ORCID Profile
0000-0002-9139-4943
Current Organisation
Legacy Research Institute
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2011
Publisher: Elsevier BV
Date: 08-2008
Publisher: Mary Ann Liebert Inc
Date: 12-2013
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 02-2009
DOI: 10.1167/IOVS.08-1767
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 17-07-2017
Publisher: Elsevier BV
Date: 02-2017
Publisher: Public Library of Science (PLoS)
Date: 18-03-2014
Publisher: Elsevier BV
Date: 03-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2011
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 25-07-2014
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2016
Publisher: American Medical Association (AMA)
Date: 05-2015
Publisher: Elsevier BV
Date: 08-2011
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 10-2006
DOI: 10.1167/IOVS.05-1598
Abstract: To evaluate the effects of false-positive (FP) response errors on mean deviation (MD), pattern standard deviation (PSD), glaucoma hemifield test (GHT), and test duration in the Humphrey Field Analyzer's (HFA II) Swedish Interactive Threshold Algorithm (SITA Carl Zeiss Meditec, Inc., Dublin, CA). Five in iduals with glaucoma (ages 52, 63, 69, 77, and 78 years) and five in iduals with normal, healthy eyes (ages 25, 34, 43, 45, and 52 years), participated in the study. Each subject was experienced in automated perimetry and performed multiple, monocular baseline SITA-standard (SITA-S) 24-2 visual field tests. In addition, normal subjects completed SITA-S 24-2 field examinations in which known frequencies of FP error were introduced (0%, 5%, 10%, 20%, or 33% frequency). Likewise, the subjects with glaucoma completed visual field examinations with 0%, 20%, and 33% error introduced during the test. Reported FP errors were significantly lower than the introduced frequency of error. The SITA algorithm more accurately identified FP errors when the MD and PSD erged from normal. Test duration increased as introduced error frequencies increased. The Statpac single-field analyses indicated that two thirds of the tests with introduced errors produced a "low-patient-reliability" determination. HFA II SITA-S underestimates patients' FP errors, particularly among normal patients. High FP error frequencies can have adverse effects on MD and PSD, leading clinicians and researchers to an inaccurate determination of the amount and severity of visual field loss.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 2015
DOI: 10.1167/TVST.4.1.8
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 27-02-2019
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 20-07-2017
DOI: 10.1167/TVST.6.4.11
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 03-2014
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 09-2013
DOI: 10.1167/TVST.2.6.3
Publisher: American Medical Association (AMA)
Date: 12-2012
DOI: 10.1001/JAMAOPHTHALMOL.2013.1137
Abstract: To compare rates of visual field (VF) change in ocular hypertensive eyes with and without optic dischemorrhage (DH). Ocular Hypertension Treatment Study subjects(minimum 10 reliable VF tests, followed up 5 years) were included. Trend analyses of VF sequences over time of DH and non-DH eyes were assessed by regression of mean deviation (MDR) and pointwise linear regression (PLR). The main outcome measures were rates of VF change in DH and non-DH eyes. Two thousand six hundred seven eyes (1378 participants) were included. The mean (SD) number of VF tests per eye was 23.7 (4.9) spanning a mean (SD) of 12.2 (2.0) years. At least 1 DH was detected in 187 eyes(7.2%), of which 52 eyes had recurrent DH. Mean deviation rate of change was significantly worse in DH compared with non-DH eyes (mean [SD], −0.17 [0.27] vs−0.07 [0.19] dB/y P<.01). Significant PLR progression occurred more frequently in eyes with DH (odds ratio,3.6 P<.01), which increased when 2 or more DHs were present (odds ratio, 4.2 P=.01). Eyes initially randomized to treatment were less likely to have a DH during follow-up. Eyes with DH had more rapid VF deterioration when assessed by global (MDR) or local (PLR)trend analysis than eyes without DH. Eyes with recurrent DH had similar rates of global VF change (MDR)when compared with eyes with a single DH but reached criteria for rapid PLR change more often. Intraocular pressure reduction in ocular hypertension reduces the risk of developing a DH. Ocular hypertensive eyes with DH should be monitored closely and may need more aggressive therapy. clinicaltrials.gov Identifier: NCT00000125
Publisher: Public Library of Science (PLoS)
Date: 10-10-2022
DOI: 10.1371/JOURNAL.PONE.0275807
Abstract: To determine the associations of blindness within rural and urban counties using a registry of blind persons and geospatial analytics. We used the Oregon Commission for the Blind registry to determine the number of persons who are legally blind, as well as licensure data to determine the density of eye care providers (optometrists and ophthalmologists) within each county of the State of Oregon. We used geospatial statistics, analysis of variance, and logistic regression to determine the explanatory variables associated with blindness within counties. We included 8350 in iduals who are legally blind within the state of Oregon in the calendar year 2015. The mean observed prevalence of registered blindness was 0.21% and ranged almost 9-fold from 0.04% to 0.58% among counties (p .001). In univariate models, higher blindness was associated with increasing median age (p = .027), minority race (p .001), decreased median household income (p .001), increased poverty within a county (p .001), and higher density of ophthalmologists (p = .003). Density of optometrists was not associated with prevalence of blindness (p = .89). The final multivariable model showed higher blindness to be associated with lower median household income, higher proportion of black race, and lower proportion of Hispanic race (p .001 for all). Geospatial analytics identified counties with higher and lower than expected proportions of blindness even when adjusted for sociodemographic factors. Clinicians and researchers may use the methods and results of this study to better understand the distribution of in iduals with blindness and the associated factors to help design public health interventions.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 15-08-2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2013
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 07-2014
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 07-05-2018
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 14-06-2012
DOI: 10.1167/IOVS.11-9065
Publisher: Elsevier BV
Date: 08-2018
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 29-01-2016
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 06-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2013
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 12-2008
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.VISRES.2005.11.019
Abstract: Studies in glaucoma patients show that standard automated perimetry results increase in variability as sensitivity decreases. However, the reasons for this change are unclear. This study presents the principle of Divergent Dysfunction as a possible explanation for this change in variability, and incorporates it into a model that can be used to simulate perimetry. A computer program was written to simulate visual field test results based on the model, using a Full Threshold testing strategy. The validity of the simulation was tested by comparing it with normal sensitivity values, and with test-retest data from 63 participants evaluated five times each over the course of 1 month. The effect on the simulated data of varying parameters of the model was investigated, such as changing the magnitude of variability and the percentages of false positive and negative responses. The correlation between subject and simulated test-retest data was 0.987. Several factors were found to affect the sensitivity-variability relationship for the simulated data, most notably the rate of sensitivity decline, the percentage of false positives, and the starting luminance of the test procedure. The principle of Divergent Dysfunction presented here provides a plausible explanation for the sensitivity-variability relationship for standard automated perimetry in glaucomatous eyes. The model and resultant simulation program aim to provide an intuitive demonstration of the principle, which can also be used to examine the effectiveness of different testing strategies. These findings have great implications for future clinical research.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 26-10-2015
Publisher: Springer Science and Business Media LLC
Date: 25-04-2012
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2019
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 15-03-2016
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 03-2015
DOI: 10.1167/TVST.4.2.10
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 13-03-2014
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2008
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2009
End Date: 2014
Funder: National Eye Institute
View Funded ActivityStart Date: 2009
End Date: 2011
Funder: National Eye Institute
View Funded ActivityStart Date: 2010
End Date: 2020
Funder: National Eye Institute
View Funded ActivityStart Date: 2011
End Date: 2022
Funder: National Eye Institute
View Funded Activity