Uncontrolled Open-angle Glaucoma Research Articles

Influence of previous argon laser trabeculoplasty on long-term effectiveness of trabeculectomy

The efficacy and safety of trabeculectomy surgery was assessed for treatment of uncontrolled open-angle glaucoma in eyes previously treated with just topical medication (118 eyes) or argon laser trabeculoplasty (65 eyes). Trabeculectomy after failure of argon laser trabeculoplasty has proved to be as effective and safe as trabeculectomy without prior laser application.

Clinical Results of Selective Laser Trabeculoplasty

Purpose: Selective laser trabeculoplasty (SLT) is a new laser procedure using a frequency-doubled Q-switched Nd:YAG laser (wavelength: 532 mm). The laser parameters are set to selectively target pigmented trabecular meshwork (TM) cells without coagulative damage to the TM structure or non-pigmented cells. We investigated the safety and efficacy of SLT in lowering intraocular pressure (IOP). Subjects and Methods: Sixty-seven eyes of 67 patients with uncontrolled open angle glaucoma were treated with the Coherent Selecta 7000 ® (Coherent Inc., Palo Alto, CA). Nineteen of 67 patients had previously received argon laser trabeculoplasty. A total of approximately 60 non-overlapping spots were placed over 180 degrees of the TM ranging from 0.5 to 1.0 mJ per pulse. The maximum energy level at which no bubble formation was observed determined choice. Results: The average preoperative IOP was 22.4 mm Hg. Six months after the operation, mean IOP reduction was 4.4 mm Hg, and mean outflow pressure (OP) reduction was 38.1%. One month after the operation 68.7% of patients responded to treatment with an OP reduction of at least 20% (“responders”). Transient IOP elevation of 5 mm Hg or greater was seen in 25.4% of patients. The success rate at 6 months after operation was 64.6% for all patients (67 eyes) and 78.2% for the responders (46 eyes). An analysis using a Cox proportional hazard model showed that a low preoperative IOP was the significant determinant for success, and the hazard ratio for the IOP increase of 5 mm Hg was 2.12. Other factors such as age, gender, past history of ALT, and goniopigment were not significantly related to success. Conclusion: SLT appears to be a safe and effective way to lower IOP.

Comparison of deep sclerectomy with collagen implant and trabeculectomy in open-angle glaucoma

Purpose: To assess the efficacy and postoperative complications of deep sclerectomywith collagen implant (DSCI), a nonpenetrating filtration procedure. Setting: Glaucoma Unit, Department of Ophthalmology, University of Lausanne, Switzerland. Methods: Forty-four eyes of 44 patients with medically uncontrolled open-angle glaucoma had DSCI and a matched control group of 44 patients, trabeculectomy. A superficial scleral flap was raised and a deep sclerectomy performed in the scleral bed. Schlemm's canal was opened, and the cornea was dissected to Descemet's membrane. At that stage, aqueous filtered through the remaining trabeculo-Descemet's membrane. A collagen implant was sutured radially in the scleral bed; the scleral flap and conjunctiva were then closed. Examinations were performed before surgery and postoperatively at 1 and 7 days and 1, 2, 3, 6, 9, 12, 15, 18, and 24 months. Results: The mean follow-up was 14.4 months ± 6.3 (SD) (range 3 to 24 months). The mean preoperative intraoperative pressure (IOP) was 26.7 ± 7.3 mm Hg. The mean postoperative IOP was 6.1 ± 4.5 mm Hg at 1 day and 11.0 ± 4.4 mm Hg at 1 week; it remained stable for the next 24 months. The success rate, defined as an IOP lower than 21.0 mm Hg without medication, was 69% in the DSCI group and 57% in the trabeculectomy group at 24 months postoperatively ( P = .047). The number of postoperative complications was significantly lower in the DSCI group than in the trabeculectomy group. Conclusions: The success rate of DSCI may be comparable to that of trabeculectomy, with fewer complications.

