- Email: [email protected]
Cataract surgery with the AlphaCor artificial cornea
Cataract surgery with the AlphaCor artificial cornea Hiroshi Eguchi, MD, Celia R. Hicks, FRCOphth, Geoffrey J. Crawford, FRACO, Donald T. Tan, FRCOphth, Gerard R. Sutton, FRACO Purpose: To review the outcomes of AlphaCor artificial cornea (Argus Biomedical Pty Ltd.) implantation concurrent with or subsequent to cataract surgery. Setting: Nonrandomized multicenter clinical trial. Methods: AlphaCor devices were implanted under an approved protocol. Extracapsular cataract extraction with intraocular lens implantation was concurrently performed in 5 cases; an additional case had a displaced cataractous lens removed after severe blunt trauma subsequent to AlphaCor implantation. Results: Cataract surgery was difficult because the view was restricted and residual soft lens matter was retained. There was an increased incidence of postoperative complications (eg, melt, glaucoma) in cataract cases compared with noncataract AlphaCor cases. The mean best corrected visual acuity was worse in cases with cataract than in cases without. Conclusions: The technique for cataract surgery in AlphaCor cases needs to be refined. Imaging studies performed postoperatively may help ascertain whether soft lens matter remains so additional antiinflammatory medication can be considered. Melting appears to be preventable by topical medroxyprogesterone 1% therapy. J Cataract Refract Surg 2004; 30:1486–1491 2004 ASCRS and ESCRS
T
he AlphaCor artificial cornea (Argus Biomedical Pty Ltd.), originally known as the Chirila Keratoprosthesis (KPro), was developed at the Lions Eye Institute of Western Australia over the past 10 years. The biocompatible, flexible “core and skirt” device has a transparent central optical core with a porous skirt that enables host corneal tissue to integrate. In February 1998, a human pilot study using the Chirila KPro Type I commenced after animal trials and 3 devices were implanted in a manner similar to standard penetrating keratoplasty (PKP). Subsequently, the KPro was modified to create the Chirila KPro Type II, now known as AlphaCor, and implanted using an intralamellar technique. Implantation of this model began in October
Accepted for publication November 20, 2003. Reprint requests to Dr. C.R. Hicks, Lions Eye Institute, 2 Verdun Street, Nedlands, 6009, Western Australia, Australia. E-mail: crhicks@ cyllene.uwa.edu.au. 2004 ASCRS and ESCRS Published by Elsevier Inc.
1998 as a multicenter clinical investigation. By March 2003, 52 AlphaCor devices had been implanted. The purpose of this study was to review the outcomes in eyes that had implantation of an AlphaCor device concurrent with or subsequent to cataract surgery.
Patients and Methods Each center obtained ethics approval and informed consent from each patient for this clinical study. The trial protocol has been described.1 Patients were only recruited if their corneal pathology was unsuited to management by conventional donor corneal grafting because of a poor prognosis demonstrated by a history of repeated failures despite systemic immunosuppression or a combination of factors, including poor ocular surface, deep vascularization, and glaucoma, particularly when immunosuppression was contraindicated. All patients had a preoperative best corrected visual acuity (BCVA) of light perception (LP) to counting fingers (CF). In 5 cases with significant lens opacity, cataract surgery was performed concurrently with AlphaCor implantation. Cataract surgery was performed subsequent to AlphaCor implan0886-3350/04/$–see front matter doi:10.1016/j.jcrs.2003.12.026
CATARACT SURGERY WITH ARTIFICIAL CORNEA
Figure 1. (Eguchi) Lens status of AlphaCor cases before AlphaCor surgery.
Figure 3. (Eguchi) The cataract incision is made after the lamella is dissected.
Figure 2. (Eguchi) Lens status of AlphaCor cases immediately after AlphaCor surgery.
tation in 1 case of severe blunt trauma that occurred 1 year after AlphaCor implantation, causing dislocation of the crystalline lens into the anterior chamber (Figures 1 and 2).
Surgical Technique A modified extracapsular cataract extraction (ECCE) technique was used in association with the AlphaCor implantation technique previously described.2,3 The AlphaCor device was implanted during stage 1 of the 2-stage surgical procedure. A half-thickness scleral incision was made 1.0 mm peripheral to the superior limbus and extended around the superior 180 degrees. A half-thickness lamellar pocket 7.0 mm in diameter was created within the cornea for AlphaCor implantation. After the posterior lamella was reflected inferiorly, a full-thickness incision was made just inside the limbus in the posterior lamella (Figure 3) for capsulorhexis, hydrodissection, nucleus expression (Figure 4), and irrigation/aspiration (I/A) of soft lens matter. A poly(methyl methacrylate) posterior chamber intraocular lens (PC IOL) was placed in the capsular bag (Figure 5). The incision in the posterior lamella was closed with interrupted 10-0 nylon sutures (Figure 6), a central 3.0 mm
Figure 4. (Eguchi) The nucleus is expressed.
opening was trephined in the posterior lamella, and the AlphaCor insertion was completed (Figure 7). Finally, a conjunctival flap was sutured with 8-0 polyglactin (Vicryl威) to cover the cornea. At stage 2 of surgery, 3 months after stage 1, the conjunctival flap and anterior corneal lamella were opened centrally to 3.0 mm, exposing the AlphaCor optic. In the case with traumatic crystalline lens displacement after AlphaCor implantation, the lens was removed from the anterior chamber through a limbal incision; no IOL was implanted.
