To investigate differences in ocular blood flow in individuals of African descent (AD) and Europe... more To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG). A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values <0.05 considered statistically significant. OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P<0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters. Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.
To assess the prediction accuracy of a novel dynamic structure-function (DSF) model to monitor gl... more To assess the prediction accuracy of a novel dynamic structure-function (DSF) model to monitor glaucoma progression. Longitudinal data of paired rim area (RA) and mean sensitivity (MS) from 220 eyes with ocular hypertension or primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. Rim area and MS were expressed as percent of mean normal based on an independent dataset of 91 healthy eyes. The DSF model uses centroids as estimates of the current state of the disease and velocity vectors as estimates of direction and rate of change over time. The first three visits were used to predict the fourth visit; the first four visits were used to predict the fifth visit, and so on up to the 11th visit. The prediction error (PE) was compared to that of ordinary least squares linear regression (OLSLR) using Wilcoxon signed-rank test. For predictions at visit 4 to visit 7, the average PE for the DSF m...
Background: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous ... more Background: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity. Methods: A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n = 30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis. Results: The mean pRNFL thickness was significantly less in the POAG (64.30 ± 14.45 m, p < 0.01), NTG (85.43 ± 9.79 m, p < 0.001) and GS (102.0 ± 9.37 m, p < 0.001) groups than in the healthy group (109.8 ± 8.32 m). The RNFL was significantly thinner across all quadrants in all study group pairs (p < 0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R 2 = 0.203 and 0.175, p = 0.013 and 0.021).
To investigate differences in ocular blood flow in individuals of African descent (AD) and Europe... more To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG). A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05 considered statistically significant. OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters. Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.
Please cite this article in press as: Khanal S, et al. Intraeye retinal nerve fiber layer and mac... more Please cite this article in press as: Khanal S, et al. Intraeye retinal nerve fiber layer and macular thickness asymmetry measurements for the discrimination of primary open-angle glaucoma and normal tension glaucoma. J Optom. (2015), http://dx.
Purpose: To investigate whether combining optic disc topography and short-wavelength automated pe... more Purpose: To investigate whether combining optic disc topography and short-wavelength automated perimetry (SWAP) data improves the diagnostic accuracy of relevance vector machine (RVM) classifiers for detecting glaucomatous eyes compared with using each test alone.
Objective: To evaluate the impact of clomiphene citrate on vision. Design: Observational study. S... more Objective: To evaluate the impact of clomiphene citrate on vision. Design: Observational study. Setting: Patients were referred to the University of Ottawa Eye Institute ophthalmology clinic from the Department of Obstetrics and Gynaecology of the Ottawa Hospital-General Campus. Patient(s): Eight adult females taking clomiphene citrate and experiencing visual disturbances. Intervention(s): Patients received a comprehensive visual evaluation twice: once during a washout period, and once during an active clomiphene citrate treatment. Main Outcome Measure(s): Ophthalmologic examination, color vision, visual acuity, contrast sensitivity, visual fields using standard automated perimetry, and foveal flicker sensitivity at high (32 Hz) and low (8 Hz) temporal frequencies.
PURPOSE-To compare the Swedish interactive thresholding algorithm (SITA) with the fullthreshold (... more PURPOSE-To compare the Swedish interactive thresholding algorithm (SITA) with the fullthreshold (FT) strategy for short-wavelength automated perimetry (SWAP).
Purpose-To compare the most recent versions of standard automated perimetry (SAP), shortwavelengt... more Purpose-To compare the most recent versions of standard automated perimetry (SAP), shortwavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) using three definitions of visual field (VF) abnormality: single-test abnormality, abnormality confirmed by the same test, and abnormality confirmed by a different test.
To compare the diagnostic accuracy of the Matrix frequency-doubling technology (FDT) 24-2, first-... more To compare the diagnostic accuracy of the Matrix frequency-doubling technology (FDT) 24-2, first-generation FDT N-30 (FDT N-30), and standard automated perimetry (SAP) tests of visual function.
Purpose: To investigate the impact of perimetric measurement scales, sample composition, and 2 st... more Purpose: To investigate the impact of perimetric measurement scales, sample composition, and 2 statistical methods on the structure-function relationship in glaucoma.
