New technique to reduce systemic side effects of timolol eye drops: The tissue press method-Cross-over clinical trial.

IMPORTANCE: Nasolacrimal occlusion (NLO) is effective in reducing systemic absorption of eye drop medication but it is difficult and often performed poorly. We propose an alternative easier and equally effective technique. BACKGROUND: To test the effectiveness of systemic absorption, we evaluated plasma concentration and ocular effects after topically administered timolol and compared to NLO. DESIGN: Cross-over trial carried out in Capital Eye Specialist, Wellington. PARTICIPANTS: A total of 21 subjects over 18 years without contraindications for topical beta-blocker medication and not using systemic beta-blockers. METHODS: During three clinic visits separated by at least one week, alternative approaches to reduce systemic eye drop absorption were tested. These were: (a) nasolacrimal (punctal) occlusion for 5 min, (b) tissue press method or (c) no intervention. Timolol plasma levels were measured 1 h after drop application. At each visit, baseline measurement of blood pressure, heart rate and intraocular pressure (IOP) were performed, and repeated 1 h after timolol 0.5% eye drop application. MAIN OUTCOME MEASURES: Comparison of timolol plasma concentration after each intervention. Secondary outcome measurements included effects on blood pressure, heart rate and IOP. RESULTS: Plasma timolol concentrations after tissue press method and NLO were significantly lower than those without intervention. Comparing tissue press method to NLO, there were no significant differences in plasma levels of timolol, blood pressure, heart rate or IOP. CONCLUSION AND RELEVANCE: The tissue press method is equally effective as NLO in reducing systemic absorption of timolol. It is also easier and faster to administer.

Optic Nerve Head Drusen: An Update.

Optic nerve head drusen are benign acellular calcium concretions that usually form early in life, just anterior to the lamina cribrosa. Improving imaging using optical coherence tomography suggests they are common and may be present in many clinically normal discs. These drusen may change in appearance in early life, but are generally stable in adulthood, and may be associated with visual field defects, anterior ischaemic optic neuropathy, or rarer complications. Based on long-term clinical data and optical coherence tomography, we propose a refined hypothesis as to the cause of optic disc drusen. Here we summarise recent findings and suggest future studies to better understand the forces involved.

Optometry-based general population survey of pupil ruff atrophy and ocular hypertension.

BACKGROUND: To evaluate and describe the pupil ruff changes and relationship to intraocular pressure, pseudoexfoliation syndrome and glaucoma status in an optometric population in New Zealand. DESIGN: Prospective cross-sectional survey of an optometric population. PARTICIPANTS: Six hundred and twenty subjects over 50 years old routinely attending the participating optometry practices. Exclusion criteria included previous intraocular surgery, ophthalmic laser, uveitis, angle closure and secondary glaucoma. METHODS: Multicentre study involving 11 optometry practices in the Wellington region, New Zealand. The pupillary ruff and associated gonioscopy findings of study participants were graded based on the previously published Pupil Ruff Atrophy grading system. Parameters evaluated include pupillary ruff absence and abnormality, pseudoexfoliation material and trabecular meshwork pigmentation. MAIN OUTCOME MEASURES: Correlations between intereye Pupil Ruff Atrophy grading differences and inter-eye intraocular pressure and cup:disc ratio differences. RESULTS: Six hundred and twenty subjects were included, with a mean age of 62.2 ± 9.1 years and mean intraocular pressure of 14.8 ± 3.4 mmHg. Four hundred and fourteen (66.8%) had bilateral pupil ruff changes and 12 (1.5%) had pseudoexfoliation. Inter-eye intraocular pressure asymmetry was significantly correlated with amount of missing pupillary ruff (r = 0.111; P = 0.022) and trabecular meshwork pigmentation (r = 0.147; P = 0.002). Inter-eye cup:disc ratio asymmetry was not correlated with any of the Pupil Ruff Atrophy grading parameters. CONCLUSIONS: Asymmetry of pupillary ruff absence and trabecular meshwork pigmentation was correlated with intraocular pressure asymmetry (but not with cup:disc ratio asymmetry) in a general optometric population setting in New Zealand.

