Survival plots of phacoemulsification and intraocular lens (IOL) implantation alone (IOL-alone); combined trabecular aspiration, phacoemulsification, and IOL implantation (asp+IOL); and standard filtering glaucoma triple procedure (triple procedure). There was a significantly higher success probability in the triple procedure group than the asp+IOL group or IOL-alone group (P=.001, log-rank test). There was also a significantly higher success probability in the asp+IOL group than the IOL-alone group (P=.001, log-rank test).
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Jacobi PC, Dietlein TS, Krieglstein GK. Comparative Study of Trabecular Aspiration vs Trabeculectomy in Glaucoma Triple Procedure to Treat Pseudoexfoliation Glaucoma. Arch Ophthalmol. 1999;117(10):1311–1318. doi:10.1001/archopht.117.10.1311
Copyright 1999 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.1999
To establish the relative safety and effectiveness of trabecular aspiration in combination with phacoemulsification and intraocular lens (IOL) implantation (asp+IOL) for decreasing intraocular pressure (IOP), and to compare the outcome of this method of treatment with that of phacoemulsification and IOL implantation alone (IOL-alone) or standard filtering glaucoma triple procedure (triple procedure).
Prospective, controlled study randomized with respect to assignment to trabecular aspiration, with a case-control design between the asp+IOL and triple procedure groups.
Seventy-four eyes of 74 patients with uncontrolled pseudoexfoliation glaucoma without a history of previous intraocular or extraocular surgery and in need of cataract surgery. Forty-eight patients were randomized to those receiving adjunctive trabecular aspiration (asp+IOL group of 26 eyes) and those given no trabecular aspiration (IOL-alone group of 22 eyes). The triple procedure group consisted of 26 cases, closely matched to the asp+IOL cases in terms of age, sex, cup-disc ratio, glaucoma medication requirements, and systemic diseases.
Temporal clear corneal phacoemulsification and foldable IOL implantation was performed in all eyes. In the asp+IOL group, trabecular aspiration was performed with a suction force of 100 to 200 mm Hg under light tissue-instrument contact using a modified intraocular aspiration probe. A modified Cairns-type trabeculectomy without adjunctive antimetabolites was performed superiorly in the triple procedure eyes after IOL implantation.
Main Outcome Measures
Surgical outcome was assessed in terms of IOP change, need of adjunctive glaucoma medication, visual acuity outcome, and complications. Surgical failure was defined as an outcome requiring additional surgical intervention or more than 1 medication to achieve IOP control to the target pressure.
Two years after surgery, success rates were 36%, 64%, and 78% in the IOL-alone, asp+IOL, and triple procedure groups, respectively (P<.001). Hyphema (46%) and ocular hypotony (11%) were observed in the triple procedure group only, whereas blood reflux (61%) and descemetolysis (19%) were seen exclusively in the asp+IOL group.
In pseudoexfoliative eyes, asp+IOL is significantly more effective than cataract surgery alone in reducing postoperative IOP and the necessity for glaucoma medication. Although trabecular aspiration in the triple procedure did not achieve pressure control in all patients, especially in the low target pressure range, the risk profile appears to be more favorable in the trabecular aspiration–treated eyes than in the filtering glaucoma triple procedure group. Trabecular aspiration in the glaucoma triple procedure could serve as a possible first-line treatment for pseudoexfoliative eyes with coexisting cataract and glaucoma.
