Molteno Implantation for Glaucoma in Young Patients - ScienceDirect

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Glaucoma in Young Patients. RICHARD A. HILL, MD,l DALE K. HEUER, MD,2 GEORGE BAERVELDT, MD,2. DON S. MINCKLER, MD,2 JAMES F. MARTONE, ...
Molteno Implantation for Glaucoma in Young Patients RICHARD A. HILL, MD, l DALE K. HEUER, MD, 2 GEORGE BAERVELDT, MD, 2 DON S. MINCKLER, MD,2 JAMES F. MARTONE, MD, MPH2

Abstract: Seventy patients younger than 21 years of age underwent Molteno implantation for nonneovascular glaucoma. Fifty-three (76%) patients had failed angle and/or conventional filtering surgery. Final intraocular pressure less than 22 mmHg (but over 5 mmHg) was achieved in 40 (62%) of the 65 patients with at least 6-month follow-up (range, 6 to 59 months; mean ± standard deviation, 22.7 ± 14.1 months); however, only 22 (34%) were controlled after the initial Molteno implantation procedure, and 54 (83%) patients underwent further glaucoma and/or nonglaucoma surgical procedures. The visual acuities remained within one line of their preoperative levels or improved in 25 (68%) of the 37 patients on whom Snellen acuities were available. The most frequent complicationsinciuded: tube-cornea touch (20%, transient in 3%), corneal edema (17%), retinal detachment (16%), tube block (10%), cataract (9%), chronic hypotony or phthisis (9%), pupillary or cyciitic membrane (9%), hyphema (7%), flat anterior chamber (6%), and large postoperative choroidal effusion (6%). Despite the high rates of subsequent surgical interventions and complications, Molteno implantation has been a useful approach for achieving intraocular pressure reduction in young patients with glaucoma. Ophthalmology 1991; 98:1042-1046

The surgical management of glaucoma in young patients, in whom goniotomy and/or trabeculotomy either has been unsuccessful or is not appropriate, is particularly Originally received: October 28, 1990. Revision accepted: March 25, 1991. Department of Ophthalmology, University of California at Irvine College of Medicine, Irvine. 2 Department of Ophthalmology, University of Southern California School of Medicine and the Doheny Eye Institute, Los Angeles. 1

Presented in part at the American Academy of Ophthalmology Annual Meeting, Atlanta, Oct/Nov 1990. Supported in part by the Foundation for Glaucoma Research, San Fran· cisco, California; National Glaucoma Research, a program of the American Health Assistance Foundation, Beltsville, Maryland; and Research to Prevent Blindness, Inc., New York, New York. The authors have neither any commercial or proprietary interest in, nor any financial interest (as consultant, reviewer, or evaluator) in Molteno implants. Furthermore, neither the authors' spouses, minor children, or blood relatives living in their households have any financial interest in, nor are the authors aware of any financial interest held by their employers, partners, or business associates in Molteno implants. Reprint requests to Richard A. Hill, MD, Department of Ophthalmology, Medical Plaza, University of California, Irvine, CA 92717.

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problematic. Filtering surgery on young patients is infrequently successful l - 3 ; however, one recent report is somewhat encouraging. 4 Furthermore, although postoperative subconjunctival 5-fluorouracil injections increase the success rate of filtering surgery in other poor prognosis patients, 5 its administration in many young patients may not be practical. Cyclodestructive procedures, such as transscleral laser cyclophotocoagulation6- 8 and cyclocryotherapy,9 are also options for intraocular pressure (lOP) control, but visual loss and other complications are frequent. Prompted by the more widespread application of glaucoma shunting devices for complicated glaucoma and by the favorable results with such devices for glaucoma in young patients,IO,11 we re-examined our experience with Molteno implantation for glaucoma in young patients.