Repeatability of primary selective laser trabeculoplasty in patients with primary open-angle glaucoma.

To determine if primary selective laser trabeculoplasty (SLT) can be repeated with clinical benefit in patients with primary open-angle glaucoma (POAG). Forty-two eyes of 42 patients with POAG were studied. All patients underwent primary SLT treatment of 40-50 shots to the trabecular meshwork over 360°. The treatment response at the initial post-SLT visit (4 weeks), and second post-SLT visit (mean 4 months), clinical success and duration of clinical success were measured. SLT was repeated in all patients after failure to maintain target intraocular pressure (IOP). The same parameters were measured after repeat SLT. The main outcome measures were success of treatment (as defined by reduction of IOP by at least 20 % and below an individually determined target pressure), duration of treatment success and reduction in IOP. No significant difference between initial and repeat treatments was found for mean reduction in IOP or success rate, or duration of success. Survival analysis found significantly longer benefit for repeat treatment compared to initial treatment (P < 0.01). Repeat SLT treatment in eyes with POAG has similar efficacy to primary SLT treatment with respect to reduction in IOP and success rates, produces a longer duration of treatment success.

Pupil ruff atrophy correlations with intraocular pressure and cup-to-disc ratio in a glaucoma clinic population.

PURPOSE: To evaluate the correlations between pupil ruff changes and associated gonioscopy findings with intraocular pressure (IOP) and cup-to-disc ratio (CDR). DESIGN: Prospective, observational, comparative study. PARTICIPANTS: A total of 103 patients from a glaucoma clinic population. Patients with pseudoexfoliation, previous intraocular surgery, and IOP-lowering medication were excluded. METHODS: Pupillary ruff and associated gonioscopy findings were graded from photographs based on the pupil ruff atrophy (PRA) grading system. Parameters evaluated include pupillary ruff absence and abnormality, pupil edge pigment, and trabecular meshwork pigment. Inter-eye differences were determined and analyzed for correlations with inter-eye differences in IOP and CDR based on Heidelberg Retinal Tomograph II imaging (Heidelberg Engineering, Dossenheim, Germany). MAIN OUTCOME MEASURES: Correlations between inter-eye PRA grading differences and inter-eye IOP and CDR differences. RESULTS: A total of 103 patients were included, with a mean age of 64 years. The average amount of abnormal and missing ruff was 9.5 and 5 clock hours, respectively. Inter-eye IOP asymmetry was significantly associated with asymmetry of amount of abnormal ruff (P = 0.034) and amount of missing ruff (P = 0.022). Inter-eye CDR asymmetry was significantly associated with asymmetry of the amount of missing ruff (P = 0.001) and trabecular meshwork pigmentation (P = 0.006). The eye with the most pupillary ruff loss was 25% more likely to have the greater CDR. CONCLUSIONS: Asymmetric pupillary ruff changes were associated with asymmetry in both IOP and CDR. However, the clinical significance of this finding requires further evaluation.

The effect of thin, thick, and normal corneas on Goldmann intraocular pressure measurements and correction formulae in individual eyes.