THERE ARE many options in treating patients with both cataract and glaucoma.1-16 Their management still remains controversial, partly because of a lack of convincing evidence for the superiority of any one surgical approach. Relevant factors that aid the ophthalmologist in deciding between therapeutic options are, among others, the level of intraocular pressure (IOP) control, amount of glaucomatous optic neuropathy, number of glaucoma medications required, visual severity of the cataract, and the compliance and general health of the patient. Admittedly, finding the most efficacious surgical regimen for the individual patient depends on all these factors, and no single surgical treatment is likely to be correct for all patients. However, performing cataract and glaucoma surgery at the same time eliminates the additional morbidity and cost associated with successive surgical procedures and results in faster rehabilitation. Recent literature1-5 shows that combining extracapsular cataract extraction, posterior chamber intraocular lens (IOL) implantation, and trabeculectomy improves visual acuity, lowers IOP, and decreases the number of glaucoma medications needed. Many studies have since been published on the efficacy of using phacoemulsification rather than extracapsular cataract extraction in the glaucoma triple procedure.6-17 Small-incision phacoemulsification with foldable IOL implantation has several theoretical advantages, including more rapid visual recovery, less induced astigmatism, shorter surgery time, and greater intraoperative control. Furthermore, glaucoma triple procedure also reduces the risk of the transient IOP spikes that often occur after cataract surgery, especially in patients with glacoma.17-22
On the other hand, some authors believe that combined cataract and glaucoma filtering surgery is associated with a higher incidence of complications and less favorable prognosis for IOP regulation and final visual acuity compared with a 2-stage surgical approach.23 The choice of the surgical approach is complicated by the known adverse effects in the combined cataract and trabeculectomy procedure, such as significant inflammatory or fibrinous reaction, transient flattening of the anterior chamber, and pronounced hyphema that can easily develop during the hypotensive postoperative phase.14-18
Previously, we described a new concept of nonfiltering glaucoma surgery—trabecular aspiration—designed to increase trabecular outflow facility in forms of secondary obstructive glaucoma, such as pseudoexfoliation glaucoma (PEXG).24 The morphological analysis of the trabecular aspirate clearly indicated the efficacy of trabecular aspiration for removing pretrabecular and intertrabecular debris in exfoliative eyes. In combination with extracapsular cataract extraction, removal of pretrabecular and intertrabecular debris through trabecular aspiration substantially lowered the IOP in a small group of cataractous eyes complicated by PEXG over a short period of time after surgery.25 Moreover, when applied as primary therapeutic surgical intervention in PEXG, this procedure also proved to be an effective tool in pressure management.26
In the present study, we compare a randomized series of combined phacoemulsification, IOL implantation, and trabecular aspiration (asp+IOL) with a series of phacoemulsification and IOL implantation alone (IOL-alone). Performing the cataract incision temporally reduces the induction of against-the-rule astigmatism and spares the superotemporal conjunctiva in both groups, making subsequent filtering procedures easier to perform. For further evaluation, trabecular aspiration–treated eyes were also compared with a case-matched group that received standard filtering glaucoma triple procedure (triple procedure). With the combined cataract and filtering approach, a temporal clear corneal incision also decreases inflammation around the filter, increasing the chances of a successful glaucoma procedure. We evaluated the impact of the 2 different approaches (ie, filtering vs nonfiltering approach) in the glaucoma triple procedure on postoperative visual acuity, the efficacy of the glaucoma procedure in reducing IOP and dependence on glaucoma medication, and complications. Further evaluation of the efficacy of combined cataract and glaucoma surgery should enhance the surgeon's ability to make an informed choice for each cataractous patient with PEXG.
The study represents an intermediate-term evaluation of an ongoing prospective study to investigate the role of trabecular aspiration as a novel nonfiltering glaucoma procedure in treating PEXG. Patients with PEXG requiring glaucoma medical therapy, in need of safeguarding against IOP spike-related optic nerve head damage during the early postoperative period, long-term improvement of glaucoma control with respect to either IOP or medical dependency, and improvement of lens-related visual acuity were invited to enroll in the randomized arm of the study. Patients with a history of uveitis, herpetic keratitis, ocular trauma, narrow angle, previous filtering or cyclodestructive procedures, and glaucoma other than PEXG were excluded. The tenets of the Declaration of Helsinki were followed, and each patient signed the informed consent form approved by the institutional review board. Regular follow-up at the University Eye Hospital of Cologne, Cologne, Germany, was mandatory for all patients seeking enrollment in the study.
