Combined endoscopic erbium:YAG laser goniopuncture and cataract surgery Nicolas Feltgen, MD, Heiko Mueller, MD, Beat Ott, PhD, Martin Frenz, PhD, Jens Funk, MD, PhD Purpose: To study the safety and efficacy of endoscopic erbium:YAG (Er:YAG) laser goniopuncture combined with cataract surgery to treat glaucoma. Setting: Department of Ophthalmology, Albert-Ludwigs-University Freiburg, Freiburg, Germany, and Institute of Applied Physics, University of Bern, Bern, Switzerland. Methods: In this nonrandominized clinical trial, 20 eyes of 20 patients with cataract and glaucoma were treated by combined phacoemulsification and Er:YAG goniopuncture. The primary study endpoints were intraocular pressure (IOP), visual acuity, and number of antiglaucoma drugs 1 year after surgery. Two- and 3-year postoperative data were also measured. This prospective treatment arm was compared to a retrospective inclusion-matched control group treated by cataract surgery alone. Results: The mean IOP dropped by 30% (23.5 mm Hg ⫾ 3.9 [SD] to 16.3 ⫾ 2.7 mm Hg) after 12 months in the laser-treated group (P⬍.0001) and by 9% (19.8 ⫾ 1.3 mm Hg to 18.1 ⫾ 1.8 mm Hg) in the control group (P ⫽ .12). After 3 years, the mean IOP in the laser group was 15.0 ⫾ 2.0 mm Hg. The mean number of antiglaucoma drugs needed decreased from 1.6 ⫾ 0.9 to 0.5 ⫾ 0.8 in the laser group (P⬍.0001) and from 1.0 ⫾ 0.9 to 0.8 ⫾ 0.9 in the control group (P ⫽ .21). Anterior chamber hemorrhage occurred in 12 eyes after laser treatment and resolved within 72 hours in all but 1 patient who was on warfarin sodium (Coumadin威) therapy. There were no cases of hypotony in either group. Conclusions: Endoscopic Er:YAG laser goniopuncture was a successful adjunct to cataract surgery in glaucoma patients. Sustained IOP reduction was achieved with few postoperative complications. J Cataract Refract Surg 2003; 29:2155–2162 2003 ASCRS and ESCRS
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mproving drainage by photoablative laser-induced microperforations in the trabecular meshwork is a new approach to glaucoma surgery. Vogel1,2 first described trabecular tissue ablation with an excimer laser in 1996 and 1997. Later, Jacobi and coauthors3–6 used an erbium:YAG (Er:YAG) laser for the same purpose. Both lasers produce precise tissue transection and ablation.7–9 In the studies by Vogel and Jacobi and coauthors, trabecular tissue ablation significantly reduced the mean intraocular pressure (IOP). Erbium:YAG laser treatment was guided by observation with a separate endoscope or with a modified Trokel goniolens. We use an integrated system that combines a laser fiber and an endoscope in a single handpiece. In a 2003 ASCRS and ESCRS Published by Elsevier Inc.
previous study, we tested this system in enucleated human eyes with melanoma.10 Precise tissue ablation of trabecular meshwork was confirmed histologically. The inner wall of Schlemm’s canal is disrupted in a highly selective manner, leaving the outer wall unaltered. We now report our clinical experience in glaucoma patients after 3 years of follow-up.
Patients and Methods The study was reviewed by the appropriate ethics committee and performed in accordance with the ethical standards of the 1964 Declaration of Helsinki. All patients gave informed consent before their inclusion in the study. Twenty eyes of 20 patients were treated by phacoemulsification and endoscopic Er:YAG laser goniopuncture for cata0886-3350/03/$–see front matter doi:10.1016/S0886-3350(03)00241-4
COMBINED ENDOSCOPIC GONIOPUNCTURE AND CATARACT SURGERY
Table 1. Patients’ characteristics. Number of Patients Laser Group (n ⫽ 20)
Parameter
Control Group (n ⫽ 18)
Glaucoma Ocular hypertension Open-angle glaucoma Pseudoexfoliation
3
3
14
11
3
4
3
3
Glaucoma damage No lesion Excavation of optic nerve head
5
8
12
7
9
7
2
6
3
3
4
Excavation and visual field defect
Figure 1. (Feltgen) The laser tip is placed in the anterior chamber (histological slide of an enucleated human eye).
