| 1. |
- Abrahamsson, Maths, 1953, et al.
(författare)
-
The occurrence of congenital cataract in western Sweden
- 1999
-
Ingår i: Acta Ophthalmologica Scandinavica. - : Wiley. - 1395-3907. ; 77:5, s. 578-580
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To estimate the occurrence of congenital cataract in a Nordic country. Methods: In 1980, we constructed a database in the Department of Ophthalmology Goteborg University, containing basic data from all cases in western Sweden diagnosed with congenital cataract. By collecting and processing these data from 1980 onwards, we hoped to improve the management of congenital cataract treatment and to optimize the outcome of the treatment. Results: In this study, the incidence of congenital cataract in the four western counties of Sweden was evaluated. The occurrence rate of all cases with congenital cataract during the study period was 36 cases per 100 000. The occurrence rate for dense bilateral and all unilateral cases were both 14 per 100 000 each. Conclusion: There were no time-related changes in incidence of congenital cataract from 1980 until today, although there was a large variation in the yearly incidence.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Ali, Sara, et al.
(författare)
-
Ocular Fundus Morphology and Visual Function in Adolescents Born Moderate-to-Late Preterm
- 2023
-
Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology. - 0146-0404 .- 1552-5783. ; 64:8
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Previous studies have mostly focused on ophthalmological complications associated with being born extremely preterm despite that moderate-to-late preterm (MLP) account for 85% of all preterm births. The aim was to examine fundus morphology and visual function in adolescents born MLP, in comparison with controls born full-term.Methods: A prospective population-based cohort study of 247 MLP individuals (110 girls, gestational age 32-36 weeks) with no syndromes or history of retinopathy of prematurity participated in a neonatal study in 2002-2004. Later on, they have been included in ophthalmological follow-up studies at age 8 (n=50) and 12 (n=22). In the present study, 50 adolescents (26 girls; mean age 16.5 years) were examined regarding best corrected visual acuity (BCVA), refraction, and ocular morphology, measured by optical coherence tomography (Topcon, Japan). A group of 50 adolescents (30 girls, mean age 16.7 years) born full-term served as controls. Participants with refraction outside +/-6 diopters were excluded. T-test was used for statistical analysis.Results: The MLP-group (n=48) showed a thinner macular retinal nerve fibre layer (RNFL) inner mean in right eye (RE) (26.4±1.5 vs 27.1±1.7 μm; p=0.029) and in left eye (LE) (26.3±1.5 vs 27.0±1.5 μm; p=0.022) compared with controls. A thinner macular RNFL outer mean was found both in RE (40.2±4.4 vs 42.6±4.2 μm; p=0.011) and LE (40.3±4.0 vs 42.1±4.3 μm; p=0.034) (Fig.1A-B). A thicker central macular retinal thickness (MRT) (249.3±20.9 vs 239.9±16.4 μm; p=0.016) and a thinner total peripapillary (pp)RNFL (104.8±8.8 vs 109.1±8.3 μm; p=0.027) were found in RE. The BCVA in best eye was lower in the MLP-group (n=50) compared with controls (-0.09±0.08 vs -0.12±0.09 logMAR; p=0.022). At age 8, MLP births showed a thinner total macular volume and a thicker foveal minimum, central MRT, and central macular RNFL in RE. At age 12, a thicker foveal minimum and thinner outer macular RNFL were found in LE.Conclusions: MLP-birth may be associated with ophthalmological macular and ppRNFL changes as well as lower BCVA in adolescence. Similar morphology findings have been shown at younger ages, thus the fundus results persist into young adulthood.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Hashas, A. S. K., et al.