OBJECTIVE: To evaluate the usefulness of the central corneal thickness (CCT)-based correction formulae for stratified CCT groups, with intraocular pressure (IOP) from the Pascal dynamic contour tonometer (PDCT) as the reference standard. DESIGN: Retrospective case series. PARTICIPANTS: Two hundred eighty-nine patients attending a specialist glaucoma practice and a mixture of normal subjects and subjects with confirmed glaucomatous optic neuropathy. METHODS: Intraocular pressure was measured using PDCT, Goldmann applanation tonometry (GAT), and the Ocular Response Analyzer (ORA; Reichert Corp, Buffalo, NY). The GAT readings were obtained before automated readings and were adjusted for CCT using 4 different correction formulae. Discrepancies between GAT and CCT-corrected GAT readings were evaluated after stratification into thin, intermediate, and thick CCT groups. The IOP measurements from GAT, the ORA, and CCT-adjusted IOP were compared against PDCT IOP measurements using Bland-Altman analysis. MAIN OUTCOME MEASURES: Mean, 95% limits of agreement, and proportion of patients with IOP difference of 20% or more between PDCT IOP and each of GAT IOP, Goldmann-correlated IOP (IOPg), corneal-compensated IOP (IOPcc), and adjusted IOP using CCT-based correction formulae. RESULTS: Average PDCT IOP values were higher than GAT, IOPg, IOPcc, and CCT-adjusted IOP. The GAT IOP readings demonstrated poor agreement with PDCT IOP (95% limits of agreement, ± 4.7 mmHg); however, IOPg, IOPcc, and adjustment of GAT IOP with CCT-based formulae resulted in even poorer agreement (range of 95% limits of agreement, ± 5.1 to 6.7 mmHg). If PDCT was used as the reference standard, there was a 26% to 39% risk of making an erroneous IOP adjustment of magnitude of 20% or more at all levels of CCT. This risk was greatest in the patients with thicker corneas (CCT, ≥568 µm). CONCLUSIONS: Adjusting IOP using CCT-based formulae resulted in poorer agreement with PDCT IOP when compared with unadjusted G AT IOP. If PDCT is the closest measure we have to intracameral IOP, there is a risk of creating clinically significant error after adjustment of GAT IOP with CCT-based correction formulae, especially in thicker corneas. This study suggests that although CCT may be useful in population analyses, CCT-based correction formulae should not be applied to individuals.

Novel grading system for pupillary ruff changes and associated features.

BACKGROUND: To evaluate the reproducibility of a new system for grading pupil ruff changes and associated findings. DESIGN: Observational comparative study. PARTICIPANTS: Forty-seven photograph sets including iris, pupil edge and ruff, and inferior anterior chamber drainage angle. METHODS: A novel system for recording pupillary ruff changes was developed, along with reference iris, pupil and gonioscopy images. A prospective masked agreement study was undertaken using two observers who graded the photograph sets using this new system. Parameters included pupillary ruff absence and abnormality, pupil edge pigment, trabecular meshwork pigment, Sampaolesi line pigment, iris root pigment, and pigment 'lumps' and 'piles'. MAIN OUTCOME MEASURES: Intraobserver and interobserver agreement for the parameters of the grading system, assessed with the intraclass correlation coefficient and Bland-Altman plots. RESULTS: Photographs of 47 eyes of 47 glaucoma suspects and glaucoma patients were evaluated. Agreement percentages of ≥95% (average 96%) and ≥60% (average 70%) were obtained for intraobserver and interobserver agreement, respectively. The average interobserver single-measure intraclass correlation coefficient and repeat-measures intraclass correlation coefficient were 0.75 (range 0.54-0.88) and 0.85 (range 0.70-0.94), respectively. There was a non-significant trend towards interobserver systematic bias on one of the nine parameters (iris stroma pigment at the pupil edge). CONCLUSION: This grading system provides a reliable and reproducible system for encoding of clinical signs of pupil ruff atrophy for clinical research.

Prospective study of surgical outcomes and bleb morphology using indocyanine green as a surgical dye in trabeculectomy with mitomycin C.

BACKGROUND: To investigate the effect of adding indocyanine green to mitomycin C in augmented trabeculectomy. DESIGN: A prospective, non-comparative interventional case series. PARTICIPANTS: A total of 37 eyes of 37 patients followed up for 1 year. METHODS: A solution containing 12.5 mg/mL of indocyanine green was added to mitomycin C, resulting in an mitomycin C concentration of 0.2-0.4 mg/mL, which was applied to bare sclera and Tenon's capsule for 3 min during trabeculectomy. MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure, bleb morphology, Moorfields Bleb Grading System scores and complications. RESULTS: Indocyanine green could be visualized on clinical examination for all eyes on the first postoperative day. Mean intraocular pressure decreased from 22.9 ± 6.2 mmHg to 12.1 ± 4.4 mmHg postoperatively (P < 0.001) at 1 year. Thirty-four eyes (91.9%) achieved an intraocular pressure of less than 21 mmHg at final visit without additional topical intraocular pressure-lowering medications. Three eyes (8.1%) developed bleb failure and required Baerveldt device implantation. There were no cases of blebitis or late bleb leak. No adverse effects attributable to indocyanine green could be identified postoperatively. CONCLUSION: The addition of indocyanine green during trabeculectomy improves the visibility of antimetabolites intraoperatively and allows for the estimation of antimetabolite treatment area intraoperatively and postoperatively. It appears to have no adverse effect on surgical outcomes and complication rates, while improving safety of antimetabolite use.