MATERIALS AND METHODS The Estelle Doheny Eye Hospital operating room logs from May 1984 through March 1990 were reviewed to compile a list of all Molteno implantation procedures performed for nonneovascular glaucoma in patients

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Table 1. Preoperative Data Summary (65 Patients') Age range (mean ± SD) Race Asian Black White Hispanic Non-Hispanic Number of failed filtering procedures Number of failed glaucoma procedures Diagnoses Phakic Infantile glaucoma Glaucoma associated with Sturge-Weber syndrome Glaucoma associated with neurofibromatosis Glaucoma associated with Crouzon's syndrome (hydrocephalus) Glaucoma associated with aniridia Glaucoma associated with juvenile rheumatoid arthritis Glaucoma associated with oculodental digital dysplasia Glaucoma associated with Peter's anomaly Juvenile glaucoma Glaucoma associated with multiple iris vessels Aphakic Glaucoma following congenital cataract extraction Glaucoma associated with rubella Glaucoma following trauma Infantile glaucoma Glaucoma associated with aniridia Glaucoma associated with juvenile rheumatoid arthritis Glaucoma associated with persistent hyperplastic primary vitreous Glaucoma associated with Peter's anomaly Glaucoma associated with Lowe's syndrome

0-20 (9.1 ± 6.5) years 5 (8%) 6 (9%) 54 (83%) 25 (38%) 29 (45%) 0-6 (0.8 ± 1.1) 0-13 (1.8 ± 2.5) 26t (40%) 14 (22%) 3 (5%) 2 (3%) (2%) (2%) (2%) (2%) (2%) (2%) 1 (2%) 39 (60%) 14 9 6 3 2

(22%) (14%) (9%) (5%) (3%)

2 (3%) (2%) (2%) (2%)

SD = standard deviation. * Data from five additional patients (one aphakic) with less than 6-month followup have not been included. t Three of those patients who were phakic before Molteno implantation underwent pars plana lensectomyIvitrectomy either in combination with Molteno implantation (one patient each with glaucoma associated with Peter's anomaly and with glaucoma associated with juvenile rheumatoid arthritis) or after Molteno implantation (one patient with infantile glaucoma).

younger than 21 years of age. All patients (or more frequently their parents) gave informed consent. The study protocol and informed consent form for Molteno implantation in patients with glaucoma with poor surgical prognoses were approved by the Los Angeles County/ University of Southern California Medical Center Institutional Review Board (research protocol #03133). In the patients on whom bilateral Molteno implantations were performed, the first eyes to undergo. Molteno implantation were considered the study eyes. Before reviewing the data, the following outcome criteria were adopted: at least 6-months follow-up; complete success equals lOP of 21 mmHg or less without antiglaucoma medication; qualified success equals lOP of 21 mmHg or less with antiglaucoma medication(s); failure equals lOP greater than 21 mmHg, chronic hypotony (lOP < 6

mmHg), loss of light perception, or other visually devastating complications. A description of the surgical technique and postoperative medications has been published elsewhere. 11 All procedures were performed by four of the authors (DKH, GB, DSM, JFM) or glaucoma fellows under their direct supervision. To reduce the risk of profound postoperative hypotony in one-stage installations, absorbable ligatures (plain catgut, rapid absorbing plain catgut, chromic, or polyglactin) were placed around the tubes posterior to the scleral grafts; tube closures after ligature placements were verified either visually or with attempted irrigation ofbalanced salt solution. The postoperative adjunctive systemic antifibrosis medications that have been advocated by Molteno and co-workers lO were not used in these patients. Some variation existed in the choice of sutures and needles that were used to secure the Molteno plates to the sclera, but in most cases 5-0 polyester fiber sutures were used on either S-14 or RD-l needles. In cases of severe scleral thinning, the Molteno plates were secured to the adjacent rectus muscles with either 6-0 polyglactin sutures or 5-0 polyester fiber sutures. Interrupted 6-0 black silk sutures on S-14 needles were passed through the episclera to mark the silicone tubes during the first stage of two-stage Molteno implantations.

RESULTS Seventy patients were reviewed; five patients with less than 6 months of follow-up have been included only in the analysis of complications (two additional patients with neovascular glaucoma were excluded from this study). Twenty-one of the patients had been included in a pre- . vious review of single-plate Molteno implantation for complicated glaucoma. 11 The patient demographic data are summarized in Table 1. Successful control ofIOP was achieved in 40 (62%) of the 65 patients on whom at least 6 months of follow-up were available (Table 2): 11 (17%) were categorized as complete successes; 29 (45%) were categorized as qualified successes; and the remaining 25 (38%) were categorized as failures. The period of follow-up on the successful patients ranged from 6 to 59 months (mean ± standard deviation, 22.7 ± 14.1). The visual acuities remained within one line of their preoperative levels or improved in 25 (68%) of the 37 patients on whom Snellen acuities were available both preoperatively and postoperatively (Table 2). Table 3 summarizes the complications on all 70 patients. To facilitate discussion we have categorized the complications as those possibly related to the Molteno tube, those attributable to the Molteno plate and/or scleral graft, or other complications.

