5. Krachmer JH. Pellucid marginal corneal degeneration. Arch Ophthalmol 1978;96:1217–1221. 6. Sherwood MB, Grierson I, Millar L, Hitchings RA. Long-term morphologic effects of antiglaucoma drugs on the conjunctiva and Tenon’s capsule in glaucomatous patients. Ophthalmology 1989;96:327–335. 7. International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical journals. Med Educ 1999;33:66 –78.
Out of 200 references, we found 35 citation errors in 32 references (three references included two errors) (Table 1). Most errors were in the title (54% of errors) or author (34%) elements of the reference; errors in other elements were rare. Many of the citation errors were minor (for example, small spelling mistakes in titles or inaccurate recording of the authors’ initials), but some mistakes were more important (for example, complete alteration of titles or total omission of the first named author). Only four of the 35 citation errors were errors from PubMed. Thirty quotations of references were not accurate, and 20 were partially accurate (Table 2). There was wide variation between the journals in the frequency of citation errors (range 0% to 35% of papers, mean 16%), but not in the frequency of quotation errors. The frequency of citation errors in our sample of ophthalmic articles was 16% and the frequency of quotation errors was 25%. The frequency of citation errors is similar to that reported for leading medical journals (average 19%, range 4.1% to 40.3%).4 A systematic review of 35 papers including over 15,000 references in nearly 100 different journals reported a higher frequency of citation errors (median 36%, range 4% to 67%), but a similar frequency of quotation errors (median 20%, range 0% to 47%).3 Citation and quotation errors are therefore relatively common within the ophthalmic literature, although of comparable frequency to other areas of the scientific literature. Only four of the 35 citation errors were found in PubMed, and so the origin of many of the errors lies with the author. Extra checks on the accuracy of citations are in place at the Journal of Cataract and Refractive Surgery (librarian checks all references), Ophthalmology (reference checker employed) and Survey of Ophthalmology (automated reference-checker program), which have a relatively low frequency of citation errors. Technical editing may therefore improve the accuracy of citations (reviewed by Wager and Middleton3). Quotations are time-consuming and expensive to check, although technical editing may improve their accuracy.3 However, it remains the responsibility of authors to verify their references against the original documents.7
Amniotic Membrane as an Adjunct to Donor Sclera in the Repair of Exposed Glaucoma Drainage Devices Poornima Rai, FRCOphth, Roberto Lauande-Pimentel, MD, and Keith Barton, MD, FRCP, FRCS To describe a novel method of repairing exposed glaucoma drainage devices (GDD) using amniotic membrane transplantation (AMT) in place of conjunctiva to cover donor sclera when conjunctival closure is hampered by adjacent scarring. DESIGN: Retrospective noncomparative interventional case series. METHODS: Consecutive case series of nine GDD erosions over 5 years repaired by a double-layer technique of scleral allograft plus AMT. RESULTS: Successful repair was achieved in seven cases. One GDD plate re-eroded after pars plana vitrectomy; a second leaked from the tube entry site. CONCLUSIONS: AMT is a safe and useful conjunctival substitute to cover donor sclera in situations where conjunctival scarring might otherwise preclude successful repair. (Am J Ophthalmol 2005;140:1148 –1152. © 2005 by Elsevier Inc. All rights reserved.) PURPOSE:
P
REFERENCES
1. de Lacey G, Record C, Wade J. How accurate are quotations and references in medical journals? Br Med J 1985;291:884 – 886. 2. Evans JT, Nadjari HI, Burchell SA. Quotational and reference accuracy in surgical journals: a continuing peer review problem. JAMA 1990;263:1353–1354. 3. Wager E, Middleton P. Technical editing of research reports in biomedical journals. Cochrane Database Method Rev 2003, MR000002. 4. Siebers R, Holt S. Accuracy of references in five leading medical journals. Lancet 2000;356:1445.