Case Reports Case 1. A 41-year-old man had an acid burn in the right eye in 1991 and PKP in 1993 that resulted in graft failure. The patient was phakic after AlphaCor surgery and had an uneventful course the first year. The BCVA was 20/200. Severe blunt trauma dislocated the crystalline lens into the anterior chamber. The lens was difficult to remove, and residual soft lens matter was visible. Uveitis developed and,
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CATARACT SURGERY WITH ARTIFICIAL CORNEA
Figure 5. (Eguchi) An IOL is inserted in the capsular bag after I/A
Figure 6. (Eguchi) The cataract incision is closed with 10-0 nylon.
of soft lens matter.
subsequently, raised intraocular pressure (IOP) and stromal melting. After it was in situ for 27 months, the device was removed and replaced with a donor graft. Although the reversal surgery was anatomically successful, graft failure gradually occurred. The visual acuity at the last examination was hand movements (HM). Case 2. A 58-year-old man had an alkali burn in the left eye in 2000 and a history of ocular herpes simplex virus (HSV) infection. After AlphaCor implantation, ECCE, and PC IOL implantation in February 2001, the BCVA improved to 20/50. The onset of stromal melting occurred at 6 months, and removal of the device was required at 10 months. The device was replaced with a donor graft. The visual acuity at the last examination was LP. Case 3. A 68-year-old man had microbial keratitis in the left eye in 2000. AlphaCor implantation, ECCE, anterior vitrectomy, and IOL implantation were performed in April 2001. Two months after stage 2 surgery, severe uveitis and glaucoma led to stromal melting at 3 months. This resulted in
Figure 7. (Eguchi) AlphaCor implantation is continued. 1488
a risk for device extrusion because of the thick retroprosthetic membrane. Retained soft lens matter was organized as a pupillary membrane. The AlphaCor device was removed and replaced with a graft at 7 months. The visual acuity at the last examination was 1/200. Case 4. A 62-year-old woman had an HSV infection in the right eye in 1970 and graft failure and HSV recurrence in that eye in 1987. AlphaCor implantation, ECCE, and PC IOL implantation were performed in June 2001, before stage 2 surgery in November 2001. During stage 2 surgery, stromal melting was observed over the peripheral skirt. Buccal mucosa and a small piece of anterior lamellar tissue were used to patch the stromal defect, and the BCVA was CF. However, the device required removal and replacement with donor corneal tissue 6 months after implantation because of recurrent melting. The visual acuity at the last examination was 20/120. Case 5. A 39-year-old man developed microbial keratitis after an acid burn in the left eye. The patient did not receive a donor graft but had AlphaCor implantation and ECCE. Early follow-up was satisfactory; however, when the anterior lamella was opened and widened 11 months later, significant stromal melting was noted. A lamellar graft and autologous conjunctiva were required to repair the melt, and the postoperative BCVA was limited to HM. Case 6. A 57-year-old man had an alkali burn in the right eye in 1971. Penetrating keratoplasty was performed in 1996 but failed. The patient had a relatively good course after AlphaCor implantation, ECCE, and PC IOL implantation in August 2001. However, a fibrous white pupillary membrane of retained lens matter was revealed after stage 2 surgery. The pupillary membrane was too tough to be perforated completely by a neodymium:YAG laser (5.8 mJ, 124 shots), and no retinal view was obtained. The patient’s visual acuity was also limited by a diabetic retinal detachment. The AlphaCor device remained in situ to date (15 months postoperatively); however, the visual acuity at the last examination was no LP.