DISCUSSION Molteno implantation successfully controlled lOP in 40 (62%) of our 65 young patients with complicated glau1043

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Table 2. Outcome Data Summary (65 Patients*) Surgical outcome Success Complete successt Qualified successt Failure Failure because of IOP§ Failure because of severe complications Follow-up range (mean ± SD; failures excluded) Visual outcome I Better Same Worse

40 (62%) 11 (17%) 29 (45%) 25 (38%) 13 (20%) 12 (18%) 6-59 (22.7 ± 14.1) months 5 (14%) 20 (54%) 12 (32%)

lOP = intraocular pressure; SD = standard deviation. * Data from five additional patients with less than 6-month follow-up have not been included; two of those patients were lost to further follow-up within 1 month of surgery; the remaining three were lost to further follow-up 5 months postoperatively when they would have otherwise have been classified as either complete (one patient) or qualified (two patients) successes. t Two patients with single plates, five with double plates, and four with two single plates; nine patients aphakic. t Twelve patients with single plates, 3 with double plates, 12 with two single plates, 1 with three plates, and 1 with four plates; 18 patients aphakic. § Four patients with single plates, eight with two single plates, and one with four plates; one patient with one single plate has undergone installation of additional singl@ plate implant, and one with two single plates has undergone installation of additional double plate implant, follow-up on both is less than 6 months. I Both preoperative and postoperative Snellen acuity unavailable on 29 patients; better = postoperative visual acuity at least two lines better than preoperative visual acuity; same = postoperative visual acuity within one line of preoperative visual acuity; worse = postoperative visual acuity at least two lines worse than preoperative visual acuity.

coma on whom at least 6 months offollow-up were available. However, only 22 (34%) patients were controlled with the initial Molteno implantation procedure; 34 (79%) of the remaining 43 patients underwent installation of additional plates. Furthermore, only 11 (17%) of 65 patients underwent one surgical procedure. Those subsequent operations, which were frequently (but not always) related to the Molteno implants, included anterior chamber reformation, corneal transplantation, operative wound revision, plate and/or tube repositioning or removal, retinal detachment repair, and surgical tube ligature release. Although some of the complications that prompted additional surgery were clearly attributable to Molteno implantation, many were consistent with the anticipated increased ocular morbidity of our patients' underlying ocular problems as well as their multiple previous surgical interventions. The incidences of tube block, tube-cornea or tube-iris touch, tube retraction, and hyphema may be minimized with careful insertion. The drainage tube should ideally be positioned just anterior to and parallel to the iris. The full-thickness scleral tract should be created with the anterior chamber at approximately physiologic depth. Intraoperative alteration of normal physiologic anterior chamber relationships (shallowing of the anterior chamber after creation of a paracentesis tract or overdeepening of the anterior chamber with viscoelastics) may result in a malpositioned tube postoperatively. To minimize the risk of tube block by iris or vitreous, the tube should be beveled 1044



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Table 3. Complications (70 Patients*) Complications Possibly tube related Tube-cornea touch Corneal edema Tube block Hyphema Band keratopathy Tube retraction Transcorneal tube erosion Plate or scleral graft related I Plate extrusion Superior corneal epithelial defects Other Retinal detachment Elevated lOP for which surgical tube ligature release performed Cataract Chronic hypotony/phthisis Pupillary /cyclitic membrane Flat anterior chamber (Seidel negative) Large postoperative choroidal effusion Conjunctival wound dehiscence Intraoperative choroidal hemorrhage Postoperative choroidal hemorrhage Uveitis Vitreous hemorrhage Conjunctival wound infection Endophthalmitis Fibrous ingrowth I I Scleral perforation

14t 12 7t 5§ 3

3

2

(20%) (17%) (10%) (7%) (4%) (4%) (3%) (1%) (1%)

