AlphaCor Artificial Cornea

Clinical Outcome

N Jirásková; P Rozsival; M Burova; M Kalfertova

Disclosures

Eye. 2011;25(9):1138-1146. 

In This Article

Results

Outcome data for every patient at every visit were collected for analysis, with no case lost to follow-up. Postoperative best-corrected VA (BCVA) ranged from hand movement to 0.8. The visual acuities post-implantation varied between visits depending upon cataract progression or optic deposits formation in some patients, and refractive correction with acuities up to 0.8 for distance and Jaeger no.1 for near vision being recorded (Table 2). Concurrent pathologies diagnosed before AlphaCor implantation that limited visual potential were present in 11 cases (73%), predominantly glaucoma causing defects in visual field in 10 eyes (67%), and traumatic retinopathy severely damaging vision in one patient (7%).

Complications can be categorized as anatomical complications related to stromal melting, optic complications related to deposition or surface spoliation, and device-unrelated complications, as summarized in Table 1.

The commonest category of complication was that related to stromal melting adjacent or anterior to the device skirt. It is defined as any episode of stromal thinning or loss, whether or not the process subsequently stabilized. This was observed in nine cases (60%; patients 1, 2, 4, 5, 7, 10, 12, 13, 15) (Figures 5 and 6). Four of these (27%; patients 7, 12, 13, 15) have required conjunctival flap, two (13%; patients 5, 13) amniotic membrane transplantations, and in two eyes (13%; patients 5, 10) a scleral patch was used. Stromal melting culminated in device explantation and replacement with donor graft in five eyes (33%; patients 1, 2, 4, 5, 10). No predisposing or risk factors for this type of complication was found.

Figure 5.

Stromal melting in patient 5.

Figure 6.

Stromal melting in patient 12.

The other main category of complications relates to surface spoilation or deposition of substances within the hydrogel optic such that vision is reduced. There have been three cases (20%; patients 1, 2, 4) of mild to moderate surface spoilation with the appearance of a contact lens 'jelly-bump' type (Figure 7). These deposits require regular cleaning using OPTI-FREE SUPRACLENS (Alcon Laboratories, Inc., Fort Worth, TX, USA); in one case (7%; patient 4) excimer laser abrasion was performed repeatedly. In one case (patient 1), deposits were observed on the optical surface of the device, at 2 years after implantation, progressing to an almost continuous crust on half of the optic periphery, with intervening clear areas, and severely affecting vision. At 4 years after implantation, stromal melting with leakage was diagnosed and explantation was performed with a new corneal graft.

Figure 7.

Optic deposits in patient 1.

Retroprosthetic membrane (fibrous closure of posterior lamellar opening) was observed in three eyes (patients 5, 7, 15), and was managed surgically in one eye (patient 15). No improvement of vision after removal of the central part of the retroprosthetic membrane was observed, because the patient developed hemophthalmus.

In one eye (patient 2), acute elevation of IOP was observed at 6 days after stage I surgery that did not respond to pharmacological treatment. Uneventful cyclocryocoagulation was performed, and the IOP was satisfactory controlled without medication. No other case of elevation IOP was observed in this series.

The commonest device-unrelated complication in our series was trauma. Two patients that were bilaterally blind before AlphaCor implantation (patients 6, 9) and have reached apparently very good postoperative visual results experienced serious injury with penetration of the device (Figure 8). In both cases, PK was performed and the damaged keratoprostheses were replaced with donor graft. One (patient 14) experienced penetrating injury in the surgical wound at 8 days after stage I surgery with AlphaCor loss. This case was managed by suturing of the wound (anterior lamella). All complications were managed without loss of the eye.

Figure 8.

Penetrating injury in patient 9.

No other complications such as endophthalmitis, glaucoma progression, retinal detachment, and inflammation were observed. The survival rate of the device at 1, 2, and 3 years was 87%, 58%, and 42%, respectively. It is necessary to emphasize that those two devices that were removed earlier than 12 months after implantation were explanted due to trauma (KPro-unrelated complication).

processing....