J CATARACT REFRACT SURG—VOL 30, JULY 2004
CATARACT SURGERY WITH ARTIFICIAL CORNEA Table 1. Summary of results in 6 cases. Indication for AlphaCor
Postop Medication Other Than Protocol*
1
AB, 1 PGF
2
AB, HSV, 0 PGF
bot tox, iopd diam
3
MK, 0 PG
4 5 6
Case
Melt
Time of Melt (Mo)
Diam, tim, ster, med, g AB
Yes
13
No
No
HM
20/200
No
27
Valt, tim, ster, g AB, AT,
Yes
6
No
No
LP
20/50
No
10
Diam, tim, ster, AT, NSAID
Yes
5
No
Yes
CF
CF
No
7
HSV, 1 PGF
Valt, doxy, ster, AT
Yes
5
No
No
HM
CF
No
6
MK, 0 PG
Ster, g AB, diam, AT, tim, doxy
Yes
11
No
Yes
HM
HM
Yes
19
AB, 1 PGF
Dim, doxy, ster
No
N/A
No
No
LP
LP
Yes
16
Preop Glaucoma
Postop Glaucoma†
Preop BCVA
Postop BCVA
In Situ
FU to Mar ’03 or Device Removed (Mo)
AB ⫽ alkali burn; AT ⫽ artificial tear preparation; BCVA ⫽ best corrected visual acuity; bot tox ⫽ botulinum toxin injection; CF ⫽ counting fingers; Diam ⫽ Diamox (oral acetazolamide); doxy ⫽ oral doxycycline; FU ⫽ follow-up; HM ⫽ hand movement; HSV ⫽ herpes simplex virus; Iopd ⫽ iopidine drops; Med ⫽ medroxyprogesterone 1% drops; MK ⫽ microbial keratitis; NSAID ⫽ topical nonsteroidal antiinflammatory drug; PG ⫽ prior grafts; PGF ⫽ prior graft failure; LP ⫽ light perception; ster ⫽ topical steroids additional to routine protocol at any stage; tim ⫽ Timolol 0.5%; g AB ⫽ any antibiotic drops in addition to protocol chloramphenicol 1%; Valt ⫽ Valtrex (oral valaciclovir). *All cases received both topical steroids and guttae chloramphenicol 1% in the early postoperative period and tetracycline 1% ointment long term. †
Ignoring any temporary therapy for transient raised intraocular pressure
Results Five cases (9.6%) required concurrent cataract surgery, and 1 (1.9%) required removal of a displaced cataractous crystalline lens after severe blunt trauma 1 year after AlphaCor surgery. Table 1 shows a summary of the results in these 6 cases. Five cases (83%) developed stromal melting during the follow-up compared with 21 of 45 cases (47%) without cataract (2 ⫽ 0.09). The mean period between cataract surgery and stromal melting was 4.2 months. In 4 of the 6 cases with cataract (67%), the AlphaCor device had to be removed and replaced by a human donor graft, with anatomical success and initial clarity. However, subsequent onset of graft rejection significantly reduced the patients’ visual acuity. Although all 6 cases had no history of glaucoma, increased IOP occurred in 5 cases (83%), 2 (33%) of which required long-term glaucoma therapy after surgery. The cataract effect was partly compounded by ocular HSV. Of 44 non-HSV cases, 16 of 40 (40%) that had no cataract surgery and 3 of 4 (75%) that had cataract surgery had melting. No stromal melting was seen in any patient taking topical medroxyprogesterone 1% (MPG). Of the 6 cataract-associated cases, none had a history of glaucoma; however, 2 (33%) required longterm therapy for glaucoma postoperatively. Of the cases without cataract, 38% had a history of glaucoma and 27% required long-term therapy postoperatively. This suggests a significant association with cataract surgery
and postoperative glaucoma in AlphaCor patients (2 ⫽ 0.03) that could be related to the management of the stromal melting or reflect a common inflammatory cause. The mean postoperative BCVA was better in cases without cataract than in those with cataract (Table 2).
Discussion Formerly, standard cataract surgery with IOL implantation was not generally considered in KPro cases because most earlier KPro devices required routine lensectomy and anterior vitrectomy. The recent development of AlphaCor, a flexible, biointegrable device that is positioned within the corneal plane, makes lensectomy, vitrectomy, and iridectomy unnecessary, reducing the risk for complications. However, when a case presents with a cataractous lens before AlphaCor implantation, the cataract clearly requires removal. The cataract effect can be compounded by ocular HSV,4 which is now considered an exclusion factor for AlphaCor surgery. It is also possible that a cataract will develop in a phakic eye after successful AlphaCor implantation, as in 1 case in our series after severe trauma. Thus, the method of cataract surgery to use with or after KPro implantation should be carefully considered. Techniques for cataract surgery with temporary keratoprostheses have been described,5 and a case of cataract
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Table 2. Best corrected visual acuity before and after AlphaCor surgery.