Bleb vascularity following post-trabeculectomy subconjunctival bevacizumab: a pilot study.

BACKGROUND: To determine whether postoperative subconjunctival bevacizumab significantly alters bleb vascularity. DESIGN: A randomized, prospective interventional study. PARTICIPANTS: Forty-three eyes from 39 patients were recruited, with 21 eyes randomized to subconjunctival injections of 5-fluorouracil, and 22 eyes to combined 5-fluorouracil/bevacizumab. METHODS: All patients who underwent uncomplicated primary antimetabolite augmented trabeculectomy who subsequently required postoperative subconjunctival 5-fluorouracil injection within 4 weeks of surgery were eligible. Patients were randomized to receive subconjunctival 5-fluorouracil only (7.5 mg/0.15 mL) or 5-fluorouracil plus bevacizumab (1.25 mg/0.05 mL). MAIN OUTCOME MEASURES: Primary outcome was bleb vascularity with secondary endpoints including visual acuity, intraocular pressure, bleb morphology, complications and total numbers of 5-fluorouracil injections were recorded at baseline, week 12 and 18 months. RESULTS: At week 12, there was no significant difference between groups for visual acuity, intraocular pressure, bleb vascularity and morphology, or total number of 5-fluorouracil injections. By 18 months, 47.4% of the 5-fluorouracil/bevacizumab group exhibited central bleb avascularity compared with 21.1% of the 5-fluorouracil group (Fisher's exact test, P = 0.17). Two bleb complications (one blebitis; one suture abscess) recorded in the 5-fluorouracil/bevacizumab group. CONCLUSIONS: After a single combined injection, a trend for increased central bleb avascularity was observed, although this effect was not sufficient to reach statistical significance. This, in addition to the occurrence of two bleb-related complications in the bevacizumab group, suggests the need for a larger clinical trial to further evaluate the safety and efficacy of bevacizumab as a modulating agent in glaucoma filtration surgery.

Poor utility of intraocular pressure correction formulae in individual glaucoma and glaucoma suspect patients.

BACKGROUND: To compare Pascal dynamic contour tonometry (DCT) measurements with Goldmann applanation tonometry (GAT) readings after adjustment with correction formulae in a population of Caucasian glaucoma and glaucoma suspect patients. DESIGN: Retrospective cross-sectional case series in a specialist glaucoma practice. PARTICIPANTS: Consecutive glaucoma and glaucoma suspect Caucasian patients. METHODS: Case notes review of the GAT and DCT intraocular pressure (IOP) measurements from patients who presented on a non-acute basis over a 30-month period. The GAT measurement was adjusted with six different correction formulae. Agreement between GAT IOP, adjusted GAT IOP and DCT IOP was evaluated with the Bland-Altman analysis. MAIN OUTCOME MEASURES: Agreement between GAT IOP (both unadjusted and adjusted) and DCT IOP. RESULTS: Data from 200 patients with a mean age of 58.4 (±12.7) years were analysed. The mean central corneal thickness was 554.8 (±36.9) µm and the mean corneal hysteresis was 9.8 (±1.9) mm Hg. Sixty five (32.5%) had confirmed glaucomatous optic neuropathy. GAT IOP demonstrated poor agreement with DCT IOP. GAT IOP was on average 2.1 mm Hg less than DCT IOP. None of the six correction formulae resulted in improved agreement with DCT IOP. General linear model analysis found no statistically significant measurement differences between the glaucoma and glaucoma suspect groups. CONCLUSIONS: GAT demonstrated poor agreement with DCT, and agreement did not improve after adjustment with correction formulae. Our results suggest that correction formulae for GAT IOP are unsuitable to clinically approximate 'true' IOP in Caucasian glaucoma and glaucoma suspect patients.

