PURPOSE. To investigate the characteristics of a spectral-domain optical coherence tomography (SD-OCT) image phenomenon known as the mirror artifact, calculate its prevalence, analyze potential risk factors, measure severity, and correlate it to spherical equivalent and central visual acuity (VA). METHODS. OCT macular cube 512 x 128 scans taken between January 2008 and February 2009 at the New England Eye Center were analyzed for the presence of mirror artifacts. Artifact severity was determined by the degree of segmentation breakdown that it caused on the macular map. A retrospective review was conducted of the medical records of patients with artifacts and of a random control group without artifacts. RESULTS. Of 1592 patients, 9.3% (148 patients, 200 eyes) had scans that contained mirror artifacts. A significantly more myopic spherical equivalent (P < 0.001), worse VA (P < 0.001), longer axial lengths (P = 0.004), and higher proportions of moderate to high myopia (P < 0.001) were found in patients with mirror artifacts than in patients without artifacts. Worse VA was associated with increased artifact severity (P = 0.04). CONCLUSIONS. In all scans analyzed, a high prevalence of mirror artifacts was found. This image artifact was often associated with patients with moderate to high myopia. Improvements in instrumentation may be necessary to resolve this problem in moderately and highly myopic eyes. Operators should be advised to properly position the retina when scanning eyes. In cases in which peripheral abnormalities in topographic measurements of retinal thickness are found, corresponding OCT scans should be examined for the presence of mirror artifacts.
Primary open-angle glaucoma patients with diabetes have significantly higher CH values than those without diabetes. CH and CCT results were positively correlated. These findings merit further investigation to assess the role of different CH values on glaucoma evaluation and susceptibility.
Purpose: To evaluate the learning effect in standard automated perimetry using SITA strategy, central 24-2 program, possible associated factors and spatial distribution in individuals with no perimetry experience. Methods: A total of 55 healthy subjects were submitted to Humphrey perimetry in two different sessions in one day. Reliability and global indices, and threshold sensitivity at each point were compared between the two examinations. The influence of potential factors (age, gender, and educational level) and the spatial distribution were evaluated regarding alterations between these two examinations. Results: The duration of the test was longer in the first session (median, 5.7 min; interquartile range [IQR], 1.7 min) than in the second (median, 5.3; IQR, 1.1 min) (p=0.002). The median (IQR) of false negative errors was 2% (6%) in the first examination and 0% (6%) in the second (p=0.04). The mean (standard deviation) in the mean deviation (MD) global index was -2.31 (1.86) dB in the first examination and -1.73 (1.69) dB in the second (p=0.07). No association was observed between the change in MD and age (p=0.29), gender (p=0.69) and educational level (p=0.27). The changes in threshold sensitivity were greater at the peripheral points than at the central points (p<0.001). Conclusion: The threshold sensitivity increased in the second examination compared to the first. No factors were associated with this change. The changes in threshold sensitivity were more evident at the peripheral points.
ABSTRACT INTRODUCTION
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Purpose: To investigate macular changes in eyes with postoperative hypotony without clinical maculopathy using high‐resolution Fourier‐domain optical coherence tomography (FD‐OCT).
Methods: Fourteen eyes of 12 patients with postoperative intraocular pressure (IOP) ≤ 6 mmHg for at least 4 weeks but with no detectable clinical features associated with hypotony maculopathy were imaged by FD‐OCT prospectively. Images were analysed by two retina specialists masked to clinical findings.
Results: Most patients were female (83%) and myopic (75%) with a mean age of 65 ± 17 [standard deviation (SD)] years (range 2–86 years). Mean central corneal thickness was 519 ± 34 μm [95% confidence interval (CI) 502–537] and mean IOP before surgery was 20 ± 8 mmHg (95% CI 15–24). During the period of hypotony (mean 15 ± 6 weeks), the average mean IOP was 4 ± 1 mmHg (95% CI 3–5). Abnormal FD‐OCT findings (retinal folds and/or intraretinal fluid) were present in eight eyes. These patients had a higher rate of visual symptoms (75% versus 17%), visual acuity loss (≥ 2 lines; 63% versus 17%) and increased mean foveal thickness (250 ± 26 versus 210 ± 12 μm; p < 0.01, Mann–Whitney U‐test) compared with those with normal FD‐OCT.
Conclusion: FD‐OCT identified subclinical macular abnormalities in over half of the eyes with postoperative hypotony. These findings were accompanied by visual disturbances and central macular thickening. FD‐OCT can be an important diagnostic tool for this disorder when clinical features are absent.
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