AlphaCor Surgery Before After
No Cataract Surgery
Cataract Surgery
Mean
Range
Mean
Range
HM
LP–20/200
HM
LP–CF
20/160
LP–20/20
20/300
LP–20/50
CF ⫽ counting fingers; HM ⫽ hand movements; LP ⫽ light perception
surgery after implantation of another modern KPro, the BioKP II, has been reported. In that case, phacoemulsification was performed 5 months after the device was implanted using a temporal incision, can-opener capsulorhexis, and hydrodissection.6 The nucleus was tipped into the anterior chamber for phacoemulsification, and the cortex was aspirated. It does not appear as though an IOL was implanted in this case, but the surgical view was reported to be good. AlphaCor implantation is a relatively new procedure, and the optimum method of cataract surgery concurrent with or subsequent to AlphaCor implantation has not been defined. Based on our preliminary data from this small study series, cataract surgery with or after AlphaCor implantation appears to be associated with a higher risk for stromal melting and raised IOP that occurs in the early to middle postoperative period. In these cases, performing I/A with a 3.0 mm opening in a conjunctival flap and corresponding 3.0 mm openings in the anterior and posterior corneal lamellae is difficult because visualization of the capsular bag is poor, especially inferiorly. Retained soft lens matter has been confirmed in most cases on ultrasound or visualized after the second stage of AlphaCor surgery, and this appears to be the stimulus for subsequent inflammation and stromal melting requiring repair with donor tissue. Further clinical experience with AlphaCor should include refinement of cataract techniques to reduce the risk for retained soft lens matter. Options include intracapsular cataract extraction, despite its attendant risks; a modified approach to ECCE or phacoemulsification/ aspiration to improve visualization of the inferior capsular bag during I/A by making additional incisions in the posterior stromal lamella; and performing the procedure after the lens is displaced into the anterior chamber. Endoscopic techniques may be preferable but are not widely available. When possible, cataract removal before 1490
AlphaCor surgery is preferable. A patient who is aphakic has the option of remaining so and receiving a higherpowered AlphaCor (AlphaCor–A) or an IOL and a standard AlphaCor (AlphaCor–P). In either case, significantly more refractive and visual acuity data will be required to establish the predictability of outcomes. When cataract surgery with AlphaCor implantation is unavoidable, care should be taken to ensure that all soft lens matter is removed. After this and before stage 2 AlphaCor surgery, an ultrasound scan, or preferably a noncontact technique, can be useful to determine whether soft lens material remains. If so, a further intraocular procedure could be planned to remove the material concurrent with stage 2 surgery and therapies such as orbital floor steroids considered to suppress inflammation. Optical coherence tomography can give good visualization of the anterior chamber7 and may be beneficial in these cases. Topical MPG 1% should be considered postoperatively for all AlphaCor patients, particularly when cataract surgery is performed, because preliminary evidence suggests that it may provide strong protection against stromal melting.8 In the first 10 trial cases, MPG was given for the first postoperative year but was stopped during the trial because of its nonapproved status. Considering the above factors, patients requiring cataract surgery with AlphaCor surgery should be advised of the increased risk for postoperative complications.
References 1. Hicks CR, Crawford GJ, Lou X, et al. Corneal replacement using a synthetic hydrogel cornea, AlphaCor娃: device, preliminary outcomes and complications. Eye 2003; 17:385–392 2. Hicks C, Crawford G, Chirila T, et al. Development and clinical assessment of an artificial cornea. Prog Retin Eye Res 2000; 19:149–170 3. Crawford GJ, Hicks CR, Lou X, et al. The Chirila keratoprosthesis: phase I human clinical trial. Ophthalmology 2002; 109:883–889 4. Hicks CR, Crawford GJ, Tan DT, et al. Outcomes of implantation of an artificial cornea, AlphaCor; effects of prior ocular herpes simplex infection. Cornea 2002; 21:685–690 5. Menapace R, Skorpik C, Grasl M. Modified triple procedure using a temporary keratoprosthesis for closed-system, small-incision cataract surgery. J Cataract Refract Surg 1990; 16:230–234 6. Legeais JM, Ellies PD, Dighiero P, Renard G. Phacoemulsification in a patient with an artificial cornea [letter]. Arch Ophthalmol 1999; 117:1669
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7. Eguchi H, Iwata A, Sogabe M, et al. [A case of secondary glaucoma studied by optical coherence tomography of the anterior segment]. [Japanese] Nippon Ganka Gakkai Zasshi 2002; 106:178–181 8. Hicks CR, Crawford GJ. Melting after keratoprosthesis implantation: the effects of medroxyprogesterone. Cornea 2003; 22:497–500 From the Lions Eye Institute and Centre for Ophthalmology and Visual Science, University of Western Australia (Eguchi, Hicks, Crawford), Nedlands, and Sydney Eye Hospital, University of New South Wales (Sutton), Sydney, Australia; and Singapore National Eye Center (Tan), Singapore, Singapore. Presented in part at the 7th ESCRS Winter Refractive Surgery Meeting, Rome, Italy, February 2003, and the ASCRS Symposium on Cataract,
IOL and Refractive Surgery, San Francisco, California, USA, April 2003. Supported in part by a grant from the National Health and Medical Research Council of Australia, Canberra, Australia. Dr. Crawford and Dr. Hicks have proprietary and minor financial interests in Argus Biomedical Pty Ltd., the manufacturer of AlphaCor. None of the other authors has a financial or proprietary interest in any material or method mentioned. Robyn Fenton assisted with preparation of the manuscript. Data on AlphaCor outcomes were contributed by Aldo Caporossi, MD, Geoffrey Crawford, MD, John Dart, MD, Nicholas Downie, MD, Tjahjono Gondhowiardjo, MD, Gunther Grabner, MD, Dennis Lam, MD, Giancarlo Prosdocimo, MD, Grant Snibson, MD, Gerard Sutton, MD, and Donald Tan, MD.
