Post-laser Intraocular Pressure Research Articles

Efficacy of a novel low-cost torchlight transcorneal transillumination for diode laser transscleral cyclophotocoagulation in adult glaucoma.

To study the outcomes of diode laser transscleral cyclophotocoagulation (TSCPC) with trans-corneal transillumination using a novel low-cost torchlight method in refractory glaucoma. This prospective interventional study included patients with refractory glaucoma who underwent TSCPC with trans-corneal transillumination (TSCPC-TI) using a novel low-cost torchlight method. Patients completing a minimum 6-month follow-up were analyzed. They were compared to a historical control group of patients who underwent TSCPC without transillumination (TSCPC-No TI) at 6-month follow-up period. We analyzed the mean laser energy delivered, post-laser intraocular pressure (IOP) reduction, number of antiglaucoma medications (AGM), the requirement of retreatment and complications of the procedure in both groups. 32 eyes of 29 patients comprised the TSCPC-TI group and were compared with 39 eyes of 37 patients in the TSCPC-No TI group. The TSCPC-TI group required lower energy than the TSCPC-No TI group (46.15 ± 22.8 Vs 80.65 ± 56.1 J p < 0.001). At 6-month follow-up, the TSCPC-TI group required lesser AGM for IOP control (2.33 ± 1.02 vs 3.02 ± 1.32 p = 0.01). There was a significantly reduced dependence of oral acetazolamide in the TSCPC-TI group at 6 months follow-up (15.6% vs 41% p = 0.03%). The success and response rates were 71.8% Vs 23.1%; p < 0.0001 and 87.5% Vs 51.2%; p = 0.001 significantly high in the TSCPC-TI group. The TSCPC-No TI group had a significantly high failure rate (12.5% Vs 48.2% p = 0.001). Hypotony (n = 1) and phthisis (n = 2) were noted TSCPC-No TI group. TSCPC with transillumination with a low-cost torchlight resulted in a more efficient and effective cycloablation than TSCPC without transillumination.

Diode Laser Transscleral Cyclophotocoagulation With a Novel Low-Cost Torchlight Method of Trans-Corneal Transillumination in Refractory Pediatric Glaucoma.

Trans-corneal transillumination (TI) aided transscleral cyclophotocoagulation (TSCPC) for intraocular pressure control of refractory pediatric glaucoma was found to be effective at 1 year. To study 1-year outcomes of diode laser TSCPC with trans-corneal TI using a novel low-cost torchlight method in refractory pediatric glaucoma. This prospective interventional study included children with refractory glaucoma who underwent TSCPC with the Oculight laser system (IRIS Medical Instruments) with trans-corneal TI (TSCPC-TI) using a novel low-cost torchlight method. Children completing a minimum 1-year follow-up were analyzed. They were compared with a historical control group of children who underwent TSCPC without TI (TSCPC-No-TI) at the 1-year follow-up period. We analyzed the mean laser energy delivered, post-laser intraocular pressure reduction, number of antiglaucoma medications (AGM), the requirement of retreatment and complications of the procedure in both groups. Forty-two eyes of 35 patients comprised the TSCPC-TI group and were compared with 31 eyes of 21 patients in the TSCPC-No-TI group. The TSCPC-TI group required lower energy than the TSCPC-No-TI group (24.7±7.8 J vs. 47.2±10.9 J, P <0.0001). Mean topical antiglaucoma drug requirement decreased from 2.9±0.08 before treatment to 0.66±0.8 at the end of 1 year in TSCPC-TI and from 2.6±1.0 before treatment to 0.6±0.77 in the TSCPC-No-TI groups, respectively ( P =0.15). There was a significantly reduced dependence of oral acetazolamide in the TSCPC-TI group at 1-year follow-up [5.7% vs. 61.9%, respectively ( P <0.001%)]. No adverse event of hypotony or choroidal detachment was noted in any group. TSCPC aided by TI with a low-cost torchlight for pediatric refractory glaucoma was found to be effective at 1 year in reducing intraocular pressure and the burden of medication.