Microendoscopic trabecular surgery in glaucoma management

ObjectiveTo evaluate the safety and efficacy of trabecular surgery under microendoscopic control in the management of advanced chronic open-angle glaucoma when the presence of corneal opacification obscures adequate visualization of the anterior segment. Study designComparative interventional case series. Participants and interventionFifteen eyes of 15 patients with medically uncontrolled open-angle glaucoma and moderate-to-severe corneal opacification underwent trabecular surgery under microendoscopic control. Seven eyes were treated by photoablative laser goniopuncture and eight eyes by goniocurettage. Main outcome measuresThe intraocular pressure (IOP) and number of medications before and after surgery were measured. Intraoperative and postoperative complications were analyzed. ResultsThe ophthalmic microendoscope was successfully used in visualizing and identifying the anterior chamber angle structures and in controlling the trabecular surgical procedures in all eyes. The IOP dropped from 34.5 ± 6.9 millimeters of mercury (mmHg) (range, 27–46 mmHg) under maximal-tolerated medical therapy before surgery to 18.5 ± 3.0 mmHg (range, 15–23 mmHg) at 21 months after surgery. Medication averaged 2.3 ± 0.6 before surgery and dropped to 1.0 ± 0.7 at last follow-up. No difference was observed in the surgical outcome between the laser-treated eyes and those receiving goniocurettage. No severe intraoperative or postoperative complications relating to either the trabecular surgery or to the use of the microendoscope were observed. ConclusionThe ophthalmic microendoscope appears to be safe and effective in simultaneously providing illumination, video recording, and clear endoscopic view of the fine details of the anterior chamber angle structures. Microendoscopy enables various trabecular surgical procedures, such as goniocurettage or photoablative laser goniopuncture, which can be performed in the presence of corneal opacification that might otherwise preclude adequate visualization and treatment. It thus appears that microendoscopic trabecular surgery may in the future be considered as an alternative choice of surgical treatment in some cases of open-angle glaucoma.

Non-penetrating deep sclerectomy and collagen implant surgery in glaucoma patients with advanced field loss.

The aim of the study was to determine the medium term intraocular pressure (IOP) lowering effects and the potential complications of non-penetrating deep sclerectomy and collagen implant (DSCI) surgery in glaucoma patients. 54 eyes of 52 patients with medically uncontrolled open angle glaucoma with advanced field loss underwent DSCI under topical anaesthesia. Follow-up period was 24 months. The mean preoperative IOP was 24.7 +/- 6.2 mmHg and decreased to 15.1 +/- 4.0 mmHg at 24 months (p = 0.0068). During the follow- up period, 36 of 54 eyes (66%) received no topical antiglaucomatous medications. In 18 eyes, monotherapy with topical beta blockers (Betaxolol HCl) was added to the regimen. At last visit, only two patients (3.8%) had IOP greater than 18 mmHg. We did not detect any additional optic disc changes, visual field or visual acuity defects postoperatively. Detailed slit-lamp examination revealed no anterior segment complications regarding the probable complications of trabeculectomy. None of the patients developed surgery related cataract. As a complication, we diagnosed one case of self-limited, shallow choroidal detachment. DSCI appears to provide considerable medium term IOP decrease with few postoperative complications without deteriorating visual acuity. Owing to our medium term results, we believe that DSCI could be a valuable alternative to trabeculectomy especially in cases of advanced medically uncontrolled open angle glaucoma.

Immediate intraocular pressure response to selective laser trabeculoplasty

BACKGROUND/AIMSSelective laser trabeculoplasty targets the pigmented trabecular meshwork cells without damage to the trabecular meshwork architecture in vitro. A study was conducted in vivo of eight eyes with uncontrolled open...

Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser trabeculoplasty): A multicenter, pilot, clinical study