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T
he AlphaCor artificial cornea (Argus Biomedical Pty Ltd.), originally known as the Chirila Keratoprosthesis (KPro), was developed at the Lions Eye Institute of Western Australia over the past 10 years. The biocompatible, flexible “core and skirt” device has a transparent central optical core with a porous skirt that enables host corneal tissue to integrate. In February 1998, a human pilot study using the Chirila KPro Type I commenced after animal trials and 3 devices were implanted in a manner similar to standard penetrating keratoplasty (PKP). Subsequently, the KPro was modified to create the Chirila KPro Type II, now known as AlphaCor, and implanted using an intralamellar technique. Implantation of this model began in October
Accepted for publication November 20, 2003. Reprint requests to Dr. C.R. Hicks, Lions Eye Institute, 2 Verdun Street, Nedlands, 6009, Western Australia, Australia. E-mail: crhicks@ cyllene.uwa.edu.au. 2004 ASCRS and ESCRS Published by Elsevier Inc.
1998 as a multicenter clinical investigation. By March 2003, 52 AlphaCor devices had been implanted. The purpose of this study was to review the outcomes in eyes that had implantation of an AlphaCor device concurrent with or subsequent to cataract surgery.
Patients and Methods Each center obtained ethics approval and informed consent from each patient for this clinical study. The trial protocol has been described.1 Patients were only recruited if their corneal pathology was unsuited to management by conventional donor corneal grafting because of a poor prognosis demonstrated by a history of repeated failures despite systemic immunosuppression or a combination of factors, including poor ocular surface, deep vascularization, and glaucoma, particularly when immunosuppression was contraindicated. All patients had a preoperative best corrected visual acuity (BCVA) of light perception (LP) to counting fingers (CF). In 5 cases with significant lens opacity, cataract surgery was performed concurrently with AlphaCor implantation. Cataract surgery was performed subsequent to AlphaCor implan0886-3350/04/$–see front matter doi:10.1016/j.jcrs.2003.12.026
CATARACT SURGERY WITH ARTIFICIAL CORNEA
Figure 1. (Eguchi) Lens status of AlphaCor cases before AlphaCor surgery.
Figure 3. (Eguchi) The cataract incision is made after the lamella is dissected.
Figure 2. (Eguchi) Lens status of AlphaCor cases immediately after AlphaCor surgery.
tation in 1 case of severe blunt trauma that occurred 1 year after AlphaCor implantation, causing dislocation of the crystalline lens into the anterior chamber (Figures 1 and 2).
Surgical Technique A modified extracapsular cataract extraction (ECCE) technique was used in association with the AlphaCor implantation technique previously described.2,3 The AlphaCor device was implanted during stage 1 of the 2-stage surgical procedure. A half-thickness scleral incision was made 1.0 mm peripheral to the superior limbus and extended around the superior 180 degrees. A half-thickness lamellar pocket 7.0 mm in diameter was created within the cornea for AlphaCor implantation. After the posterior lamella was reflected inferiorly, a full-thickness incision was made just inside the limbus in the posterior lamella (Figure 3) for capsulorhexis, hydrodissection, nucleus expression (Figure 4), and irrigation/aspiration (I/A) of soft lens matter. A poly(methyl methacrylate) posterior chamber intraocular lens (PC IOL) was placed in the capsular bag (Figure 5). The incision in the posterior lamella was closed with interrupted 10-0 nylon sutures (Figure 6), a central 3.0 mm
Figure 4. (Eguchi) The nucleus is expressed.
opening was trephined in the posterior lamella, and the AlphaCor insertion was completed (Figure 7). Finally, a conjunctival flap was sutured with 8-0 polyglactin (Vicryl威) to cover the cornea. At stage 2 of surgery, 3 months after stage 1, the conjunctival flap and anterior corneal lamella were opened centrally to 3.0 mm, exposing the AlphaCor optic. In the case with traumatic crystalline lens displacement after AlphaCor implantation, the lens was removed from the anterior chamber through a limbal incision; no IOL was implanted.