The study group consisted of 74 eyes of 74 cataractous patients with coexisting PEXG undergoing phacoemulsification with IOL implantation. Forty-eight consecutive patients were randomized to either adjunctive trabecular aspiration (asp+IOL group of 26 eyes) or no trabecular aspiration (IOL-alone group of 22 eyes). All patients who fulfilled the inclusion criteria but opted against enrollment in this ongoing prospective randomized study of trabecular microsurgery or who were not able to reappear for regular follow-up visits were treated by standard filtering glaucoma triple procedure (triple procedure) using conventional trabeculectomy without the use of antimetabolites. For each asp+IOL case, a triple procedure case that best matched the asp+IOL group with respect to age, race, sex, cup-to-disc ratio (C:D), and any systemic diseases (diabetes mellitus, hypertension) was chosen for comparison.
Preoperative evaluation included measurement of best-corrected visual acuity on a standard illuminated Snellen acuity chart in a darkened room, quantitative visual field testing, measurement of IOP, gonioscopy, anterior- and posterior-segment slitlamp biomicroscopy, indirect ophthalmoscopy of the retina, and ultrasonography where required. In most patients, visual field testing was performed by computerized automated perimetry using the Humphrey Visual Field Analyzer (Humphrey Instruments, San Leandro, Calif). For patients with preterminal optic nerve atrophy, dense nuclear cataract, or both, manual kinetic perimetry with the Goldmann-type bowl perimeter was the preferred method of visual field examination.
Surgical technique and medication were standardized at the time of study. Treatment before surgery included oral acetazolamide (500 mg, intravenously), mannitol infusion (Osmo-fundin 125 mL, intravenously; Alcon, Houston, Tex), oculopression for 10 to 15 minutes, and prophylactic antibiotic drops and ointment. All procedures were performed by 1 of 2 experienced surgeons (P.C.J. and G.K.K.) as follows: In all patients, a self-sealing, 3-step incision was prepared using a Thornton-Fine ring to fix the globe. A partial-thickness groove, 3.5 mm in length and one third to one half corneal thickness in depth, was created with a trifaced diamond microkeratome along the temporal corneoscleral limbus. A corneal tunnel was dissected 2.0 mm into clear cornea with a crescent diamond knife. After paracentesis of 2 side ports, each 90° from the temporal meridian, a bent triangular lance was inserted and moved forward to the corneal apex of the tunnel, at which point its tip penetrated the residual inner corneal lamella and a 2.8-mm internal valve was created to allow for subsequent procedures. These included viscoelastic injection, continuous curvilinear capsulorrhexis, hydrodissection, hydrodelineation, endocapsular phacoemulsification, and bimanual aspiration of the remaining cortical lens material using balanced salt solution followed by widening of the tunnel to 3.5 mm and in-the-bag implantation of a foldable IOL. Where necessary, the pupil was dilated with sphincterotomies or iris retraction hooks. Following IOL implantation, the pupil was constricted with intracameral application of acetylcholine chloride (Miocol; Ciba Vision Ophthalmics, Grossostheim, Germany).
Thereafter, in the asp+IOL group, the inferior circumference of the anterior chamber angle was cleaned out by trabecular aspiration as described in detail previously.24,26 Briefly, for intracameral access, both preexisting paracenteses were used. First, the irrigation cannula was introduced into the eye to stabilize the globe and to deepen the anterior chamber. Then followed intracameral insertion of the trabecular aspirator, a modified aspiration probe, which was pushed forward carefully in the opposite chamber angle and directed against the trabeculum. The tip of the modified aspiration probe is 400 µm wide and horizontally angled at 45° to comply with the configuration of the anterior chamber angle. The intracameral portion of the aspiration cannula is convexly shaped to prevent damage to the iris-lens diaphragm during this intraocular maneuver. Under tender instrument-tissue contact, suction pressure between 100 and 200 mm Hg was applied over 4 to 5 clock hours of the inferior and lateral circumference of the chamber angle for 2 to 3 minutes. The corneal paracenteses only rarely demanded suturing at the end of the procedure.