The prophylactic effect of betaxolol 0.5% versus brimonidine 0.2% on IOP elevation after Nd:YAG laser posterior capsulotomy

ABSTRACT Clinical relevance Posterior capsule opacification is a common late complication of cataract surgery. Posterior capsule opening with Nd:YAG laser, which is the standard treatment, may cause transient elevation of intraocular pressure (IOP). Background To evaluate the efficacy of betaxolol 0.‌5% compared to brimonidine 0.2%, in prevention of intraocular pressure increase after Nd:YAG Laser posterior capsulotomy. Methods In a double masked randomised clinical trial, 38 eyes from 38 pseudophakic patients over 21 years of age who had significant posterior capsule opacification after phacoemulsification were randomly assigned to receive either betaxolol 0.‌5% (18 eyes) or brimonidine 0.‌2% (20 eyes) one hour before Nd:YAG Laser posterior capsulotomy.‌ Exclusion criteria were: glaucoma or history of glaucoma surgery, active uveitis, active ocular infection, pregnancy, unstable cardiovascular condition and severe asthma and lung diseases. Intraocular pressure was measured by Goldmann applanation tonometry, 1 hour before applying the laser and 4 hours after the laser application. Results There was no statistically significant difference between the two groups regarding the baseline mean IOP and the 4-hour post-laser mean IOP. There was a statistically significant decrease in the 4-hour post-laser mean IOP as compared to the baseline mean IOP in each group. The mean IOP change in the betaxolol group, was −2.39 ± 1.79 mm Hg and in the brimonidine group was −4.25 ± 2.20 mm Hg. The difference was statistically significant (P = 0.007). None of the patients experienced clinically significant IOP increase (≥5 mm Hg) in either group. Conclusion Use of a single topical dose of betaxolol 0.5% and brimonidine 0.2%, 1 hour before laser treatment, can prevent significant acute IOP increase after Nd:YAG laser posterior capsulotomy, and betaxolol may provide a new alternative for prophylactic use.

Laser peripheral iridoplasty for chronic angle closure.

Laser peripheral iridoplasty for chronic angle closure.

Frequency of Raised Intraocular Pressure and its Correlations to the energy used following Neodymium YAG Laser Posterior Capsulotomy in Pseudophakes

Objective: To determine the frequency of raised intraocular pressure in pseudophakic undergoing Nd YAG laser posterior capsulotomy.&#x0D; To compare the frequency of raised intraocular pressure in pseudophakic undergoing high and low energy Nd YAG laser posterior capsulotomy&#x0D; Methods: This Descriptive case series included 140 patients with pseudophakic posterior capsular opacity. After dilating the pupils with tropicamide Nd YAG laser posterior capsulotomy was performed and the total amount of energy used was noted. The frequency of raised IOP in post-laser patients and comparison of frequencies of raised IOP undergoing high and low energy Nd YAG laser posterior capsulotomies (≤ 50 MJ labeled as low energy and &gt; 50 MJ labeled as high energy) were calculated&#x0D; Results: The mean age was 57.37 ±8.74. Mean pre laser IOP was 15.15 and post-laser IOP was 17.50. The rise in IOP was normal in 82.9% and raised in 17.1%. In lower energy group normal IOP was found in 35.7% and raised in 2.9%. In a higher energy group, normal IOP was found in 47.1%, and raised IOP was found to be 14.3%.&#x0D; Conclusion: Higher the energy used during the Nd YAG laser posterior capsulotomy procedure, more is the chance of a rise in post-laser intraocular pressure as compared to those in which lesser energy was being used.

Effect of neodymium: yttrium aluminum garnet laser posterior capsulotomy on intraocular pressure

Objective: To find out whether there exists a correlation between the quantum of energy used and the amount of rise of intraocular pressure (IOP) following neodymium: yttrium aluminum garnet (Nd: YAG) laser capsulotomy. Materials and Methods: A total of 110 patients who had undergone Nd: YAG laser posterior capsulotomy for the management of posterior capsule opacification with a minimum of 3 months following cataract surgery were enrolled after taking written informed consent. After detailed history and ocular examination, Nd: YAG laser capsulotomy was performed. Prelaser IOP was noted. Nd: YAG laser posterior capsulotomy was performed. Laser energy used was noted following which postlaser IOP was also recorded after 1, 2, and 4 h postprocedure. Paired t-test was used for the comparison of means of IOP and energy levels. Receiver operating characteristic analysis was used to predict the cut-off value of energy on the basis of change of IOP from baseline. Results: The mean energy used in the Nd: YAG laser posterior capsulotomy procedure for all patients was 58.57 ± 34.63 mJ. The mean IOP at 1st h follow-up was 15.32 ± 2.91 mmHg, at 2nd h follow-up was 16.24 ± 3.23 mmHg, and at 4th h follow-up was 16.18 ± 3.35 mmHg. At all three follow-ups, the mean change in IOP was found to be statistically significant (P Conclusion: Postlaser IOP rise is minimal and transient; it varies with the amount of energy used.