Antiglaucoma drugs needed 1
1
ract and coexisting glaucoma or ocular hypertension. Patients were scheduled for surgery when visual acuity was worse than 0.5. Glaucoma patients with progression in visual field loss or excavation of the optic nerve head were included only when IOP did not exceed 25 mm Hg. Otherwise, these patients were treated by combined phacoemulsification and trabeculectomy. Patients with higher preoperative IOP were included if the visual field and optic nerve head showed no progressive damage. Eyes with previous surgery or laser therapy for glaucoma or with other severe eye disease were excluded. Patients were examined postoperatively at 3 days, 6 weeks, 6 months, and 1, 2, and 3 years. Twenty eyes (20 patients) completed the 12-month follow-up and 15 eyes, the 3-year follow-up. Primary study endpoints were IOP, visual acuity, and number of antiglaucoma drugs 1 year after surgery. The postoperative values at 2 and 3 years were collected retrospectively and not compared to those in the control group.
Accepted for publication February 27, 2003. From the Department of Ophthalmology, Albert-Ludwigs-University Freiburg (Feltgen, Mueller, Funk), Freiburg, Germany, and Institute of Applied Physics, University of Bern (Ott, Frenz), Bern, Switzerland. None of the authors has a financial or proprietary interest in any material or method mentioned. Reprint requests to Dr. med. Nicolas Feltgen, Universita¨ts-Augenklinik, Killianstrasse 5, 79106 Freiburg, Germany. E-mail:
[email protected]. uni-freiburg.de. 2156
The mean age was 77.5 years ⫾ 9.7 (SD) in the lasertreated group and 80.4 ⫾ 7.9 years in the control group. Table 1 shows the patients’ characteristics. This prospective treatment arm was compared to a retrospective-inclusion matched control group of 18 eyes of 18 glaucoma patients who had cataract surgery by the same surgeon. The surgical procedure was identical in the 2 groups except for the laser goniopuncture.
Laser Goniopuncture Laser goniopuncture was performed with the Sklerotom 2.9 Endognost System Er:YAG laser (Schwind) in freerunning mode at a wavelength of 2.94 mm. When laser energy was adjusted to between 5 mJ and 16 mJ, the pulse duration was 160 s. Light was delivered via a 300 mm diameter, 11.2 cm long sapphire fiber rod. The energy output was adjusted to 16 mJ, resulting in a radiant exposure of 22.6 J/cm2 to the trabecular meshwork. Output energy and pulse length were determined in all fibers used. The endoscope and laser fiber were housed in a single, 1100 mm diameter tube.
Cataract Surgery and Laser Treatment Cataract surgery was performed by phacoemulsification through a clear corneal tunnel incision. A foldable intraocular lens was implanted. In the laser-treatment group, the pupil was constricted by an injection of acetylcholine chloride (Miochol威). After sodium hyaluronate 3% (Rayvisc) was injected, the endoscope laser unit was inserted into the anterior chamber through the tunnel incision and advanced to the opposing chamber angle (Figure 1). In a previous study,10 the laserinduced trabecular holes were verified histologically (Figure 2). To prevent energy loss caused by absorption in the surrounding fluid, care was taken to ensure the laser tip gently touched the trabecular meshwork (Figure 3). In all eyes, 180 degrees of the trabecular meshwork (half circumfer-
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Figure 2. (Feltgen) Left: Histologically confirmed hole in trabecular meshwork (arrows). Right: Nontreated trabecular meshwork (asterisk ⫽ Schlemm’s canal).
ence) were treated with 18 single laser pulses. The laser effects were not overlapping and were distributed equally. This corresponded to an overall opening distance of Schlemm’s canal of approximately 1.27 mm2 (18 ⫻ 300 m diameter). Postoperatively, eyes were treated with dexamethasone eyedrops (Ultracortenol威) in both groups.