11** (16%) 8

(11%)

6tt (9%)

6H(9%) (9%) (6%) (6%) (3%) 2 (3%) 2§§ (3%) 2 (3%) 2 (3%) 1 (1%) 1 (1%) 1 (1%) 1 (1%)

6 4 4 2

lOP = intraocular pressure. * Includes five patients with less than 6-month follow-up; two of those patients were lost to further follow-up within 1 month of surgery; the remaining three were lost to further follow-up 5 months postoperatively. t Transient only in two patients; seven patients underwent surgical procedures for repOSitioning of the tube (five complicated by corneal edema); remaining five patients did not undergo surgical tube repositioning procedure (two complicated by corneal edema; one complicated by band keratopathy with corneal edema). t Two with vitreous-tube block; two with iris-tube block; one with retrocorneal fibrous memrane-tube block; one with interplate tube block between proximal and distal plates of double plate implant; and one with pupillary /cyclitic membranetube block. § One with corneal blood staining. I One patient's nonstudy eye had recurrent scleritis and subsequently suffered plate extrusion, retinal detachment, and phthisis; one other patient's nonstudy eye also suffered plate extrusion. ** Ten in aphakic eyes; one in phakic eye; two additional patients also suffered retinal detachments as sequelae of choroidal hemorrhages. tt Represents 26% incidence of cataract among 23 patients phakic after initial Molteno implantation procedure. H Developed after retinal detachments in four patients and after endophthalmitis in one patient; remaining one patient had previously undergone cyclocryotherapy; one eye subsequently enucleated. §§ Both eyes subsequently developed retinal detachments; one eye ultimately enucleated. 1111 Presumably occurred through incompletely closed scleral tract left after tube removed during complicated retinal detachment repair.

toward the cornea. Careful scrutiny for any vitreous present in the anterior chamber (or scleral depression for a tube placed through the pars plana) will decrease the risk of vitreous tube block postoperatively; however, this complication may still occur many months after surgery at the time of a posterior vitreous detachment. Tube retraction may be minimized by allowing an extra 1 to 2 mm of tube in the eye to compensate for subsequent growth or eye wall stretching in very young patients. Hy-

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phema is most likely to occur if the full-thickness scleral tract is made too posteriorly (penetrating the ciliary body) or with insertion of the Molteno tube through a peripheral anterior synechia resulting in an iris tear. Transcorneal tube erosion occurred in two patients. Emergent penetrating keratoplasties were performed when, although Seidel negative, the tubes were observed on the corneal epithelial surface. Two hypotheses for those occurrences have been suggested: the tubes, possibly related to episcleral scarring and traction on the tube and/ or scleral remodeling around the tube, have been observed to move progressively anteriorly in young patients even after the initial 3 to 6 months after surgery during which the tube's position typically stabilizes in adults. Additionally, the scleral grafts placed over the tube may create dellen, which might predispose to progressive corneal thinning (and eventual perforation) overlying the tubes; however, a corneal dellen was not observed in either of the two patients in whom transcorneal tube erosion occurred. Bilateral superior corneal epithelial defects developed in one child, which resolved with lubrication. Molteno plate extrusion was observed in one patient (and in two other patients' nonstudy eyes). We attribute the relatively infrequent occurrence of this complication to posterior placement of the plates (ideally 8 to 10 mm in the upper nasal quadrant and 10 to 12 mm in the upper temporal quadrant). Separate closure of Tenon's capsule and conjunctiva during the Molteno implantations are preferred for limbus-based conjunctival flaps. Of the complications not necessarily attributable to the Molteno tubes or plates, retinal detachments have been the most frequent, with 11 (16%) patients suffering rhegmatogenous or traction retinal detachments not related to choroidal hemorrhages (retinal detachments developed in two additional patients after postoperative massive suprachoroidal hemorrhages). Retinal detachments are a frequent (sometimes late) complication for patients who have undergone surgery for congenital cataracts I 1-15; consequently, it is not surprising that 10 of those 11 patients in whom retinal detachments developed were aphakic. The incidence of retinal detachment among the 43 patients who were aphakic before or immediately after their initial Molteno implantation procedure was 23%. Scleral perforation during Molteno implantation has been infrequent. However, studies on retinal detachment after strabismus surgery I 6-20 indicate that the incidence of scleral perforation during strabismus surgery is generally underestimated by clinicians. The incidence of postoperative retinal detachment in such cases of scleral perforation is also much lower than would be expected. Scleral perforation was noted in one patient during the first stage of a two-stage Molteno implantation (which was performed during a posterior lip ' sclerectomy, anterior vitrectomy, and intraocular lens implant removal). The site of the scleral perforation was treated with prophylactic retinal cryopexy. This patient's postoperative course was complicated by a retinal detachment. The retinal detachment that subsequently developed was caused by a giant retinal tear unrelated to the site of scleral perforation. The vitreoretinal surgeons who performed the retinal detach-