(författare)
-
A new diagnostic method for retinal breaks in patients with posterior vitreous detachment: Ultra-wide-field imaging with the Zeiss Clarus 700
- 2023
-
Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X .- 1755-3768. ; 101:6, s. 627-635
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeThis study was performed with the aim of finding a more convenient and less time-consuming method to diagnose retinal breaks in posterior vitreous detachment (PVD) patients. MethodsA prospective double-blind observational case study was performed with patients who were admitted to the Eye Emergency Department Sahlgrenska University Hospital with PVD symptoms and approved to participate in the study (n = 128). Standard slit lamp examination was compared with images from a Zeiss Clarus 700 ultra-wide-field camera (UWFC). Patients were examined and photographed by an independent operator. Data and image review was performed by three independent reviewers with varying experience. Retinal break detection with the two different methods (detailed eye examination by well-trained ophthalmologist and UWFC evaluations) was analysed statistically. ResultsAfter excluding diagnoses other than PVD as well as unclear images due to cataracts, vitreous bleeding, etc., a total of 103 eyes with PVD were evaluated. A total of 38 ruptures in 25 patients were detected by routine examination and were subjected to laser treatment. UWFC images were reviewed by three ophthalmology consultants and compared with routine examinations. Sensitivity values in detecting retinal ruptures in UWFC images of the three reviewers were 0.89, 0.87 and 0.79, and specificity values were 0.88, 0.86 and 0.93 (kappa values: 0.742, 0.689 and 0.728) respectively. ConclusionAlthough there have been rapid developments in imaging with UWFC in recent years and it is a very promising method for the future, routine clinical examination is still the only valid method for the detection of retinal tears today.
|
|
| 9. |
- Keasar, Chen, et al.
(författare)
-
An analysis and evaluation of the WeFold collaborative for protein structure prediction and its pipelines in CASP11 and CASP12
- 2018
-
Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Every two years groups worldwide participate in the Critical Assessment of Protein Structure Prediction (CASP) experiment to blindly test the strengths and weaknesses of their computational methods. CASP has significantly advanced the field but many hurdles still remain, which may require new ideas and collaborations. In 2012 a web-based effort called WeFold, was initiated to promote collaboration within the CASP community and attract researchers from other fields to contribute new ideas to CASP. Members of the WeFold coopetition (cooperation and competition) participated in CASP as individual teams, but also shared components of their methods to create hybrid pipelines and actively contributed to this effort. We assert that the scale and diversity of integrative prediction pipelines could not have been achieved by any individual lab or even by any collaboration among a few partners. The models contributed by the participating groups and generated by the pipelines are publicly available at the WeFold website providing a wealth of data that remains to be tapped. Here, we analyze the results of the 2014 and 2016 pipelines showing improvements according to the CASP assessment as well as areas that require further adjustments and research.
|
|
| 10. |
- Knutsson, Per, 1978, et al.
(författare)
-
Correction of static and non-common path aberrations in an adaptive optics system using inherent calibration data
- 2021
-
Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 29:3, s. 3406-3414
-
Tidskriftsartikel (refereegranskat)abstract
- For low-order adaptive optics systems, a method that is able to correct for system aberrations in the final focal plane is presented. The paper presents a novel figure of merit, corresponding to the integrated non-normalized tip-tilt-free optical transfer function. The inherent singular value decomposition modal content of the interaction matrix is used to optimize this figure of merit. The method has proven to be stable and robust, providing a simple mean to facilitate diffraction limited imaging in an experimental setup for ophthalmic applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
|
|
| 11. |
- KNUTSSON, PER, et al.
(författare)
-
Correction of static and non-common path aberrations in an adaptive optics system using inherent calibration data
- 2021
-
Ingår i: Optics Express. - 1094-4087. ; 29:3, s. 3406-3414
-
Tidskriftsartikel (refereegranskat)abstract
- For low-order adaptive optics systems, a method that is able to correct for system aberrations in the final focal plane is presented. The paper presents a novel figure of merit, corresponding to the integrated non-normalized tip-tilt-free optical transfer function. The inherent singular value decomposition modal content of the interaction matrix is used to optimize this figure of merit. The method has proven to be stable and robust, providing a simple mean to facilitate diffraction limited imaging in an experimental setup for ophthalmic applications.
|
|
| 12. |
- Lind, Alexandra, et al.