Effect of Anticoagulants and Surgeon-Related Factors on Short-term Outcomes of Laser Peripheral Iridotomy

To assess the effects of surgeon-related factors on laser peripheral iridotomy (LPI) outcomes by comparing residents and glaucoma specialists, and to look for demographic and clinical predictive factors associated with LPI complications. Retrospective cohort study. Patients who underwent LPI performed by a resident physician were included as cases, and patients who underwent LPI performed by a glaucoma specialist were included as controls. In patients who underwent multiple sessions of laser therapy, only the information from the first session of each eye was included in the study. Demographic and clinical information were gathered from the pre-LPI, 1-week, 1-month, and 3-month follow-up visits. The following information was recorded from the LPI session: total laser energy, presence of bleeding, and post-laser intraocular pressure (IOP). Information gathered from the follow-up visits included visual acuity (VA), IOP, hyphema, and need to repeat LPI. A logistic regression analysis with modification for rare events was used to examine the relationship between the dependent variables and the group, adjusted for the clinical and demographic characteristics of patients. The LPI procedure parameters (total energy), postoperative VA and IOP, risk for complications, and need for re-treatment were compared between groups using odds ratio (OR) measurements. A total of 333 eyes were included in the study. The residents used statistically significant higher total energy compared with the glaucoma specialists' group (P < 0.001). After adjusting for demographic characteristics, antiplatelet/anticoagulant use, and laser energy parameters, we found that the patients of the residents group had a significantly increased likelihood for re-treatment within 3 months (OR, 3.38; 95% confidence interval [CI], 1.31-8.73) and anterior chamber bleeding (OR, 7.48; 95% CI, 1.07-52.02). Although LPI is an effective and minimally invasive procedure, evidence shows that a higher level of experience leads to clinically and statistically significant better outcomes.

Resident-performed laser peripheral iridotomy in primary angle closure, primary angle closure suspects, and primary angle closure glaucoma.

PurposeTo investigate the power use and complication frequency of resident-performed laser peripheral iridotomy (LPI).MethodsA retrospective analysis of 196 eyes from 103 patients who underwent neodymium: yttrium-aluminum-garnet laser iridotomy performed by resident physicians from January 1, 2010 through April 30, 2015 at a university-based county hospital was done. All patients were treated for primary angle closure, primary angle closure suspects, and primary angle closure glaucoma. Data were collected on pre- and post-laser intraocular pressure (IOP), ethnicity, laser parameters and complications. Mean power use and frequency of complications were evaluated. Complications included elevated post-laser IOP at 30–45 minutes (≥8 mmHg), hyphema, aborted procedures, and lasering non-iris structures. The number of repeated LPI procedures, was also recorded.ResultsMean total power used for all residents was 78.2±68.7 mJ per eye. Power use by first-year trainees was significantly higher than second- and third-year trainees (103.5±75.5 mJ versus 73.7±73.8 mJ and 67.2±56.4 mJ, respectively, p=0.011). Complications included hyphema or microhyphema in 17.9% (35/196), IOP spikes in 5.1% (10/196), aborted procedures in 1.1% (3/196) and lasering non-iris structures in 0.5% (1/196). LPI was repeated in 22.4% of cases (44/196) with higher incidence of repeat LPI among non-Caucasian compared to the Caucasian subjects (p=0.02). Complication rates did not differ with increased training (p=0.16).ConclusionTotal power used for LPI decreased with increased resident training, while the complication rate did not differ significantly among resident classes. Complication rates were comparable to rates reported in the literature for attending-performed LPIs.

Selective laser trabeculoplasty for early glaucoma: analysis of success predictors and adjusted laser outcomes based on the untreated fellow eye.

