engleski

Phacoemulsification for Primary Angle Closure Glaucoma and Cataract

INTRODUCTION Chronic angle-closure glaucoma is characterized by a permanent closure of the angle as a result of peripheral anterior synechiae. It is defined as an eye with an occludable drainage angle, and features indicating that trabecular obstruction by the peripheral iris had occurred, such as peripheral anterior synechiae, or an increased IOP associated with glaucomatous optic neuropathy (1, 2). Because of the absence of symptoms, chronic angle closure, particularly in eyes with normal intraocular pressure, and without glaucomatous damage, is missed more often than not (2, 3). The patophysiology of the angle closure is not well understood, but various mechanisms, or a combination of mechanisms may contribute. These mechanisms include relative pupillary block, plateau iris configuration, and phacomorphic angle closure (4). Persistent angle closure after peripheral iridectomy suggests a major contribution of the lens component. Although some studies show a rise in, or no effect on IOP after cataract extraction in glaucomatous eyes, evidence is accumulating that there is a long-term improvement in glaucoma control after cataract surgery (5). We report the outcome of primary phacoemulsification in patients with chronic angle closure and uncontrolled intraocular pressure. PATIENTS AND METHODS We prospectively recruited 18 consecutive patients with primary angle closure glaucoma and concurrent cataract for phacoemulsification and posterior chamber intraocular implantation at the eye clinic, University hospital &laquo ; ; Sestre milosrdnice&raquo ; ; , Zagreb from June 2001 to April 2003. Before surgery, all study eyes underwent a complete ophthalmologic examination. Vertical and horizontal cup-disc ratios of the optic nerve head were documented, and automated visual field tests using the Octopus computerized perimetry were performed before surgery. A Goldmann 3 &#8211; mirror goniolens was used to evaluate the chamber angle. The selection of patients was based on gonioscopic appearance. Inclusion criteria included variable degree of synechial angle closure occluding the trabeculum, confirmed by indentation gonioscopy. In all cases IOP was higher than 22 mmHg despite of maximal tolerated antiglaucoma medical therapy. Yag-laser iridotomy was performed in l5 eyes and argon laser iridoplasty in 5 eyes. Visually disabling cataract with visual acuity of 0, 1 or worse was present in all eyes. Exclusion criteria included uveitic angle closure, rubeotic angle closure and previous filtering surgery. All preoperative antiglaucoma medications, with the exception of miotics, were continued up until the operation. Parabulbar anesthesia was used for all patients. Standard phacoemulsification with posterior chamber intraocular lens (Alcon MA30BA Fort Worth TX) implantation through corneal tunnel was performed. Two anterior chamber paracentesis wounds were made at the 11 and 1 o'clock positions. Angle viscodissection was performed by viscoelastic (HealonGV, Pharmacia, Sweden). Subconjunctival steroids were given at the end of the surgical procedure. Postoperatively, topical dexamethason-neomycin was prescribed for 6 weeks, and antiglaucoma medications were adjusted according to the IOP response. Immediate postoperative IOP elevations were treated with oral carbonic anhydrase inhibitors and/or oral glycerin in addition to beta blocking agents. Patients were examined daily for 3 days after the operation, then weekly, and then monthly. Follow up examination included visual acuity testing, slit lamp examination of the anterior segment, and gonioscopy of the angle with and without indentation. The IOP was measured using applanation tonometry, and fundus examination was also performed. RESULTS The mean age of the patients was 68, 8 +/- 5, 8 years. All patients in this series had a chronic angle closure glaucoma, with a variable degree of synechial closure, and coexisting cataract with visual acuity of 0, 1 or worse. The duration of IOP increase ranged from 2-10 months (mean 7, 4 months). Five out of eighteen eyes had a history of acute primary angle-closure glaucoma attack in the treated eye. All the operations were performed under peribulbar anesthesia by one surgeon (Z.M.). In all cases posterior foldable acrylic IOL (range22-27 D) was implanted (Fig 1.). Postoperatively, there was low to moderate anterior chamber flare and cells in all treated eyes. Intraoperatively, two cases of capsular tearing, one of which also required an anterior vitrectomy, three cases of intermittent iris prolapse, and one