Lesya M Shuba

• Dalhousie University

Purpose To investigate whether macular perfusion density (PD) changes measured over time by optical coherence tomography angiography (OCTA) are detectable before progressive macular ganglion cell layer (GCL) thinning in early glaucoma. Methods This prospective longitudinal cohort study involved patients with early open-angle glaucoma and healthy s...

Background/aims Optical coherence tomography angiography (OCT-A) images are subject to variability, but the extent to which learning impacts OCT-A measurements is unknown. We determined whether there is a learning effect in glaucoma patients and healthy controls imaged with OCT-A. Methods Ninety-one open-angle glaucoma patients and 54 healthy cont...

Purpose Post-acute non-arteritic ischemic optic neuropathy (NAION) and glaucomatous optic neuropathy (GON) can be difficult to differentiate clinically. Our objective was to identify optical coherence tomography (OCT) parameters to help differentiate these optic neuropathies. Methods We compared 12 eyes of 8 patients with NAION and 12 eyes of 12 p...

Importance: Estimating the rate of glaucomatous visual field change provides practical assessment of disease progression and has implications for management decisions. Objective: To assess the rates of visual field change in patients receiving treatment for glaucoma compared with healthy individuals over an extensive follow-up period and to quan...

Glaucoma is a condition characterized by optic neuropathy and corresponding visual field loss. Even in the presence of excellent imaging tests of the optic nerve, it is critical to understand the functional consequences of the disease. In this chapter, we review the various types of perimetry tests, testing strategies, test outputs, progression ana...

Purpose To determine the impact of glaucoma severity on rates of change of minimum rim width (MRW), peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer (GCL) thickness. Design Prospective, cohort study. Methods Glaucoma patients and healthy subjects had optical coherence tomography scans at 6-month intervals. Individual...

https://iovs.arvojournals.org/article.aspx?articleid=2773314

Objective: To determine whether the 10-2 test of the Humphrey Field Analyzer detected a higher proportion of abnormal visual fields compared to the 24-2 test in the central 10° in patients with early visual field damage. Design: Prospective observational study. Participants: Patients with early open-angle glaucoma and healthy controls. Method...

Purpose To identify characteristics of patients with early open-angle glaucoma exhibiting greater macular perfusion density (PD) loss compared to macular ganglion cell layer (GCL) thickness loss. Design Cross-sectional study. Methods Optical coherence tomography (OCT) imaging of the optic nerve head and macula was conducted in patients and health...

Correction of automated retinal layer segmentation in the peripapillary retina led to significant differences in perfusion density measured with optical coherence tomography angiography in the retinal plexuses. Segmentation accuracy should be checked prior to interpretation.

Background/aims Quantitative analysis of optical coherence tomography angiography (OCT-A) images requires a reproducible approach that accounts for sectoral loss. The objective of this study was to determine whether an index that accounts for both global (perfusion density, PD) and asymmetric loss of perfusion, rather than PD alone, more reliably m...

Background/Aims To determine the effect of glaucoma on outer retinal layer thickness in eyes with horizontal hemifield visual field (VF) defects. Methods We conducted a cross-sectional study in glaucomatous eyes with repeatable (in three or examinations) horizontal hemifield VF (programme 24–2) defect defined as: all five nasal VF locations immedi...

Purpose: To determine whether: (1) change in lamina cribrosa depth occurs more frequently than change in neuroretinal parameters in glaucoma, and (2) Bruch's membrane or anterior sclera should be used as a reference plane when measuring laminar depth. Design: Prospective observational study. Participants: One hundred fifty-five glaucoma patien...

Purpose: To determine whether structural abnormalities of the lamina cribrosa explain the presence of optic disc hemorrhages, we determined the spatial concordance between disc hemorrhages and laminar disinsertions from the sclera. Design: Prospective noninterventional study. Participants: From open-angle glaucoma patients followed up prospect...

Purpose: To determine whether beta and gamma peripapillary atrophy (PPA) areas measured with optical coherence tomography (OCT) enhances glaucoma diagnosis in myopic subjects. Methods: We included 55 myopic glaucoma patients and 74 myopic nonglaucomatous controls. Beta-PPA comprised the area external to the clinical disc margin, with absence of...

Purpose: Ruling out glaucoma in myopic eyes often poses a diagnostic challenge because of atypical optic disc morphology and visual field defects that can mimic glaucoma. We determined whether neuroretinal rim assessment based on Bruch's membrane opening (BMO), rather than conventional optic disc margin (DM)-based assessment or retinal nerve fiber...

