Combined phacoemulsification, intraocular lens implantation, and vitrectomy for eyes with coexisting cataract and vitreoretinal pathology

Combined Phacoemulsification, Intraocular Lens Implantation, and Vitrectomy for Eyes With Coexisting Cataract and Vitreoretinal Pathology ANNA-MARIA DEMETRIADES, MD, JOHN D. GOTTSCH, MD, ROBERT THOMSEN, MD, AMR AZAB, MD, WALTER J. STARK, MD, PETER A. CAMPOCHIARO, MD, EUGENE DE JUAN, JR., MD, AND JULIA A. HALLER, MD

● PURPOSE:

To report the preoperative, intraoperative, and postoperative outcomes of combining phacoemulsification and posterior chamber intraocular lens (IOL) implantation with pars plana vitrectomy in eyes with significant cataract and coexisting vitreoretinal pathology. ● DESIGN: Retrospective, consecutive, interventional case series. ● METHODS: Charts of patients undergoing combined procedures at the Wilmer Ophthalmologic Institute between March 1995 and May 2000 were reviewed. ● RESULTS: In all, 122 eyes of 111 patients were identified. Patient ages ranged from 27 to 89 years (mean 65). Forty-three eyes had diabetic retinopathy; 11 had undergone vitrectomy previously. Macular pathology (hole, membrane, choridal neovascularization) was present in 69 eyes. The most common indications for surgery were diabetic vitreous hemorrhage, macular hole, epiretinal membrane, and retinal detachment. In all cases, phacoemulsification and IOL implantation were performed before vitreoretinal surgery. Preoperative vision ranged from 20/30 to light perception and postoperative vision ranged from 20/20 to no light perception. In 105 patients vision improved, in 7 there was no change, and in 10 vision decreased. Postoperative complications included opacification of the posterior capsule, increased intraocular pressure, corneal epithelial defects, vitreous hemorrhage, retinal detachment and iris capture by the IOL. ● CONCLUSIONS: Combined surgery is a reasonable alternative in selected patients. Techniques that may simAccepted for publication Oct 1, 2002. InternetAdvance publication at ajo.com Oct 7, 2002. From the Wilmer Ophthalmological Institute, The Johns Hopkins Medical Institutions, Baltimore, Maryland. Inquiries to Julia A. Haller, MD, Maumenee 740, Wilmer Eye Institute, The Johns Hopkins Medical Institutions, 600 N. Wolfe St, Baltimore, MD 21287-9353; fax: (410) 614-7632; e-mail: [email protected] 0002-9394/03/$30.00 PII S0002-9394(02)01972-4

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plify surgery and reduce complications include: careful, limited, curvilinear capsulorhexis; in-the-bag placement of IOLs; use of IOLs with larger optics; suturing of cataract wounds before vitrectomy; use of miotics and avoidance of long-acting dilating drops in patients with intravitreal gas; and use of wide-field viewing systems. (Am J Ophthalmol 2003;135:291–296. © 2003 by Elsevier Science Inc. All rights reserved.)

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ATIENTS WITH VITREORETINAL DISEASE REQUIRING

surgical intervention frequently have coexisting lens opacification. Cataracts increase in prevalence with age, as do vitreoretinal pathologies such as macular holes, epiretinal membranes, and retinal detachments. Diabetes is another contributing factor that results in the development of both retinal disease and cataracts. In addition, vitrectomy itself causes cataracts to progress.1 Thus, phakic eyes requiring vitreoretinal surgery may be candidates for concurrent cataract removal, both to maximize surgical visualization of the retina and to avoid the need for the patient to undergo a second procedure for cataract extraction soon after vitreoretinal surgery. Combining phacoemulsification and intraocular lens (IOL) implantation with pars plana vitrectomy in eyes with significant cataract and coexisting vitreoretinal pathology is becoming increasingly common. Several studies have reported the authors’ experience with combined surgery using a variety of techniques.2–17 In this study, we review our experience with a large series of combined cases and compare the results with previous reports. This study includes a comparatively large number of macular surgery cases, which in general have better visual potential and thus perhaps more reason to consider a combined procedure initially to allow maximum visual rehabilitation.

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RIGHTS RESERVED.