ment repair procedures on our patients believed that the retinal detachments had been caused by formed vitreous traction with subsequent hole formation and/or proliferative vitreoretinopathy, and their operative reports included no mention of ocular perforation or linear chorioretinal scars. Nonetheless, to reduce the risk of scleral perforation, scleral fixation sutures are placed with spatula needles, especially in myopic and/or buphthalmic eyes with thin sclera; in patients with marked scleral thinning, plates should be sutured to the adjacent rectus muscles, rather than the underlying sclera itself. We are also evaluating smaller needles (such as the S-24 needle on 5-0 polyester fiber suture material and the S-29 needle on 6o polyester fiber suture material) to secure the Molteno explant to the sclera, and additional needles (such as the TG 140-8 needle on 6-0 black silk suture material) to mark the Molteno tube during the first stage of two-stage installations. The 26% incidence of postoperative cataracts among the 23 phakic patients possibly reflects the transient hypotony that commonly occurs after initiation of flow through the Molteno system and/or the frequent need for additional surgical interventions. Of the six patients who developed cataracts, two were noted to have had flat anterior chambers (corneal/lenticular or drainage tube touch) postoperatively requiring reformation and another (who developed a posterior subcapsular cataract) had underlying uveitis. Furthermore, the six patients who developed cataracts had undergone 1 to 5 (mean ± standard deviation, 2.8 ± 1.7) additional procedures after their initial Molteno implantation, compared with 0 to 5 (mean ± standard deviation, 1.6 ± 1.6) additional procedures among the 17 patients who were not noted to have developed cataracts. Chronic hypotony or phthisis (9%) and pupillary or cyclitic membrane formation (9%) occurred more frequently than expected; nonetheless, these incidences were believed to reflect the ocular morbidity of our patients' underlying ocular problems and their multiple previous and/or subsequent surgical interventions (Table 3). Flat anterior chambers (corneal lenticular touch) were noted in four patients (6%); however, given the difficulty in examining many young patients postoperatively, the actual incidence of flat anterior chambers may have been higher. Major contributing factors may have been low scleral rigidity in buphthalmic eyes or in eyes that have had extensive anterior vitrectomies. The authors frequently fill anterior chambers (as well as posterior chambers in aphakic eyes) with viscoelastic agents during twostage procedures to minimize hypotony, and thus reduce the risk of flat anterior chambers, serous choroidal detachments, and choroidal hemorrhages. Our 62% success rate with Molteno implantation for glaucoma in this series of young patients is only slightly better than the 54% success rate with single-plate Molteno implantation in our initial report that was limited to patients younger than 13 years of age. II The only minimal improvement in outcome despite frequent installation of mUltiple plates may be attributable to earlier use and broader application of this approach to complicated glau1045

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comas in young patients. Our results are also substantially less favorable than Molteno and co-workers'lO 95% success rate in juvenile glaucoma, possibly reflecting differences in our patient populations and/or the potentially beneficial effects of their antifibrosis regimen, 12 which we have been reluctant to use because of concern about systemic toxic effects. Nonetheless, Molteno implantation appears to be a viable option for the management of complicated glaucoma in young patients, especially since all other surgical modalities also afford equivocal success rates and substantial complications of their own. Based on the frequent need for additional plates in this study, as well as preliminary results of a prospective, randomized clinical trial of single- versus double-plate Molteno implantation,21 the authors now prefer a primary double-plate Molteno implantation whenever technically feasible. Clinical judgment should be used in patients with chronic uveitis, previous cyclodestructive procedures, or ischemic vascular disease. It is also our impression that two-stage installations have fewer postoperative complications. The single-plate Molteno implant was among the first generation of useful devices for the drainage of aqueous. Apparently desirable modifications of current artificial drainage devices include optimizing the implant material or the filtering areas for specific patients; temporary plugs or valves to limit aqueous flow through the tube in the early postoperative period, thereby reducing the risk of hypotony and its sequelae; and delivery of relatively nontoxic agents, which could be delivered locally (or ideally be incorporated in the drainage devices themselves) to improve the ultimate permeability of the bleb capsules surrounding the drainage devices. With continued evolution, artificial drainage devices should become an even more valuable part of our armamentarium for the management of patients with glaucoma with poor surgical prognoses.

