Analysis on scattering characteristics of Love-type wave due to surface irregularity in a piezoelectric structure.

Surface irregularity in piezoelectric sensors causes scattering of Love-type waves, which may lead to significant signal insertion loss. Also, as the reflected wave field in the piezoelectric sensor is increased due to surface irregularity, the input interdigital transducer (IDT) can be damaged. The present analysis confers the characteristics of Love-type waves scattered through surface irregularity in piezoelectric composite structures with different shaped surface irregularity, e.g., rectangular shaped, parabolic shaped, and triangular notch shaped. The expressions of phase and group velocities of scattered Love-type waves are derived for electrically open and short conditions. Also, expressions of mechanical displacement and electrical potential function due to incident and scattered Love-type waves are deduced for both electrical conditions. It is reported from the analysis that the increase in vertical irregularity parameter causes stronger reflected wave fields. Also, with the increase in piezoelectricity of the superficial layer, signal insertion loss and strength of reflected wave field diminish.

A common variant near TGFBR3 is associated with primary open angle glaucoma.

Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10(-33)), we observed one SNP showing significant association to POAG (CDC7-TGFBR3 rs1192415, ORG-allele = 1.13, Pmeta = 1.60 × 10(-8)). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis.

Latanoprost for open-angle glaucoma (UKGTS): a randomised, multicentre, placebo-controlled trial.

BACKGROUND: Treatments for open-angle glaucoma aim to prevent vision loss through lowering of intraocular pressure, but to our knowledge no placebo-controlled trials have assessed visual function preservation, and the observation periods of previous (unmasked) trials have typically been at least 5 years. We assessed vision preservation in patients given latanoprost compared with those given placebo. METHODS: In this randomised, triple-masked, placebo-controlled trial, we enrolled patients with newly diagnosed open-angle glaucoma at ten UK centres (tertiary referral centres, teaching hospitals, and district general hospitals). Eligible patients were randomly allocated (1:1) with a website-generated randomisation schedule, stratified by centre and with a permuted block design, to receive either latanoprost 0·005% (intervention group) or placebo (control group) eye drops. Drops were administered from identical bottles, once a day, to both eyes. The primary outcome was time to visual field deterioration within 24 months. Analyses were done in all individuals with follow-up data. The Data and Safety Monitoring Committee (DSMC) recommended stopping the trial on Jan 6, 2011 (last patient visit July, 2011), after an interim analysis, and suggested a change in primary outcome from the difference in proportions of patients with incident progression between groups to time to visual field deterioration within 24 months. This trial is registered, number ISRCTN96423140. FINDINGS: We enrolled 516 individuals between Dec 1, 2006, and March 16, 2010. Baseline mean intraocular pressure was 19·6 mm Hg (SD 4·6) in 258 patients in the latanoprost group and 20·1 mm Hg (4·8) in 258 controls. At 24 months, mean reduction in intraocular pressure was 3·8 mm Hg (4·0) in 231 patients assessed in the latanoprost group and 0·9 mm Hg (3·8) in 230 patients assessed in the placebo group. Visual field preservation was significantly longer in the latanoprost group than in the placebo group: adjusted hazard ratio (HR) 0·44 (95% CI 0·28-0·69; p=0·0003). We noted 18 serious adverse events, none attributable to the study drug. INTERPRETATION: This is the first randomised placebo-controlled trial to show preservation of the visual field with an intraocular-pressure-lowering drug in patients with open-angle glaucoma. The study design enabled significant differences in vision to be assessed in a relatively short observation period. FUNDING: Pfizer, UK National Institute for Health Research Biomedical Research Centre.

Retinal Microvascular Dysfunction Occurs Early and Similarly in Mild Alzheimer's Disease and Primary-Open Angle Glaucoma Patients.

Purpose: To assess the similarities and differences in retinal microvascular function between mild Alzheimer's disease (AD) patients, early-stage primary open angle glaucoma (POAG) patients and healthy controls. Methods: Retinal vessel reactivity to flickering light was assessed in 10 AD, 19 POAG and 20 healthy age matched control patients by means of dynamic retinal vessel analysis (DVA, IMEDOS, GmbH, Jena, Germany) according to an established protocol. All patients additionally underwent BP measurements and blood analysis for glucose and lipid metabolism markers. Results: AD and POAG patients demonstrated comparable alterations in retinal artery reactivity, in the form of an increased arterial reaction time (RT) to flicker light on the final flicker cycle (p = 0.009), which was not replicated by healthy controls (p > 0.05). Furthermore, the sequential changes in RT on progressing from flicker one to flicker three were found to differ between healthy controls and the two disease groups (p = 0.001). Conclusion: AD and POAG patients demonstrate comparable signs of vascular dysfunction in their retinal arteries at the early stages of their disease process. This provides support for the concept of a common underlying vascular aetiology in these two neurodegenerative diseases.

