Efficacy Of Argon Laser Trabeculoplasty Research Articles

Experience with argon laser trabeculoplasty in Nigerians

To report the safety and efficacy of Argon Laser Trabeculoplasty (ALT) in reducing intraocular pressure (IOP). This was a retrospective study performed on 25 eyes of 25 patients. Consecutive patients who met the inclusion criteria for ALT were recruited from the ophthalmic clinic of the University College Hospital Ibadan, Nigeria and followed up for a minimum period of six months. Two criteria were used to define successful response. Criterion 1 was defined as IOP reduction of 3mmHg or more without additional intervention while criterion 2 was IOP reduction of 20% or more from the pretreatment IOP. Data was analyzed using SPSS version 16. Frequencies and means were generated to observe patterns of variable distribution among the patients. P value < 0.05 was considered significant. The mean pretreatment IOP was 19.9 ±3.1mmHg, (range of 16 to 26 mmHg). Mean post treatment IOP at 6 months was 14.9 ±2.2 mmHg, (range of 11 to 19 mmHg). Mean IOP reduction at one year was 4.6 mmHg, representing a 22.3% drop. There was a statistically significant greater IOP reduction in eyes (P<0.001) with higher pretreatment IOP. Based on criterion 1 and 2, 84.0% of the patients had successful outcome at six months while at one year, 76.9% were successful based on criterion one. To the best of our knowledge, this is the first study to report the efficacy of ALT in Nigerians. ALT is safe and effective in reducing IOP in Nigerians. ALT is safe and effective in reducing intraocular pressure in this population of Nigerians. The present study did not receive any funds.

Mechanisms of action and efficacy of argon laser trabeculoplasty and selective laser trabeculoplasty

Since the 1980s, laser trabeculoplasty has served as an effective way to lower intraocular pressure in patients with primary or secondary open angle glaucomas, both as an initial therapy or in conjunction with hypotensive medications. This manuscript will describe the proposed mechanisms of action of argon laser trabeculoplasty and selective laser trabeculoplasty, as well as review current studies of the therapeutic effect of these interventions. The exact mechanisms by which argon laser and selective laser trabeculoplasty lower intraocular pressure are not known. There are several theories, however, and we discuss the three most common ones: the mechanical theory, the cellular (biologic) theory, and the cell division theory. Since both lasers are applied to the same tissue and produce similar results, they most likely produce their effects in comparable ways. We also describe the results of several studies comparing these devices. Most show them to be equally effective at lowering intraocular pressure; however, there are a few circumstances when selective laser trabeculoplasty may be a better option than argon laser trabeculoplasty. Argon laser and selective laser trabeculoplasty are safe and effective procedures for lowering intraocular pressure. The results of ongoing clinical trials will help further define their role in the management of patients with open angle glaucoma.

Efficacy of argon laser trabeculoplasty in primary open-angle and pseudoexfoliative glaucoma: Long-term follow-up

A retrospective study was performed to evaluate the long-term efficacy of argon laser trabeculoplasty in 131 patients (148 eyes) with primary open-angle or pseudoexfoliative glaucoma. Success was defined as an intraocular pressure of 22 mm Hg or less, no further glaucoma surgery, and use of comparable or lower-dose topical antiglaucoma treatment. Efficacy of laser trabeculoplasty decreased with time (follow-up, 6 to 120 months). Good results persisted for about 2.5 years in 50% of cases.

A review of argon and selective laser trabeculoplasty as primary treatments of open‐angle glaucoma

It is generally accepted within the ophthalmic community that medical therapy is the preferred primary treatment in open‐angle glaucoma, followed by laser trabeculoplasty if the medical therapy is unsuccessful, with surgery employed more as an end‐stage option when these avenues have been exhausted. This review discusses the efficacy of argon laser trabeculoplasty, alone and in comparison with medical therapy as a primary treatment of glaucoma. It will also discuss the new laser technique, selective laser trabeculoplasty.