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DESIGN

TABLE 1. Indications for Vitreoretinal Surgery

THIS STUDY WAS A RETROSPECTIVE, CONSECUTIVE INTER-

ventional case series of patients who underwent vitreoretinal surgery at the same time as phacoemulsification and IOL implantation.

METHODS THE CLINIC CHARTS AND OPERATIVE REPORTS FROM CASES

performed by three vitreoretinal surgeons between March 1995 and May 2000 at the Wilmer Ophthalmological Institute were retrospectively reviewed to identify patients who had undergone combined procedures. We identified 122 eyes of 111 patients who underwent combined phacoemulsification, IOL implantation, and vitreoretinal surgery during the study period. Patients with less than 6 weeks’ follow-up were excluded. The preoperative clinical data obtained for each patient included age, sex, preoperative visual acuity, type and extent of cataract, vitreoretinal disease, and previous laser or intraocular surgeries. Intraoperative data included type of IOL, surgical incision site; vitreoretinal procedure performed, and intraoperative complications. The postoperative data obtained included visual acuity with postoperative refraction, length of follow-up, postoperative complications, and subsequent surgical procedures (for example, vitreoretinal reoperation, neodymium:yttrium-aluminum-garnet [YAG] laser capsulotomy).

WE IDENTIFIED 122 EYES OF 111 PATIENTS (71 FEMALE) WHO

fit study criteria. The mean age was 65 years (range, 27 to 89 years). All eyes in the study had cataracts. Diabetic retinopathy was present in 43 eyes. Eleven eyes had undergone previous vitrectomy. Follow-up ranged from 6 weeks to 42 months (mean, 9 months). The indications for vitreoretinal surgery are summarized in Table 1. The most common indications for surgery were diabetic vitreous hemorrhage (34 eyes; 28%), macular hole (33 eyes; 27%), and epiretinal membrane (33 eyes; 27%). A total of 69 eyes (56.4%) had vitreoretinal surgery for macular disease, including 33 eyes with macular hole, 33 eyes with epiretinal membrane, 2 eyes with vitreomacular traction, and 1 eye with subfoveal choroidal neovascularization. Of the 33 cases with macular hole, 6 were reoperations for persistent or recurrent holes. In the 7 eyes (5.7%) with nondiabetic vitreous hemorrhage, 2 were associated with uveitis, 2 with trauma, 1 with central retinal vein occlusion, 1 with neovascular age-related macular degeneration, and 1 with radiation retinopathy. Retinal detachment was present in 2 eyes (1.6%) of which 1 had a macular hole and myopia and the other had AMERICAN JOURNAL

No. of Eyes

% Total

Diabetic vitreous hemorrhage Macular hole Epiretinal membrane Traction retinal detachment Nondiabetic vitreous hemorrhage Vitreous opacities Retinal detachment Vitreomacular traction Subfoveal choroidal neovascularization Total

34 33 33 8 7 2 2 2 1 122

28 27 27 6.7 5.7 1.6 1.6 1.6 0.8 100

proliferative vitreoretinopathy. Of the 2 eyes with vitreous opacities, 1 had large cell lymphoma. The indications for cataract surgery included visually significant cataracts that precluded adequate visualization necessary for vitreoretinal surgery. Lens surgery was also performed if rapid postoperative cataract progression was judged very likely, for example, in eyes undergoing reoperation, eyes with repeated gas injections and eyes where very anterior vitreous tissue dissection was required during the procedure. Vitreoretinal procedures performed included vitrectomy, peeling of the posterior hyaloid membrane, epiretinal membrane peeling, photocoagulation, cryotherapy, fluid– gas exchange, central posterior capsulectomy, and gas or silicone oil injection. In all cases, phacoemulsification (scleral tunnel incision or clear corneal incision) and IOL implantation (one-piece polymethylmethacrylate [PMMA] or acrylic foldable IOL) was performed before the vitreoretinal procedure. In all but one case, the IOLs were implanted in the capsular bag. In the remaining case, the IOL was placed in the ciliary sulcus because of concern about instability of the capsular bag. Intraoperative objectives of vitreoretinal surgery were accomplished in all cases. Preoperative vision ranged from 20/30 to light perception (mean, 20/200). Postoperative vision ranged from 20/20 to no light perception (mean, 20/50). One eye with preoperative vision of light perception and vitreous hemorrhage due to uveitis had continued inflammatory disease, developed hypotony, and dropped to no light perception vision postoperatively. In 105 eyes visual acuity improved by 3 lines or more on the Snellen chart, in seven vision remained within 3 lines of preoperative levels, and in 10 vision had decreased at last follow-up. In the cases where vision decreased, it was judged to be on the basis of progressive retinal deterioration from the underlying disease process or capsular opacification The most common postoperative complication was opacification of the posterior capsule (Table 2). Fifty-one eyes underwent primary central posterior capsulectomy at