In patients who received a standard trabeculectomy after phacoemulsification and IOL implantation (triple procedure), a modification of a Cairns-type guarded filtering procedure was performed. Limbus-based conjunctival flaps were created approximately 8 to 10 mm posterior to the limbus, exposing the sclera. Mild diathermy was used to establish hemostasis, and a diamond keratome was used to facilitate dissection of a 3 × 4-mm scleral flap with the base of the flap at the limbus overlying the trabecular meshwork. The floor of the scleral flap was freed by dissecting approximately 50% of scleral thickness 0.5 mm into clear cornea. This was followed by resection of a corneoscleral block (3 × 1 mm) and a basal iridectomy. The scleral flap was reapposed with two to three 10-0 nylon sutures. The anterior chamber was reformed through the inferior paracentesis, and the Tenon layer and conjunctiva were closed with a 9-0 polyglactin 370 running suture.
All patients received an identical topical regimen in the postoperative period, including 50 mg of mezlocillin (Baypen; Bayer, Leverkusen, Germany) and 2 mg of dexamethasone hydrochloride (Fortecortin; Merck, Darmstadt, Germany) injected subconjunctivally, immediately after surgery. During postoperative recovery, each patient received topical corticosteroid drops and a combination of corticosteroid and antibiotic ointment at night, the dosage being rapidly reduced depending on the degree of postoperative inflammation. Digital or focal compression and postoperative laser suture lysis were performed whenever necessary to attempt to lower IOP to target pressure. A postoperative inflammatory response was defined as fibrin threads, membranes, or a cellular flare as observed by slitlamp examination.
Two to 4 days before surgery, IOP was measured 5 times a day over a period of 15 hours, and the mean was taken as baseline pressure. Goldmann applanation tonometry was done at the slitlamp in a double-masked fashion by the same examiner. After surgery, the mean number of glaucoma medications, best-corrected visual acuity, and IOPs were assessed at 1, 3, 6, 12, 18, and 24 months, and at last follow-up in all patients. The number of postoperative pressure determinations at a specific visit varied from 3 to as many as 5 individual determinations for some patients. Analogous mean IOP was taken as the baseline value. Since some visual acuities were expressed in nonnumerical terms, they were assigned a rank value (Table 1) and compared using statistical tests for nonparametric data (Wilcoxon signed rank test). Bleb status and patency of the peripheral iridectomy were evaluated in the triple procedure group. Before glaucoma surgery and admittance to the present study were considered, great care was taken to seek the most effective and tolerable medical treatment for IOP reduction 1 to 3 months before surgery (ie, medications being used prior to surgery were discontinued to determine if they were superfluous). After surgery, pressure-reducing medication was discontinued in all patients for at least 5 days. Thereafter, recommencement of medical treatment was titrated according to the postoperative pressure measurements. However, no change in type of medication was performed.
Failure was defined as the need for an additional antiglaucoma surgical or laser treatment (except for laser suture lysis), including bleb needling revision, or the need for more than 1 medication to reduce IOP to the target pressure as described by Shin et al.27 The target pressure was set before surgery and implemented in accordance with our clinical practice. In the majority of patients receiving long-term therapy, we regarded the IOPs at which there was no progression of the glaucomatous optic nerve damage to be acceptable as the target pressure. In the cases of progressive optic nerve damage, however, we set the initial target pressure at least 20% below the damaging pressure and not higher than 20 mm Hg. In the absence of information on previous stability, the initial target pressure was based on the severity of existing optic nerve damage.1 That is, we arbitrarily set the initial target pressure no higher than 15 mm Hg in eyes with a vertical C:D of 0.9 or greater, no higher than 18 mm Hg in the group with a C:D of 0.7 or higher but less than 0.9, and no higher than 20 mm Hg in the early glaucoma group with a C:D less than 0.7. However, transient IOP elevation within the first 3 weeks after surgery was excluded from determination of success or failure. Follow-up was artificially terminated when subsequent nonglaucoma surgery was performed.
