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.

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.Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2012;119:1546-1551 (C) 2012 by the American Academy of Ophthalmology.

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 mu m).Conclusions: Adjusting IOP using CCT-based formulae resulted in poorer agreement with PDCT IOP when compared with unadjusted GAT 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.Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2012;119:443-449 (C) 2012 by the American Academy of Ophthalmology.

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 x 4 mm scleral flap) or microtrabeculectomy (2 x 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.

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.

AbstractBackground: 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.

AbstractBackground: 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.

PURPOSE:To evaluate optic nerve diameter changes in glaucomatous and nonglaucomatous eyes during transient elevation of intraocular pressure (IOP).METHODS:This prospective experimental study included 100 subjects: 38 with glaucoma and 62 without glaucoma. Elevation of IOP to an average of 64 mm Hg for less than 30 seconds was induced in one eye of all subjects by means of a modified LASIK suction ring. The optic nerve heads were imaged before and during the elevation.RESULTS:During IOP elevation, optic disc area and linear disc measurements increased by a small but significant amount (3.89%, P < 0.0001 and 0.96%, P = 0.01, respectively). Distances between retinal landmarks did not change significantly (P = 0.25). A smaller optic disc at baseline (P = 0.004) and increased central corneal thickness (CCT; P = 0.011) were associated with a greater increase in disc area relative to other fundus dimensions during IOP elevation. Disc area increased less in patients with glaucoma (P = 0.015). In a multivariate model including age, glaucoma status, CCT, and baseline disc area, there was a small but significant negative correlation between disc area enlargement and baseline optic disc diameter (P = 0.017).CONCLUSIONS:Transient elevation of IOP in adult eyes resulted in increases in disc area and linear disc dimensions, but not in retinal dimensions. The degree of enlargement appears to be less in patients with glaucoma than without and greater with increased corneal thickness. A multivariate model showed that the amount of disc area increase was inversely proportional to baseline disc area but was not related to glaucoma status or CCT. (ClinicalTrials.gov number, NCT00328835).

AbstractPurpose: To assess agreement between the iCare rebound tonometer and Goldmann tonometry and to assess the influence of central corneal thickness and the value of scleral rebound tonometer readings.Methods: Prospective single‐centre cross‐sectional study comparing iCare rebound tonometer (RT) intraocular pressure (IOP) readings taken from corneal and scleral locations to Goldmann applanation tonometer (GAT) readings in 100 subjects attending ophthalmology clinics.Results: There was a significant difference between RT and GAT, with RT tending to overestimate IOP. The mean difference between RT and GAT measurements was 3.36 mmHg. The mean difference between the log of RT and the log of GAT measurements was 0.2356, a ratio of 1.27 (P < 0.0001). A formula derived from a linear regression analysis suggested that a 10% increase in CCT increased the RT IOP reading by 9.9%. Scleral RT readings showed no relationship to GAT readings.Conclusions: The rebound tonometer cannot replace the Goldmann tonometer in the office setting given the wide limits of agreement between the two devices. Corneal rebound tonometer readings are influenced by CCT whereas scleral rebound tonometer readings are of no value.

Summary Modern-day oil exploration pushes operators into harsher and more-difficult drilling environments in the search for hydrocarbon reserves. Eastern Canada is one of those environments where deep water and the need to penetrate through thick salt sheets greatly increases difficulties faced by drillers. This paper describes a case history of deepwater subsalt drilling and examines the requirements for success. This paper also details the challenges using seismic data, of prewell planning for dealing with high pore-pressures and variable fracture gradients. Experience shows that prewell engineering differs considerably from conditions actually encountered that require rapid adjustments based on actual well data. In the case reported here, a fluid influx occurred at a depth where planning indicated a significantly lower pore-pressure. This influx directly led to losing a bottomhole assembly (BHA), sidetracking, and a re-evaluation of the well data and pore-pressure regimes possible at that depth. This paper also highlights the need for flexible well designs able to respond to unanticipated drilling hazards and wellbore problems. In the case history reported here, the 11¾-in. casing was set 511 m higher than originally planned because of pore-pressure increases. This decision had a significant effect later in the well construction program, requiring the use of expandable casing not originally in the well program. This paper illustrates on-the-fly modification of drilling designs to rapidly deploy unplanned equipment, the use of unconventional borehole sizes, and the use of newer technology such as rotarysteerable assemblies for side-track kickoff. The paper will also discuss the optimized use of hole openers and expandable casing and the potential effects of expandable casing on subsequent hole-opener use. These dynamic modifications and immediate implementation of lessons learned allowed successful drilling to a record depth for eastern Canada.

AbstractPurpose: To investigate correlations between optical coherence tomography macular thickness measurements and visual acuity after cataract surgery.Methods: Sixty‐two patients underwent routine cataract surgery as part of a randomized clinical trial of oral Cox‐2 inhibitor prophylaxis of cystoid macular oedema. Optical coherence tomography was used to quantify several parameters of macular thickness. Optical coherence tomography measurements were obtained before surgery, day one, week two and week six after surgery. These measurements were then correlated with logMAR best‐corrected visual acuity.Results: Optical coherence tomography macular thickness parameters increased after surgery by up to 20%. A significant correlation was identified between foveal minimum macular thickness and best‐corrected visual acuity at day one and week six after surgery. Other macular parameters failed to show any significant correlation. At day one and week six, the 10 patients with greatest macular thickness had significantly lower visual acuity than the other patients.Conclusion: In this study routine cataract surgery caused an increase in macular thickness. Some significant positive correlations between macular thickness and best‐corrected visual acuity were found, although not for all parameters or time points. There may be a threshold relationship between degree of foveal anatomic change and significant loss of visual acuity.