David Birch | Retina Foundation of the Southwest (original) (raw)
Address: Dallas, Texas, United States
less
Uploads
Papers by David Birch
Investigative Ophthalmology & Visual Science, 2016
Investigative Ophthalmology & Visual Science, 2017
American Journal of Ophthalmology, 2021
PURPOSE To estimate and compare cross-sectional scotopic versus mesopic macular sensitivity losse... more PURPOSE To estimate and compare cross-sectional scotopic versus mesopic macular sensitivity losses measured by microperimetry, and to report and compare the longitudinal rates of scotopic and mesopic macular sensitivity losses in ABCA4 gene associated Stargardt Disease (STGD1). DESIGN Multicenter prospective cohort study. METHODS Participants: 127 molecular confirmed STGD1 patients enrolled from 6 centers in the USA and Europe and followed every 6 months for up to 2 years. OBSERVATION PROCEDURES The Nidek MP-1S device was used to measure macular sensitivities of the central 20° under mesopic and scotopic conditions. The mean deviations (MD) from normal for mesopic macular sensitivity for the fovea (within 2° eccentricity) and extrafovea (4°-10° eccentricity), and the MD for scotopic sensitivity for the extrafovea were calculated. Linear mixed effects models were used to estimate mesopic and scotopic changes. MAIN OUTCOME MEASURES Baseline mesopic mean deviation (mMD) and scotopic MD (sMD) and rates of longitudinal changes in the mMDs and sMD. RESULTS At baseline, all eyes had larger sMD, and the difference between extrafoveal sMD and mMD was 10.7 dB (p<.001). Longitudinally, all eyes showed a statistically significant worsening trend: the rates of foveal mMD and extrafoveal mMD and sMD changes were 0.72 (95%CI: 0.37 to 1.07), 0.86 (95%CI: 0.58 to 1.14) and 1.12 (95%CI: 0.66 to 1.57) dB/year, respectively. CONCLUSIONS In STGD1, in extrafovea, loss of scotopic macular function preceded and was faster than the loss of mesopic macular function. Scotopic and mesopic macular sensitivities using microperimetry provide alternative visual function outcomes for STGD1 treatment trials.
Vision Research, Jun 1, 1975
Abstract Behavioral measurements of visual sensitivity were obtained from hooded rats on a threec... more Abstract Behavioral measurements of visual sensitivity were obtained from hooded rats on a threechoice discrimination task. Increment threshold measurements reveal the occurrence of a distinct Purkinje shift. Photopic spectral sensitivity functions for this animal have peaks at 500 and 580 nm. The results of chromatic adaptation suggest that this photopic sensitivity function results from interactions between two mechanisms with peak sensitivities near 520 and 540 nm. Along with previous behavioral and electrophysiological results, these findings suggest that the rat possesses at least three different spectral mechanisms—a scotopic mechanism with a peak sensitivity at 500 nm and two photopic mechanisms whose peak sensitivities may be about 520 and 540 nm.
Investigative Ophthalmology & Visual Science, Dec 20, 2011
Investigative Ophthalmology & Visual Science, Jun 10, 2020
Investigative Ophthalmology & Visual Science, Jun 23, 2017
Investigative Ophthalmology & Visual Science, Jun 23, 2017
Investigative Ophthalmology & Visual Science, Sep 26, 2016
We examined the ability of patients with Stargardt disease to perform a global hyperacuity task. ... more We examined the ability of patients with Stargardt disease to perform a global hyperacuity task. Stimuli were circular D4 contours and their deformations. A spatial 2 AFC paradigm was employed. In each trial, the patients indicated which of two stimuli was deformed. The patients showed a substantial elevation in the threshold for detecting circular D4 deformation while still retaining relatively good visual acuity. The results support the hypothesis that optimal performance for detecting circular D4 deformation involves some kind of global mechanism. The results also suggest the global hyperacuity is an effective test for quantifying early visual loss from macular degeneration.