BackgroundTo identify success predictors and to study the role of the fellow untreated eye as a co-variable for adjustment of intraocular pressure (IOP) outcomes following selective laser trabeculoplasty (SLT) in early open-angle glaucoma (OAG) patients.MethodsA case series was carried out. Patients with uncontrolled early OAG or ocular hypertension (inadequate IOP control requiring additional treatment) underwent SLT (one single laser session) performed by the same surgeon in a standardized fashion. The same preoperative medical regimen was maintained during follow-up for all patients. Post-treatment assessments were scheduled at week 1 and months 1, 2, and 3. In order to account for possible influence of IOP fluctuation on laser outcomes, post-laser IOP values of the treated eye of each patient were also analyzed adjusting for IOP changes (between visits variation) of the untreated fellow eye (adjusted analysis). Pre and post-laser IOP values were compared using paired t-test. Factors associated with the magnitude of IOP reduction were investigated using multiple regression analysis.ResultsA total of 45 eyes of 45 patients were enrolled. Mean IOP was reduced from 20.8 ± 5.1 to 14.9 ± 2.9 mmHg at month 3 (p < 0.001). Adjusted success rate (defined as IOP reduction ≥ 20%) was 64% and mean percentage of IOP reduction was 23.1 ± 14.3% at last follow-up visit. Considering unadjusted post-laser IOP values, it was found a 20% greater absolute IOP reduction (median [interquartile range] 6 mmHg [4–7] vs 5 mmHg [3–7]; p = 0.04), with a success rate of 76%. Although baseline IOP was significantly associated with both adjusted and unadjusted post-laser IOP reduction, a stronger association was found when unadjusted IOP values were considered (p < 0.001 and R 2 = 0.35; p < 0.001 and R 2 = 0.67, respectively). Age, mean deviation (MD) index, central corneal thickness and type of glaucoma were not significant predictors (p ≥ 0.150).ConclusionsIn this group of patients with early OAG or ocular hypertension, our short-term results confirmed SLT as a safe and effective alternative for IOP reduction. Although better outcomes were found in eyes with higher preoperative IOP, this effect was mitigated when results were adjusted to the fellow untreated eye (to the influence of between visits-IOP fluctuations).

Nd:Yag laser goniopuncture for deep sclerectomy: efficacy and outcomes.

To report on the safety and efficacy of Nd: YAG laser goniopuncture (LGP) for postsurgical intraocular pressure increase after deep sclerectomy (DS) in a consecutive cohort of open-angle glaucoma patients. This case series included 56 eyes from 49 consecutive patients who underwent LGP between November 2008 and March 2015. Prior to LGP, patients had undergone DS augmented with mitomycin C and injectable cross-linked hyaluronic acid implant between October 2008 and May 2014. Demographic variables, type of glaucoma, prior phacoemulsification, intraocular pressure (IOP), best-corrected visual acuity, execution of post-LGP maneuvres, and post-LGP complications were analyzed. The success rate of the procedure was analyzed using the Kaplan-Meier survival curve. Univariate and multivariate analyses were performed using the Cox proportional hazard regression model in order to highlight variables associated with a failure to achieve surgical success. Mean IOP was 23.0 mmHg prior to LGP, and 12.5, 11.8, and 10.5 mmHg at 6, 12, and 24 months after LGP respectively. Post-laser IOP was significantly lower than pre-laser IOP at every time point. For an IOP ≤ 15 mmHg, success rates were 85 % at 6 months, 76 % at 1 year, and 62 % at 2 years. Thirty-eight eyes underwent prophylactic iridotomy and iridoplasty prior to LGP. Iris prolapse into the trabeculo-descemetic window following LGP occurred in 6/18 eyes (33.3 %) of the non-pretreated and in 1/38 eyes (2.6 %) of the pretreated group. One case of choroidal detachment and one delayed suprachoroidal hemorrhage occurred after LGP execution in two non-pretreated eyes. LGP is a relatively safe and effective complementary adjunct to deep sclerectomy that makes it possible to further lower IOP and avoid additional filtering surgery. Prophylactic iridotomy and localized iridoplasty may permit the frequency of post-LGP complications to be reduced.