Comparison of standard trabeculectomy versus microtrabeculectomy as a surgical treatment for glaucoma: a randomized clinical trial.

BACKGROUND: To determine the effect of scleral flap size on the medium-term intraocular pressure control and complication rates after augmented trabeculectomy. DESIGN: Prospective randomized clinical trial. PARTICIPANTS: Glaucoma patients undergoing primary trabeculectomy. Exclusion criteria included previous ocular surgery apart from cataract surgery, secondary glaucoma and age under 18. METHODS: Patients were randomized to either standard trabeculectomy (4 × 4 mm scleral flap) or microtrabeculectomy (2 × 2 mm scleral flap), both with adjustable sutures and antimetabolites. Bleb needling was performed as required. Patients were evaluated at day 1, weeks 1, 3, 6 and months 3, 6, 12, 18 and 24 postoperatively. MAIN OUTCOME MEASURES: Vision, intraocular pressure, complications and failure (intraocular pressure ≥ 21 mmHg or not reduced by ≥20% from baseline, intraocular pressure ≤ 5 mmHg, repeat glaucoma surgery and no light perception vision). RESULTS: Forty-one patients were recruited; 20 had standard trabeculectomy, and 21 had microtrabeculectomy. At 2 years, the mean intraocular pressure and cumulative probability of failure was 12.4 ± 4.6 mmHg and 0.28 for standard trabeculectomy, and 11.5 ± 3.6 mmHg and 0.27 for microtrabeculectomy (P = 0.50 and 0.89, respectively). One patient in each group required Baerveldt device implantation. Vision reduced ≥2 Snellen lines in 15% in the standard trabeculectomy group and 25% in the microtrabeculectomy group, mainly from cataract (P = 0.48). CONCLUSION: Both trabeculectomy techniques achieved good intraocular pressure reduction and had similar complication rates. Scleral flap size had no significant effect on medium-term intraocular pressure control and complication profile.

Selective Laser Trabeculoplasty: Outcomes of Multiple Repeat Treatments.

PURPOSE: To characterize intraocular pressure (IOP) reduction, effect duration, and side effect profile of repeat selective laser trabeculoplasty (SLT) used as primary stand-alone treatment for open-angle glaucoma (OAG). The secondary aim was to investigate covariates associated with treatment response to SLT. DESIGN: Retrospective chart review. PARTICIPANTS: A total of 52 patients with treatment-naïve OAG who received 3 installments of 3600 SLT as stand-alone glaucoma therapy. When both eyes met the inclusion criteria, only right eye data were used for analysis. METHODS: The study was conducted in a single specialist practice. First, second, and third SLT (SLT1, SLT2, SLT3, respectively) treatments were compared for IOP reduction and effect duration. Eyes were classified as "treatment responders" if they had ≥20% IOP reduction 4 to 8 weeks post-SLT compared with baseline. Effect duration was the interval between SLT and the time point at which the surgeon decided inadequate IOP control necessitated repeat SLT. Individuals were excluded if they underwent intraocular surgery during the study period or received treatment with adjunctive ocular hypotensive medications. MAIN OUTCOME MEASURES: Reduction in IOP post-SLT and effect duration between treatments. RESULTS: Mean age at SLT1 was 58 years; 50% were male, and 92% were phakic. The SLT1 and SLT3 both resulted in mean 27% IOP reduction at 4 to 8 weeks, whereas SLT2 led to 26% IOP reduction. Response rate (≥20% IOP reduction at 4-8 weeks) was 79% for SLT1, 73% for SLT2, and 81% for SLT3, but the difference was not statistically significant. Response to repeat SLT was not significantly associated with previous SLT outcome. Effect duration was 22.2 months, 33.8 months, and 28.9 months after SLT1, SLT2, and SLT3, respectively. Effect duration was significantly longer after SLT2 (P = 0.0006) and SLT3 (P = 0.0444) compared with SLT1. There was no significant association between SLT response and gender, lens status, or OAG subtype. CONCLUSIONS: For primary stand-alone treatment in OAG, initial and repeat SLTs produced comparable percentage IOP reduction, but repeat SLTs had longer effect duration. Intraocular pressure response to SLT was not predictive of the IOP response to subsequent, repeat SLT treatment.