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TABLE 2. Postoperative Complications Complication

No. of Eyes

Opacified posterior capsule Increased intraocular pressure Corneal epithelial defects Vitreous hemorrhage Corneal edema Iris capture by intraocular lens optic Fibrin anterior chamber inflammation Retinal detachment Persistent macular hole Hypotony Visual field defect Macular pigmentary change Recurrent traction retinal detachment Total

21* 15† 14 5 5 4 3 2 2 1 1 1 1 75

% Total

28.4 20.3 18.9 6.7 6.7 5.3 4.0 2.7 2.7 1.4 1.4 1.4 1.4 100

*Twenty-one of 71 eyes that did not undergo primary capsulectomy at the time of procedure. † Of the 15 eyes with increased IOP, one was due to pupillary block glaucoma.

the time of surgery. Twenty-one of the 71 remaining eyes developed significant capsular opacity postoperatively (30%). Increased intraocular pressure (IOP ⬎ 24 mm Hg) was found in 15 eyes of which one case was due to pupillary block. Additional complications included corneal epithelial defects (14 eyes), vitreous hemorrhage (5 eyes), and significant corneal edema (5 eyes). Iris capture by the IOL optic occurred in 4 eyes; 1 was repositioned with viscoelastic on the first postoperative day and 1 was repositioned at reoperation after the macular hole failed to close. Fibrin anterior chamber inflammation occurred in 3 eyes, retinal detachment occurred in 2 eyes, and 2 holes failed to close. One case each of hypotony, visual field defect, macular pigmentary changes, and chronic recurrent traction detachment was noted.

DISCUSSION IN CASES WHERE CATARACTS COEXIST WITH VITREORETI-

nal pathology, surgeons have struggled to optimize retinal visualization during vitreous surgery and improve postoperative visual rehabilitation for their patients while minimizing complications. Several studies have reported combined procedure series and described favorable outcomes. Blankenship2 reported success in 10 patients with diabetic retinopathy treated using a technique of pars plana lensectomy followed by placement of a posterior chamber IOL in the ciliary sulcus on the residual anterior capsule. The IOL was placed at the end of the procedure so as not to interfere with the vitreoretinal surgery. Kokame VOL. 135, NO. 3

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and coworkers3 reported a series of 15 diabetic eyes, 9 of which underwent pars plana lensectomy and placement of an IOL on the anterior lens capsule after vitrectomy and 6 of which had extracapsular cataract extraction with IOL placement before vitrectomy. Koenig and associates4 discussed 8 vitreoretinal procedures (6 for proliferative diabetic retinopathy) combined with phacoemulsification in which 6 had IOL implantation in the capsular bag at the end of the procedure. Benson and coworkers11 described 24 eyes (15 with proliferative diabetic retinopathy) in which cataract surgery, 16 by extracapsular cataract extraction, and 8 by phacoemulsification was performed with posterior chamber IOL implantation preceding vitrectomy. Good visualization of the posterior segment was obtained and surgical objectives were achieved. In two cases, wounds leaked during the vitrectomy but were easily sutured, and in one case neovascular glaucoma developed postoperatively. Menchini and associates14 reported six diabetic patients successfully treated with preplacement of the infusion line followed by extracapsular cataract extraction, pars plana vitrectomy, and IOL placement at the end of the procedure. These authors recommended that combined surgery should be restricted to cases of limited duration, where adequate laser had been performed and minimal iris vascular changes were present. Further work by Koenig and coworkers12 enlarged their series to 18 eyes (10 with proliferative diabetic retinopathy) in which an infusion line was placed and clamped at the start of the procedure, a corneoscleral incision made, and a “can opener” capsulotomy performed followed by phacoemulsification then vitrectomy, and the IOL implanted at the close of the procedure. In terms of complications, the authors reported one case of pupillary block due to fibrinous iritis treated with a YAG peripheral iridectomy. They further recommended not using an IOL if traction or retinal detachment extended into the periphery. Foster and associates13 described 20 eyes (10 with proliferative diabetic retinopathy), in 19 eyes an infusion cannula was introduced before extracapsular cataract surgery and posterior chamber IOL placement. Cataract extraction was followed by vitrectomy. One eye in this series developed neovascular glaucoma, one pupillary block and two posterior synechiae. The authors commented that the combined technique provided clear anterior and posterior segment media, thus facilitating surgery. Mamalis and coworkers7 reported successful treatment of seven patients with phacoemulsification through a scleral tunnel incision, combined with vitrectomy; in three eyes IOL placement was delayed until after the vitreoretinal procedure, a strategy recommended by the authors in cases where the vitrectomy was anticipated to be complicated or difficult. The Hurley and Barry8 series of five eyes in 1996 did well with phacoemulsification through a scleral tunnel incision and IOL placement, as did the seven eyes reported by McElvanney and Talbot9 with a slightly VITREORETINAL PATHOLOGY

