Prior Argon Laser Trabeculoplasty Research Articles

Long term efficacy of repeat selective laser trabeculoplasty.

Purpose:To evaluate long term intraocular pressure (IOP) control after repeat selective laser trabeculoplasty (SLT).Methods:This single center study retrospectively reviews the electronic medical records of patients with open angle glaucoma undergoing repeat SLT. Eyes with prior argon laser trabeculoplasty, or incisional surgery before or during the study period were excluded. Demographics, laser parameters, number of glaucoma medications and IOP at baseline and after 1, 4, 8, 12, 18 and 24 months were collected. The percentage of subjects with IOP reduction >20% and ≥15% from baseline was determined.Results:A total of 45 eyes of 25 subjects with mean age of 73 ± 9 years undergoing repeat SLT were included. Repeat SLT was performed at a mean interval of 28.3 ± 12.7 months after initial treatment. Mean IOP reductions were statistically significant with repeat SLT as compared to baseline at 1, 4, 8, 12, 18 and 24 months’ follow-up. Change in IOP after first and repeat SLT were comparable at most time points except at 4, 8 and 12 months when initial treatment had yielded significantly greater reductions. At 24 months, 29% and 39% of eyes achieved IOP reduction >20% and ≥15% respectively after repeat SLT as compared to 36% and 54% of eyes following initial treatment (P > 0.05).Conclusion:Repeat SLT is effective in lowering IOP up to 24 months. Long term IOP control was achieved in 29–39% of eyes following repeat treatment in this cohort of patients.

Repeat Selective Laser Trabeculoplasty

To evaluate the efficacy of repeat 360-degree selective laser trabeculoplasty (SLT) in glaucoma patients with prior successful 360-degree SLT. Retrospective chart review. Forty-four eyes of 35 patients, > or =18 years of age, with open-angle glaucoma (primary open-angle, pseudoexfoliation, or pigmentary glaucoma), uncontrolled on maximum tolerable medical therapy, underwent an initial 360-degree SLT (SLT1), which was successful for > or =6 months, but eventually lost efficacy and was followed by a repeat 360-degree SLT (SLT2). Patients with prior argon laser trabeculoplasty or other glaucoma surgery, before or during the study period, were excluded. Intraocular pressure (IOP) measurements were recorded before each procedure and 1 to 4 weeks, 1 to 3 months, and 5 to 8 months posttreatment and 15 to 21 weeks after the initial SLT. Reduction in IOP after SLT1 and SLT2 was significantly less with repeat treatment at 1 to 3 months, with average decreases of -5.0 and -2.9 mm Hg, respectively (P=0.01), but there were no statistically significant differences between treatments at the other equivalent time points. Using a definition of "success" as > or =20% peak IOP reduction, success rates for SLT1 and SLT2 were not significantly different. There was also no significant difference in eyes that received SLT2 6 to 12 months after SLT1 compared with those that received SLT2 12 months or more after SLT1. Our findings suggest that repeat 360-degree SLT may be safe and effective after an initially successful 360-degree SLT has failed. These results may be achieved as early as 6 months after the first treatment.

Résultats à deux ans de la trabéculoplastie sélective au laser dans le glaucome à angle ouvert et l’hypertonie oculaire