La trabéculoplastie au laser sélectif (TLS) : notre expérience chez le noir africain

The purpose of our study was to evaluate in the short and medium term, intraocular pressure results after selective laser trabeculoplasty in black patients with chronic open angle glaucoma or isolated ocular hypertension. We conducted a retrospective study with a mean 12.5-month follow-up in black patients who underwent SLT. Inclusion criteria were: an open iridocorneal angle greater than or equal to Schaeffer grade 3, data recorded and available on trabecular pigmentation, data on SLT parameters available, and intraocular pressure by Goldmann applanation tonometry recorded.A positive result was defined as a post-laser IntraOcular Pressure (IOP) less than 21 mmHg after 1-month follow-up. The main motivation was the reduction of number of eye drops used. Performed first was a treatment of the inferior 180° (3:00-9:00), possibly supplemented by a second session at 15 days or 1 month if a pressure decrease was noted after the first session. IOP results were evaluated prior to SLT, immediately following SLT and then depending on the drop in pressure. Statistical analysis was performed using the EPI.info 7 software. A total of 69 eyes of 40 patients treated with SLT were identified. The mean IOP prior to SLT was 18.3 mmHg ± 4. Our results showed 90% of patients who positively responded to the treatment (10% failure) with a mean IOP decrease of 2.3 ± 1 mmHg, that is 13%, by the second week. The mean pressure decrease continued to 4.78 ± 1 mmHg for patients (30%) in the group treated for 360°, that is 27% in the same period of time. SLT permitted discontinuation of a prostaglandin in 60% (42 cases). Eyes on triple-drug therapy went from 23 before SLT to 5 following SLT (a 26% decline), eyes on two medications went from 32 to 16 (24% decline). In result association tests, only pigmentation of the angle and visual field stage had a statistically significant probability. In our experience, SLT is indicated in black patients to potentiate less effective treatments, to reduce the number of drops in order to limit side effects, but also to avoid or delay monotherapy treatment-naïve, hypertensive eyes. In the short and medium term, SLT brought about an IOP decrease in 90% of black patients, and discontinuation of a prostaglandin in 60% of our patients. In addition, the iridocorneal angle in blacks appears to be less pigmented than previously thought, and a protocol systematically treating 360° seems to provide better results.

A Randomized Clinical Trial of Selective Laser Trabeculoplasty Versus Argon Laser Trabeculoplasty in Patients With Pseudoexfoliation

To evaluate the efficacy of selective laser trabeculoplasty (SLT) versus argon laser trabeculoplasty (ALT) in lowering the intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension secondary to pseudoexfoliation. Multicentered randomized clinical trial. A total of 76 eyes from 60 patients with pseudoexfoliation and uncontrolled IOP were recruited from 5 Canadian academic institutions. Patients with prior laser trabeculoplasty, ocular surgery within 6 months, previous glaucoma surgery, an advanced visual field defect, current steroid use, and monocular patients were excluded. Eyes were randomized to receive either 180-degree SLT or 180-degree ALT by a nonblocked randomization schedule stratified by center. The primary outcome was the change in IOP at 6 months versus baseline and secondary outcomes included change in number of glaucoma medications after laser. Baseline variables included age, sex, angle grade, angle pigmentation, and number of glaucoma medications. Of the 76 eyes, 45 eyes received SLT and 31 eyes received ALT. The overall age was 72.9 years (65% females). The baseline IOPs in the SLT and ALT groups were 23.1 and 25.2 mm Hg, respectively (P=0.03). The IOP reduction 6 months after SLT was -6.8 mm Hg and post-ALT was -7.7 mm Hg (P>0.05). The SLT group had reduced glaucoma medications by 0.16 medications at 6 months and the ALT group had no decrease in medications over the same time period (P=0.59). There were no postlaser IOP spikes in either group. ALT and SLT are equivalent in lowering IOP at 6 months posttreatment in patients with PXF.

Role of Laser Iridoplasty in the Management of Angle Closure Mechanisms other than Pupillary Block.