Investigative Ophthalmology & Visual Science, May 1, 2006
Investigative Ophthalmology & Visual Science, May 10, 2007
Investigative Ophthalmology & Visual Science, May 1, 2004
Investigative Ophthalmology & Visual Science, 2016
Investigative Ophthalmology & Visual Science, 2017
American Journal of Ophthalmology, 2021
PURPOSE To estimate and compare cross-sectional scotopic versus mesopic macular sensitivity losse... more PURPOSE To estimate and compare cross-sectional scotopic versus mesopic macular sensitivity losses measured by microperimetry, and to report and compare the longitudinal rates of scotopic and mesopic macular sensitivity losses in ABCA4 gene associated Stargardt Disease (STGD1). DESIGN Multicenter prospective cohort study. METHODS Participants: 127 molecular confirmed STGD1 patients enrolled from 6 centers in the USA and Europe and followed every 6 months for up to 2 years. OBSERVATION PROCEDURES The Nidek MP-1S device was used to measure macular sensitivities of the central 20° under mesopic and scotopic conditions. The mean deviations (MD) from normal for mesopic macular sensitivity for the fovea (within 2° eccentricity) and extrafovea (4°-10° eccentricity), and the MD for scotopic sensitivity for the extrafovea were calculated. Linear mixed effects models were used to estimate mesopic and scotopic changes. MAIN OUTCOME MEASURES Baseline mesopic mean deviation (mMD) and scotopic MD (sMD) and rates of longitudinal changes in the mMDs and sMD. RESULTS At baseline, all eyes had larger sMD, and the difference between extrafoveal sMD and mMD was 10.7 dB (p<.001). Longitudinally, all eyes showed a statistically significant worsening trend: the rates of foveal mMD and extrafoveal mMD and sMD changes were 0.72 (95%CI: 0.37 to 1.07), 0.86 (95%CI: 0.58 to 1.14) and 1.12 (95%CI: 0.66 to 1.57) dB/year, respectively. CONCLUSIONS In STGD1, in extrafovea, loss of scotopic macular function preceded and was faster than the loss of mesopic macular function. Scotopic and mesopic macular sensitivities using microperimetry provide alternative visual function outcomes for STGD1 treatment trials.
Vision Research, Jun 1, 1975
Abstract Behavioral measurements of visual sensitivity were obtained from hooded rats on a threec... more Abstract Behavioral measurements of visual sensitivity were obtained from hooded rats on a threechoice discrimination task. Increment threshold measurements reveal the occurrence of a distinct Purkinje shift. Photopic spectral sensitivity functions for this animal have peaks at 500 and 580 nm. The results of chromatic adaptation suggest that this photopic sensitivity function results from interactions between two mechanisms with peak sensitivities near 520 and 540 nm. Along with previous behavioral and electrophysiological results, these findings suggest that the rat possesses at least three different spectral mechanisms—a scotopic mechanism with a peak sensitivity at 500 nm and two photopic mechanisms whose peak sensitivities may be about 520 and 540 nm.
Investigative Ophthalmology & Visual Science, Dec 20, 2011
Investigative Ophthalmology & Visual Science, Jun 10, 2020
Investigative Ophthalmology & Visual Science, Jun 23, 2017
Investigative Ophthalmology & Visual Science, Jun 23, 2017
Investigative Ophthalmology & Visual Science, Sep 26, 2016
We examined the ability of patients with Stargardt disease to perform a global hyperacuity task. ... more We examined the ability of patients with Stargardt disease to perform a global hyperacuity task. Stimuli were circular D4 contours and their deformations. A spatial 2 AFC paradigm was employed. In each trial, the patients indicated which of two stimuli was deformed. The patients showed a substantial elevation in the threshold for detecting circular D4 deformation while still retaining relatively good visual acuity. The results support the hypothesis that optimal performance for detecting circular D4 deformation involves some kind of global mechanism. The results also suggest the global hyperacuity is an effective test for quantifying early visual loss from macular degeneration.
Investigative Ophthalmology & Visual Science, May 1, 2006
Investigative Ophthalmology & Visual Science, May 10, 2007
Investigative Ophthalmology & Visual Science, May 1, 2004