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different variety of techniques. Scharwey and associates10 described 38 eyes, all of which underwent clear corneal phacoemulsification and vitrectomy with IOL placement at the close of the procedure. The authors commented that both visual outcome and complications were dependent upon the underlying vitreoretinal pathology and were not related to the combined procedure technique. Our series of 122 eyes further expands on the observations made previously in several ways. Our series reflects the increasing trend toward surgical intervention for macular indications. Whereas previous series dealt primarily with eyes with complications of diabetic retinopathy, many of which had relatively poor visual potential, our series includes 69 eyes with macular disorders (epiretinal membrane, macular hole, vitreomacular traction, and subfoveal choroidal neovascularization), many of which can be expected to recover excellent reading vision. A study by Tornambe and coworkers5 reviewed a series of 25 eyes in which cataract extraction with intraocular lens insertion was combined with macular hole surgery. The authors suggested that combined procedures were particularly suitable for phakic patients who cannot tolerate the face-down position during macular hole repair.5 Simcock and Scalia16 reported a small series of 13 eyes with macular holes which underwent combined procedures, after which 11 of 13 holes closed. Surgery involved postplacement of the IOL in the capsular bag after the vitreous surgery had been completed. Twelve of 13 eyes experienced some visual acuity improvement, ranging from 1 line in three eyes to 5 lines in two eyes.16 Lahey and associates17 recently published their series of 89 consecutive patients with macular holes who underwent surgical procedures very much like the one we describe, with phacoemulsification and posterior chamber IOL insertion, followed by vitrectomy and air–fluid exchange and C3F8 infusion. All eyes in this series had posterior capsulotomies performed at surgery. The authors credit the lens removal and more complete vitrectomy provided by combined surgery with allowing for an increased gas fill, longer tamponade and improved hole closure rate. They achieved an 89% hole closure rate with one operation, and 65% improved to 20/40 or better visual acuity. The authors noted a 9% rate of iris synechiae to the capsular opening, a problem we may have avoided in all but four patients by using short-acting dilating drops postoperatively. Whether this was related to their 8% rate of vision-threatening cystoid macular edema is unclear. Careful evaluation of results in patients with macular holes is important because such eyes have excellent visual potential and will develop progressive lens opacity in virtually all cases. These are patients for whom efficient and timely visual rehabilitation must be achieved with minimum risk. Gas bubble-related risks after cataract surgery are the most significant. One of these relates to IOL power. Suzuki and associates6 have pointed out the slight myopic shift that occurs in eyes with a gas bubble, in which the IOL comes to rest slightly anterior to where it 294