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ERMANENT REPAIR OF AN EXTRUDING GLAUCOMA
drainage device (GDD) may be difficult to achieve in eyes with extensive conjunctival scarring from ocular surface disease or previous surgery such as scleral buckling. Donor sclera may melt if inadequately covered with conjunctiva, yet adequate mobilization may be hampered by the above factors. Failure to repair an exposed GDD may necessitate removal1,2 or risk endophthalmitis.3 We report the outcome of nine exposed GDD repaired using donor sclera with an overlying amniotic membrane transplant (AMT) used as an alternative to conjunctival closure. Accepted for publication Jul 2, 2005. From Moorfields Eye Hospital, London, United Kingdom (P.R., R.L.-P., K.B.); and Universidade de São Paulo, São Paulo, Brazil (R.L.-P.). Inquiries to Keith Barton, MD, FRCP, FRCS, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, United Kingdom; fax: ⫹44 207 566 2972; e-mail:
[email protected] OF
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FIGURE. Surgical technique of repairing exposed glaucoma drainage device using donor sclera covered with amniotic membrane as an alternative to conjunctiva. Conjunctiva overlying exposed tube (a) is reflected (b) to provide adequate exposure. Donor scleral patch is applied over exposed portion of the tube (c) and then covered with amniotic membrane transplant (d), which is sutured under surrounding conjunctival edge to provide overlap (e). Patient 1: (f) preoperative state, (g) day 1 after surgery showing avascular amniotic membrane. (h through j) Progressive integration of amniotic membrane on top of donor sclera 3 weeks, 5 weeks, and 11 months after surgery.
VOL. 0, NO. 0
BRIEF REPORTS
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FIGURE. Continued
VOL. 140, NO. 6 TABLE. Summary of Clinical Course of Nine Cases of Exposed Glaucoma Drainage Devices Repaired Using Amniotic Membrane Transplantation as an Alternative to Conjunctival Advancement Over Donor Sclera
BRIEF REPORTS
Preop VA
VA at Follow-up
Preop IOP
IOP at Follow-up
Length of Follow-up (mo)
6
N/A
6/24
N/A
15
63
Uveitis, anterior chamber IOL
Host flap
1
HM
HM
8
20
57
MMC
Host flap
23
6/9
6/9
17
10
48
Molteno (SP)
MMC
Host flap
21
HM
PL
12
16
43
43
Baerveldt 350
Nil
Donor
CF
NLP
8
2
41 from first repair
F
39
Molteno (SP)
Nil
Donor
6/12
6/12
0
14
7
F
17
Molteno (SP)
MMC
Donor
1st 11⁄2 2nd 8 3rd 17 4th 11 1st 2 2nd 11 10
Postpolymorphous dystrophy, chronic angle closure Uveitis, prior vitrectomy/delamination Prior silicone oil (after removal) and penetrating keratoplasty Uveitis with retinal vasculitis
HM
CF
5
20
8
M
60
Molteno (DP)
Nil
Host flap
PL
PL
4
6
9
M
45
Baerveldt 350
MMC
Donor
1st 39 mo 2nd 99 mo 6
29 from first repair 25 after repair 16
6/60
HM
2
28
12
Patient
Sex
Age (y)
Tube Type
Antimetabolite
Donor Slcera
1
M
71
MMC
None
2
M
40
Molteno (SP) (pars plana insertion) Molteno (SP)
MMC
3
F
45
Molteno (SP)
4
M
78
5
M
6
Tube Erosion (mo)
Comment
Marfan syndrome, aphakic Uveitis, aphakic Penetrating trauma, aphakic Uveitis, aphakic
SP ⫽ single plate; DP ⫽ double plate; MMC ⫽ mitomycin C; IOL ⫽ intraocular lens transplant; VA ⫽ visual acuity; y ⫽ years; mo ⫽ months; N/A ⫽ not applicable.