PURPOSE. To compare the diagnostic accuracy of conventional sector-based analysis with a method devised to detect the smallest localized neuroretinal rim and retinal nerve fiber layer thickness (RNFLT) damage. METHODS. One eye of 151 glaucoma patients and 83 healthy controls (median age and MD, 71.7 and 66.7 years, and -3.6 and -0.3 dB, respectivel...

Purpose: To describe longitudinal rates of change of neuroretinal parameters in patients with glaucoma and healthy controls, and to evaluate the influence of covariates. Design: Prospective longitudinal study. Participants: Treated patients with glaucoma (n = 192) and healthy controls (n = 37). Methods: Global disc margin-based neuroretinal...

Purpose: To determine the rate of glaucomatous visual field change in routine clinical care. Methods: Mean deviation (MD) rate was computed in one randomly selected eye of all glaucoma patients and suspects with ≥5 examinations in a tertiary eye-care center. Proportions of "fast" (MD rate, <-1 to -2 dB/y) and "catastrophic" (<-2 dB/y) progressor...

Purpose: To study changes in lamina cribrosa position and prelaminar tissue thickness (PTT) after surgical IOP reduction in glaucoma patients. Methods: Twenty-two patients (mean age, 71.4 years) were imaged with spectral domain optical coherence tomography (SD-OCT; 24 radial B-scans centered on the optic nerve head [ONH]) before trabeculectomy o...

To investigate the rate of visual field and optic disc change in patients with distinct patterns of glaucomatous optic disc damage. Prospective longitudinal study. A total of 131 patients with open-angle glaucoma with focal (n = 45), diffuse (n = 42), and sclerotic (n = 44) optic disc damage. Patients were examined every 4 months with standard auto...

The aims of the study were to determine the effects of anisosmotic bathing solution on selected properties of I(Ks), the slowly activating delayed-rectifier K(+) current important for repolarization of the action potential in cardiac cells. Guinea-pig ventricular myocytes were voltage-clamped using either the ruptured-patch or perforated-patch tech...

Terodiline, an anticholinergic/antispasmodic drug effective in the treatment of urinary incontinence, is presently restricted due to adverse side effects on cardiac function. To characterize its effects on cardiac L‐type Ca ²⁺ ‐channel current carried by Ca ²⁺ ( I Ca,L ) and Ba ²⁺ ( I Ba,L ), concentrations ranging from 0.1 to 100 μ M were applied...

To evaluate the correlation between the amount of pseudoexfoliation (PXF) material on the anterior lens capsule, pigment in the iridocorneal angle, presenting intraocular pressure (IOP) and severity of glaucoma in patients with PXF glaucoma/syndrome. Anterior lens capsule PXF material and iridocorneal pigment of 98 untreated patients with PXF syndr...

The regulation of cardiac Cl ⁻ current ( I C1 ) by tyrosine and serine/threonine phosphorylation was examined in guinea‐pig and rat ventricular myocytes. The protein tyrosine kinase (PTK) inhibitor genistein (GST) and phosphotyrosine phosphatase (PTP) inhibitor sodium orthovanadate (VO 4 ) were used to modify tyrosine phosphorylation, whereas forsk...

The objective of this study on guinea-pig and rabbit ventricular myocytes was to evaluate the sensitivities of swelling-activated Cl- current (ICl(swell)) and cAMP-dependent cystic fibrosis transmembrane regulator (CFTR) Cl- current (ICl(CFTR)) to block by dideoxyforskolin and verapamil. The currents were recorded from whole-cell configured myocyte...

The cardiac electrophysiological effects of S-oxybutynin, a single-enantiomer drug under evaluation for the management of urinary incontinence, have been investigated and compared with those of terodiline, an incontinence agent withdrawn following reports of QT lengthening and ventricular tachyarrhythmia. Membrane currents were recorded from whole-...

The objective of this study was to determine the effects of anion replacement on volume-sensitive anion current in guinea-pig ventricular myocytes. Myocytes in the conventional whole-cell voltage-clamp configuration were superfused and dialysed with Na(+)-, K(+)-, and Ca(2+)-free solution, and exposed to external 75 mM Cl- solution of one-half norm...

The objective of this study was to investigate the cardioactive properties of oxybutynin, a drug that is widely prescribed for management of voiding dysfunction. Membrane currents were recorded from whole-cell-configured guinea pig ventricular myocytes, and action potentials were recorded from guinea pig and rabbit papillary muscles. L-type Ca2+ cu...