To compare the diagnostic results of four perimetric tests and to identify useful parameters from... more To compare the diagnostic results of four perimetric tests and to identify useful parameters from each for determining abnormality. METHODS. One hundred eleven eyes with glaucomatous optic neuropathy (GON), 31 with progressive optic neuropathy (PGON) 53 with ocular hypertension, and 51 with no disease were included (N ϭ 246). Visual field results were not used to classify the eyes. Short-wavelength automated perimetry (SWAP), frequency-doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and standard automated perimetry (SAP) were performed. Receiver operating characteristic (ROC) curves were used to compute the areas under the curves (AUC) and sensitivity levels at given specificities for a variety of abnormality criteria. The agreement among tests for abnormality, location, and extent of visual field deficit were assessed. RESULTS. AUC analysis: When the normal group was compared with the GON group, the FDT pattern SD (PSD) area was larger than the HPRP PSD (P ϭ 0.020), and the FDT area of total deviation (TD) Ͻ5% was larger than the HPRP mean deviation (MD; P ϭ 0.004). When the normal group was compared with the PGON group, the FDT area of pattern deviation (PD) Ͻ5% was larger than the SWAP PSD (P ϭ 0.020). A difference from previous work was that AUCs for PSD or the best SAP were not significantly poorer than those in the function-specific tests. At set specificities, FDT yielded higher sensitivities than all other tests for all parameters. The agreement among tests for abnormality was fair to moderate ( ϭ 247-0.563). When loss was present on more than one test, the quadrant of the visual field affected was the same in 95% (79/83) of eyes. The number of eyes identified and number of abnormal quadrants increased across groups with increasing certainty of glaucoma. CONCLUSIONS. At equal specificity, no single perimetric test was always affected, whereas others remained normal. Several pa-rameters at suggested criterion values provided good sensitivity and specificity. FDT showed the highest sensitivity overall, with SAP performing better than in prior reports. Of note, the same area of the retina was identified as damaged in all tests.
... We do not attribute this finding to an artifact of the OCT associated with the fixed-diameter... more ... We do not attribute this finding to an artifact of the OCT associated with the fixed-diameter circularscans. ... Lyne Racette, PhD; Catherine Boden, PhD; Shannon L. Kleinhandler, BSc; Christopher A. Girkin, MD; Jeffrey M. Liebmann, MD; Linda M. Zangwill, PhD; Felipe A. Medeiros ...
To investigate differences in ocular blood flow in individuals of African descent (AD) and Europe... more To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG). A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05 considered statistically significant. OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters. Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.
To assess the prediction accuracy of a novel dynamic structure-function (DSF) model to monitor gl... more To assess the prediction accuracy of a novel dynamic structure-function (DSF) model to monitor glaucoma progression. Longitudinal data of paired rim area (RA) and mean sensitivity (MS) from 220 eyes with ocular hypertension or primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. Rim area and MS were expressed as percent of mean normal based on an independent dataset of 91 healthy eyes. The DSF model uses centroids as estimates of the current state of the disease and velocity vectors as estimates of direction and rate of change over time. The first three visits were used to predict the fourth visit; the first four visits were used to predict the fifth visit, and so on up to the 11th visit. The prediction error (PE) was compared to that of ordinary least squares linear regression (OLSLR) using Wilcoxon signed-rank test. For predictions at visit 4 to visit 7, the average PE for the DSF m...
Background: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous ... more Background: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity. Methods: A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n = 30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis. Results: The mean pRNFL thickness was significantly less in the POAG (64.30 ± 14.45 m, p < 0.01), NTG (85.43 ± 9.79 m, p < 0.001) and GS (102.0 ± 9.37 m, p < 0.001) groups than in the healthy group (109.8 ± 8.32 m). The RNFL was significantly thinner across all quadrants in all study group pairs (p < 0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R 2 = 0.203 and 0.175, p = 0.013 and 0.021).
To investigate differences in ocular blood flow in individuals of African descent (AD) and Europe... more To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG). A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05 considered statistically significant. OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters. Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.
Please cite this article in press as: Khanal S, et al. Intraeye retinal nerve fiber layer and mac... more Please cite this article in press as: Khanal S, et al. Intraeye retinal nerve fiber layer and macular thickness asymmetry measurements for the discrimination of primary open-angle glaucoma and normal tension glaucoma. J Optom. (2015), http://dx.
Purpose: To investigate whether combining optic disc topography and short-wavelength automated pe... more Purpose: To investigate whether combining optic disc topography and short-wavelength automated perimetry (SWAP) data improves the diagnostic accuracy of relevance vector machine (RVM) classifiers for detecting glaucomatous eyes compared with using each test alone.
