Efficacy of gonioscopy-assisted transluminal trabeculotomy in advanced-age glaucoma patients.

BACKGROUND: The prevalence and severity of many etiologies of glaucoma increase with age, often requiring surgery later in life. Surgery in the most aged demographic, however, poses multiple unique physiologic and psychosocial challenges with variable outcomes. In this study, we evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in an advanced-age population (>85 years of age). METHODS: This is a single-centre retrospective cohort study of consecutive patients who underwent GATT at or above 85 years of age. This included patients with GATT of any circumferential extent (90°-360°) with or without concurrent phacoemulsification cataract surgery. The primary outcome measure was proportion of successful surgeries at 1 year by the "complete success" criteria (intraocular pressure [IOP] <17 mm Hg on no medications 3 months after surgery with no additional interventions). Secondary outcomes included proportion of successful surgeries by alternative criteria, cross-sectional analyses of IOPs and medication use, and analyses of postoperative complications and interventions. RESULTS: Forty eyes of 31 patients were included in the study. Mean baseline IOP was 16.75 ± 7.33 mm Hg on 1.60 ± 1.43 classes of medication. At 1 year, the cumulative survival by Kaplan-Meier analysis was 46.6%. There was a statistically significant reduction in IOP at all postoperative time points to a mean of 11.78 ± 3.07 mm Hg at the last follow-up. There were postoperative complications in 18 eyes, with hyphema and corneal edema accounting for the majority. CONCLUSIONS: This study provides evidence that GATT is a safe and effective intervention in advanced-age glaucoma populations.

Cytomegalovirus as a cause of recurrent corneal endotheliitis in the Canadian population.

OBJECTIVE: To report the clinical manifestations, response to antiviral treatment, and long-term visual outcomes of cytomegalovirus endotheliitis in a Canadian population. DESIGN: Retrospective case series. PARTICIPANTS: A total of 9 eyes of 7 patients referred to a cornea subspecialty clinic in a major Canadian centre with corneal endotheliitis. METHODS: A retrospective review of all patients presenting with corneal endotheliitis to 1 corneal surgeon was completed. Patients underwent anterior chamber biopsy with positive cytomegalovirus polymerase chain reaction. All patients received systemic valganciclovir for a minimum of 3 months. Primary outcomes included visual acuity, intraocular pressure control, medication dependence, and corneal status. RESULTS: The average follow-up was 76.4 ± 11.8 months. Two patients had bilateral disease. Corneal manifestations included linear, disciform, and circinate patterns of endotheliitis. Best-corrected visual acuity improved from a mean of 0.48 ± 0.19 logMAR at presentation to 0.24 ± 0.11 logMAR at last follow-up. Intraocular pressure decreased from a peak of 35 ± 3.1 mm Hg to 14.2 ± 4.3 mm Hg. Antiglaucoma medications were reduced from 2.6 ± 0.45 to 0.89 ± 0.29 agents. Two eyes required endothelial transplantation. Valganciclovir therapy was well tolerated by all patients; at the time of last follow-up, all patients were stable on low-dose valganciclovir at an average dose of 1395 mg per week. CONCLUSIONS: Cytomegalovirus is an uncommon but clinically significant cause of corneal endotheliitis that must be considered in the differential diagnosis of corneal endotheliitis, even in the immunocompetent population. Our results support prior findings that this entity responds robustly to oral valganciclovir and demonstrate for the first time the efficacy of chronic low-dose antiviral maintenance therapy.

Stabilization of refractive error and associated factors following small incision phacoemulsification cataract surgery.

BACKGROUND: Accumulating evidence suggests that refractive stabilization occurs rapidly following small incision cataract surgery. Nonetheless, many guidelines still suggest waiting four to 6 weeks before prescribing corrective lenses. This study was undertaken to supplement the existing literature regarding refractive stabilization, and evaluate multiple contributing factors that could dissuade clinicians from confidently correcting refractive error in the early post-operative course following routine cataract surgeries. METHODS: Adult patients undergoing phacoemulsification cataract surgery with uncomplicated surgeries and post-surgical courses at the Calgary Ophthalmology Centre (Calgary, Alberta, Canada) were included in this prospective observational case series. Exclusion criteria included known corneal dystrophies, infectious keratitis, complicated surgery or toric/multifocal IOLs. Data was collected at weekly intervals for a total of 6 weeks. Collected data included autorefraction, visual acuity, corneal pachymetry, and effective lens position. RESULTS: One hundred six eyes of 104 patients were included in this study. Post-operative sphere, cylinder and spherical equivalent were not significantly different at any post-operative week compared with week six, and 80-86% of patients were within 0.5D of last follow-up spherical equivalent at any week. The secondary outcomes of central corneal thickness, effective lens position and visual acuity did, however, exhibit significant differences between early post-operative weeks and last follow-up values. CONCLUSIONS: These data suggest that refractive error can be effectively measured and corrected as early as one-week post-operatively in the majority of patients, though other measures of post-operative stability including central corneal thickness, effective lens position and visual acuity can require up to 4 weeks to stabilize. Thus a conservative and pragmatic approach may be to wait until 4 weeks post-operatively prior to obtaining refractive correction following uncomplicated phacoemulsification cataract surgery.

