| 1. |
- Alhamami, Mastour, et al.
(författare)
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Comparison of Cysts in Red and Green Images for Diabetic Macular Edema
- 2017
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Ingår i: Optometry and Vision Science. - 1040-5488 .- 1538-9235. ; 94:2, s. 137-149
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate whether cysts in diabetic macular edema are better visualized in the red channel of color fundus camera images, as compared with the green channel, because color fundus camera screening methods that emphasize short-wavelength light may miss cysts in patients with dark fundi or changes to outer blood retinal barrier.Methods: Fundus images for diabetic retinopathy photoscreening were acquired for a study with Aeon Imaging, EyePACS, University of California Berkeley, and Indiana University. There were 2047 underserved, adult diabetic patients, of whom over 90% self-identified as a racial/ethnic identify other than non-Hispanic white. Color fundus images at nominally 45 degrees were acquired with a Canon Cr-DGi non-mydriatic camera (Tokyo, Japan) then graded by an EyePACS certified grader. From the 148 patients graded to have clinically significant macular edema by the presence of hard exudates in the central 1500 [mu]m of the fovea, we evaluated macular cysts in 13 patients with cystoid macular edema. Age ranged from 33 to 68 years. Color fundus images were split into red, green, and blue channels with custom Matlab software (Mathworks, Natick, MA). The diameter of a cyst or confluent cysts was quantified in the red-channel and green-channel images separately.Results: Cyst identification gave complete agreement between red-channel images and the standard full-color images. This was not the case for green-channel images, which did not expose cysts visible with standard full-color images in five cases, who had dark fundi. Cysts appeared more numerous and covered a larger area in the red channel (733 +/- 604 [mu]m) than in the green channel (349 +/- 433 [mu]m, p < 0.006).Conclusions: Cysts may be underdetected with the present fundus camera methods, particularly when short-wavelength light is emphasized or in patients with dark fundi. Longer wavelength techniques may improve the detection of cysts and provide more information concerning the early stages of diabetic macular edema or the outer blood retinal barrier.
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| 2. |
- Arthur, Edmund, et al.
(författare)
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Central Macular Thickness in Diabetic Patients : A Sex-based Analysis
- 2019
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Ingår i: Optometry and Vision Science. - : American Academy of Optometry. - 1040-5488 .- 1538-9235. ; 96:4, s. 266-275
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Tidskriftsartikel (refereegranskat)abstract
- SIGNIFICANCE The pathological changes in clinically significant diabetic macular edema lead to greater retinal thickening in men than in women. Therefore, male sex should be considered a potential risk factor for identifying individuals with the most severe pathological changes. Understanding this excessive retinal thickening in men may help preserve vision. PURPOSE The purpose of this study was to investigate the sex differences in retinal thickness in diabetic patients. We tested whether men with clinically significant macular edema had even greater central macular thickness than expected from sex differences without significant pathological changes. This study also aimed to determine which retinal layers contribute to abnormal retinal thickness. METHODS From 2047 underserved adult diabetic patients from Alameda County, CA, 142 patients with clinically significant macular edema were identified by EyePACS-certified graders using color fundus images (Canon CR6-45NM). First, central macular thickness from spectral domain optical coherence tomography (iVue; Optovue Inc.) was compared in 21 men versus 21 women without clinically significant macular edema. Then, a planned comparison contrasted the greater values of central macular thickness in men versus women with clinically significant macular edema as compared with those without. Mean retinal thickness and variability of central macular layers were compared in men versus women. RESULTS Men without clinically significant macular edema had a 12-μm greater central macular thickness than did women (245 ± 21.3 and 233 ± 13.4 μm, respectively; t40 = −2.18, P = .04). Men with clinically significant macular edema had a 67-μm greater central macular thickness than did women (383 ± 48.7 and 316 ± 60.4 μm, P < .001); that is, men had 55 μm or more than five times more (t20 = 2.35, P = .02). In men, the outer-nuclear-layer thickness was more variable, F10,10 = 9.34. CONCLUSIONS Underserved diabetic men had thicker retinas than did women, exacerbated by clinically significant macular edema.
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| 3. |
- Baskaran, Karthikeyan, et al.