(författare)
-
Ocular Dimensions in Relation to Growth and Metabolic Factors in Adolescents Born Moderate-to-Late Preterm
- 2023
-
Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology. - 0146-0404 .- 1552-5783. ; 64:8
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: The majority of all preterm birth are moderate-to-late preterm (MLP) birth, defined as birth at 32–36 weeks of gestation. These individuals have an elevated morbidity risk compared with full-term individuals; however, little is known of the ocular development. The purpose of the present study was to evaluate ocular dimensions in relation to growth and metabolic factors in MLP adolescents.Methods: In this prospective cohort study, 50 MLP adolescents participated (26 girls; mean gestational age 35.0 weeks; mean age 16.5 years). When recruited at birth, the exclusion criteria were chromosomal abnormalities, severe malformations, syndromes, or being born to mothers with chronic diseases. A control group consisted of 50 adolescents born full-term (30 girls; 40.3 weeks; 16.7 years). Total axial length (TAL), palpebral fissure length (PFL), and intercanthal distance (ICD) were measured. The TAL was evaluated using optical biometry (IOL Master). The PFL and ICD were measured using a ruler. Head circumference, length, weight, body mass index, and serum levels of insulin-like growth factor I and insulin-like growth factor binding protein 3 were evaluated. Serum levels of the metabolic factors leptin and adiponectin were measured. The MLP and control group were compared regarding all variables using Mann Whitney U-test. Ocular dimensions were analyzed to find any possible association with growth and metabolic factors using Spearman rank correlation.Results: The MLP group had shorter TAL and PFL, and wider ICD compared with controls, shown in Table 1. There was no significant difference regarding growth, leptin, or adiponectin. Within the MLP group, TAL correlated with length (right eye (RE) r=0.46, p<0.001; left eye (LE) r=0.48, p<0.001), head circumference (RE r=0.46, p<0.001; LE r=0.44, p=0.001), and weight (RE r=0.53, p<0.001; LE r=0.51, p<0.001). The PFL correlated with length (RE r=0.53, p<0.001; LE r=0.58, p<0.001), and leptin (RE r=-0.43, p=0.004; LE r=-0.46, p=0.002). No other significant correlation was found.Conclusions: In the present study, being born MLP were shown to impact ocular growth including TAL, PFL, and ICD. Furthermore, these variables were found to be associated with leptin levels and general growth.
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
- Martin, Lene, et al.
(författare)
-
Resolution visual fields in children surgically treated for bilateral congenital cataract
- 2008
-
Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 49:8, s. 3730-3733
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. To evaluate visual acuity (best corrected visual acuity) and peripheral sensitivity, measured by high-pass resolution (HRP) visual fields, in children surgically treated for congenital cataract. METHODS. Acuity and peripheral sensitivity were recorded from 16 children, aged 10 to 15 years, either surgically treated for bilateral dense cataract before the age of 4.6 months (n = 10) or surgically treated for bilateral partial cataract at ages 4 to 139 months (n = 6). Data from 22 healthy children, mean age 11 years, served as control. RESULTS. The children with cataract had significantly (P < 0.0001) lower decimal acuity in their better eye (median, 0.55; range, 0.1-1.3) than did the control subjects (median, 1.2; range, 1.0-1.6). Five children were visually impaired according to the World Health Organization's definition (i.e., acuity in the better eye <0.3). The children with previous dense bilateral cataract showed significantly lower peripheral sensitivity than did the control subjects (P = 0.004). Significant correlations were observed between acuity and visual field parameters. CONCLUSIONS. Dense cataract, even when surgically treated before the age of 4.6 months, causes persistent impairment of spatial vision, both in the fovea and the visual field. The effect on the visual field is less pronounced than that on visual acuity. This finding has to be taken into account when evaluating visual field results in, for example, the diagnosis of glaucoma, a frequent complication after cataract surgery in early infancy.
|
|
| 17. |
- Ovik, Titus, et al.
(författare)
-
Foveal thickness and vascular variables in adolescents born moderate-to-late preterm
- 2024
-
Ingår i: Acta Ophthalmologica. - : John Wiley & Sons. - 1755-375X .- 1755-3768.