Selective Laser Trabeculoplasty versus Argon Laser Trabeculoplasty in Glaucoma Patients Treated Previously with 360° Selective Laser Trabeculoplasty: A Randomized, Single-Blind, Equivalence Clinical Trial.

PURPOSE: The effectiveness of selective laser trabeculoplasty (SLT) was compared with argon laser trabeculoplasty (ALT) in a randomized clinical trial for patients with medically uncontrolled open-angle glaucoma who have previously received 360° SLT. DESIGN: An active equivalence parallel armed randomized control trial. PARTICIPANTS: Patients with open-angle glaucoma including pigmentary dispersion syndrome and pseudoexfoliation syndrome were enrolled into the study from 7 different sites across Canada. METHODS: One setting of 180° of either SLT or ALT was assigned randomly and applied to each participant. MAIN OUTCOME MEASURES: The change in intraocular pressure (IOP) from baseline to 12 months was compared between the 2 groups. RESULTS: A total of 132 patients were recruited, 2 of which dropped out early in the study, leaving 130 patients who completed the study as per protocol. For those, the study's primary outcome was calculated. The IOP change at 1 year in comparison to baseline for SLT vs. ALT was found to be different by 0.33 mmHg between the 2 groups (3.16 for SLT and 2.83 for ALT) and was not statistically significant (P = 0.71) Further analysis, though, showed that SLT had a significantly lower IOP reduction at early time points: 1 week and 1 month, but this effect was lost by 3 months. Corresponding to this finding was the strong trend for ALT to fail more quickly than SLT. Although repeatable, the first repeat SLT reduced IOP to only about half compared with initial SLT treatment. CONCLUSIONS: The comparison at 12 months following the laser therapy showed that both modalities lowered the IOP with approximately 3 mmHg, yet essentially all of the time-to-failure analyses favored SLT over ALT. The repeat SLT effect was found to be half of the initial treatment.

Cadaver corneoscleral model for angle surgery training.

PURPOSE: To assess a new training model (Tackdriver) for new-generation microinvasive glaucoma surgeries (MIGS). SETTING: Resident training centers in Canada. DESIGN: Evaluation of technology. METHODS: Human cadaver corneoscleral rims recovered after Descemet-stripping endothelial keratoplasty or not suitable for transplantation were acquired from an eye bank. The tissue was fixated with a single tack through the center of the cornea, which was inverted in a concave fashion. A water-based medical lubricant was used for placement of a goniolens after visualization of the anterior chamber and the trabecular meshwork. Microbypass stent (iStent) insertion and gonioscopy-assisted transluminal trabeculotomy (GATT) were practiced on this model. The model was qualitatively assessed for ease of preparation, accuracy of surgical simulation, and the number and variety of MIGS procedures that can be performed. RESULTS: Efficient high-volume training was performed for microbypass stent insertion using first-generation and second-generation microbypass stents. The GATT procedure was also performed as a final step in a titratable fashion in 90-, 180-, or 270-degree segments or a complete 360-degree treatment. The model simulated bimanual angle surgery with good fidelity. CONCLUSIONS: The training model allowed for high-volume bimanual MIGS training for techniques such as microbypass stent insertion and removal as well as GATT. Preparation was relatively simple, efficient, and cost-effective compared with other models. Inverting the specimen allowed the trainee to practice MIGS techniques independent of the tissue's corneal clarity. Other MIGS techniques and angle training procedures can be adopted to this model.

Evaluation of a modified protocol for selective laser trabeculoplasty.

PURPOSE: To compare the intraocular pressure (IOP) response to a modified protocol for selective laser trabeculoplasty (SLT) to standard protocols for SLT and argon laser trabeculoplasty (ALT). MATERIALS AND METHODS: A retrospective study of 318 eyes of 284 patients diagnosed with either primary open angle, pigmentary or pseudoexfoliation glaucoma who underwent laser trabeculoplasty from September 1997 to September 2005. One hundred and two patients, who underwent a modified SLT protocol with 100 overlapping laser spots over 180 degrees of trabecular meshwork were compared with 89 patients who received SLT with 100 nonoverlapping spots over 360 degrees and another 127 patients who received ALT with 50 spots over 180 degrees. IOPs were measured at baseline and postoperatively at 1 hour, 6 weeks, 4 months, and 14 months. Regression models, based on the observed data, were used to predict the fall in IOP in the 3 groups, controlling for differences in baseline pressure. RESULTS: The IOP response to overlapping SLT was significantly worse than to nonoverlapping SLT or ALT, both of which had similar responses. Baseline IOP was the only preoperative factor that predicted response to ALT (P<0.0001) and nonoverlapping SLT (P=0.0019) at all follow-up times. There were no statistically significant predictive factors for IOP reduction in the overlapping SLT group. CONCLUSIONS: Overlapping application of SLT results in a poorer IOP response compared with ALT and nonoverlapping SLT.