Terodiline was widely prescribed for urinary incontinence before reports of adverse cardiac effects that included bradycardia, QT lengthening, and ventricular tachyarrhythmia. The present study on guinea pig papillary muscles and ventricular myocytes was undertaken to gain insight into the cardioactive properties of the drug. Clinically relevant co...

When guinea-pig papillary muscles were depolarized to ca. -30 mV by superfusion with K+-free Tyrode's solution supplemented with Ba2+, Ni2+, and D600, addition of Cs+ transiently hyperpolarized the membrane in a reproducible manner. The size of the hyperpolarization (pump potential) depended on the duration of the preceding K+-free exposure; peak a...

The involvement of guanine nucleotide-binding proteins (G proteins) in the activation of cardiac adenosine 3′,5′-cyclic monophosphate (cAMP)-dependent cystic fibrosis transmembrane conductance regulator (CFTR) Cl– current (I Cl) by the tyrosine kinase inhibitor genistein (GST) was investigated in guinea-pig ventricular myocytes. Pertussis toxin (PT...

Guinea pig ventricular myocytes in whole cell configuration were treated with tyrosine kinase (TK) inhibitors [genistein (Gst), tyrphostin A23 (T23), and tyrphostin A25 (T25)] and with inactive analogs [daidzein, genistin, and tyrphostin A1 (T1)] to measure effects on L-type Ca2+ current (ICa,L). Gst inhibited ICa,L (IC50 = 47 microM) without affec...

The antispasmodic agent terodiline has cardiotoxic effects that include QT lengthening. To determine whether inhibition of inwardly-rectifying K+ current (I(K1)) might be a factor in the cardiotoxicity, we measured I(K1) in guinea pig ventricular myocytes. Terodiline reduced outward I(K1) with an IC50 of 7 microM; maximal reduction was 60% with 100...

Prolongation of the QT interval and malignant ventricular arrhythmia have been observed in patients administered terodiline for urinary incontinence. Since this adverse reaction might be caused by inhibition of delayed‐rectifier K ⁺ current ( I K ), we investigated whether clinically relevant (10 μ m ) concentrations of the drug modify I K in guine...

To identify factors involved in the modification of cardiac electromechanical activity caused by hyperosmotic solution. Membrane potentials and contractions were recorded from isolated papillary muscles, and membrane ionic currents were measured in isolated ventricular myocytes by using the ruptured patch or perforated patch voltage clamp method. A...

1. The regulation of cardiac Cl- current (ICl) by tyrosine and serine/threonine phosphorylation was examined in guinea-pig and rat ventricular myocytes. The protein tyrosine kinase (PTK) inhibitor genistein (GST) and phosphotyrosine phosphatase (PTP) inhibitor sodium orthovanadate (VO4) were used to modify tyrosine phosphorylation, whereas forskoli...

Genistein (GST), an inhibitor of protein tyrosine kinase (PTK), Na 3 VO 4 (VO 4 ), an inhibitor of phosphotyrosine phosphatase (PTPase), and forskolin (FSK), an activator of the cyclic AMP‐dependent, cystic fibrosis transmembrane conductance regulator (CFTR) Cl ⁻ channel, were applied to guinea‐pig ventricular myocytes to probe for a possible role...

1. Although earlier studies with phorbol esters indicate that protein kinase C (PKC) may be an important regulator of Cl- current (Icl) in cardiac cells, there is a need for additional quantitative data and investigation of conflicting findings. Our objectives were to measure the magnitude, time course, and concentration-dependence of Icl activated...

1. Kinase-mediated chloride currents (ICl) in guinea-pig ventricular myocytes were activated by application of phorbol ester or forskolin, and compared with currents induced by hyposmotic swelling. Swelling-activated current was identified as ICl from changes in reversal potential, outward rectification and conductance when the Cl-gradient was modi...

Active and inactive phorbol esters were applied to guinea pig ventricular myocytes to study the responses of L-type Ca2+ (ICa,L) and L-type Na+ (INa,L) currents. Phorbol 12-myristate 13-acetate (PMA) (10-100 rM) never stimulated ICa,L or INa,L and frequently depressed them by 5-30% in a voltage-independent manner. However, the phorbol ester consist...

Superfusion of guinea pig papillary muscles with Tyrode's solution that contained 0.3% to 10% dimethyl sulfoxide (DMSO) caused a small hyperpolarization, a prolongation of the action potential (e.g., 4%, 15% and 33% prolongation with 1%, 5% and 10% DMSO, respectively) and a reduction (< or = 14%) in the maximal upstroke velocity (Vmax). Action pote...