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Ten consecutive GDD exposures were repaired by one surgeon (K.B.) during a 5-year period. Nine were repaired by using donor sclera and AMT. The tenth had freely mobile conjunctiva, and AMT was not used. The nine cases repaired using AMT are reported here. A successful repair was defined as 12 months’ follow-up from the date of first repair without reexposure. In each case, conjunctiva was reflected around the exposure site. After examination for leakage, the exposed GDD tube, if loose, was secured to sclera with 9-0 Prolene sutures and covered with full-thickness donor sclera secured with interrupted 10-0 nylon. Surrounding conjunctival edges were undermined and AMT edges sutured under adjacent conjunctiva with a locked continuous 10-0 Vicryl or in a groove under adjacent limbus with buried 10-0 nylon sutures (Figure). Donor sclera was obtained from Moorfields Eye Hospital Eye Bank, stored in 70% ethanol, soaked overnight in normal saline, transferred to framycetin sulfate 0.5% for 2 hours, and rinsed in normal saline just before use. AMT was supplied from the North London Tissue Bank after harvesting according to a standard protocol.4 Institutional review board approval was not required because AMT and sclera were in routine clinical use and patients were not randomized. Data accumulation was performed in conformity with the laws of the United Kingdom and the tenets of the Declaration of Helsinki. The technique described was successful in repairing seven of nine cases of GDD exposure after a mean of 42 months’ (range 12 to 63 months) follow-up. Individual cases are detailed in the Table. In four cases, AMT was used because of recurrent erosion despite conventional repair. In five cases, conventional closure was not attempted because excessive scarring restricted conjunctival mobilization. AMT acts as a scaffold for regrowth of conjunctival epithelium5 and after a period of time appears indistinguishable from other conjunctiva that has undergone surgery. Initially promising potential in an animal model of filtration surgery6 was not fulfilled when repair of leaking trabeculectomy blebs was attempted in humans.7 Persistent avascularity of AMT filtration blebs was noted in the above study,7 and this feature has differentiated AMT filtering blebs from AMT transplanted for other conjunctival conditions. In the current study, persistent avascularity was observed only in patient 6, one of two patients in whom repair was unsuccessful; this was the only case in which AMT formed part of an inadvertent filtering bleb. In patient 5, the other patient who failed to respond, the implant eroded rapidly, possibly because of active ocular inflammation (retinal vasculitis and aggressive neovascularization), although anterior migration of the plate was also noted later, after several retinal surgical procedures. Correction of the cause of erosion was also important for a successful repair. In patients 1 and 7, mobile tubes were 1152
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secured tightly to sclera. In patients 2 and 9, a tube ligature positioned so that the knot abraded overlying conjunctiva was replaced. In patient 6, a knot eroded directly through donor sclera in combination with a leak from the GDD plate that was positioned too close to limbus. In this case, the GDD was replaced in addition to the repair. This series suggests that AMT may be used satisfactorily to cover donor sclera in eyes with an extruding GDD where extensive scarring or conjunctival shortening hampers closure, if the causative mechanisms of tube erosion can be corrected. REFERENCES
1. Lotufo DG. Postoperative complications and visual loss following Molteno implantation. Ophthalmic Surg 1991; 22:650 – 656. 2. Melamed S, Cahane M, Gutman I, Blumenthal M. Postoperative complications after Molteno implant surgery. Am J Ophthalmol 1991;111:319 –322. 3. Gedde SJ, Scott IU, Tabandeh H, et al. Late endophthalmitis associated with glaucoma drainage implants. Ophthalmology 2001;108:1323–1327. 4. Prabhasawat P, Barton K, Burkett G, Tseng SC. Comparison of conjunctival autografts and amniotic membrane grafts for pterygium excision. Ophthalmology 1997;104:974 –985. 5. Kim JC, Tseng SC. Transplantation of preserved human amniotic membrane for surface reconstruction in severely damaged rabbit corneas. Cornea 1995;14:473– 484. 6. Barton K, Budenz DL, Khaw PT, Tseng SC. Glaucoma filtration surgery using amniotic membrane transplantation. Invest Ophthalmol Vis Sci 2001;42:1762–1768. 7. Budenz DL, Barton K, Tseng SC. Amniotic membrane transplantation for repair of leaking glaucoma filtering blebs. Am J Ophthalmol 2000;130:580 –588.
Histopathologic Examination of Conjunctival Tophi in Gouty Arthritis Wayne R. Lo, MD, Geoffrey Broocker, MD, and Hans E. Grossniklaus, MD To report a case of conjunctival tophi in a 59-year-old woman with gouty arthritis. DESIGN: Observational case report. METHODS: A 59-year-old woman with a 25-year history of severe gouty arthritis presented with bilateral chalky white conjunctival deposits. Conjunctival biopsies were PURPOSE:
Accepted for publication Jul 2, 2005. From the Departments of Ophthalmology (W.R.L., G.B., H.E.G.) and Pathology (H.E.G.), Emory University School of Medicine, Atlanta, Georgia. Inquiries to Hans E. Grossniklaus, MD, L.F. Montgomery Ophthalmic Pathology Laboratory, BT 428 Emory Eye Center, 1365B Clifton Road NE, Atlanta, GA 30322; phone: (404) 778-4611 fax: (404) 778-5089; e-mail:
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DECEMBER 2005