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would without the bubble. They suggest that this should be taken into consideration when calculating the lens power in these eyes.6 Iris capture by the IOL optic occurred in four eyes in our series, all of which had clear corneal incisions with 6-mm optic diameter foldable acrylic IOLs placed. It may be that 6.5 mm or larger optic IOLs will remain more securely in the capsular bag and behind the pupil, and we now use these exclusively in our cases. We also believe a continuous curvilinear capsulorhexis incision in the anterior capsule, not overly large, and in-thebag IOL placement allow greater stability of the IOL. Corneoscleral incisions may allow more anterior chamber stability and a tighter wound during subsequent vitreoretinal manipulations, but this is not certain from our data. Cataract incision location varied in this series, and optimum location can not be determined with statistical significance from our data. There was no wound leakage with either scleral tunnel or clear corneal incision in the study population. Both scleral and corneal incisions were sutured before the vitrectomy. To avoid postoperative gas-related complications, we also recommend constricting the pupil with a miotic at the close of the procedure. Postoperatively, we suggest dilating gas-filled eyes once daily with short-acting agents such as tropicamide 1% rather than with long-acting agents such as atropine. This, combined with topical corticosteroids, may help prevent formation of synechiae and minimize the chance of pupillary capture by the IOL. In all cases in this series, as opposed to many others, both cataract surgery by phacoemulsification and IOL implantation were performed before the vitrectomy. It is technically advantageous for the surgical team to operate in this sequence, because the cataract surgeon can perform his or her part of the procedure and leave the retinal specialist to complete the case. It is possible that small incision phacoemulsification surgery with foldable IOLs allow better retinal visualization after cataract extraction than older techniques. We were aggressive in optimizing our view of the posterior ocular structures, using techniques such as scraping the edematous cornea, lavaging and aspirating hemorrhage and pigment from the anterior chamber off the surface of the IOL, excising opaque posterior capsule, and using iris retractors for miosis. Wide field viewing systems were frequently used for the vitreoretinal procedures, and this newer modality may also account for our ability to accomplish our retinal surgical objectives in all cases, despite the previous cataract extraction and IOL placement. Problems with visualizing the peripheral fundus described in the past, particularly in terms of the prismatic edge effect of the IOLs, were perhaps obviated by this as well. Scleral depression was also used successfully despite the IOL and sutured small cataract wound incision. We recommend aborting vitreoretinal surgery after cataract extraction, however, if visualization is too poor to safely accomplish surgical objectives. OF

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Cases in which cataract surgery may better be performed separately include difficult internal limiting membrane or epiretinal membrane dissections in which even subtle endothelial edema might compromise the view required for distinguishing tissue planes. It is possible that techniques such as indocyanine green dye staining might also facilitate these cases. Additionally, eyes with low visual potential, especially those that require extensive peripheral dissection and those in which the capsular and IOL structures might serve as anterior scaffolding (for example, eyes with severe uncontrolled proliferative diabetic retinopathy or severe cases of proliferative vitreoretinopathy), might better be approached by lensectomy alone. Visual results in this study are very much what we would expect from a series of vitreoretinal procedures of this nature. In 105 eyes visual acuity improved by 3 lines or more on the Snellen chart, in 7 vision remained within 3 lines of preoperative levels, and in 10 vision had decreased at last follow-up. In the cases where vision decreased, it was judged to be on the basis of progressive retinal deterioration from the underlying disease process or capsular opacification. Complications were in most cases typical of postoperative vitreoretinal patients with the surgical indications in this series. A few postoperative complications, specifically posterior capsule opacification, pupillary block, and pupillary capture by the IOL optic, were related to the combined procedure and would not have been expected to occur in cases of vitrectomy alone. Opacification of the posterior capsule has been mentioned as a frequent postoperative anterior segment complication in eyes with combined surgery.10 We found a high rate of posterior capsule opacification in our series, 21 of 71 eyes (30%) that did not undergo primary capsulectomy at the time of surgery. This is particularly high in view of the relatively short follow-up of eyes in this series (mean 9 months). Retention of an intact posterior capsule has been described as valuable in previous series of diabetic eyes to reduce the likelihood of neovascular glaucoma.15 Neovascular glaucoma has been described as a complication of the combined procedure.7,10 We did not encounter this complication in our series, perhaps because of aggressive panretinal photocoagulation before surgery and extensive endophotocoagulation into the periphery with wide field viewing intraoperatively. Nevertheless, anterior segment neovascularization should remain a consideration for surgeons treating severe cases of proliferative diabetic retinopathy. In all other eyes, we recommend considering primary central posterior capsulectomy. Drawbacks to this study include the relatively shortterm follow-up of some eyes, although the mean is 9 months. By limiting the study to eyes with at least 6 weeks follow-up, we were able to observe all eyes until all or most of the gas bubble, if any, had resorbed. The majority of common postoperative complications would thus arise within this time period. An additional drawback is the VOL. 135, NO. 3