Results are expressed as mean±SD. Patient demographics, including age, sex, vertical C:D, and the presence of diabetes mellitus and age-related maculopathy, were compared. Preoperative and postoperative mean IOPs by Goldmann applanation, mean number of glaucoma medications, and best-corrected Snellen visual acuity at 1 and 2 weeks, and at 1, 3, 6, 12, 24, and 30 months were compared. Intraoperative and postoperative complications were evaluated.
The data were analyzed using 2-tailed, unpaired t test, χ2 test, Mann-Whitney U test, repeated-measures analysis of variance, Kruskal-Wallis test, and Kaplan-Meier survival tables with log-rank test (Mantel-Cox) for estimation of success.
Preoperative patient demographics, including age, sex, severity of glaucoma (vertical C:D), number of glaucoma medications, IOP, visual severity of cataract, presence of diabetes, hypertension, or age-related maculopathy, and mean months of follow-up, did not differ significantly between the 3 groups (Table 2). The postoperative IOPs were significantly lower than the preoperative IOPs at all times in all 3 groups (P<.001) (Table 3). The mean preoperative and postoperative IOPs at 3, 6, 12, 24, and 30 months were not significantly different in the 3 groups. However, mean postoperative IOPs at 1, 2, and 4 weeks did differ significantly (P<.05). The mean IOPs in the triple procedure group at 1 and 2 weeks (14.3±4.8 and 14.8±3.6 mm Hg) were significantly lower than the asp+IOL group (18.3±2.1 and 18.2±2.0 mm Hg) and the IOL-alone group (21.6±4.4 and 21.3±3.1 mm Hg). At 1 month postoperatively, triple procedure eyes (17.4±2.4 mm Hg) still had significantly lower IOP than the IOL-alone group (21.3±3.1 mm Hg). The percentage of patients who had pressure spikes of greater than 21 mm Hg in the first 2 weeks or first month postoperatively was significantly higher in the IOL-alone group (9 eyes, 41%) than in the asp+IOL group (2 eyes, 7%) or triple procedure group (1 eye, 3%). In contrast, patients with transient ocular hypotony (IOP <6 mm Hg) were only seen in the triple procedure group (3 eyes, 11%). Pressure spikes greater than 5 mm Hg above preoperative IOP occurred in neither group.
Preoperatively, the mean number of glaucoma medications did not differ significantly between any of the groups. Overall, the postoperative mean number of glaucoma medications was significantly lower than the preoperative number of glaucoma medications at all times (Table 3). Mean number of glaucoma medications was significantly lower in the triple procedure group compared with the asp+IOL group from the first postoperative month onward (P=.001). Similarly, the mean number of medications was significantly lower in the triple procedure group and asp+IOL group compared with the IOL-alone group at all times after the first postoperative months (Table 3). The percentage of patients who were controlled without additional glaucoma medication at 6 months and 2 years after surgery was lowest in the triple procedure eyes (22 eyes [84%] and 22 eyes [65%], respectively), followed by the asp+IOL group (14 eyes [53%] and 10 eyes [38%], respectively) and IOL-alone group (4 eyes [18%] and 2 eyes [9%], respectively).
Before surgery, best-corrected visual acuity ranged from 20/50 to light perception in each of the 3 groups. Results of preoperative and postoperative best-corrected visual acuity did not vary significantly between these 3 groups, but the ranking system (Table 1) and the Wilcoxon test revealed a statistically significant postoperative improvement in visual acuity in all groups (Table 4).
