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Astigmatism and Pseudoaccommodation in Pseudophakic Eyes
noAdvanced IOLs with circumferential zones of different power provide pseudoaccommodation. We investigated the potential for power variation with meridian, namely astigmatism, to provide pseudo-accommodation. With appropriate power and axis orientations, acceptable pseudo-accommodation can be achieved
Performance Analysis of Cone Detection Algorithms
Many algorithms have been proposed to help clinicians evaluate cone density
and spacing, as these may be related to the onset of retinal diseases. However,
there has been no rigorous comparison of the performance of these algorithms.
In addition, the performance of such algorithms is typically determined by
comparison with human observers. Here we propose a technique to simulate
realistic images of the cone mosaic. We use the simulated images to test the
performance of two popular cone detection algorithms and we introduce an
algorithm which is used by astronomers to detect stars in astronomical images.
We use Free Response Operating Characteristic (FROC) curves to evaluate and
compare the performance of the three algorithms. This allows us to optimize the
performance of each algorithm. We observe that performance is significantly
enhanced by up-sampling the images. We investigate the effect of noise and
image quality on cone mosaic parameters estimated using the different
algorithms, finding that the estimated regularity is the most sensitive
parameter.
This paper was published in JOSA A and is made available as an electronic
reprint with the permission of OSA. The paper can be found at the following URL
on the OSA website: http://www.opticsinfobase.org/abstract.cfm?msid=224577.
Systematic or multiple reproduction or distribution to multiple locations via
electronic or other means is prohibited and is subject to penalties under law.Comment: 13 pages, 7 figures, 2 table
The Relationship of the Clinical Disc Margin and Bruch's Membrane Opening in Normal and Glaucoma Subjects.
PurposeWe tested the hypotheses that the mismatch between the clinical disc margin (CDM) and Bruch's membrane opening (BMO) is a function of BMO area (BMOA) and is affected by the presence of glaucoma.MethodsA total of 45 normal eyes (45 subjects) and 53 glaucomatous eyes (53 patients) were enrolled and underwent radial optic nerve head (ONH) imaging with spectral domain optical coherence tomography. The inner tip of the Bruch's membrane (BM) and the clinical disc margin were marked on radial scans and optic disc photographs, and were coregistered with custom software. The main outcome measure was the difference between the clinical disc area (CDA) and BMOA, or CDA-BMOA mismatch, as a function of BMOA and diagnosis. Multivariate regression analyses were used to explore the influence of glaucoma and BMOA on the mismatch.ResultsGlobal CDA was larger than BMOA in both groups but the difference was statistically significant only in the normal group (1.98 ± 0.37 vs. 1.85 ± 0.45 mm2, P = 0.02 in the normal group; 1.96 ± 0.38 vs. 1.89 ± 0.56 mm2, P = 0.08 in the glaucoma group). The sectoral CDA-BMOA mismatch was smaller in superotemporal (P = 0.04) and superonasal (P = 0.05) sectors in the glaucoma group. The normalized CDA-BMOA difference decreased with increasing BMOA in both groups (P < 0.001). Presence or severity of glaucoma did not affect the CDA-BMOA difference (P > 0.14).ConclusionsClinical disc area was larger than BMOA in normal and glaucoma eyes but reached statistical significance only in the former group. The CDA-BMOA mismatch diminished with increasing BMOA but was not affected by presence of glaucoma. These findings have important clinical implications regarding clinical evaluation of the ONH
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