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: It is well established that children born very preterm are at increased risk for ocular abnormalities including altered foveal morphology. However, little is known about how children born moderate-to-late preterm (MLP), gestational age 32 + 0-36 + 6 weeks, are affected later in life. This study investigates foveal avascular zone (FAZ) area, vascular density (VD), central foveal thickness (CFT) and ganglion cell layer thickness (GCL++) of adolescents born MLP without history of retinopathy of prematurity and compare the results with full-term controls.METHODS: In a prospective population-based cohort study, 50 adolescents (26 girls; mean age 16.5 years) born MLP were examined with optical coherence tomography (OCT) and OCT angiography (OCT-A). FAZ and VD were obtained from OCT-A scans and adjusted for ocular magnification. CFT and GCL++ were obtained from the OCT scans. The results from the MLP individuals were compared with the results from 49 healthy full-term controls (29 girls; mean age 16.7 years).RESULTS: The results showed statistically significant differences in FAZ area (0.22 vs 0.28 mm2; p = 0.0032) and CFT (198.1 vs 187.1 μm; p = 0.0010) between the MLP group and controls. Strong correlations between FAZ area and CFT (r = -0.773, p < 0.0001) and GCL++ (r = -0.924, p < 0.0001) were found in the MLP group. There were no differences in VD.CONCLUSIONS: Our results show that adolescents born MLP have a smaller FAZ area and an increased CFT compared with full-term controls. These results indicate that adolescents born MLP have similar parafoveal changes as children born extreme or very preterm.
|
|
| 18. |
- Owner-Petersen, Mette, et al.
(författare)
-
Multi-object wavefront sensor with spatial filtering
- 2007
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to an adaptive optics sensor intended for simultaneous detection of several wavefronts on a common camera target. The sensor is intended for use in connection with multi-conjugate adaptive optics (MCAO), where several wavefront measurements are needed at the same time. The sensor includes a spatial filter taking out signals resulting from parasitic reflections of the reference sources and from unwanted parts of the object.
|
|
| 19. |
|
|
| 20. |
- Popovic, Zoran, 1966
(författare)
-
Adaptive optics ophthalmoscopes
- 2017
-
Ingår i: Handbook of Visual Optics Vol. II - Instrumentation and Vision Correction. Pablo Artal (red.). - Boca Raton, FL, USA : CRC Press, Taylor & Francis Group. - 9781482237924 ; , s. 91-102
-
Bokkapitel (refereegranskat)
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Popovic, Zoran, 1966, et al.
(författare)
-
Dual Conjugate Adaptive Optics Prototype for Wide Field High Resolution Retinal Imaging
- 2012
-
Ingår i: Adaptive Optics Progress. - Rijeka : Intech. - 9789535108948 ; , s. 3-21
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Retinal imaging is limited due to optical aberrations caused by imperfections in the optical media of the eye. Consequently, diffraction limited retinal imaging can be achieved if optical aberrations in the eye are measured and corrected. Information about retinal pathology and structure on a cellular level is thus not available in a clinical setting but only from histological studies of excised retinal tissue. In addition to limitations such as tissue shrinkage and distortion, the main limitation of histological preparations is that longitudinal studies of disease progression and/or results of medical treatment are not possible. Adaptive optics (AO) is the science, technology and art of capturing diffraction-limited images in adverse circumstances that would normally lead to strongly degraded image quality and loss of resolution. In non-military applications, it was first proposed and implemented in astronomy. AO technology has since been applied in many disciplines, including vision science, where retinal features down to a few microns can be resolved by correcting the aberrations of ocular optics. As the focus of this chapter is on AO retinal imaging, we will focus our description to this particular field.