The Kaplan-Meier survival plots for all 3 groups are shown in Figure 1. Using the Kaplan-Meier survival curve, cumulative life-table success rates for the IOL-alone group were 45% at 6 months and 36% at 1 and 2 years. In the asp+IOL group the success rates were 89% at 6 months, 71% at 1 year, and 64% at 2 years. The differences between the 2 groups were statistically significant (P=.001). The triple procedure group had cumulative life-table success rates of 92%, 88%, and 78% at 6 months, 1 and 2 years postoperatively. The differences in the probability of success were statistically significant when compared with the asp+IOL and the IOL-alone group (P=.001).
Intraoperative and postoperative complications are shown in Table 5. Combining all 3 groups, minor zonulolysis (<2 clock hours) occurred during cataract surgery in 10 eyes (6 of those already presenting slight lens subluxation before surgery). Posterior capsule tear without vitreous loss occurred in 2 eyes, and capsular tear with vitreous loss occurred in 1 eye. In all of these patients, an IOL could be securely implanted into the sulcus. Posterior capsule opacification requiring Nd:YAG laser capsulotomy arose in 36 eyes. In 2 eyes, subclinical IOL decentration was found, both of them already having had minor zonulolysis intraoperatively. All these cataract surgery–related complications were equally distributed among groups (Table 5). Hyphema was the most common complication in the triple procedure group, occurring in 12 eyes (46%) and causing a transient reduction of best-corrected visual acuity. None of them, however, required surgical reintervention, such as lavage of the anterior chamber. Conversely, hyphema was found in neither the asp+IOL group nor the IOL-alone group. The incidence of fibrinous reaction was significantly higher in the triple procedure group, and was observed in 38%, 19%, and 13% of eyes in the triple procedure, asp+IOL, and IOL-alone groups, respectively. The difference in the incidence of fibrinous reaction between the asp+IOL group and the IOL-alone group was not significant. Likewise, the prevalence of anterior synechia formation was higher in the triple procedure group (15%) compared with the asp+IOL group (8%) and IOL-alone group (4%). Ocular hypotony (IOP <6 mm Hg) lasting longer than 2 weeks was detected exclusively in the triple procedure group. In the 3 eyes (8%) with hypotony (IOPs ranging from 1 to 4 mm Hg), the condition resolved spontaneously without surgical intervention. In the triple procedure group, a total of 7 patients (26%) required digital massage of the filtering bleb at the 1- and 2-day postoperative visits, because they had an IOP greater than target pressure. This intervention succeeded in adequate lowering of the IOP in 5 patients (19%), so that these patients required no additional intervention. In the remaining 2 eyes (8%), argon laser suture lysis was successfully performed to lower their IOP further. Filtering bleb revision (ie, needling, resection of Tenon cysts, wound leak) was performed in 3 eyes (11%), resulting in filtration failure, despite these measures, in 2 eyes (8%). Blood reflux from Schlemm canal was only found in the asp+IOL group (61%). Hyphema formation or sustained bleeding into the anterior chamber was not associated with this. Likewise, minute descemetolyses without further sequelae were seen in asp+IOL eyes only.
Pseudoexfoliation syndrome is often associated with both open-angle glaucoma and cataract formation. Various studies28-31 have demonstrated that the clinical course is likely to be more serious in PEXG compared with primary open-angle glaucoma. Levels of IOP, progression of visual defects, and glaucomatous optic neuropathy are more pronounced in PEXG.28-30 Moreover, exfoliative eyes respond less readily to medical therapy, so that many of these eyes require early surgery.32 The reason for this is still not fully understood. Besides, cataracts are disproportionately likely and their surgical correction more problematic in pseudoexfoliation syndrome than in nonpseudoexfoliative patients. The vast majority of lens opacities in pseudoexfoliative syndrome are nuclear sclerotic in type.33 Reported intraoperative difficulties include increased corneoendothelial and iris pigment epithelial fragility, increased vascular leakage and inflammation, fibrin deposition, zonular instability often associated with zonular dialyses, and vitreous loss.34-38 Postoperative problems may include an increased risk of synechia formation and pupillary block, rapid development of capsular thickening requiring laser capsulotomy, cystoid macular edema in the presence of capsular trauma resulting in vitreous loss, transient IOP spikes, and progression of glaucomatous optic neuropathy.37,38
Consequently, PEXG coexisting with cataract poses a management dilemma. On the one hand, given the potential intraoperative and postoperative complications in exfoliative eyes, it is advisable to avoid or minimize perioperative problems by keeping the surgical procedure as simple as possible, ie, favoring a 2-stage approach rather than a combined operation. On the other hand, a combined approach eliminates additional morbidity and costs, reduces the risk of transient postoperative pressure spikes, and may result in faster rehabilitation.