Objective: To evaluate the impact of clomiphene citrate on vision. Design: Observational study. S... more Objective: To evaluate the impact of clomiphene citrate on vision. Design: Observational study. Setting: Patients were referred to the University of Ottawa Eye Institute ophthalmology clinic from the Department of Obstetrics and Gynaecology of the Ottawa Hospital-General Campus. Patient(s): Eight adult females taking clomiphene citrate and experiencing visual disturbances. Intervention(s): Patients received a comprehensive visual evaluation twice: once during a washout period, and once during an active clomiphene citrate treatment. Main Outcome Measure(s): Ophthalmologic examination, color vision, visual acuity, contrast sensitivity, visual fields using standard automated perimetry, and foveal flicker sensitivity at high (32 Hz) and low (8 Hz) temporal frequencies.
PURPOSE-To compare the Swedish interactive thresholding algorithm (SITA) with the fullthreshold (... more PURPOSE-To compare the Swedish interactive thresholding algorithm (SITA) with the fullthreshold (FT) strategy for short-wavelength automated perimetry (SWAP).
Purpose-To compare the most recent versions of standard automated perimetry (SAP), shortwavelengt... more Purpose-To compare the most recent versions of standard automated perimetry (SAP), shortwavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) using three definitions of visual field (VF) abnormality: single-test abnormality, abnormality confirmed by the same test, and abnormality confirmed by a different test.
To compare the diagnostic accuracy of the Matrix frequency-doubling technology (FDT) 24-2, first-... more To compare the diagnostic accuracy of the Matrix frequency-doubling technology (FDT) 24-2, first-generation FDT N-30 (FDT N-30), and standard automated perimetry (SAP) tests of visual function.
Purpose: To investigate the impact of perimetric measurement scales, sample composition, and 2 st... more Purpose: To investigate the impact of perimetric measurement scales, sample composition, and 2 statistical methods on the structure-function relationship in glaucoma.
To compare the diagnostic results of four perimetric tests and to identify useful parameters from... more To compare the diagnostic results of four perimetric tests and to identify useful parameters from each for determining abnormality. METHODS. One hundred eleven eyes with glaucomatous optic neuropathy (GON), 31 with progressive optic neuropathy (PGON) 53 with ocular hypertension, and 51 with no disease were included (N ϭ 246). Visual field results were not used to classify the eyes. Short-wavelength automated perimetry (SWAP), frequency-doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and standard automated perimetry (SAP) were performed. Receiver operating characteristic (ROC) curves were used to compute the areas under the curves (AUC) and sensitivity levels at given specificities for a variety of abnormality criteria. The agreement among tests for abnormality, location, and extent of visual field deficit were assessed. RESULTS. AUC analysis: When the normal group was compared with the GON group, the FDT pattern SD (PSD) area was larger than the HPRP PSD (P ϭ 0.020), and the FDT area of total deviation (TD) Ͻ5% was larger than the HPRP mean deviation (MD; P ϭ 0.004). When the normal group was compared with the PGON group, the FDT area of pattern deviation (PD) Ͻ5% was larger than the SWAP PSD (P ϭ 0.020). A difference from previous work was that AUCs for PSD or the best SAP were not significantly poorer than those in the function-specific tests. At set specificities, FDT yielded higher sensitivities than all other tests for all parameters. The agreement among tests for abnormality was fair to moderate ( ϭ 247-0.563). When loss was present on more than one test, the quadrant of the visual field affected was the same in 95% (79/83) of eyes. The number of eyes identified and number of abnormal quadrants increased across groups with increasing certainty of glaucoma. CONCLUSIONS. At equal specificity, no single perimetric test was always affected, whereas others remained normal. Several pa-rameters at suggested criterion values provided good sensitivity and specificity. FDT showed the highest sensitivity overall, with SAP performing better than in prior reports. Of note, the same area of the retina was identified as damaged in all tests.
... We do not attribute this finding to an artifact of the OCT associated with the fixed-diameter... more ... We do not attribute this finding to an artifact of the OCT associated with the fixed-diameter circularscans. ... Lyne Racette, PhD; Catherine Boden, PhD; Shannon L. Kleinhandler, BSc; Christopher A. Girkin, MD; Jeffrey M. Liebmann, MD; Linda M. Zangwill, PhD; Felipe A. Medeiros ...
The 6th edition of the Visual Field Digest is a comprehensive and practical guide to perimetry an... more The 6th edition of the Visual Field Digest is a comprehensive and practical guide to perimetry and the Octopus perimeter. This edition not only presents all key features of the Octopus perimeter, but also explains fundamentals of perimetric testing with more than 200 illustrations in an easy to grasp and practical manner and concludes with a clinical case section. This makes the Visual Field Digest an invaluable resource for clinicians, residents, students, researchers and visual field examiners.
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