REFERENCES 1. Beauchamp GR, Parks MM. Filtering surgery in children: barriers to success. Ophthalmology 1979; 86: 170-80.

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2. Gressel MG, Heuer DK, Parrish RK II. Trabeculectomy in young patients. Ophthalmology 1984; 91: 1242-6. 3. Veldman E, Greve EL. Glaucoma filtering surgery, a retrospective study of 300 operations. Doc Ophthalmol1987; 67:151-70. 4. Burke JP, Bowell R. Primary trabeculectomy in congenital glaucoma. Br J Ophthalmol1989; 73:186-90. 5. The Fluorouracil Filtering Surgery Study Group. Fluorouracil filtering surgery study one-year fOllow-up. Am J Ophthalmol1989; 108:62535. 6. Klapper RM, Wandel T, Donnenfeld E, Perry HD. Transscleral neodymium:YAG thermal cyclophotocoagulation in refractory glaucoma: a preliminary report. Ophthalmology 1988; 95:719-22. 7. Trope GE, Ma S. Mid-term effects of Neodymium:YAG transscleral cyclocoagulation in glaucoma. Ophthalmology 1990; 97:73-5. 8. Hampton C, Shields MB, Miller KN, Blasini M. Evaluation of a protocol for transscleral neodymium:YAG cyclophotocoagulation in one hundred patients. Ophthalmology 1990; 97:910-17. 9. Aminlari A. Cyclocryotherapy in congenital glaucoma. Glaucoma 1981; 1:331. 10. Molteno ACB, Straughan JL, Ancker E. Control of bleb fibrosis after glaucoma surgery by anti-inflammatory agents. S Afr Med J 1976; 50:881-5. 11. Falls HF. Developmental cataracts: results of surgical treatment in one hundred and thirty-one cases. Arch Ophthalmol1943; 29:210-23. 12. Knapp A. Operative prognosis of congenital cataract. Arch Ophthalmol 1944; 32:519. 13. Cordes FC. Retinal detachment following congenital cataract surgery: a study of 112 enucleated eyes. Am J Ophthalmol1960; 50:716-29. 14. Kanski JJ, Elkington AR, Daniel R. Retinal detachment after congenital cataract surgery. Br J Ophthalmol1974; 58:92-5. 15. Toyofuku H, Hirose T, Schepens CL. Retinal detachment following congenital cataract surgery. I. Preoperative findings in 114 eyes. Arch Ophthalmol1980; 98:669-75. 16. Wagner RS, Nelson LB. Complications following strabismus surgery. Int Ophthalmol Clin 1985; 25(4):171-8. 17. McLean JM, Galin MA, Baras I. Retinal perforation during strabismus surgery. Am J Ophthalmol1960; 50:1167-9. 18. Havener WH, Kimball OP. Scleral perforation during strabismus surgery. Am J Ophthalmol1960; 50:807-8. 19. Gottlieb F, Castro JL. Perforation of the globe during strabismus surgery. Arch Ophthalmol1970; 84:151-7. 20. Basmadjian G, Labelle P, Dumas J. Retinal detachment after strabismus surgery. Am J Ophthalmol1975; 79:305-9. 21. Heuer DK, Lloyd MA, Abrams DA, et al. Preliminary report of a randomized clinical trial of single plate versus double plate Molteno implantation for glaucomas in aphakia and pseudophakia. In: Krieglstein GK, ed. Glaucoma Update IV. Berlin: Springer-Verlag, 1991; 244-9.