(författare)
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Benefit of Adaptive Optics Aberration Correction at Preferred Retinal Locus
- 2012
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Ingår i: Optometry and Vision Science. - 1040-5488 .- 1538-9235. ; 89:9, s. 1417-1423
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE.: To investigate the effect of eccentric refractive correction and full aberration correction on both high- and low-contrast grating resolution at the preferred retinal locus (PRL) of a single low-vision subject with a long-standing central scotoma. METHODS.: The subject was a 68-year-old women with bilateral absolute central scotoma due to Stargardt disease. She developed a single PRL located 25 degrees nasally of the damaged macula in her left eye, this being the better of the two eyes. High- (100%) and low-contrast (25 and 10%) grating resolution acuity was evaluated using four different correction conditions. The first two corrections were solely refractive error corrections, namely, habitual spectacle correction and full spherocylindrical correction. The latter two corrections were two versions of adaptive optics corrections of all aberrations, namely, habitual spectacle correction with aberration correction and full spherocylindrical refractive correction with aberration correction. RESULTS.: The mean high-contrast (100%) resolution acuity with her habitual correction was 1.06 logMAR, which improved to 1.00 logMAR with full spherocylindrical correction. Under the same conditions, low-contrast (25%) acuity improved from 1.30 to 1.14 logMAR. With adaptive optics aberration correction, the high-contrast resolution acuities improved to 0.89/0.92 logMAR and the low-contrast acuities improved to 1.04/1.06 logMAR under both correction modalities. The low-contrast (10%) resolution acuity was 1.34 logMAR with adaptive optics aberration correction; however, with purely refractive error corrections, she was unable to identify the orientation of the gratings. CONCLUSIONS.: Correction of all aberrations using adaptive optics improves both high- and low-contrast resolution acuity at the PRL of a single low-vision subject with long-standing absolute central scotoma
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| 4. |
- Baskaran, Karthikeyan, et al.
(författare)
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Influence of age on peripheral ocular aberrations.
- 2011
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Ingår i: Optometry and Vision Science. - 1040-5488 .- 1538-9235. ; 88:9, s. 1088-1098
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE.: To compare peripheral lower and higher order aberrations across the horizontal (±40°) and inferior (-20°) visual fields in healthy groups of young and old emmetropes. METHODS.: We have measured off-axis aberrations in the groups of 30 younger (24 ± 3 years) and 30 older (58 ± 5 years) emmetropes. The aberrations of OD were measured using the COAS-HD VR Shack-Hartmann aberrometer in 10° steps to ±40° horizontally and -20° inferiorly in the visual field. The aberrations were quantified with Zernike polynomials for a 4 mm pupil diameter. The second-order aberration coefficients were converted to their respective refraction components (M, J45, and J180). Mixed between-within subjects, analysis of variance were used to determine whether there were significant differences in the refraction and aberration components for the between-subjects variable age and the within-subjects variable eccentricity. RESULTS.: Peripheral refraction components were similar in both age groups. Among the higher order coefficients, horizontal coma (C3) and spherical aberration (C4) varied mostly between the groups. Coma increased linearly with eccentricity, at a more rapid rate in the older group than in the younger group. Spherical aberration was more positive in the older group compared with the younger group. Higher order root mean square increased more rapidly with eccentricity in the older group. CONCLUSIONS.: Like the axial higher order aberrations, the peripheral higher order aberrations of emmetropes increase with age, particularly coma and spherical aberration.
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| 5. |
- Baskaran, Karthikeyan, et al.
(författare)
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Repeatability of Peripheral Aberrations in Young Emmetropes
- 2010
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Ingår i: Optometry and Vision Science. - 1040-5488 .- 1538-9235. ; 87:10, s. 751-759
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE.: The purpose of this study is to assess the intrasession repeatability of ocular aberration measurements in the peripheral visual field with a commercially available Shack-Hartmann aberrometer (complete ophthalmic analysis system-high definition-vision research). The higher-order off-axis aberrations data in young healthy emmetropic eyes are also reported.METHODS.: The aberrations of the right eye of 18 emmetropes were measured using an aberrometer with an open field of view that allows peripheral measurements. Five repeated measures of ocular aberrations were obtained and assessed in steps of 10 degrees out to +/-40 degrees in the horizontal visual field (nasal + and temporal -) and -20 degrees in the inferior visual field. The coefficient of repeatability, coefficient of variation, and the intraclass correlation coefficient were calculated as a measure of intrasession repeatability.RESULTS.: In all eccentric angles, the repeatability of the third- and fourth-order aberrations was better than the fifth and sixth order aberrations. The coefficient of variation was <30% and the intraclass correlation coefficient was >0.90 for the third and fourth order but reduced gradually for higher orders. There was no statistical significant difference in variance of total higher-order root mean square between on- and off-axis measurements (p > 0.05). The aberration data in this group of young emmetropes showed that the horizontal coma (C13) was most positive at 40 degrees in the temporal field, decreasing linearly toward negative values with increasing off-axis angle into the nasal field, whereas all other higher-order aberrations showed little or no change.CONCLUSIONS.: The complete ophthalmic analysis system-high definition-vision research provides fast, repeatable, and valid peripheral aberration measurements and can be used efficiently to measure off-axis aberrations in the peripheral visual field
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| 6. |
- Beckman, Claes, 1962-
(författare)
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Comparison of two glare measurement methods through light scattering modeling.
- 1992
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Ingår i: Optometry and Vision Science. - : Ovid Technologies (Wolters Kluwer Health). - 1040-5488 .- 1538-9235. ; 69:7, s. 532-7
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Tidskriftsartikel (refereegranskat)abstract
- Two methods used for evaluation of glare in patients with opacities of the ocular media are compared. One is a low contrast letter test and the other is a direct light scattering meter. Theoretical expressions for the measures obtained from the two different glare tests are derived in terms of the point spread function. Measurements on healthy test persons wearing diffusive glasses with known light scattering properties were in good agreement with the theory. Data from 26 cataractous eyes are presented and discussed in light of the theory.