In vivo fluorescence mode confocal microscopy of subepithelial tissues in glaucoma filtering blebs.

BACKGROUND AND OBJECTIVE: The miniaturization of confocal imaging technology has resulted in the development of a handheld confocal microscope probe capable of fluorescence mode imaging. Findings in the subepithelial tissues of glaucoma filtering blebs using this novel approach for proof of concept are described. PATIENTS AND METHODS: A fiberoptic confocal imaging probe using an illumination wavelength of 488 nm was applied to the bleb surface of 11 eyes after topical or subconjunctival administration of sodium fluorescein. The imaging plane was moved to the subepithelial region and multiple images from multiple bleb regions were captured at a resolution of 1,024 x 1,024 pixels per square inch. RESULTS: High-quality images of the bleb wall structure, vasculature, and superficial sclera were obtained and demonstrated subcellular detail. Lateral resolution was between 1 and 1.5 microm and axial resolution was approximately 30 microm. Identifiable structures in the failing blebs included vasculature (including individual erythrocytes, pericytes, and vascular endothelium); microcystic structures; and cells within the Tenon's tissue, some of which resembled fibroblasts. CONCLUSION: Fluorescence mode imaging of ocular subsurface detail is a viable and promising tool for assessment of wound healing and other processes in trabeculectomy blebs. The ability to image fluorophores creates the possibility of functional imaging.

Changes in Caucasian eyes after laser peripheral iridotomy: an anterior segment optical coherence tomography study.

BACKGROUND: To evaluate by anterior segment optical coherence tomography (AS-OCT) the changes in the anterior chamber structures in Caucasian eyes after laser peripheral iridotomy (PI). METHODS: Retrospective study of consecutive Caucasian primary angle closure suspect (PACS), primary angle closure (PAC) or primary angle closure glaucoma (PACG) patients who underwent laser PI over a 25-month period at a specialist glaucoma practice. The AS-OCT images of the temporal and nasal angles (in light and dark) before and after laser PI were analysed. The parameters studied were trabecular-iris angle (TIA), angle opening distance (AOD), trabecular-iris space area (TISA), trabecular-iris contact length (TICL), iris thickness (IT) and maximum iris bow height (MIBH). RESULTS: Images of 71 eyes of 71 patients were assessed. The mean age at laser PI was 60.3 ± 10.0 years. Forty (56.3%) were women, and 14 (19.7%) had PACG. The mean time from laser PI to the follow-up AS-OCT scan was 5.92 ± 3.22 weeks. The IT did not alter significantly after laser PI, but there were significant increases in the TIA, AOD and TISA, as well as a significant decrease in MIBH, in both light and dark. There was no difference in the magnitude of change seen between the temporal and nasal angles, or between PACS/PAC and PACG eyes. CONCLUSION: In Caucasian eyes, laser PI resulted in significant angle widening (increased TIA, AOD and TISA) and iris profile flattening (decreased MIBH) at the temporal and nasal angles based on AS-OCT imaging in both light and dark.

Optic disc area and correlation with central corneal thickness, corneal hysteresis and ocular pulse amplitude in glaucoma patients and controls.

BACKGROUND: To examine the relationships between optic disc area and parameters measured at the cornea; central corneal thickness (CCT), corneal hysteresis (CH) and ocular pulse amplitude (OPA) in glaucoma subjects and controls. METHODS: In this prospective experimental study, patients underwent measurement of CCT, OPA, CH and optic disc imaging with the Heidelberg Retina Tomograph II (HRT-II). Pearson's correlation coefficient was calculated to assess the associations between optic disc area and CCT, OPA and CH. RESULTS: A total of 100 patients, 38 with glaucoma and 62 controls were examined. In a univariate analysis of this group, CCT and CH were significantly lower in glaucoma patients (P = 0.01). CCT was inversely correlated with optic disc surface area (Pearson's correlation coefficient r = -0.200; P = 0.05). This inverse correlation did not achieve statistical significance when glaucoma patients and controls were analysed separately. There was no statistically significant association between optic disc area and OPA or CH. CONCLUSIONS: There was an inverse relationship between CCT and optic disc area in this study group. No association was found between optic disc area and OPA or CH.