Statistical Analysis Comparison of the differences between the laser-treatment group and the control group were evaluated by a U test. Within-group preoperative and postoperative values were compared by an analysis of variance (Bonferroni-Dunn). Results are given as mean ⫾ standard deviation. Success was defined as a postoperative IOP below 21 mm Hg and an IOP decrease from preoperatively by at least 20% without reoperation.
Figure 3. (Feltgen) The laser tip placed in the chamber angle (endoscopic view and schematic).
Results The cataract surgery was uneventful in all cases. Two patients in the laser-treatment group died between 2 years and 3 years after surgery. Laser-Treatment Group Table 2 and Figure 4 show the mean IOP in the laser-treated group over time. After 2 years (11 patients)
and 3 years (15 patients), the mean IOP was significantly lower than preoperatively. At 1 year, the treatment was considered successful (IOP ⬍21 mm Hg and 20% less than preoperatively with no reoperation) in 15 of 20 eyes (75%) and at 3 years, in 11 of 15 eyes. Because only 15 of 20 patients fulfilled the 3-year follow-up,
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Table 2. Mean IOP over time.
Table 3. Number of glaucoma medications required over time.
IOP (mm Hg)
Number of Medications
Mean ⫾ SD
Difference*
P Value
23.5 ⫾ 3.9
—
—
6 wk
16.2 ⫾ 2.7
7.3 ⫾ 2.8
.0001
6 mo
15.7 ⫾ 1.8
7.8 ⫾ 4.9
12 mo
16.3 ⫾ 2.7
7.3 ⫾ 3.2
Examination Preoperative
Mean ⫾ SD
P Value
1.6 ⫾ 0.9
—
6 wk
0.5 ⫾ 0.8
.0001
.0001
6 mo
0.4 ⫾ 0.8
.0001
.0001
12 mo
0.5 ⫾ 0.8
.0001
Postoperative
Examination Preoperative Postoperative
2y
15.0 ⫾ 3.5
8.5 ⫾ 5.5
.0001
2y
0.4 ⫾ 0.6
.0001
3y
15.0 ⫾ 2.0
8.5 ⫾ 5.0
.0001
3y
0.6 ⫾ 0.7
.0001
the success rate was 73%. There were no significant changes in IOP between 6 weeks, 6 months, 12 months, 2 years, and 3 years (Figure 5). Table 3 shows the mean number of antiglaucoma medications required over time. Visual acuity improved from 0.29 ⫾ 0.13 preoperatively to 0.80 ⫾ 0.20 at 12 months (P⬍.0001) (Figure 6). The mean acuity was 0.76 ⫾ 0.22 at 2 years (P⬍.0001) and 0.61 ⫾ 0.24 at 3 years (P⬍.0017). One patient developed age-related macular degeneration (ARMD) that was treated twice by photodynamic therapy 2.5 years after cataract surgery with Er:YAG gonioscopy. Moderate retrograde bleeding from Schlemm’s canal occurred in 12 eyes (Figure 7). Mild hyphema was observed in all 12 eyes on the first postoperative day but resolved within the following 72 hours in all cases (Figure 8). One patient with fibrin reaction required anterior chamber revision.