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| 7. |
- Beckman, Claes, 1962-
(författare)
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Evaluation of a clinical glare test based on estimation of intraocular light scatter.
- 1991
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Ingår i: Optometry and Vision Science. - : Ovid Technologies (Wolters Kluwer Health). - 1040-5488 .- 1538-9235. ; 68:11, s. 881-7
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Tidskriftsartikel (refereegranskat)abstract
- A glare test based on psychophysical estimation of intraocular light scatter and using a flickering, annular glare source was evaluated. The parameters determining the accuracy of the test were studied. In particular the influence of background light and flicker frequency were investigated and optimum values for best accuracy were found. Based on these findings a versatile and simple apparatus was constructed. Forty patients with various degrees of cataract were investigated in a clinical study. Patients, who subjectively experience severe glare problems, indeed show high glare values as measured with the apparatus. No obvious relation between visual acuity and glare score was found. In comparison with glare tests using a stationary glare source the use of a flickering glare source is advantageous in terms of sensitivity and accuracy.
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| 8. |
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| 9. |
- Bro, Tomas, et al.
(författare)
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Relatively Stable Prevalence of Myopia among Swedish Children Aged 4 to 7 Years between 2015 and 2020
- 2023
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Ingår i: Optometry and Vision Science. - : LIPPINCOTT WILLIAMS & WILKINS. - 1040-5488 .- 1538-9235. ; 100:1, s. 91-95
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Tidskriftsartikel (refereegranskat)abstract
- SIGNIFICANCEThe global increase of myopia has caused a lot of debate the last years. Previous research of myopia in the Nordic population has shown diverse results, and only a few Swedish studies have been published in the subject the last two decades.PURPOSEThis study aimed to analyze trends in the prevalence of myopia in a population of Swedish children.METHODSA retrospective analysis of medical records for children between 4 and 7 years of age in a region in Sweden was performed. The inclusion criterion was a first glasses prescription for myopia between 2012 and 2020. Children with other eye diseases or syndromes affecting the eye and vision were excluded. Age, sex, uncorrected visual acuity, and cycloplegic refractive values were extracted. The number of myopic children was compared with population data to calculate incidence and estimate prevalence.RESULTSDuring the study period, 427 children between 4 and 7 years old in an average population of 17,200 children were prescribed glasses for myopia. The incidence for myopia increased from 0.11% in 2012 to 0.39% in 2020 (P < .05). In 2015 to 2020, the prevalence of myopia for the same age group increased from 0.5 to 1.2% (P < .05). Linear regression of the prevalence of myopia showed a significant increase in the age group of 7 years (beta = 0.2%, R-2 = 0.82, P <= .05).CONCLUSIONSThis study found a relatively stable prevalence of myopia among Swedish children aged 4 to 7 years between 2015 and 2020. The prevalence of 1.6% among 7-year-old children is not higher than in previous Scandinavian studies.
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| 10. |
- Bro, Tomas, et al.
(författare)
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The Effects of Visual Field Loss from Stroke on Performance in a Driving Simulator
- 2022
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Ingår i: Optometry and Vision Science. - : LIPPINCOTT WILLIAMS & WILKINS. - 1040-5488 .- 1538-9235. ; 99:9, s. 679-686
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Tidskriftsartikel (refereegranskat)abstract
- SIGNIFICANCE: Visual field loss is a common consequence of stroke and often precludes driving. However, legal visual requirements for drivers licenses are largely without scientific basis. PURPOSE: This study aimed to examine the effects of different types of homonymous visual field loss after stroke on simulated driving. METHODS: Data on performance and safety from a traffic simulator test for 153 participants with withdrawn drivers licenses due to visual field loss from stroke were retrospectively compared with data from 83 healthy individuals without visual deficits in a cross-sectional study. The 93 individuals in the stroke group who regained their driving licenses after a successful simulator test were then followed in a national accident database. RESULTS: Sixty-five percent of the stroke participants passed the simulator test (95% confidence interval, 57 to 72%). Younger patients were more successful than older. However, classification by neither type of homonymous visual field loss nor side of visual field loss was predictive of driver safety. Participants with hemianopia had their lateral lane position dislocated to the nonaffected side of the visual field. None of the participants with a regained license were involved in motor vehicle accidents 3 to 6 years after the test. CONCLUSIONS: In this large cohort, driver safety could not be predicted from the type of homonymous visual field loss. Even individuals with severe visual field loss might be safe drivers. Therefore, it seems reasonable to provide an opportunity for individualized assessments of practical fitness to drive in circumstances of licensing issues. This study demonstrates the potential of using a standardized driving simulator test for such assessments of fitness to drive.
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