Case Reports Case 1. A 41-year-old man had an acid burn in the right eye in 1991 and PKP in 1993 that resulted in graft failure. The patient was phakic after AlphaCor surgery and had an uneventful course the first year. The BCVA was 20/200. Severe blunt trauma dislocated the crystalline lens into the anterior chamber. The lens was difficult to remove, and residual soft lens matter was visible. Uveitis developed and,
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CATARACT SURGERY WITH ARTIFICIAL CORNEA
Figure 5. (Eguchi) An IOL is inserted in the capsular bag after I/A
Figure 6. (Eguchi) The cataract incision is closed with 10-0 nylon.
of soft lens matter.
subsequently, raised intraocular pressure (IOP) and stromal melting. After it was in situ for 27 months, the device was removed and replaced with a donor graft. Although the reversal surgery was anatomically successful, graft failure gradually occurred. The visual acuity at the last examination was hand movements (HM). Case 2. A 58-year-old man had an alkali burn in the left eye in 2000 and a history of ocular herpes simplex virus (HSV) infection. After AlphaCor implantation, ECCE, and PC IOL implantation in February 2001, the BCVA improved to 20/50. The onset of stromal melting occurred at 6 months, and removal of the device was required at 10 months. The device was replaced with a donor graft. The visual acuity at the last examination was LP. Case 3. A 68-year-old man had microbial keratitis in the left eye in 2000. AlphaCor implantation, ECCE, anterior vitrectomy, and IOL implantation were performed in April 2001. Two months after stage 2 surgery, severe uveitis and glaucoma led to stromal melting at 3 months. This resulted in
Figure 7. (Eguchi) AlphaCor implantation is continued. 1488
a risk for device extrusion because of the thick retroprosthetic membrane. Retained soft lens matter was organized as a pupillary membrane. The AlphaCor device was removed and replaced with a graft at 7 months. The visual acuity at the last examination was 1/200. Case 4. A 62-year-old woman had an HSV infection in the right eye in 1970 and graft failure and HSV recurrence in that eye in 1987. AlphaCor implantation, ECCE, and PC IOL implantation were performed in June 2001, before stage 2 surgery in November 2001. During stage 2 surgery, stromal melting was observed over the peripheral skirt. Buccal mucosa and a small piece of anterior lamellar tissue were used to patch the stromal defect, and the BCVA was CF. However, the device required removal and replacement with donor corneal tissue 6 months after implantation because of recurrent melting. The visual acuity at the last examination was 20/120. Case 5. A 39-year-old man developed microbial keratitis after an acid burn in the left eye. The patient did not receive a donor graft but had AlphaCor implantation and ECCE. Early follow-up was satisfactory; however, when the anterior lamella was opened and widened 11 months later, significant stromal melting was noted. A lamellar graft and autologous conjunctiva were required to repair the melt, and the postoperative BCVA was limited to HM. Case 6. A 57-year-old man had an alkali burn in the right eye in 1971. Penetrating keratoplasty was performed in 1996 but failed. The patient had a relatively good course after AlphaCor implantation, ECCE, and PC IOL implantation in August 2001. However, a fibrous white pupillary membrane of retained lens matter was revealed after stage 2 surgery. The pupillary membrane was too tough to be perforated completely by a neodymium:YAG laser (5.8 mJ, 124 shots), and no retinal view was obtained. The patient’s visual acuity was also limited by a diabetic retinal detachment. The AlphaCor device remained in situ to date (15 months postoperatively); however, the visual acuity at the last examination was no LP.