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.

Comparative Study of the Efficacy of Argon Laser Trabeculoplasty for Exfoliation and Primary Open-Angle Glaucoma

To investigate the efficacy of argon laser trabeculoplasty (ALT) for the treatment of primary open-angle glaucoma (POAG) and of glaucoma associated with exfoliation syndrome (EXF). Review of > 200 charts from patients treated with ALT between 1981 and 1987 identified 66 POAG and 29 EXF eyes that underwent initial 180 degrees treatment. Variables including baseline intraocular pressure (IOP), age, sex, angle pigmentation, and follow-up IOP were studied with numerous statistical analyses. Multiple failure modes were used to define failure rate. All POAG and EXF patients were white. The baseline pre-ALT IOP was 23.2 +/- 6.1 mm Hg for the POAG group and 25.8 +/- 5.9 mm Hg for the EXF group (p < .06). Mean follow-up time was 27 +/- 22 months for POAG eyes and 23 +/- 20 months for EXF eyes. Using failure mode 4 (glaucoma surgery, third laser, IOP < or = 22 mm Hg, or two consecutive IOPs > 85% of original baseline IOP), the 1-year failure rates were 40% (POAG) and 18% (EXF), and the 3-year rates were 58% (POAG) and 47% (EXF), p < 0.89 by log-rank test. A Cox proportional hazards model controlling for baseline IOP, age, sex, and angle pigmentation demonstrated that exfoliation status did not affect progression to filtering surgery (p > 0.60). Using multiple failure modes, the results suggest that the success rate of ALT in exfoliation glaucoma tends to decrease over time, but then stabilizes at this reduced value at a level similar to that of POAG. By 3 years, there is a substantial failure rate in both POAG eyes and EXF eyes. Although the initial response to ALT in EXF patients is greater, the long-term outcome is similar for both groups.

Long-term Efficacy of Argon Laser Trabeculoplasty: A 10-year Follow-up Study

Argon laser trabeculoplasty (ALT) is commonly used in the treatment of open-angle glaucoma. Varying success rates in lowering intraocular pressure (IOP) and controlling glaucoma are reported in studies with follow-up periods from 1 to 5 years, and few reports are available with follow-up to 10 years. The authors retrospectively reviewed the efficacy of ALT in patients followed up to 10 years. Ninety-three patients with open-angle glaucoma underwent 360 degrees ALT. Mean follow-up was 52 +/- 43 months (mean +/- standard deviation; range, 1-132 months). Successful treatment at the time of final follow-up was defined as a decrease in IOP of 3 mmHg or greater from pretreatment level, IOP of 19 mmHg or less, stable visual field, stable optic nerve, and no further laser or surgical intervention. The decrease in IOP was 8.9 +/- 5.4 mmHg at 1 year, 10.0 +/- 4.2 mmHg at 5 years, and 8.9 +/- 5.2 mmHg at 10 years. The probability of success at 1 year was 77%, at 5 years 49%, and at 10 years 32%. Failure was most common in the first year after treatment (23%), and thereafter failure occurred at a rate of 5% to 9% per year. The mean decrease in IOP for all 93 eyes at time of maximum follow-up was 6.1 +/- 7.1 mmHg. Argon laser trabeculoplasty is an effective means for reducing IOP in many patients followed for an extended time. However, up to one half of eyes within 5 years of ALT and two thirds of eyes within 10 years may require additional laser or surgical intervention for glaucoma control.