Selective laser trabeculoplasty (SLT) is a relatively new treatment strategy for the treatment of glaucoma. Its principle is similar to that of argon laser trabeculoplasty (ALT), but may lead to less damage to the trabecular meshwork. We assessed the 2-year efficacy of SLT in a noncomparative consecutive case series. Any adult patient either suspected of having glaucoma or with open-angle glaucoma, whose treatment was judged insufficient to reach target intraocular pressure (IOP), could be recruited. IOP and number of glaucoma treatments were recorded over 2 years after the procedure. Our sample consisted of 44 consecutive eyes of 26 patients, aged 69+/-8 years. Eyes were treated initially on the lower 180 degrees . Three of them were retreated after 15 days on the upper 180. Fourteen eyes had ocular hypertension, 17 primary open-angle/normal-tension glaucoma, 11 pseudoexfoliation (PEX) glaucoma, and two pigmentary glaucoma. Thirty-six eyes had previously been treated and continued to be treated with topical anti-glaucoma medication, ten had had prior ALT, nine iridotomy, and 12 filtering surgery. The 2-year-follow up could not be completed for eight eyes because they needed filtering surgery. In the remaining 36 eyes, IOP decreased by a mean of 17.2%, 3.3 mmHg, (19.2+/-4.7 to 15+/-3.6 mmHg) after 2 years (p<0.001). As a secondary outcome, the number of glaucoma treatments decreased from 1.44 to 1.36 drops/patient. Other results according to subgroups of patients are analyzed: the greatest IOP decrease occurred in eyes that had never been treated with anti-glaucoma medication or with PEX glaucoma. SLT was probably valuable in a few eyes after filtering surgery; however, the statistical power of the study was not strong enough to draw a firm conclusion. When expressed in survival curves after 2 years, however, only 48% and 41% of eyes experienced a decrease of more than 3 mmHg or more than 20% of preoperative intraocular pressure, respectively. SLT decreases IOP somewhat for at least 2 years without an increase in topical glaucoma treatment. However, it cannot totally replace topical glaucoma treatment. In the future, patient selection should be improved to decrease the cost/effectiveness ratio.

Selective laser trabeculoplasty retreatment after prior argon laser trabeculoplasty: 1-year results

Background: Argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) are treatments for open-angle glaucoma. Many patients have previously received ALT but could benefit from further treatment. The purpose of this study was to examine whether SLT provided clinical benefit for patients who had previously received complete argon treatment. Methods: This was a prospective, partially randomized, comparison study. The study compared the effect after 1 year of SLT in patients with open-angle glaucoma (primary, pigmentary, or pseudoexfoliation) who had previously received 360° of ALT with the effect of laser treatment (ALT or SLT) given for the first time in patients with this condition. Ninety-six subjects were given 180° of laser trabeculoplasty. When both eyes qualified for treatment, the first eye treated was included in the analysis. Twenty-seven subjects were treated with SLT after previously receiving 360° of ALT therapy; the remainder were given their first laser treatment, 30 being randomly assigned by coin toss to receive SLT and 39 to receive ALT. Results: The mean intraocular pressure (IOP) before treatment was 21.5 mm Hg (SLT after ALT), 22.9 mm Hg (SLT), and 22.0 mm Hg (ALT), with no statistical difference among the groups ( p > 0.05). The mean IOP at 1 year was 16.7 mm Hg (SLT after ALT), 17.1 mm Hg (SLT), and 16.4 mm Hg (ALT). The IOP for all 3 groups was statistically significantly lower than at baseline ( p < 0.001), but there were no differences among the groups in this respect ( p > 0.05). At 1 year, the percentage IOP reductions from baseline were 23% (SLT), 19.3% (SLT after ALT), and 24% (ALT). There were no differences among the groups in the number of medications used before the laser, although there was a small but statistically significant decrease in the number of medications used before or after the laser treatment in both the SLT and the SLT after ALT group, but not the ALT group. Interpretation: SLT retreatment can produce a clinically useful decrease in IOP at 1 year, similar to that obtained by ALT, in patients who have had prior argon laser treatment. SLT may be a useful adjunctive therapy when 360° of ALT has already been performed.

Trabeculectomy with Mitomycin C: Outcomes and Risk Factors for Failure in Phakic Open-Angle Glaucoma