ABSTRACTPurpose: To investigate the treatment outcomes of argon laser peripheral iridoplasty (ALPI) in angle closure mechanisms other than pupillary block.Methods: We conducted a comprehensive chart review to evaluate consecutive patients who underwent ALPI due to unsuccessful laser iridotomy (whenever the angles remained occludable) between July 2009 and April-2012. An occludable angle was defined as the posterior trabecular meshwork not visible for ≤180° without indentation on dark room gonioscopy. Eyes with previous incisional surgery or more than 90° of peripheral anterior synechiae were excluded. Main data collected were age, presence of glaucoma, pre- and postlaser intraocular pressure (IOP), angle-status, and underlying angle closure mechanism. Main outcomes were post ALPI angle widening on gonioscopy and magnitude of IOP reduction.Results: A total of 41 eyes (27 patients) with persistent occlu-dable angles were initially included in the analysis, comprising approximately 14% of the 196 patients (321 eyes) that had under gone laser iridotomy during the predefined period. Among these cases, most common angle closure mechanisms were plateauiris (56%) and lens-induced component (34%). Patients with plateau iris were mostly women and younger than those with lens-induced component (p ≤ 0.03). A total of 35 eyes (23 patients) underwent ALPI (63% had glaucoma). Mean IOP was significantly reduced from 18. 2 ± 4.7 to 14.6 ± 3.8 (p < 0.01), with no significant difference between patients with plateau iris and lens-induced components (p = 0.22). Over 91% of these eyes showed nonoccludable angles following ALPI (follow-up of 11.8 ± 3.3 months).Conclusion: In this series of middle-aged patients with occlu-dable angles, despite a patent iridotomy, ALPI was a useful procedure independent of the underlying mechanism, leading to angle widening and moderate IOP reduction in most cases.How to cite this article: Prado VG, Dorairaj S, Biteli LG, Sousa AKS, Moreno PAM, Lopes FS, Prata TS. Role of Laser Iridoplasty in the Management of Angle Closure Mechanisms other than Pupillary Block. J Curr Glaucoma Pract 2014;8(2):82-84.

Longitudinal alterations in the dynamic autoregulation of optic nerve head blood flow revealed in experimental glaucoma.

To use a novel dynamic autoregulation analysis (dAR) to test the hypothesis that the optic nerve head (ONH) blood flow (BF) autoregulation is disrupted during early stages of experimental glaucoma (EG) in nonhuman primates. Retinal nerve fiber layer thickness (RNFLT, assessed by optical coherence tomography) and ONH BF (assessed by laser speckle imaging technique) were measured biweekly before and after unilateral laser treatment to the trabecular meshwork. Each nonhuman primate was followed until reaching either an early stage of damage (RNFLT loss < 20%, n = 6) or moderate to advanced stages of damage (RNFLT loss > 20%, n = 9). At each test, dAR was assessed by characterizing ONH BF changes during the first minute of rapid manometrical intraocular pressure (IOP) elevation from 10 to 40 mm Hg. The dAR analysis extracted the following parameters: baseline BF, average BF 10 seconds before IOP elevation; BFΔmax, maximum BF change from baseline BF; Tr, time from baseline BF to the BFΔmax; Kr, average descending BF rate. Mean postlaser IOP was 20.2 ± 5.9 and 12.3 ± 2.6 mm Hg in EG and control eyes, respectively (P < 0.0001). Compared with prelaser values, baseline BF was higher in early EG, but lower in moderate to advanced EG (P = 0.01). Tr was increased and Kr was reduced in both stages (P < 0.01). BFΔmax was smaller in the early EG (P = 0.05) and remained low in the moderate to advanced EG (P = 0.15). No changes in the parameters were observed in control eyes. Chronic IOP elevation causes ONH autoregulation dysfunction in the early stage of EG, characterized by a disrupted BF response and delayed Tr, revealed by dAR analysis.

Effectiveness of diode laser trans-scleral cyclophotocoagulation in patients following silicone oil-induced ocular hypertension in Chinese eyes

We evaluated the effectiveness of diode laser trans-scleral cyclophotocoagulation (TSCPC) on intraocular pressure (IOP) in nine patients having raised IOP following use of silicone oil (SO) for retinal detachment (RD) surgery in a retrospective observational case series. Diode laser TSCPC was applied at a power setting of 1.75 to 2.5 watts, for two sec with a maximum of 30 applications. The patients were followed up for 40 to 312 weeks. The mean pre-laser IOP was 32.06 mm Hg (SD 7.32). The mean post-laser IOP at one month, three months and six months was 17.89 mm Hg (SD 8.23), 21.89 mm Hg (SD 8.16) and 21.67 mm Hg (SD 7.55) respectively. The final IOP (at the last follow-up) was 19.56 mm Hg (SD 7.85) (P=0.021). Seven of them had undergone SO removal. In our observation, effectiveness of TSCPC in long-term control of SO-induced ocular hypertension was limited as compared to short-term control of IOP.