Two patients required another operation for glaucoma. The first patient, who was on warfarin sodium (Coumadin威) therapy, had severe anterior chamber bleeding that required 4 reoperations including cyclophotocoagulation, anterior chamber revision, and a neodymium:YAG (Nd:YAG) iridotomy within 1 month of the Er:YAG goniopuncture. The IOP was 15 mm Hg at 1 year and 13 mm Hg at 3 years, and the visual acuity was 0.3 and 0.2, respectively, as a result of cystoid macular edema. The second patient required cyclophotocoagulation for an IOP of 33 mm Hg on antiglaucoma eyedrops 8 weeks after surgery. This patient was initially treated for an IOP of 37 mm Hg. The IOP was 24 mm Hg at 1 year and 15 mm Hg at 3 years and the visual acuity, 0.6 and 0.4, respectively. These 2 patients were excluded from IOP analysis (Figure 5). Therefore, Figure 5 and the mean postoperative IOP values resemble the course of IOP after single glaucoma surgery with the Er:YAG
Figure 4. (Feltgen) Reduction in IOP in the laser-treated group 1
Figure 5. (Feltgen) Reduction in IOP in the laser-treated group in
year postoperatively (circle ⫽ reoperated patients).
the first 3 postoperative years.
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laser. However, the visual acuity in these 2 patients was analyzed and is included in Figure 6. No other severe complications such as fibrin reaction, synechias, or hypotony occurred within the first year. Control Group As the control group was analyzed retrospectively, follow-up data at 6 weeks were not available for all patients. The mean IOP dropped from 19.8 ⫾ 1.3 mm Hg preoperatively to 17.2 ⫾ 2.3 mm Hg (difference 2.6 ⫾ 2.1 mm Hg) at 6 months (P ⫽ .013) and to 18.1 ⫾ 1.8 mm Hg (difference 1.7 ⫾ 1.9 mm Hg) at 12 months (P ⫽ .12) (Figures 9 and 10, respectively). The IOP
Figure 6. (Feltgen) Preoperative and postoperative visual acuity in
reduction in the control group was significantly less than that in the laser-treated group at all visits (P⬍.001). The number of antiglaucoma drugs needed decreased from 1.0 ⫾ 0.9 preoperatively to 0.8 ⫾ 0.7 at 6 months (P ⫽ .18) and to 0.8 ⫾ 0.9 at 12 months (P ⫽ .21). Visual acuity improved from 0.27 ⫾ 0.12 preoperatively to 0.79 ⫾ 0.21 at 12 months (P ⫽ .008) (Figure 11). Two patients had reduced visual acuity (0.3) resulting from ARMD 12 months after surgery. Treatment was successful (as defined above) in 2 of 18 eyes (11%).
Discussion Our results indicate that Er:YAG laser goniopuncture results in a sustained reduction in IOP in glaucoma patients. The procedure was safe and easily combined with cataract surgery. In Er:YAG goniopuncture, laser-induced microperforations connect the anterior chamber to Schlemm’s canal, improving the outflow facility.4,11,12 Untreated regions of the trabecular meshwork remain unchanged. This method markedly differs from other laser techniques in trabecular surgery such as argon trabeculoplasty. In argon laser treatment, tissue conformation is changed by heat and is followed by scar formation. Tractional forces exerted by scar tissue cause a degree of dilation of trabecular meshwork pores.13 In this respect, Er:YAG goniopuncture is more comparable to conventional goniopuncture and trabec-
the laser-treated group.
Figure 7. (Feltgen) Chamber angle 1 day postoperatively (arrows ⫽
Figure 8. (Feltgen) Chamber angle 3 days postoperatively (arrows ⫽
treated areas).
treated areas).