To evaluate long-term tonometric outcomes of trabeculectomy with adjunctive mitomycin C (MMC) and its efficacy in achieving a range of intraocular pressures (IOP) in phakic patients with open-angle glaucoma. Retrospective cohort study. Three levels of success were defined by these criteria: (A) IOP < or =18 mmHg and IOP reduction of 20%; (B) IOP < or =15 mmHg and IOP reduction of 25%; and (C) IOP < or =12 and IOP reduction of 30%. Kaplan-Meier survival analyses were used to assess outcomes. Cox's proportional hazard regression analysis was used to identify risk factors for failure. Two hundred twenty-five phakic patients (292 eyes) with open-angle glaucoma, > or =40 years of age at time of trabeculectomy. The primary outcome was qualified success rate (with or without medications) according to the defined criteria. Secondary outcomes include IOP level and number of medications at 1 and 3 years after surgery, postoperative complications, and need for further glaucoma surgery. Mean IOP (+/-standard deviation) decreased from 18.8 mmHg (+/-6.1 mmHg) before surgery to 11.3 mmHg (+/-4.5 mmHg) at 1 year and 11.1 mmHg (+/-4.2 mmHg) at 3 years (P<0.001 for both). The mean number of medications decreased from 2.8 (+/-1.0) to 0.4 (+/-0.7) at 1 year and 0.7 (+/-1.0) at 3 years (P<0.001 for both). The success rates were 85%, 84%, and 79% at 1 year for criteria A, B, and C, respectively; and 62%, 56%, and 46% for these criteria, respectively, at 3 years. Postoperative laser suture lysis was associated with a higher rate of failure for criteria B and C (P<0.001 for both), the hazard ratio (HR) was 1.7 for criteria B and 2.0 for criteria C. Prior argon laser trabeculoplasty was associated with higher risk of failure for criteria C (HR = 1.6; P = 0.05). Trabeculectomy with MMC effectively reduces IOP in phakic open-angle glaucoma, but long-term low IOPs are achieved in only half of the cases. Laser suture lysis after trabeculectomy and prior argon laser trabeculoplasty are associated with a higher risk of failure when low IOPs are required.

Long-term follow-up of 700 trabeculectomies

A major focus of our study was to determine the value of postoperative intraocular pressure (IOP) in predicting the outcome of trabeculectomy (TE). The medical charts of 547 patients undergoing glaucoma filtering surgery at the Department of Ophthalmology of the University of Cologne from 1987 to 1996 were reviewed. The eyes with congenital glaucoma and those treated with anti-metabolites were excluded. Defining the qualified criteria for success of trabeculectomy as an IOP </21 mm Hg throughout the entire study period, no evidence of progressive disc damage or further visual field loss, no decrease in visual acuity and no additionally required surgical intervention due to glaucoma, there was a success rate of 44.4%. In 50% the tonometric failure took place within the first 34 days trabeculectomy. No significant difference in survival by sex (p = 0.53), surgical technique, limbal versus fornix-based flap (p = 0.28) and by type of glaucoma (p = 0.26) was shown. But the patient group with prior argon laser trabeculoplasty had a significant lower success rate in terms of normalization of IOP (p = 0.03). There was no significant difference in the outcome of trabeculectomy between the first and second eye. The identification of patients at risk of failure in terms of IOP in the early post-operative period is possible, thus, closer follow-up and early medical or surgical intervention may be indicated. Should trabeculectomy be the therapy of first choice in the early stage of glaucoma and in case of failure in the first eye, this would allow options, such as the use of anti-metabolites in the second eye.

Factors associated with elevated complication rates after partial-thickness or full-thickness glaucoma surgical procedures in the United States during 1994

Objective The purpose of the study was to identify factors associated with an increased risk of complications after partial-thickness or full-thickness glaucoma surgery. Design A retrospective, cohort analysis. Participants A total of 24,206 Medicare patients who were older than 65 years of age and who were enrolled in Medicare in 1994 underwent partial-thickness or full-thickness glaucoma surgical procedures in 1994. Intervention The authors obtained data on all glaucoma surgery claims to the Health Care Finance Administration in 1994 and analyzed complication rates using hierarchical logistic regression, separately smoothing four sets of regression coefficients (state-level effects, systemic and ocular diagnoses, prior ocular surgeries, and concomitant ocular surgeries). Main outcome measure Patients were classified as having complications if their records showed at least one of the following occurrences after surgery: retinal detachment repair, endophthalmitis, scleral fistula revision—repair, or cyclodestruction. Results The risk of complications was greater for full-thickness procedures than for partial-thickness procedures (odds ratio [OR] = 1.51; 95% confidence interval [CI] = 1.07, 2.12). Compared to glaucoma surgeries performed without an additional intraocular procedure, glaucoma surgery with prior phacoemulsification (OR = 0.51; 95% CI = 0.35, 0.74) was associated with lower complication rates, as was glaucoma surgery with prior argon laser trabeculoplasty (OR = 0.62; 95% CI = 0.44, 0.88). A concomitant vitrectomy (OR = 1.86, 95% CI = 1.35, 2.56) was associated with greater odds of a complication. The mean follow-up of subjects was 184 days (standard deviation, ±107), whereas the mean time to a complication was 49 days (standard deviation, ±63). Conclusion The risk of an early postoperative complication after full-thickness procedures appears to be greater than that after partial-thickness procedures. Concomitant intraocular procedures performed in conjunction with glaucoma surgery, such as a vitrectomy, can substantially increase the risk of retinal detachment repair, endophthalmitis, scleral fistula revision—repair, and/or cyclodestruction.

