," Dr. Gearinger concluded. "Further follow-up is needed to determine the appropriate nomogram for keratorefractive power in these growing eyes and [for] refractive outcomes." 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。 初稿
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作者:admin@医学,生命科学 2011-01-03 17:53
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