Influence of Treatment Protocol on the Long-Term Efficacy of Argon Laser Trabeculoplasty

Forty-five phakic eyes of 36 patients with open-angle glaucoma and uncontrolled intraocular pressure despite maximally tolerated medication underwent initial argon laser trabeculoplasty (ALT) in 1981 and 1982 as part of a prospective, randomized study to evaluate the effectiveness of different treatment standards. Each eye had been randomly assigned to receive either 100 laser applications over 360 degrees of trabecular meshwork, 50 applications over 180 degrees , or 50 applications over 360 degrees in a single session. Further treatment in each group was based on clinical standards prevailing at the time. The long-term results were analyzed using Kaplan-Meier survival analyses. By 4 years after initial ALT, six of the 15 remaining eyes in group 1 (40%), one of 14 eyes in group 2 (7%), and two of 13 eyes in group 3 (15%) had undergone filtration surgery, and one eye in group 1 (7%), three eyes in group 2 (21%), and three eyes in group 3 (23%) had received further ALT. By 7 years after initial ALT, seven of the nine remaining eyes in group 1 (78%), one of 12 eyes in group 2 (8%), and four of 12 eyes in group 3 (33%) received filtration surgery, and two eyes in group 1 (22%), three eyes in group 2 (25%), and four eyes in group 3 (33%) had received further ALT. Kaplan-Meier survival curves predict the following probabilities of avoiding either repeat ALT or filtration surgery at 4 years after an initial ALT: group 1, 54 +/- 12%; group 2, 76 +/- 12%; and group 3, 62 +/- 11%. Our results suggest that performing 50 rather than 100 burns at initial ALT may significantly delay the need for additional surgical or repeat laser intervention.

Long‐term efficacy of low power argon laser trabeculoplasty

We studied the long-term efficacy of argon laser trabeculoplasty, applying low-power (a mean of 450 mW), a duration of 0.1 second, and a small number of burns (a mean total energy of 1.85 J) over 90 to 120 degrees of the trabecular meshwork. Fifty-four eyes with poorly controlled open-angle glaucoma were treated. The mean follow-up was 46 months. The mean intraocular pressure decrease was 5.3 mmHg in 35 eyes at one year, 6.1 mmHg in 23 eyes at 3 years, 5.1 mmHg in 13 eyes at 5 years, and 5.4 mmHg in 5 eyes at 6 years. Life-table analysis showed that the probability of success was 58% at one year, 49% at 3 years, and 46% at 5 years. Both the incidence and magnitude of the intraocular pressure rise in the early post-laser period were minimal and no serious complications were observed.

Long-term Efficacy of Argon Laser Trabeculoplasty

Long-term efficacy of 360° argon laser trabeculoplasty was studied in 118 eyes of 93 patients with uncontrolled chronic open-angle glaucoma. The mean intraocular pressure (IOP) decrease was 8.9 ± 5.4 mmHg (mean ± standard deviation [SD] in 71 eyes at 1 year, 9.3 ± 4.3 mmHg (mean ± SD) in 51 eyes at 3 years, and 10.3 ± 3.9 mmHg (mean ± SD) in 28 eyes at 5 years. The probability of success at 4 years (decrease in IOP ≥ 3 mmHg, IOP ≤ 19 mmHg, stable visual field, stable optic nerve, and no further laser or surgical intervention) was 52%. Pretreatment IOP, diagnosis, previous operations, age, and sex were not significant determinants for success or failure. Eyes receiving argon laser trabeculoplasty before cataract surgery maintained control of IOP after surgery. Failure was most common in the first year after treatment (23%), and thereafter failure occurred at a rate of 7 to 10% per year.

Three-year Efficacy of Argon Laser Trabeculoplasty

The authors report on the effect of argon laser trabeculoplasty on intraocular pressure (IOP) over a 3-year period with a mean follow-up period of 1.8 years in patients with uncontrolled primary open-angle glaucoma who had not undergone prior surgery. An analysis of the effect of laser trabeculoplasty using the criteria for success of an IOP of 22 mmHg or less with no further laser trabeculoplasty or glaucoma surgery, showed a cumulative success of 79% (112 eyes) at 1 year, 69% (85 eyes) at 2 years, and 59% (58 eyes) at 3 years. Similar results are presented for 22 eyes from patients with pseudoexfoliation glaucoma. The authors conclude that although the initial success rate of laser trabeculoplasty is high, it diminishes progressively over time.