patient with hyphema formation were encountered. The latter cleared spontaneously within few days without complications. The most common complication in the early postoperative period (Tbl 1.) was corneal edema in 6 eyes (33%), followed by fibrinous iritis in 5 eyes (28%), transient pressure spikes in 5 eyes (28%), and wound leak in one eye (6%). All complications were successfully treated by the application of topical steroids and/or IOP lowering medications. The trabecular meshwork was hard to identify, but all eyes showed a widening of the chamber angle, and /or less peripheral anterior synechias on gonioscopy. The central anterior chamber depth was increased after operative procedure (2, 4 +/-0, 34 mm preoperatively versus 3, 7 +/-0, 34 mm postoperatively). After a mean follow up of 10, 4 months the best-corrected visual acuity was better than the preoperative in 12 eyes, unchanged in 5 eyes, and worse in one eye (Fig 2.). The mean preoperative intraocular pressure calculated from a diurnal IOP curve was 26, 4 +/- 6, 6 mmHg and 6 months postoperatively it decreased to 17, 4 +/- 3, 1 mmHg. At the same time in 10 eyes (56%) IOP was under 21 mmHg, and these eyes were without medications. In 5 eyes (28%) high IOP was controlled with antiglaucoma medications. In 3 eyes (17%) despite antiglaucoma medications IOP was still high, and filtering procedure had to be performed. The mean number of postoperative medications was also decreased (2, 2 +/-0, 8 preoperatively, 0, 9 +/- 0, 46 postoperatively) (Tbl 2). DISCUSSION Crystalline lens plays an important role in the patophysiology of the primary angle closure glaucoma. The role of iridolenticular apposition leading to a relative pupillary block has been well documented as a pathophysiological mechanism in primary angle closure glaucoma (10, 11). Anatomic predispositions such as shallow anterior chamber, axial hyperopia, small corneal diameter, reduced anterior chamber volume, increased thickness and curvature of the crystalline lens, sequenced with an age&#8211; related laxity of the zonules and crystalline lens growth, both resulting in forward displacement of the iris &#8211; lens diaphragm, are conductive to the development of a relative pupillary block in primary angle closure glaucoma (13). At present, Nd:YAG laser iridotomy is recommended as the primary treatment for primary angle closure glaucoma, but these patients need to be observed closely for treatment failure. Nd:YAG laser iridotomy alone may not offer long-term IOP control in all patients, and in those cases second line medical therapy has been recommended. Both the beta-blocker timolol 0, 5%, and the prostaglandin analog latanoprost 0, 005% decreased IOP (14). Surgical treatments include cataract extraction, goniosynechiolysis, trabeculectomy, goniosynechiolysis, iridoplasty, combination of these procedures, or cyclodestruction and glaucoma implant (12). The reason for improved IOP after cataract extraction in glaucoma patients remains uncertain. Proposed theories include improved access to the trabecular meshwork by anterior chamber deepening, or a change in a force directed on the ciliary processes, atrophy of the ciliary processes, and improved outflow facility (15, 16). Some biometric data confirm the importance of the &laquo ; ; lens factor&raquo ; ; in the pathogenesis of relative pupillary block obtained by Scheimpflug image (13). Using ultrasonographic biomicroscopy, Kurimoto et all found apparent differences in iris position between phakic and pseudophakic eyes. The anterior chamber was 1, 37 times deeper, and the angle 1, 57 times wider after cataract surgery. They showed that the iris was pushed forward by the lens in phakic eyes and shifted backward after lens removal. These findings suggest that lens extraction with IOL implantation is an effective therapeutic option for patients with primary angle closure glaucoma. Yang and Hung(14) prospectively studied eyes with primary angle-closure glaucoma before and after cataract extraction, and established that the mean anterior chamber depth was 2, 04 mm +/- 0, 29 mm preoperatively and 3, 44 +/- 0, 16 mm postoperatively. Gunning and Greve (15) compared the long term effects of extraction of incipient cataracts or clear lenses with filtering surgery on glaucoma control in patients with primary angle-closure glaucoma. Glaucoma control was achieved in 68% of eyes in both groups. Filtration surgery was associated with multiple surgical interventions and deterioration in visual function. In our study normotension was achieved in 15 patients (78%) with angle-closure glaucoma. Mean postoperative