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retrospective nature of the series. In particular, cases were preselected to be favorable for combined procedures. In conclusion, phacoemulsification and endocapsular IOL implantation can be safely performed in selected cases at the same time as vitreous surgery. The combined approach may be particularly useful in eyes with macular disorders and good visual potential. Based on extensive experience with the combined procedure, we suggest that careful attention to the capsule incision, in-the-bag placement of a larger-sized IOL, sutured cataract incision, primary capsulectomy in selected cases, and use of wide field viewing systems may optimize results and minimize complications. Constricting the pupil at the close of surgery and avoiding protracted dilation in the early postoperative period may also be particularly useful in eyes with long-acting gas bubbles.

REFERENCES 1. Faulborn J, Conway BP, Machemer R. Surgical complications of pars plana vitreous surgery. Ophthalmology 1978;85: 116 –125. 2. Blankenship GW. Posterior chamber intraocular lens implantation during pars plana lensectomy and vitrectomy for diabetic complications. Graefe Arch Clin Exp Ophthalmol 1989;227:136 –138. 3. Kokame GT, Flynn HW, Blankenship GW. Posterior chamber intraocular lens implantation during diabetic pars plana vitrectomy. Ophthalmology 1989;96:603–610. 4. Koenig SB, Han DP, Mieler WF. Combined phacoemulsification and pars plana vitrectomy. Arch Ophthalmol 1990; 108:362–364. 5. Tornambe PE, Poliner LS, Grote K. Macular hole surgery without face-down positioning. A pilot study. Retina 1997; 17:179 –185. 6. Suzuki Y, Sakuraba R, Mizutani H, Matsuhashi H, Nabazawa M. Postoperative refractive error after simultaneous vitrectomy and cataract surgery. Ophthalmic Surg Laser 2000;31: 271–275. 7. Mamalis N, Teske MP, Kreisler KR, Zimmerman PL, Crandall AS, Olson RJ. Phacoemulsification combined with pars plana vitrectomy. Ophthalmic Surg 1991;22:194 –198. 8. Hurley C, Barry P. Combined endocapsular phacoemulsification, pars plana vitrectomy, and intraocular lens implantation. J Cataract Refract Surg 1996;22:462–466. 9. McElvanney AM, Talbot EM. Posterior chamber lens implantation combined with pars plana vitrectomy. J Cataract Refract Surg 1997;23:106 –110. 10. Scharwey K, Pavlovic S, Jacobi KW. Combined clear corneal phacoemulsification, vitreoretinal surgery, and intraocular lens implantation. J Cataract Refract Surg 1999;25:693–698. 11. Benson WE, Brown GC, Tasman W, McNamara JA. Extracapsular cataract extraction, posterior chamber lens insertion, and pars plana vitrectomy in one operation. Ophthalmology 1990;97:918 –921. 12. Koenig SB, Mieler WF, Han DP, Abrams GW. Combined phacoemulsification, pars plana vitrectomy, and posterior chamber intraocular lens insertion. Arch Ophthalmol 1992; 110:1101–1104. 13. Foster RE, Lowder CY, Meisler DM, Zakov ZN, Meyers SM.

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Gordon ME. Neovascular glaucoma after intracapsular and extracapsular cataract extraction in diabetic patients. Am J Ophthalmol 1985;100:637–643. 16. Simcock PR, Scalia S. Phaco-vitrectomy for full-thickness macular holes. Acta Ophthalmol Scand 2000;78:684 –686. 17. Lahey JM, Francis RR, Fong DS, Kearney JJ, Tanaka S. Combining phacoemulsification with vitrectomy for treatment of macular holes. Br J Ophthalmol 2002;86:876 –878.

Combined extracapsular cataract extraction, posterior chamber intraocular lens implantation, and pars plana vitrectomy. Ophthalmic Surg 1993;24:446 –452. 14. Menchini U, Azzolini C, Camesasca FI, Brancato R. Combined vitrectomy, cataract extraction, and posterior chamber intraocular lens implantation in diabetic patients. Ophthalmic Surg 1991;22:69 –73. 15. Poliner LS, Christianson DJ, Escoffery RF, Kolker AE,

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