J CATARACT REFRACT SURG—VOL 30, JULY 2004
CATARACT SURGERY WITH ARTIFICIAL CORNEA Table 1. Summary of results in 6 cases. Indication for AlphaCor
Postop Medication Other Than Protocol*
1
AB, 1 PGF
2
AB, HSV, 0 PGF
bot tox, iopd diam
3
MK, 0 PG
4 5 6
Case
Melt
Time of Melt (Mo)
Diam, tim, ster, med, g AB
Yes
13
No
No
HM
20/200
No
27
Valt, tim, ster, g AB, AT,
Yes
6
No
No
LP
20/50
No
10
Diam, tim, ster, AT, NSAID
Yes
5
No
Yes
CF
CF
No
7
HSV, 1 PGF
Valt, doxy, ster, AT
Yes
5
No
No
HM
CF
No
6
MK, 0 PG
Ster, g AB, diam, AT, tim, doxy
Yes
11
No
Yes
HM
HM
Yes
19
AB, 1 PGF
Dim, doxy, ster
No
N/A
No
No
LP
LP
Yes
16
Preop Glaucoma
Postop Glaucoma†
Preop BCVA
Postop BCVA
In Situ
FU to Mar ’03 or Device Removed (Mo)
AB ⫽ alkali burn; AT ⫽ artificial tear preparation; BCVA ⫽ best corrected visual acuity; bot tox ⫽ botulinum toxin injection; CF ⫽ counting fingers; Diam ⫽ Diamox (oral acetazolamide); doxy ⫽ oral doxycycline; FU ⫽ follow-up; HM ⫽ hand movement; HSV ⫽ herpes simplex virus; Iopd ⫽ iopidine drops; Med ⫽ medroxyprogesterone 1% drops; MK ⫽ microbial keratitis; NSAID ⫽ topical nonsteroidal antiinflammatory drug; PG ⫽ prior grafts; PGF ⫽ prior graft failure; LP ⫽ light perception; ster ⫽ topical steroids additional to routine protocol at any stage; tim ⫽ Timolol 0.5%; g AB ⫽ any antibiotic drops in addition to protocol chloramphenicol 1%; Valt ⫽ Valtrex (oral valaciclovir). *All cases received both topical steroids and guttae chloramphenicol 1% in the early postoperative period and tetracycline 1% ointment long term. †
Ignoring any temporary therapy for transient raised intraocular pressure
Results Five cases (9.6%) required concurrent cataract surgery, and 1 (1.9%) required removal of a displaced cataractous crystalline lens after severe blunt trauma 1 year after AlphaCor surgery. Table 1 shows a summary of the results in these 6 cases. Five cases (83%) developed stromal melting during the follow-up compared with 21 of 45 cases (47%) without cataract (2 ⫽ 0.09). The mean period between cataract surgery and stromal melting was 4.2 months. In 4 of the 6 cases with cataract (67%), the AlphaCor device had to be removed and replaced by a human donor graft, with anatomical success and initial clarity. However, subsequent onset of graft rejection significantly reduced the patients’ visual acuity. Although all 6 cases had no history of glaucoma, increased IOP occurred in 5 cases (83%), 2 (33%) of which required long-term glaucoma therapy after surgery. The cataract effect was partly compounded by ocular HSV. Of 44 non-HSV cases, 16 of 40 (40%) that had no cataract surgery and 3 of 4 (75%) that had cataract surgery had melting. No stromal melting was seen in any patient taking topical medroxyprogesterone 1% (MPG). Of the 6 cataract-associated cases, none had a history of glaucoma; however, 2 (33%) required longterm therapy for glaucoma postoperatively. Of the cases without cataract, 38% had a history of glaucoma and 27% required long-term therapy postoperatively. This suggests a significant association with cataract surgery
and postoperative glaucoma in AlphaCor patients (2 ⫽ 0.03) that could be related to the management of the stromal melting or reflect a common inflammatory cause. The mean postoperative BCVA was better in cases without cataract than in those with cataract (Table 2).
Discussion Formerly, standard cataract surgery with IOL implantation was not generally considered in KPro cases because most earlier KPro devices required routine lensectomy and anterior vitrectomy. The recent development of AlphaCor, a flexible, biointegrable device that is positioned within the corneal plane, makes lensectomy, vitrectomy, and iridectomy unnecessary, reducing the risk for complications. However, when a case presents with a cataractous lens before AlphaCor implantation, the cataract clearly requires removal. The cataract effect can be compounded by ocular HSV,4 which is now considered an exclusion factor for AlphaCor surgery. It is also possible that a cataract will develop in a phakic eye after successful AlphaCor implantation, as in 1 case in our series after severe trauma. Thus, the method of cataract surgery to use with or after KPro implantation should be carefully considered. Techniques for cataract surgery with temporary keratoprostheses have been described,5 and a case of cataract
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Table 2. Best corrected visual acuity before and after AlphaCor surgery.