IOP is decreased to 17, 4 +/- 3, 1 mm Hg, and the number of postoperative medications was reduced as well. Gonioscopy is the preferred method to predict the likelihood of success of lens extraction on glaucoma control. However, the extent of peripheral anterior synechiae is sometimes difficult to establish, and hard to distinguish from the so-called appositional angle-closure(14). From our experience, we believe that in contrast to long &#8211; standing synechial closure, appositional closure may be terminated by performing the lens extraction. Early intervention with phacoemulsification and IOL implantation prevents synechia formation and eliminates lens &#8211; induced narrowing of the angle. Surgery can be performed earlier if laser iridotomy does not work, and in our cases the angle was opened using the viscoelastic material, without mechanical synechiolysis. In view of our findings, we believe that the sequence a cataract extraction procedure via a corneal incision, with optional trabeculectomy reserved for a later period, may be a more attractive alternative in carefully selected patients with primary angle closure glaucoma. The use of phacoemulsification, although technically more demanding, might be even safer in these eyes with shallow anterior chamber and high vitreous pressure. Finally, preserving the conjunctiva, by using a clear-corneal approach, facilitates any subsequent filtration procedures that may be required. We are aware of the small number of patients in our case series, and a relatively short follow up time. In order to determine the best surgical approach to the treatment of primary angle closure glaucoma, and to compare the efficacy of the treatment options such as trabeculectomy, lens extraction, phaco-trabeculectomy or goniosynechiolysis, a prospective trial would be necessary. Table 1. Early postoperative complications Complication Number of eyes % Corneal edema 6 33 Fibrinous iritis 5 28 IOP spikes 5 28 Wound leak 1 6 Figure 1. Pseudophakia with air bubble in the anterior chamber following phacoemulsification. Note the iris sphincter rupture at 9 o&#8217; clock and peripheral iridotomy at 4 o'clock position. Figure 2. Postoperative best corrected visual acuity (BCVA) in operated patients Table 2. The mean preoperative and postoperative number of antiglaucoma medications Mean number of medications SD Preoperative 2, 2 0, 8 Postoperative 1st month 1, 7 0, 6 3rd month 1, 2 0, 5 6th month 0, 9 0, 46 Mann Whitney test Preoperative vs. 1st month: p<0, 001 Preoperative vs. 3rd month: p<0, 001 Preoperative vs. 6th month: p<0, 001 REFERENCES 1.KurimotoY, Park M, Sakaue H, Kondo T. Changes in the anterior chamber configuration after small-incision cataract surgery with posterior chamber intraocular lens implantation. 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Eye 1999 ; 13:26-30. 8.Teekhasaenee C, Ritch R. Combined phacoemulsification and goniosynechiolysis for uncontrolled chronic angle-closure glaucoma after acute angle-closure glaucoma. Ophthalmology 1999 ; 106:669-674 ; discussion by EL Greve, FP Gunning, 674-675. 9.Seah SK, Foster PJ, Chew PT, et al. Incidence of acute primary angle closure glaucoma in Singapore. An island-wide survey. Arch Ophtalmol 1997 ; 115:1436-40. 10.Wong TY, Foster PJ, Seah SK, Chew PT. Rates of hospital admissions for primary angle closure glaucoma among Chinese, Malays, and Indians in Singapore. Br J Ophthalmol 2000 ; 84:990-2. 11.Foster PJ, Buhrmann R, Quigley HA, Johnson GJ. The definition and classification of glaucoma in prevalence surveys. Br J Ophthalmol 2002 ; 86:238-42. 12. Fleck BW, Wright E, Fairley EA. A randomized prospective comparison of operative peripheral iridectomy and Nd:YAG laser iridectomy treatment of acute angle closure glaucoma: 3 Year visual acuity and intraocular pressure control outcome. Br J Opthalmol 1997 ; 81:884-8. 13.Aung T, Tow SL, Yap EY, et al. Trabeculectomy for acute primary angle closure. Ophthalmology 2000 ; 107:1298-302. 14.Tanihara H, Negi A, Akimoto M, Nagata M. Long-term results of non-filtering surgery for the treatment of primary angle-closure glaucoma. Graefes Arch Clin Exp Ophthalmol 1995 ; 233:563-7. 15.Teekhasaenee C, Ritch R. Combined phacoemulsification and goniosynechiolysis for uncontrolled chronic angle-closure glaucoma after acute angle-closure glaucoma. Ophthalmology 1999 ; 106:669-74. 16.Ang LP, Aung T, Chew PT. Acute primary angle closure in an Asian population: long-term outcome of the fellow eye after prophylactic laser peripheral iridotomy. Ophthalmology 2000 ; 107:2092-6.

phacoemulsificatio; angle closure glaucoma

nije evidentirano