Lower energy levels adequate for effective transcleral diode laser cyclophotocoagulation in Asian eyes with refractory glaucoma

To study the treatment parameters for diode laser cyclophotocoagulation (DLCP) in Asian Indian eyes using laser energy titrated to clinical response. This prospective interventional longitudinal study included 66 eyes of 66 patients with varied aetiology refractory glaucoma, no previous cycloablation, and minimum 1 year follow-up. DLCP was performed using the Oculight Diode laser system IRIS( Medical Instruments Inc., CA, USA). Power used per spot was titrated according to the audible 'pops' indicating tissue microexplosion. The mean laser energy delivered, post-laser intraocular pressure (IOP) reduction, complications, and requirement of re-treatment in various subgroups were analyzed. Differences in energy delivered in each subgroup were assessed by analysis of variance with post hocBonferroni corrections. Linear regression analysis was used to identify possible predictive factors for failure of cyclodiode therapy. The mean total energy delivered per eye was 87.80+/-31.8 J (range 105.4+/-36.8 J in neovascular glaucoma (NVG) to 61.5+/-8.8 J in uveitic glaucoma (P=0.134)). Mean pre treatment IOP was 36.4+/-10.7 mmHg, which reduced to 19.4+/-9.8 mmHg (P<0.001) at 1 week, and 15.6+/-6.6 mmHg at 1 year. At 1 year, 58 of 66 patients had IOP<22.0 mmHg (response rate 87.8%), and six patients had hypotony (success rate 78.8%). The uveitic glaucoma group had 100% success rate. NVG group required maximum re-treatments. DLCP with a titrated energy protocol needs resulted in lower energy in Asian Indian eyes compared to that reported in literature, and different energy levels are needed for different diseases. 'Standard treatment parameters' for DLCP may be inappropriate for all diseases and all races.

The Influence of Peripheral Iridotomy on the Intraocular Pressure Course in Patients With Pigmentary Glaucoma

To evaluate the influence of laser peripheral iridotomy on the long-term intraocular pressure course for patients with pigmentary glaucoma. Retrospective analysis of data contributed by members of the American Glaucoma Society on patients with bilateral pigmentary glaucoma, who received uniocular laser iridotomy. The main outcome measure was the post-laser intraocular pressure course of the treated eyes, compared with the fellow, untreated eyes. Sixty patients were included in the study, 46 of whom were observed for a minimum of 2 years (mean 70.3 +/- 26.0 months; range 24-113 months). Among the 14 patients who were observed for less than 2 years, the mean intraocular pressure in the treated eyes increased 0.36 +/- 2.63 mm Hg, compared with the fellow, untreated eyes. Among the 46 patients, observed for 2 years or more, the mean intraocular pressure in the treated eyes decreased 4.0 +/- 5.4 mm Hg, compared with 1.9 +/- 3.8 mm Hg in the fellow eyes (P = 0.005). However, analysis by linear models indicates that a higher mean baseline intraocular pressure in the treated eyes accounts for the apparent treatment effect of laser peripheral iridotomy. The study does not provide support for the benefit of laser peripheral iridotomy in the long-term intraocular pressure control of patients with pigmentary glaucoma, when the data are subjected to rigid statistical analysis. This does not disprove the benefit of laser iridotomy in this patient population, but underscores the need for a large, prospective study to address the question.