Objective To investigate the safety and efficacy of a new laser procedure using a q-switched 532-nm neodymium (Nd):YAG laser, also called “selective laser trabeculoplasty,” to lower intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). The laser parameters were set to selectively target pigmented trabecular meshwork (TM) cells without coagulative damage to the TM structure or nonpigmented cells. Design Nonrandomized, prospective, clinical trial. Participants Thirty eyes of 30 patients with uncontrolled OAG (OAG group) and 23 eyes of 23 patients with uncontrolled OAG treated previously with argon laser trabeculoplasty (ALT group) were observed for 4 to 26 weeks. Forty-four of the 53 eyes were observed for 26 weeks. Intervention Patients were treated with the Coherent Selecta 7000 (Coherent, Inc, Palo Alto, CA) frequency-doubled q-switched Nd:YAG laser (532 nm). A total of approximately 50 nonoverlapping spots were placed over 180° of the TM at energy levels ranging from 0.6 to 1.2 mJ per pulse. After surgery, patients were maintained with the identical drug regimen as that before treatment. Results Both the OAG and ALT groups showed similar IOP reductions over time. Seventy percent of patients in each group responded to treatment with an IOP reduction of least 3 mmHg. At 26 weeks of follow-up, mean IOP reduction was 5.8 mmHg (23.5%, P < 0.001) for the OAG group and 6.0 mmHg (24.2%, P < 0.001) for the ALT group. The untreated eye showed a 9.7% ( P < 0.001) reduction of IOP at 26 weeks. However, the IOP difference between the treated and untreated eyes was statistically significant at P < 0.003. Transient IOP elevation of 5 mmHg or greater was seen in 24% of patients. Conclusion The selective laser trabeculoplasty appears to be a safe and effective method to lower IOP in patients with OAG and patients treated previously with ALT. A reduction of IOP can be achieved without coagulation of the TM.

Five-year results of a randomized, prospective, clinical trial of diode vs argon laser trabeculoplasty for open-angle glaucoma

PURPOSE: To evaluate the safety and efficacy of laser trabeculoplasty (LTP) with a semiconductor diode laser (810 nm, [DLT]) vs an argon blue-green laser (488 to 514 nm, [ALT]). METHODS: In a prospective, randomized clinical trial, 50 eyes of 46 patients with uncontrolled open-angle glaucoma on maximally tolerated medical therapy were treated and followed at regular intervals for 5 years. Fifty laser spots were applied over 180 degrees using either maximal laser power or sufficient power to produce blanching or a small bubble (570 to 850 mW, DLT; 400 to 1,100 mW, ALT). We performed DLT using a 100-μm spot size, a 0.5-second exposure, and a Ritch lens; we conducted ALT with a 50-μm spot, a 0.1-second exposure, and a Goldmann lens. Patients in the study were followed until trabeculectomy was required. RESULTS: The mean follow-up times ± SD for all eyes were 38.6 ± 5.4 months, DLT (n = 22; range, 1 to 68 months) and 35.5 ± 4.8 months, ALT (n = 28; range, 1 to 66 months). Those in the diode laser group (n = 16) who had more than 1 year of follow-up were tracked for 49.4 months, and those in the argon laser group (n = 21) were tracked for 45.8 months. There were no significant differences in the mean pretreatment intraocular pressures (IOPs): 21.2 mm Hg, DLT (n = 22) and 21.5, ALT 21.5 mm Hg (n = 28); P = .81] or in mean final IOPs (15.7 mm Hg, DLT and 17.1 mm Hg, ALT; P = .19). Time to surgical failure showed no significant differences, with 50% of the DLT eyes and 58% of the ALT eyes surviving at 5 years ( P = .59). CONCLUSION: In eyes with open-angle glaucoma and unsatisfactory IOP control on maximally tolerated medical therapy, DLT and ALT are equally effective in lowering IOP over a 5-year period.

An ultrasound biomicroscopic study of eyes after deep sclerectomy with collagen implant

Objective This study aimed to assess the natural history of eyes after deep sclerectomy with collagen implant (DSCI), a nonperforating glaucoma-filtering surgery. Design The design was a prospective, longitudinal, observational, and nonrandomized study. Participants Forty-five eyes of 41 patients with medically uncontrolled open-angle glaucoma were studied. Intervention Deep sclerectomy with collagen implant was performed. Main outcome measures Ultrasound biomicroscopy (UBM) of the sclerectomy site was performed 1, 2, 3, 6, 9, 12, and 18 months after surgery. The following parameters were assessed: length and height of the collagen implant, thickness of the residual trabeculodescemetic membrane, and bleb appearance. Results Mean intraocular pressure decreased from a preoperative value of 26.3 ± 3.5 mmHg (mean ± standard deviation) to a postoperative value of 16.6 ± 3.1 mmHg (mean ± standard deviation) at 18 months ( P < 0.001). The UBM findings showed a subconjunctival filtration with a nonperforated thin trabeculodescemetic membrane. In 23 eyes (51%), a hypoechoic area in the suprachoroidal space was observed. The thickness of the trabeculodescemetic membrane was stable throughout the study with a mean value of 0.13 mm ± 0.02 (mean ± standard deviation) at 18 months. The collagen implant dissolved slowly within 6 to 9 months, leaving a tunnel in the sclera. Conclusions The UBM findings are consistent with intraocular pressure lowering by aqueous filtration through the thin remaining trabeculodescemetic membrane to an area under the scleral flap, which was maintained open by the collagen implant. The authors speculate that aqueous humor then reached the subconjunctival space and, eventually, was filtered through the thin scleral wall into the suprachoroidal space. Complete resorption of the collagen implant occurred between 6 and 9 months after surgery.