Single perioperative triamcinolone injection versus standard postoperative steroid drops after uneventful phacoemulsification surgery: Randomized controlled trial.

PURPOSE: To evaluate the safety and efficacy of a single perioperative sub-Tenon's injection of triamcinolone following cataract surgery and its effect on the incidence of early pseudophakic cystoid macular edema (CME). SETTING: Ophthalmology Department, Queen's Medical Centre University Hospital, Nottingham. United Kingdom. METHODS: This prospective randomized controlled trial included 54 eyes (54 patients) having routine cataract surgery. Twenty-seven eyes received the conventional postoperative care with steroid drops (drops group), whereas the other 27 were given a perioperative sub-Tenon's injection of triamcinolone (injection group); 10 of these received 20 mg, and the remaining 17 eyes had 30 mg triamcinolone. All patients were evaluated preoperatively and at days 1, 8, 30, and 90. The outcome measures evaluated were logMAR best corrected visual acuity (BCVA), anterior chamber flare (Kowa-500 flare meter), intraocular pressure, and slitlamp biomicroscopy. Oral fluorescein angiograms were performed at 30 and 90 days to detect angiographic CME. RESULTS: The mean logMAR BCVA improved from a baseline of 0.38 +/- 0.38 (SD) and 0.44 +/- 0.26 to 0.02 +/- 0.14 and 0.0 +/- 0.07 at 90 days in the steroid drops and injection groups, respectively. (P = .59). The mean flare increased from a baseline of 8.9 +/- 3.2 photons/ms and 8.3 +/- 3.7 photons/ms in the steroid drops and injection groups, respectively, to a maximum of +/-14.1 photons/ms and 25.8 +/- 7.5 photons/ms at day 8. Mean flare decreased to 15.8 +/- 9.7 photons/ms and 13.8 +/- 10.1 photons/ms at 30 days (P = .48, difference between groups) and 10.4 +/- 3.6 photons/ms and 9.8 +/- 3.1 photons/ms at 90 days, respectively, in the 2 groups. Subanalysis revealed lowest peak flare (17.9 +/- 7.9 photons/ms) at 8 days in the group that received 30 mg triamcinolone. CONCLUSIONS: A single sub-Tenon's injection of 30 mg triamcinolone seem to be safe and effective as a route of steroid delivery after uneventful phacoemulsification surgery. Larger numbers in patients at high risk are required to assess its effectiveness in reducing the risk for pseudophakic CME.

Imatinib as a cause of cystoid macular edema following uneventful phacoemulsification surgery.

Cystoid macular edema (CME) is an important cause of visual impairment following phacoemulsification surgery. Imatinib is a new drug that is being used as adjunctive therapy in the management of various malignancies. A reported ocular side effect of this drug is spontaneous retinal edema. We report the case of a patient on imatinib who developed significant premature CME following uneventful phacoemulsification surgery. This resolved soon after cessation of imatinib therapy, and there was an improvement in visual acuity.

An overview of the eye in diabetes.

The three papers in this symposium are based on presentations to an RSM meeting on the Diabetic Eye, held on 9 April 2003. The matter is particularly topical because the National Service Framework for Diabetes calls for a high-quality retinal screening programme. After a review of the various ophthalmic conditions likely to be encountered in diabetic patients (A Negi, S A Vernon) we proceed to the most important, diabetic retinopathy, with a discussion of screening methods (D M Squirrell, J F Talbot) and an account of laser treatments (J G F Dowler). Colour versions of the clinical photographs are available online [www.jrsm.org]. Publication was coordinated by Professor Susan Lightman, of Moorfields Eye Hospital, London, UK.

Primary open-angle glaucoma vs normal-tension glaucoma: the vascular perspective.