AlphaCor Surgery Before After
No Cataract Surgery
Cataract Surgery
Mean
Range
Mean
Range
HM
LP–20/200
HM
LP–CF
20/160
LP–20/20
20/300
LP–20/50
CF ⫽ counting fingers; HM ⫽ hand movements; LP ⫽ light perception
surgery after implantation of another modern KPro, the BioKP II, has been reported. In that case, phacoemulsification was performed 5 months after the device was implanted using a temporal incision, can-opener capsulorhexis, and hydrodissection.6 The nucleus was tipped into the anterior chamber for phacoemulsification, and the cortex was aspirated. It does not appear as though an IOL was implanted in this case, but the surgical view was reported to be good. AlphaCor implantation is a relatively new procedure, and the optimum method of cataract surgery concurrent with or subsequent to AlphaCor implantation has not been defined. Based on our preliminary data from this small study series, cataract surgery with or after AlphaCor implantation appears to be associated with a higher risk for stromal melting and raised IOP that occurs in the early to middle postoperative period. In these cases, performing I/A with a 3.0 mm opening in a conjunctival flap and corresponding 3.0 mm openings in the anterior and posterior corneal lamellae is difficult because visualization of the capsular bag is poor, especially inferiorly. Retained soft lens matter has been confirmed in most cases on ultrasound or visualized after the second stage of AlphaCor surgery, and this appears to be the stimulus for subsequent inflammation and stromal melting requiring repair with donor tissue. Further clinical experience with AlphaCor should include refinement of cataract techniques to reduce the risk for retained soft lens matter. Options include intracapsular cataract extraction, despite its attendant risks; a modified approach to ECCE or phacoemulsification/ aspiration to improve visualization of the inferior capsular bag during I/A by making additional incisions in the posterior stromal lamella; and performing the procedure after the lens is displaced into the anterior chamber. Endoscopic techniques may be preferable but are not widely available. When possible, cataract removal before 1490
AlphaCor surgery is preferable. A patient who is aphakic has the option of remaining so and receiving a higherpowered AlphaCor (AlphaCor–A) or an IOL and a standard AlphaCor (AlphaCor–P). In either case, significantly more refractive and visual acuity data will be required to establish the predictability of outcomes. When cataract surgery with AlphaCor implantation is unavoidable, care should be taken to ensure that all soft lens matter is removed. After this and before stage 2 AlphaCor surgery, an ultrasound scan, or preferably a noncontact technique, can be useful to determine whether soft lens material remains. If so, a further intraocular procedure could be planned to remove the material concurrent with stage 2 surgery and therapies such as orbital floor steroids considered to suppress inflammation. Optical coherence tomography can give good visualization of the anterior chamber7 and may be beneficial in these cases. Topical MPG 1% should be considered postoperatively for all AlphaCor patients, particularly when cataract surgery is performed, because preliminary evidence suggests that it may provide strong protection against stromal melting.8 In the first 10 trial cases, MPG was given for the first postoperative year but was stopped during the trial because of its nonapproved status. Considering the above factors, patients requiring cataract surgery with AlphaCor surgery should be advised of the increased risk for postoperative complications.
References 1. Hicks CR, Crawford GJ, Lou X, et al. Corneal replacement using a synthetic hydrogel cornea, AlphaCor娃: device, preliminary outcomes and complications. Eye 2003; 17:385–392 2. Hicks C, Crawford G, Chirila T, et al. Development and clinical assessment of an artificial cornea. Prog Retin Eye Res 2000; 19:149–170 3. Crawford GJ, Hicks CR, Lou X, et al. The Chirila keratoprosthesis: phase I human clinical trial. Ophthalmology 2002; 109:883–889 4. Hicks CR, Crawford GJ, Tan DT, et al. Outcomes of implantation of an artificial cornea, AlphaCor; effects of prior ocular herpes simplex infection. Cornea 2002; 21:685–690 5. Menapace R, Skorpik C, Grasl M. Modified triple procedure using a temporary keratoprosthesis for closed-system, small-incision cataract surgery. J Cataract Refract Surg 1990; 16:230–234 6. Legeais JM, Ellies PD, Dighiero P, Renard G. Phacoemulsification in a patient with an artificial cornea [letter]. Arch Ophthalmol 1999; 117:1669
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7. Eguchi H, Iwata A, Sogabe M, et al. [A case of secondary glaucoma studied by optical coherence tomography of the anterior segment]. [Japanese] Nippon Ganka Gakkai Zasshi 2002; 106:178–181 8. Hicks CR, Crawford GJ. Melting after keratoprosthesis implantation: the effects of medroxyprogesterone. Cornea 2003; 22:497–500 From the Lions Eye Institute and Centre for Ophthalmology and Visual Science, University of Western Australia (Eguchi, Hicks, Crawford), Nedlands, and Sydney Eye Hospital, University of New South Wales (Sutton), Sydney, Australia; and Singapore National Eye Center (Tan), Singapore, Singapore. Presented in part at the 7th ESCRS Winter Refractive Surgery Meeting, Rome, Italy, February 2003, and the ASCRS Symposium on Cataract,
IOL and Refractive Surgery, San Francisco, California, USA, April 2003. Supported in part by a grant from the National Health and Medical Research Council of Australia, Canberra, Australia. Dr. Crawford and Dr. Hicks have proprietary and minor financial interests in Argus Biomedical Pty Ltd., the manufacturer of AlphaCor. None of the other authors has a financial or proprietary interest in any material or method mentioned. Robyn Fenton assisted with preparation of the manuscript. Data on AlphaCor outcomes were contributed by Aldo Caporossi, MD, Geoffrey Crawford, MD, John Dart, MD, Nicholas Downie, MD, Tjahjono Gondhowiardjo, MD, Gunther Grabner, MD, Dennis Lam, MD, Giancarlo Prosdocimo, MD, Grant Snibson, MD, Gerard Sutton, MD, and Donald Tan, MD.
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