AlphaCor Artificial Cornea

Clinical Outcome

N Jirásková; P Rozsival; M Burova; M Kalfertova

Disclosures

Eye. 2011;25(9):1138-1146. 

In This Article

Materials and Methods

The AlphaCor device, inclusion criteria, surgical techniques, and recommended management protocol have been described in details elsewhere, namely by Hicks et al.[1,2,4,20,22,23] Briefly, this keratoprosthesis (KPro) is approved for implantation into adults with an absence of current inflammation, and satisfactory tear film in cases of corneal blindness not treatable successfully by means of standard penetrating keratoplasty (PK) with donor corneal tissue. The study was conducted in conformance with the international ethics requirements, and all patients gave informed consent.

In this series, AlphaCor has been used in 15 eyes of 15 patients; 14 men (93%) and 1 woman (7%). The mean age of patients at the time of the surgery was 57 years, range 30–81 years. Patients typically had complex ocular histories with multiple pathologies: serious chemical burn in seven cases (47%), penetrating injury (dilaceratio bulbi) in two eyes (13%), bullous corneal dystrophies in four cases (27%), herpes simplex viral infection (HSV) in one eye (7%), and ocular cicatricial pemphigoid (OCP) in one case (7%) (Table 1). Mean preoperative visual acuity (VA) was hand movement (Table 2). Seven patients (47%) had bilateral blindness; in eight patients (53%), visual functions of the other eye were normal or significantly better than in the operated eye. Twelve patients (80%) had a history of prior failed PKs of the operated eye (mean 2.2; range 1–7). Three patients (20%; one with OCP and two with bilateral serious chemical burn) had no previous donor PK in the operated eye, but underwent multiple failed PKs in the other eye. All cases showed 3–4 quadrants of deep vessels (Figures 1 and 2). Four eyes (27%) were phakic, five eyes (33%) were aphakic, and six eyes (40%) were pseudophakic (posterior chamber intraocular lenses (PC IOL) in five cases, and Morcher PC IOL in one case). Ten eyes (67%) had secondary glaucoma that had been previously managed by trabeculectomies with or without antimetabolites or cryocoagulation. One patient (7%) had bilateral pseudoexfoliative glaucoma. Intraocular pressure (IOP) was satisfactory controlled before AlphaCor surgery in all eyes. One patient with OCP was indicated for repeated electrolysis of trichiasis, and fornix and lid reconstruction surgery before AlphaCor implantation. All patients were educated about the importance of regular lid hygiene and received lubricating agents to improve the tear film.

Figure 1.

Patient 4 before stage I AlphaCor implantation.

Figure 2.

Patient 12 before stage I AlphaCor implantation.

There are two stages to device implantation, separated by at least 3 months. In the first, a corneal lamellar pocket is created with a central opening in the posterior lamella, the device is positioned with its optic centered over the trephination, and the access wound is closed. In the stage II surgery, tissue anterior to the optic is removed to expose the device as a full-thickness corneal replacement centrally, whereas its skirt remains integrated within the stromal pocket. All surgeries were performed by two surgeons (NJ, PR) at the Department of Ophthalmology, University Hospital, Hradec Králové, except for the first stage of the first AlphaCor implantation that was provided for legislative reasons by Professor Bleckmann at Schlosspark-Klinik, Berlin, Germany. Stage I surgery was performed in all cases under general anesthesia using a traditional 180° entry wound in 12 cases (80%), and central trephination—'within graft' technique in three cases (20%). Cataract surgery was performed concurrently with AlphaCor implantation in two cases (13%). Circular continuous capsulorhexis, extracapsular cataract extraction, bimanual irrigation/aspiration were performed through a central opening in the posterior lamella. In one eye, a PC IOL was implanted and in one case the eye was left aphakic and model AlphaCor-A was used. Stage II surgery was performed in nine cases, (60%) at 3–11 months (mean 4.9 months), after the stage I surgery under topical anesthesia. It was abandoned in five eyes (33%) because of thinning of the anterior lamella, and in one case (7%) because of the trauma and AlphaCor loss at 8 days after stage I surgery. There were no serious perioperative complications. Of the four cases that were phakic after AlphaCor implantation, one showed subsequent progression of lenticular opacity (Figure 3) and uneventful phacoemulsification with PC IOL implantation was performed at 18 months after stage II surgery (Figure 4).

Figure 3.

Patient 8 before cataract surgery at 18 months after stage II AlphaCor implantation.

Figure 4.

Patient 8 after cataract surgery at 18 months after stage II AlphaCor implantation.

Topical tobramycin (0.3%) or chloramphenicol (0.5%) and dexamethasone (0.1%) gtt (Tobradex gtt or Spersadex gtt) were administered five times a day as routine postoperative long-term medications. Lubrication drops (Tears Naturale II (ALCON-COUVREUR n.v., Puurs, Belgium), Vidisic gel) were applied in six cases. It was not possible to use topical medroxyprogesterone (1%) in our patients for legislative reasons. Disposable soft contact lenses (D55, WILENS or ACUVUE, Johnsons & Johnsons, Jacksonville, FL, USA) were used in 11 cases for postoperative refractive error correction and/or surface protection of the device. Oral doxycycline (100 mg twice a day) was administered in 15 patients. Intraocular pressure was estimated digitally, or using Tono-Pen XL (MEDTRONIC SOLAN, Jacksonville, FL, USA).

All patients were strongly encouraged to stop smoking and/or avoid exposure to cigarette or environmental smoke. They were also educated about the necessity of long-term treatment and protection of the operated eye. Follow-up period ranged from 12 to 67 months.

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