Argon Laser Trabeculoplasty and Pilocarpine Effects on Outflow Facility in the Cynomolgus Monkey

We sought to determine whether and how prior argon laser trabeculoplasty (ALT) alters outflow facility, the pilocarpine-induced facility increase, and the morphology of the trabecular meshwork in cynomolgus monkeys. Eleven cynomolgus monkeys underwent unilateral 360 degrees argon laser trabeculoplasty, eight in two 180 degrees sessions (seven 3 months apart, one 11 days apart) and three in a single session. Intraocular pressure (IOP, Golmann ap-planation tonometry), aqueous humor flow rate (AHFR, fluorophotometry), total outflow facility (two-level constant pressure perfusion) and response to intracameral pilocarpine, and morphology (light and scanning/transmission electron microscopy) were determined at various times. Resting total perfusion outflow facility 3 and 6 months after 360 degrees ALT was 30% higher in ALT-treated than in contralateral untreated eyes. There were no consistent or statistically significant differences between ALT-treated and contralateral untreated eyes in (a) IOP or AHFR before ALT, 5 weeks after initial 180 ALT, or 5 weeks after the second 180 ALT; (b) post-intracameral pilocarpine facility, or the dose-dependent facility response to pilocarpine 10 weeks after the initial 180 ALT or 3 and 6 months after the second 180 ALT; or (c) light or electron microscopic appearance of the trabecular meshwork or inner wall of Schlemm's canal 3-17 months after 360 ALT. This study indicates that (a) ALT alters the biomechanical properties of the monkey trabecular meshwork so as to modestly increase its hydraulic conductivity without affecting the facility response to pilocarpine-induced ciliary muscle contraction; and (b) young healthy monkey outflow tissues exhibit remarkable reparative and homeostatic capabilities.

Tenon's Cyst Formation After Trabeculectomy With Mitomycin C

One hundred eyes of 100 patients in whom Tenon's cysts (TCs) developed in the early postoperative period following trabeculectomy with mitomycin C were retrospectively studied to determine their incidence, possible risk factors associated with their development, and the clinical course of the patients in whom they occurred. The incidence of TC formation was 29/100 (29%). Significantly more cysts developed in the men than in the women. There were no significant differences between those patients in whom TCs developed and those in whom they did not in terms of age, race, type of preoperative medications, mean preoperative intraocular pressure (IOP), prior argon laser trabeculoplasty, prior trabeculectomy, prior Tenon's cyst formation, or prior cataract surgery. The 29 patients in whom a Tenon's cyst developed had a mean follow up of 22.0 +/- 12.9 weeks, with a mean IOP at the last examination of 14.2 +/- 6.3 mm Hg (as compared with 20.7 +/- 8.3 mm Hg at the time of diagnosis). One patient required a repeat trabeculectomy with mitomycin C. Two patients required bleb needling, subsequent TC excision, and eventual seton placement. Of the remaining 26, 14 (54%) required no glaucoma medication for IOP control, 11 (42%) required one, and 1 (4%) required two.

Long-term Follow-up of Neodymium:YAG Laser Angle Surgery for Open-angle Glaucoma

Seventy-nine eyes (61 patients) with open-angle glaucoma and uncontrolled intraocular pressure (IOP) of 23 mmHg or more despite maximal tolerated medical therapy and prior argon laser trabeculoplasty (75 eyes) were treated with neodymium:YAG (Nd: YAG) laser angle surgery and followed for at least 1 year. Ten pulses of 10 mJ were applied to the midtrabecular meshwork over 40° in the most visible portion of the angle. The IOP was controlled successfully (≤22 mmHg) in 60 eyes (76%) 1 month after treatment and in 36 of 78 eyes (46%) 1 year after treatment. Long-term complications included two eyes with advanced glaucoma that lost central fixation despite good IOP control after treatment.