Efficacy of Argon Laser Trabeculoplasty in Aphakic and Pseudophakic Eyes

This study evaluated the efficacy of argon laser trabeculoplasty (ALT) in patients with aphakia or pseudophakia. The authors retrospectively analyzed 63 eyes of 63 patients with aphakia or pseudophakia who had uncontrolled open-angle glaucoma and were treated with 180 degrees or 360 degrees ALT. The mean intraocular pressure (IOP) before ALT was 25.1 mm Hg (+/- 8.1 mm Hg). Two years after ALT, the mean IOP in the successfully treated group was 15.4 mm Hg. The mean survival time (50% success rate) for all treated eyes was 23 months, and treatment was successful in 34% of eyes at 36 months. Pseudophakic eyes had a better response than aphakic eyes (P = .06), and eyes that had extracapsular surgery did better than eyes with intracapsular surgery (P = .07). ALT in aphakic or pseudophakic eyes with uncontrolled glaucoma is a safe, reasonably effective treatment that can delay the need for trabeculectomy.

Photographic Documentation of the Loss of Medullated Nerve Fibers of the Retina in Uncontrolled Primary Open Angle Glaucoma

We report the first case of retinal myelin loss associated with uncontrolled primary open angle glaucoma (POAG). The clinical features, visual fields, and serial disc photos documenting the changes are described. The literature regarding this phenomenon in other forms of optic neuropathy and the specific implications in glaucoma patients are discussed. A 75-year-old black man with POAG had medullated nerve fibers of the retina bilaterally abutting the optic discs inferonasally. Optic disc appearance and visual fields were stable over 6 years. The patient was then lost to follow-up for 2 years and returned with elevated intraocular pressures (IOPs), visual acuity and field loss, progressive optic disc damage, peripapillary atrophy, and disappearance of retinal myelin on the left greater than the right. Retinal myelin loss occurred in areas of nerve fiber layer dropout. Loss of medullated nerve fibers in the retina occurs secondary to anterograde axonal degeneration as a nonspecific response to any form of optic atrophy. The apparent paucity of glaucoma patients with retinal myelin may be due to late referral rather than any inherent protective effect of retinal myelin against elevated IOP.

Ultrasound biomicroscopy of eyes undergoing deep sclerectomy with collagen implant.

To assess the intraocular pressure (IOP) lowering mechanism of deep sclerectomy with collagen implant (DSCI), a non-penetrating glaucoma surgery. Nine eyes of nine patients with medically uncontrolled open angle glaucoma underwent DSCI. Ultrasound biomicroscopy (UBM) of the sclerectomy site was performed 1 month after surgery. The following factors were assessed: length and height of collagen implant, and thickness of the residual trabeculocorneal membrane. Postoperative IOP decreased significantly in all nine eyes from a preoperative mean value of 25.8 (SD 4.8) mm Hg to a postoperative (1 month) mean value of 11.3 (6.3) mm Hg (p = 0.001). In all nine eyes, UBM at 1 month after surgery showed a subconjunctival filtration through the thin trabeculocorneal membrane and through the scleral flap around the collagen implant. In four cases, a hypoechoic area in the suprachoroidal space was observed and might represent ciliary body detachment or be due to suprachoroidal drainage of aqueous humour through the thin deep scleral wall. At 1 month after surgery the mean trabeculocorneal membrane thickness was 110.1 (16.8) microns, and the mean length and height of the collagen implant were 2.3 (0.1) mm and 1.1 (0.1) mm respectively. DSCI lowered IOP by allowing aqueous filtration through a thin trabeculocorneal membrane to the subconjunctival space and, eventually, to the suprachoroidal space.