OBJECTIVE: To compare and contrast the presence of ocular and systemic vascular function in patients with newly diagnosed and previously untreated primary open-angle glaucoma (POAG) vs those with normal-tension glaucoma (NTG) and comparable early-stage, functional loss. METHODS: The systemic vascular function of 19 patients with POAG, 19 patients with NTG, and 20 healthy individuals serving as controls was assessed using 24-hour ambulatory blood pressure monitoring, peripheral pulse-wave analysis, and carotid intima-media thickness. Retinal vascular reactivity to flicker light was assessed using dynamic retinal vessel analysis (Imedos, GmbH). RESULTS: Compared with controls, patients with POAG and those with NTG exhibited similarly increased nocturnal systemic blood pressure variability (P = .01), peripheral arterial stiffness (P = .02), carotid intima-media thickness (P = .04), and reduced ocular perfusion pressure (P < .001). Furthermore, on dynamic retinal vessel analysis, both glaucoma groups exhibited steeper retinal arterial constriction slopes after cessation of flicker (P = .007) and a similarly increased fluctuation in arterial and venous baseline diameter (P = .008 and P = .009, respectively) compared with controls. CONCLUSIONS: Patients with POAG or NTG exhibit similar alterations in ocular and systemic circulation in the early stages of their disease process. This finding highlights the importance of considering vascular risk factors in both conditions and raises questions about the current separation of the two conditions into distinct clinical entities.

Coexistence of macro- and micro-vascular abnormalities in newly diagnosed normal tension glaucoma patients.

PURPOSE: To investigate the coexistence of ocular microvascular and systemic macrovascular abnormalities in early stage, newly diagnosed and previously untreated normal tension glaucoma patients (NTG). METHODS: Retinal vascular reactivity to flickering light was assessed in 19 NTG and 28 age-matched controls by means of dynamic retinal vessel analysis (IMEDOS GmbH, Jena, Germany). Using a newly developed computational model, the entire dynamic vascular response profile to flicker light was imaged and used for analysis. In addition, assessments of carotid intima-media thickness (IMT) and pulse wave analysis (PWA) were conducted on all participants, along with blood pressure (BP) measurements and blood analyses for lipid metabolism markers. RESULTS: Patients with NTG demonstrated an increased right and left carotid IMT (p = 0.015, p = 0.045) and an elevated PWA augmentation index (p = 0.017) in comparison with healthy controls, along with an enhanced retinal arterial constriction response (p = 0.028), a steeper retinal arterial constriction slope (p = 0.031) and a reduced retinal venous dilation response (p = 0.026) following flicker light stimulation. CONCLUSIONS: Early stage, newly diagnosed, NTG patients showed signs of subclinical vascular abnormalities at both macro- and micro-vascular levels, highlighting the need to consider multi-level circulation-related pathologies in the development and progression of this type of glaucoma.

Diode laser cycloablation in adult glaucoma: long-term results of a standard protocol and review of current literature.

BACKGROUND: To study the long-term efficacy and safety of diode laser cycloablation under a standard protocol in refractory glaucoma. METHODS: A retrospective study involving 42 eyes (39 patients), observed for 36-84 (mean 65.7) months after cycloablation involving 14 burns of 2-W power and 2-s duration, over 270 degrees of the ciliary body. RESULTS: By final review, mean intraocular pressure (IOP) had dropped by 50.3% from 31.4 +/- 8.8 mmHg before treatment to 15.6 +/- 6.3 mmHg (P < 0.0001). Thirty-seven of the 42 eyes (88.1%) achieved IOP < 22 mmHg. Thirty-five of the 42 eyes (83.3%) eyes achieved IOP reduction > or = 30% from baseline levels. The mean number of antiglaucoma medications per eye dropped from 2.55 +/- 0.83 to 1.71 +/- 1.44 (P = 0.0004). The percentage of eyes requiring oral acetazolamide dropped from 92.9% to 11.9% (P < 0.0001). About 59.6% of eyes required multiple treatment sessions (mean 2.17). Twenty-seven (64.3%) eyes suffered deterioration, 11 (26.2%) maintained stability and 4 (9.5%) exhibited improvement of visual acuity. No relationship between the number of treatment sessions and visual outcome was evident. CONCLUSIONS: This conservative repeatable protocol affords delivery of the minimum dose of photocoagulation necessary to achieve a safe, long-term ocular hypotensive response, while minimizing the risk of serious adverse effects, and is valuable in the difficult treatment of refractory glaucoma.