TRABECULAR ASPIRATION is a relatively new concept in nonfiltering surgery in PEXG and might help to solve this management problem of coexisting cataract and glaucoma in exfoliative eyes. The main advantage of trabecular aspiration over standard filtering procedures lies in its attempt to increase the outflow facility along natural pathways.24-26 Being a nonfistulating glaucoma procedure without transscleral drainage of aqueous humor into the subconjunctival space, it reduces the occurrence of postoperative complications typically associated with filtering procedures. In previous studies,24-26 we already demonstrated that trabecular aspiration is capable of removing pretrabecular and intratrabecular debris by means of high-pressure "vacuum cleaning," resulting in significant IOP reduction. In a prospective series of 22 patients with PEXG, we performed trabecular aspiration as a primary antiglaucoma procedure.26 In 19 eyes (86%), this procedure resulted in a consistent pressure reduction from the fifth postoperative day onward. At 2 years after surgery, mean IOP reduction was still 16 mm Hg, with nearly 50% of eyes being controlled without additional glaucoma medications. Serious intraoperative complications or postoperative side effects were not observed in these eyes.
In the present study, cataractous patients with coexisting PEXG were randomized to receive combined trabecular aspiration, phacoemulsification, and IOL implantation (asp+IOL) or phacoemulsification and IOL implantation alone (IOL-alone), to determine whether trabecular aspiration is equally safe and effective in glaucoma triple procedure. Both asp+IOL and IOL-alone resulted in significant decreases in number of medications required and IOP. However, from the first postoperative month onward, glaucoma medication requirement was significantly higher in the IOL-alone group. Furthermore, at all times the success rates were significantly lower in the IOL-alone group. Conversely, we observed a beneficial effect of trabecular aspiration on IOP control (48% from baseline), glaucoma medication, and success rate of achieving target pressure without any increase of intraoperative and postoperative complications.
For further evaluation of the possible future role of trabecular aspiration in glaucoma triple procedure in pseudoexfoliative eyes, the randomized cases of the asp+IOL group were case-matched with a consecutive series of combined trabeculectomy, phacoemulsification, and IOL implantation (as standard filtering glaucoma triple procedure). Before surgery, baseline data did not differ significantly between these 2 groups. With respect to pressure reduction, supportive medical treatment, and success rate, the present standard triple procedure group fared better than did the trabecular aspiration–treated eyes. Nevertheless, in view of the safety of the surgical procedure, this observed increase in success rate is compromised by an increase in incidence and severity of intraoperative and postoperative complications. In the trabecular aspiration group, no decline in visual acuity was observed, whereas 3 eyes of the filtering group experienced a transient loss of visual acuity, due to a prolonged phase of ocular hypotony. Moreover, in the trabecular aspiration group, no major intraoperative and postoperative complications related to the aspiration procedure were encountered, and notably no transient phase of ocular hypotony, choroidal effusion, or reduced anterior chamber depth. The main complication or intraoperative sign of effective treatment was a blood reflux from Schlemm canal in approximately 60% of the patients, but in none of the treated eyes was this followed by sustained bleeding in the anterior chamber angle or hyphema formation. A small descemetolysis at the area treated, indicating localized corneoendothelial stripping, was noted in 19% of the patients. Thus far, no corneal haze or edema has occurred. Conversely, in the triple procedure group, hyphema was the most common complication, followed by transient ocular hypotony, the latter being associated with choroidal detachment, flattening of the anterior chamber, IOL decentration, and a transient loss of visual acuity.