Combined Phacoemulsification, Endoscopic Ciliary Process Photocoagulation, and Intraocular Lens Implantation in Glaucoma Management

The safety and efficacy of combined cataract extraction and intraocular lens (IOL) implantation with endoscopic ciliary process photocoagulation in glaucoma management was evaluated. Ten patients with uncontrolled open-angle glaucoma and cataract prospectively underwent concomitant phacoemulsification, endoscopic ciliary process photocoagulation, and posterior chamber IOL implantation. With a mean follow up of 19.2 months, the mean intraocular pressure (IOP) decreased from 31.4 mm Hg preoperatively to 13.5 mm Hg postoperatively, an absolute decrease of 57%. This represented a significant decrease for each of the patients. The visual acuity of each also improved. Transient vitreous hemorrhage developed in one patient, but no cystoid macular edema or any other significant complications occurred and all eyes were quiet. There were no lens implant dislocations. There was no progressive visual field loss at 1 month post surgery, but such loss was noted in one patient 1 year after treatment. Good IOP control on no medical therapy was attained in one half of the patients. It may be concluded that this combined procedure provided effective management of cataract and glaucoma with a minimum of postoperative care. The safety and efficacy of this approach as compared with cataract surgery combined with filtration remains to be determined.

5-fluorouracil and Mitomycin C in Pseudophakic Patients

Purpose: Previous studies have shown that 5-fluorouracil (5-FU) and mitomycin C enhance the success rate of filtration surgery in aphakic eyes. However, eyes with posterior chamber implants have not been specifically studied. This study was performed to compare the safety and efficacy of 5-FU with that of mitomycin C in eyes that have posterior chamber implants and undergo filtration surgery for uncontrolled glaucoma.Methods: Eighty eyes of 74 patients who had previous cataract surgery with posterior chamber implants and who subsequently required trabeculectomy for uncontrolled open-angle glaucoma were randomized to receive either subconjunctival postoperative 5-FU or intraoperative mitomycin C.Results: Twelve months after surgery, intraocular pressures (IOPs) averaged 12.8 ± 5.5 mmHg (mean ± standard deviation) in the mitomycin C group and 14.8 ± 3.8 mmHg in the 5-FU group (P = 0.001). Mitomycin C-treated eyes received an average of 0.6 medications for IOP control, and 5-FU-treated eyes received an average of 1.05 medications (P = 0.03). There was no significant difference in complications between the two groups.Conclusion: Mitomycin C appears be a viable alternative to 5-FU in patients with posterior chamber implants with uncontrolled glaucoma who require filtration surgery.

Apraclonidine and Argon Laser Trabeculoplasty

Sixty patients with medically uncontrolled open-angle glaucoma (intraocular pressure greater than 21 mm Hg) were randomly assigned to one of two treatment regimens with apraclonidine before undergoing 360-degree argon laser trabeculoplasty. One drop of apraclonidine 1% was instilled one hour before and immediately after laser treatment in 30 eyes or apraclonidine was delivered only after trabeculoplasty in 30 eyes. Intraocular pressure before laser treatment, number of antiglaucoma medications, and the laser treatment settings were comparable between the two groups. The mean and percent change in intraocular pressures were similar in both treatment groups one and two hours after trabeculoplasty. One drop of apraclonidine 1% instilled immediately after argon laser trabeculoplasty prevented intraocular pressure increase one hour and two hours postoperatively as effectively as its instillation both one hour before and immediately after laser treatment.

Bilateral Argon Laser Trabeculoplasty in Primary Open-Angle Glaucoma

We performed bilateral argon laser trabeculoplasty on 34 patients with medically uncontrolled open-angle glaucoma. Preoperative intraocular pressure was greater than 21 mm Hg, with a less than 3-mm Hg difference between the two eyes. Laser treatment (360 degrees) was performed on both eyes within a three-month interval. Mean (+/- S. D.) baseline intraocular pressure was similar in the first- (26.9 +/- 3.7 mm Hg) and second- (26.5 +/- 3.3 mm Hg) treated eyes. One hour after treatment, four first- and four second-treated eyes had a greater than 30% increase in intraocular pressure. The one-hour change in pressure was highly correlated between the two eyes (r = .794, P less than .0001). Intraocular pressure was reduced (P less than .0001) one, two, and three years after treatment in both the first and second-treated eyes. The percentages of first- and second-treated eyes with a pressure of less than or equal to 21 mm Hg were similar at one, two, and three years. Pressure response between the two eyes was correlated (P less than .0001) at year 1 (r = .815), 2 (r = .757), and 3 (r = .886) after laser therapy.