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ulotomy. However, these methods differ in the perforation size achieved. The well-defined microperforations in Er:YAG goniopuncture inflict only minor trauma and seemingly hamper overall trabecular meshwork stability to a much less extent than the larger tissue disruptions caused by conventional trabecular surgery. This could explain the mild inflammatory response and absence of fibrin reaction in our study. An animal study found scarring of trabecular microperforations with progressive fibroblastic proliferation in rabbits treated with the Er:YAG.3 In that study, the IOP remained unchanged even though initial trabecular dissection was confirmed histologically. It is pre-
sumed that the small perforations achieved by 200 m diameter laser tips were prone to reocclusion. In addition, the preoperative IOP in the animal eyes may have been too low to sufficiently perfuse the pores. We used 300 m diameter fibers, resulting in larger pores that may allow more aqueous flow to rinse the openings postoperatively, avoiding secondary occlusion. When Er:YAG laser effects on trabecular meshwork were studied in porcine and human enucleated eyes, increased outflow facility was found.4,11,12 Accordingly, an IOP reduction is expected. In the present study, the IOP reduction in the laser-treated group was significantly greater than in a retrospective control group that had the same inclusion criteria. The success rate, defined as postoperative IOP below 21 mm Hg and at least 20% less than preoperatively, was significantly higher in the laser-treated group. This is in line with the results in other studies.1,2,5,6,14,15 These results continued through the last follow-up at 3 years. Preoperative IOP in the control group was lower than in the laser-treated group; thus, less IOP reduction was expected. However, the IOP reduction in the control group, approximately 2 mm Hg after treatment, is in line with results in studies of the IOP-lowering effect of cataract surgery alone.16 The 6- and 12-month IOPs in the laser-treated group were lower than those 6 weeks after treatment. This could be the result of further dilation of the laserinduced perforations. As the laser-induced IOP reduction was stable at 12 months, we assume the effect of
Figure 10. (Feltgen) Reduction in IOP in the control group in the first 12 postoperative months.
Figure 11. (Feltgen) Preoperative and postoperative visual acuity in the control group.
Figure 9. (Feltgen) Reduction in IOP in the control group 1 year postoperatively.
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“filling-in” by proliferating endothelial cells described after trabeculotomy in monkeys17 did not occur. This assumption is confirmed by the results 2 and 3 years postoperatively. We did not compare these results with those in the control group as 2 to 3 years was not a defined endpoint at the beginning of the study. The complication rate of combined Er:YAG laser goniopuncture and cataract surgery in our study was lower than that of other combined approaches such as trabeculectomy and phacoemulsification.18,19 Besides mild intraocular hemorrhage, which resolved spontaneously within 72 hours, 3 patients had complications. The first patient had a postoperative fibrin reaction that required anterior chamber revision. The IOP was sufficiently lowered by Er:YAG goniopuncture. The second patient was on Coumadin therapy, and the fellow eye had combined cataract surgery and trabeculectomy 2 years previously. At that time, a pronounced fibrin reaction and posterior synechias required repeated cyclophotocoagulation, anterior chamber revision, and Nd:YAG iridotomy within 3 months postoperatively. Given that bleeding is likely in such cases, concomitant anticoagulant therapy might be an exclusion criterion for Er:YAG laser goniopuncture. Whether patients with significantly elevated IOP benefit from Er:YAG goniopuncture must be clarified. The third patient who required a reoperation had a preoperative IOP above 30 mm Hg (37 mm Hg). Laser goniopuncture reduced the IOP to 33 mm Hg. Cyclophotocoagulation was necessary. The treatment was not considered successful according to our definition. As the fiber-rod diameter and the radiant exposure to trabecular tissue were optimized in histological studies, we recommend not altering these parameters. In patients with significantly elevated IOP, it might be preferable to place more than 18 laser pulses. However, we did not repeat Er:YAG goniopuncture in this patient. Based on our experience with combined Er:YAG goniopuncture and phacoemulsification, we intend to perform endoscopic laser goniopuncture in phakic eyes as well. The risk of touching the lens seems minimal as the anterior chamber can be extended and stabilized sufficiently with viscoelastic material. Because trabecular meshwork photoablation is controlled by an endoscope, it can even be used in eyes with an opaque cornea. Another advantage of this method is its clear corneal approach. In cases in which the IOP remains too high,
further glaucoma surgery is not hampered by conjunctival scars. This “minimally invasive” approach may supplement the established techniques in glaucoma surgery.
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