Pseudoexfoliation glaucoma is a syndrome of progressive optic neuropathy with characteristic optic nerve cupping and visual field defects. In the management of glaucoma, the ophthalmologist strives to achieve a stable range of pressures deemed unlikely to cause further optic nerve damage in a particular patient. Therefore, in our survival analysis, an individual criterion was used in each individual case. That is, we considered success or failure according to individualized target pressures and not on the basis of a uniform IOP cutoff. In this context, any interpretation of success rates should take into account that the absolute IOP-reducing capacity will always be higher in filtering procedures than in nonfiltering procedures. While filtering surgery can be expected to produce IOP levels in the low teens, IOP levels after trabecular aspiration are in the high teens. If the mechanism by which IOP levels are lowered by trabecular aspiration is the relief of outflow resistance within the trabecular meshwork, then the relatively high postoperative IOP levels may simply represent the sum of episcleral venous pressure, intracanalicular resistance, and the resistance to aqueous humor flow of the trabecular meshwork. As a result, successful trabecular aspiration may at best achieve "normalization" of IOP levels. However, eyes that have already sustained severe damage to the optic nerve head or visual field defects may not tolerate simple "normalization" of IOP levels but may require lower IOP levels. In these instances, filtration surgery may have merits that would justify consideration of a standard glaucoma triple procedure. Consequently, careful determination of the final risk-benefit ratio is crucial in each individual case.
In all patients treated with glaucoma triple procedure, there was a slow but steady regression of effect noticeable during the follow-up period. In addition to a slight decrease in mean IOP reduction, we also observed an increase in antiglaucoma medication requirements over time, which was noticeably higher in the asp+IOL group. This regressive tendency may be explained by the undiminished production of exfoliative material within the affected eyes. Even though trabecular aspiration can relieve the trabecular meshwork of its obstructive debris, thereby increasing outflow capacity, the production and liberation of pigment granules and exfoliative substances over time are not affected. Further analysis of re–trabecular aspiration, which was not investigated in this study, will show the value of enhancement procedures.
In the past, various attempts have been made to develop surgical techniques that allow simultaneous cataract and glaucoma surgery. Some authors believe that combined surgery is associated with a higher incidence of complications and less favorable prognosis for IOP control compared with a 2-stage approach. One serious problem in the early postoperative phase, in addition to severe inflammatory or fibrinous reactions, is a flattened anterior chamber. Furthermore, during this hypotensive phase, choridal detachment, maculopathy, and hyphema can easily develop. Trying to counteract a possible flattening of the anterior chamber in the early postoperative phase by filling the chamber with viscoelastics increases the risk of postoperative pressure spikes.
The surgical procedure recommended here offers a solution to this dilemma. As a technically undemanding modification of irrigation-aspiration, trabecular aspiration in combination with phacoemulsification and IOL implantation makes it possible to maintain a closed system throughout the surgery and thereafter. Although trabecular aspiration in glaucoma triple procedure did not achieve target pressure in all patients, especially in the low target pressure range, the risk profile appears to be more favorable in the trabecular aspiration–treated eyes than in the filtering glaucoma triple procedure group. Ab interno trabecular aspiration increases outflow facility along the trabecular meshwork and precludes the need of additional episceral preparation, which can be time-consuming. Moreover, subconjunctival filtration, especially when combined with cataract surgery, can be difficult to titrate. In addition, a clear corneal approach leaves the conjunctiva superiorly untouched for possible future filtration surgery.
Accepted for publication June 16, 1999.
This work was supported in part by Deutsche Forschungsgemeinschaft, Bonn, Germany (JA 717/3-1).
Reprints: Philipp C. Jacobi, MD, University Eye Hospital of Cologne, Joseph-Stelzmannstrasse 9, 50931 Cologne, Germany (e-mail: Philipp.Jacobi@uni-koeln.de).
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