Immediate Increase in Aqueous Humour Endothelin 1 Concentration and Intra-Ocular Pressure after Argon Laser Trabeculoplasty in the Rabbit

Purpose: To investigate the immediate changes of aqueous humour endothelin 1 (ET-1) concentration and intra-ocular pressure (IOP) after argon laser trabeculoplasty (ALT) in the rabbit. Methods: Standard ALT was performed in one eye of 11 pigmented rabbits. IOP was measured with a Tono-Pen-2 tonometer before treatment, under general anaesthesia. Postlaser IOP measurements followed by aqueous humour aspiration were performed under general anaesthesia 30 and 60 min after treatment in 6 and in 5 animals, respectively. Results: The aqueous humour ET-1 concentration was significantly higher (55.0 pg/ml) after ALT than in the contralateral eyes without laser treatment (8.2 pg/ml, p = 0.001). IOP increased significantly after ALT (p = 0.007) but remained unaltered (p = 0.10) in the contralateral eyes without treatment. No statistically significant difference was found either in postlaser IOP elevation or in interocular ET-1 difference between the groups. Conclusions: The results suggest that in the rabbit the increase in aqueous humour ET-1 concentration after ALT is immediate, detectable even 30 min after the laser treatment, followed by no further increase during the second 30-min period after ALT, and associated with an immediate postlaser IOP elevation within 1 h after ALT. These findings may suggest a similar response to ALT in the human eye, since a similar immediate IOP elevation is frequently observed after ALT in the clinical practice.

Neodymium: YAG transconjunctival laser revision of late-failing filtering blebs

Objective To study the effectiveness of neodymium:YAG (Nd:YAG) laser transconjunctival revision of late-failing filtering blebs. Design Retrospective, noncomparative case series. Participants Thirty consecutive patients from a glaucoma referral practice at the Ohio State University Department of Ophthalmology. Intervention Transconjunctival Nd:YAG laser revision of blebs diagnosed as failing secondary to episcleral fibrosis. Main outcome measure Reduction in intraocular pressure (IOP) and survival of bleb. Results Reduction in IOP was attained in 24 (80%) of 30 patients with a mean prelaser IOP of 21.21 mmHg and a mean 1-week postlaser IOP of 13.97 mmHg ( P < 0.0001). These results were maintained at the 1-, 3-, and 12-month follow-up visits with mean IOPs of 16.31 mmHg ( P = 0.0008), 14.81 mmHg ( P < 0.0001), and 15.25 mmHg ( P = 0.0003), respectively. Two-year data were available on a small number of patients (4) with a mean of 15.25 mmHg ( P = 0.0085). Mean time interval between trabeculectomy and laser revision was 31 months. Conclusion Late-failing filtering blebs are often amenable to Nd:YAG transconjunctival revision.

Increase of endothelin-1 concentration in aqueous humour induced by argon laser trabeculoplasty in the rabbit. A preliminary study.

To investigate the impact of argon laser trabeculoplasty (ALT) on endothelin-1 (ET-1) concentration of aqueous humour and intraocular pressure (IOP) in the rabbit. Standard ALT was performed on one eye of 19 pigmented rabbits. A modified treatment in which the laser light was focused on the inner limbal surface (argon laser scleroplasty, ALS) was also performed on one eye of a further 15 rabbits. IOP was measured with a Tono-Pen-2 tonometer before treatment, under general anaesthesia. Post-laser IOP measurements followed by aqueous humour aspiration were performed under general anaesthesia 4, 24 and 120 hours after treatment. IOP readings were considered relative values, since the tonometer was calibrated to the human eye and not to the rabbit eyeball. Different groups of animals were used for the tests after each time period. The groups of 4 hours time consisted of 9 animals which had undergone ALT and 5 which had undergone ALS. All the other groups consisted of 5 animals each. In the ALT group IOP decreased following treatment, and the IOP change (a relative change) showed a significant difference between the treated and the control eyes at all three follow-up times (paired t-test, p<0.05), and a significant interaction was found between treatment and follow-up time (ANOVA, p<0.05). Concentration of ET-1 in the aqueous humour of the treated eyes increased by about an order of magnitude 4 hours after ALT, compared to the contralateral control eyes (103.66+/-41.59 pg/ml versus 8.75+/-2.95 pg/ml, Wilcoxon matched pairs test, p<0.01). ET-1 concentration 24 and 120 hours after ALT, however, did not differ significantly from the corresponding contralateral control values. In the ALS group neither IOP change nor aqueous humour ET-1 concentration differed in a statistically significant manner between the treated and control eyes. The results suggest that ALT is followed by an immediate and short-term increase of aqueous humour ET-1 concentration in the rabbit, probably due to leakage from the uveal tissue.