Long-term follow-up of argon laser trabeculoplasty for uncontrolled open-angle glaucoma.

Between May 1978 and October 1981, 82 phakic eyes in 72 patients with uncontrolled open-angle glaucoma underwent 360 degrees argon laser trabeculoplasty. Continued long-term follow-up has shown a decreasing pressure-lowering effect. The peak pressure lowering was 9.7 mm Hg at two months, 7.3 mm Hg at two years, 6.8 mm Hg at four years, and 4.9 mm Hg at five years. In 1982, we reported a 77% success rate, but, after five years of observation, the success rate is 46%. However, our clinical population is unique in that the majority of our patients (57%) are black. The most important factor in the long-term success rate appears to be race. Only 32% of cases involving black patients were successful, while 65% of cases involving white patients were successful. A Kaplan-Meier survival curve analysis revealed that the median time to an intraocular pressure greater than 21 mm Hg was 12 months for black patients and 60 months for white patients.

Q-Switched Neodymium-YAG Laser Angle Surgery in Open-angle Glaucoma

In a short-term pilot study, we evaluated Q-switched neodymium-YAG laser angle surgery in 25 eyes from 22 patients with medically uncontrolled open-angle glaucoma. All eyes had unacceptable intraocular pressures (IOPs), despite maximum tolerated medical therapy, argon laser trabeculoplasty, and prior intraocular filtration surgery (eight eyes). Using a pulse energy of 10 millijoules, ten spots were placed approximately 4 degrees apart in the mid-trabecular meshwork using an Nd-YAG laser (Coherent 9900). The mean preoperative and final postoperative IOPs were 30 +/- 6 mm Hg and 21 +/- 8 mm Hg, respectively. The mean follow-up time was five (+/- 3) months (range, two to 14 months). The final postoperative IOP was less than 22 mm Hg in 17 eyes (68%). Holes within the trabecular meshwork were visible in 14 eyes, and laser therapy was associated with the liberation of debris into the anterior chamber in all eyes. Complications included transient postoperative IOP elevation (eight eyes), angle bleeding (six eyes), and posterior displacement of the iris root (four eyes).

Argon laser trabeculoplasty as initial therapy for glaucoma.

Argon laser trabeculoplasty (ALT) was used as the initial treatment in 30 eyes of 20 patients with uncontrolled open-angle glaucoma in Egypt. None of the patients had received previous medical or surgical therapy. The average reduction of intraocular pressure with ALT alone was 10.1 mm Hg. Medical and surgical glaucoma therapy was avoided in 83% (25 eyes) of the treated eyes during an average follow-up period of 7 1/2 months. The data indicate that ALT can be used as a safe and effective initial treatment for glaucoma in developing countries where socioeconomic factors make the medical treatment of glaucoma impractical.

Four-year Experience with Argon Laser Trabecular Surgery in Uncontrolled Open-angle Glaucoma

Eighty-two phakic eyes with uncontrolled open-angle glaucoma underwent 360° argon laser trabecular surgery. There was a 77% success rate with a mean follow-up of 24 months in the successful group. A glaucoma diagnosis of exfoliation syndrome or open-angle glaucoma, an age greater than 60, and a baseline pressure of less than 26 mmHg were each associated with an increased success rate. The mean pressure change in the treated eye reached its maximum at two months, with a 9.7 mmHg decrease, and the pressure lowering effect slowly decreased with time to a 5.9 mmHg decrease at 42 months. It increased again at 48 months. Failure occurred within two years in 18 of the 19 eyes, and the remaining eye failed at 36 months. Longterm tonographic data shows significant improvement in outflow through 30 months. Argon laser trabecular surgery continues to enjoy an excellent riskvs-benefit ratio, but its use should still be limited to patients with uncontrolled open-angle glaucoma on maximum medical therapy who are surgical candidates.