Loss of Pressure Control Resulting from Tube Bending during Glaucoma Drainage Tube Perforations.

PURPOSE: Tube perforations are a common method of achieving early intraocular pressure control with ligated glaucoma drainage devices (GDDs). Our purpose was to investigate how bending GDD tubes affects the performance of needle perforations. DESIGN: Experimental report. PARTICIPANTS: Twenty silicone GDD tubes attached to 27 G Rycroft cannulae tied with 7-0 Vicryl 10 mm from the cannulae tips. METHODS: Silicone GDD tubing was fitted over a 27 G Rycroft cannula and tied with a 7-0 suture 10 mm from the cannula tip. The tube was perforated 4 mm from the cannula tip with a 25 G needle (tube was kept straight). The tube was secured in a 50-mm water bath. Aqueous food dye was infused through the cannula from an adjustable height. The tube was observed under magnification while the height of the fluid column was adjusted to establish the pressure gradient at which the tube leaked dye (opening pressure) and ceased to leak (closing pressure), while the tube was held straight and bent 90 degrees. Measurements were repeated after a second perforation and a third perforation. Ten tubes were tested this way with 3 sequential slits. The entire experiment was repeated with another 10 tubes, but this time the tube was allowed to bend within the 3.5-mm open prongs of a needle holder during needle perforation. MAIN OUTCOME MEASURES: Opening and closing pressures. RESULTS: For each tube, the opening and closing pressures were similar and highly reproducible, but there was wide variation between tubes. In the tubes kept straight when perforated, the opening/closing pressure ranged from 5 to 25 cmH2O. The opening and closing pressures of slits made in the bent tube were significantly lower, frequently leaking at <1 cmH2O. Bending the tube after perforation could close a slit and prevent leakage at high perfusion pressure. The second and third successive perforations caused lower opening and closing pressures. CONCLUSIONS: Tube perforations behave like pressure-sensitive valves, opening whenever intraluminal pressure increases above a specific value. However, we found a large variation in the performance of fenestrations made with a 25-G hypodermic needle. Allowing the GDD tube to bend during needle perforation increases the risk of very low opening and closing pressures.

Selective laser trabeculoplasty versus topical medication as initial glaucoma treatment: the glaucoma initial treatment study randomised clinical trial.

BACKGROUND/AIMS: To determine if selective laser trabeculoplasty (SLT) is superior to topical medication as a first-line treatment for glaucoma on quality of life (QoL) and clinical outcomes. METHODS: In this international, longitudinal, multisite randomised controlled trial, treatment naïve mild-to-moderate primary open angle or exfoliation glaucoma patients were randomised 1:1 to SLT or topical medication. Glaucoma-specific QoL (primary outcome) was measured using the Glaucoma Outcomes Assessment Tool (GOAT; 342 items, 12 domains). Secondary outcomes included rate of successful intraocular pressure (IOP) reduction (>25% reduction from baseline) and presence of ocular surface disease including conjunctival hyperaemia and eyelid erythema. Our intention-to-treat analysis was performed at months 12 and 24. RESULTS: Of 167 enrolled patients, 83 and 84 were randomised to SLT and topical medication, respectively; and 145 (n=75 SLT, n=70 medication) completed 24-month follow-up. While both treatment arms achieved significant within-group gains in GOAT outcomes at both endpoints, SLT patients reported a greater between-group improvement in 'social well-being' compared with medication patients (mean±SE=0.28±0.13; p=0.034) at 24 months. At month 24, the rate of successful IOP reduction was 18.6% (95% CI 3.0% to 34.3%, p=0.022) higher (absolute difference) in the medication compared with SLT group. More individuals in the medication group had conjunctival hyperaemia and eyelid erythema compared with SLT at 24 months. CONCLUSION: Overall, we did not find evidence that SLT was superior to medication in improving glaucoma-specific QoL. While we found superior IOP reduction in the medication arm, eyelid erythema and conjunctival hyperaemia were more prevalent in these patients compared with the SLT group. TRIAL REGISTRATION: ACTRN12611000720910.