|
|
| 24. |
|
|
| 25. |
- Popovic, Zoran, 1966
(författare)
-
Neural limits of visual resolution
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aims: The aim of this thesis was to formulate a model of retinal neural circuitry in humans based on morphological estimates of retinal cone and ganglion cell populations, to compare results based on this model to psychophysical measurements of visual resolution and identify the retinal neural factors that limit visual resolution.Materials & Methods: Total displacement of central ganglion cells from foveal cones was obtained by estimating the length of fibers of Henle in four human retinas along the nasal or vertical hemi-meridians. Quantitative estimates of ganglion cell and cone densities were made using a modified disector method in vertically sectioned human retinas and ganglion cell densities were adjusted for central displacement. High-pass Resolution Perimetry (HRP) thresholds were used as a psychophysical estimate of visual resolution throughout this work. Functional magnetic resonance imaging (fMRI) estimates of the human linear cortical magnification factor were obtained from the literature. Resolution and detection thresholds of computer generated high-pass filtered optotypes were recorded under equal lighting and luminance conditions.Results: We obtained quantitative estimates describing total displacement of ganglion cells from cones within the central 3 mm (11 deg) of the human retina and established a model of the retinal vertical pathway from cones to ganglion cells based on quantitative estimates of cone and ganglion cell densities as well as calculated effective ganglion cell densities. Center-to-center separation of the effective sampling area of one midget ganglion cell independently of its type (ON or OFF), i.e. the estimated receptive field, proved to be a good predictor of visual resolution within the central 20 deg of the human retina. Strong linear relationships through the origin were established between ganglion cell separations and HRP thresholds. The overrepresentation of the fovea and immediately surrounding retina in the human striate cortex was confirmed to be the result of an increase in devoted cortical distance per central ganglion cell. A dependence on contrast was found with and without correction for peripheral refractive errors for both resolution and detection thresholds of three high-pass filtered optotypes, irrespective of the task being resolution or detection. A linear proportionality through the origin was shown between resolution and detection thresholds and ganglion cell separation.Conclusions: Presented results of lateral displacement support and extend previous analyses of the relation within the human fovea between quantitative cell distributions and psychophysical measurements. The separation of estimated receptive fields can be interpreted as a limiting factor of visual resolution in the human retina. Intra-individual comparisons of HRP thresholds and ganglion cell separations support the hypothesis of a direct proportionality through the origin between retinal ganglion cell separation and HRP thresholds. There is a non-linear scaling between central retinal subunits and dedicated striate cortical distance in man, with an overrepresentation of the fovea and immediately surrounding retina in the striate cortex. None of the investigated high-pass filtered optotypes were found to be contrast limited irrespective of the task being resolution or detection. This result is quite the contrary of that reported for gratings and indicates that classical sampling theory may need modification before it can be applied to high-pass filtered optotypes.
|
|
| 26. |
- Popovic, Zoran, 1966, et al.
(författare)
-
Noninvasive imaging of human foveal capillary network using dual-conjugate adaptive optics.
- 2011
-
Ingår i: Investigative ophthalmology & visual science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 52:5, s. 2649-55
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To demonstrate noninvasive imaging of human foveal capillary networks with a high-resolution, wide-field, dual-conjugate adaptive optics (DCAO) imaging instrument. METHODS: The foveal capillary networks of five healthy subjects with no previous history of ocular or neurologic disease or surgery were imaged with a novel high-resolution, wide-field DCAO instrument. The foveal avascular zone (FAZ) in each image was defined using a manual procedure. An automated algorithm based on publicly available and custom-written software was used to identify vessels and extract morphologic FAZ and vessel parameters. Capillary densities were calculated in two annular regions of interest (ROIs) outside the FAZ (500 μm and 750 μm outer radius from the foveal center) and in the superior, inferior, temporal, and nasal quadrants within the two ROIs. RESULTS: Mean FAZ area was 0.302 ± 0.100 mm(2), and mean capillary density (length/area) in the inner ROI was 38.0 ± 4.0 mm(-1) and 36.4 ± 4.0 mm(-1) in the outer ROI. The difference in ROI capillary density was not significant. There was no significant difference in quadrant capillary density within the two ROIs or between quadrants irrespective of ROI. CONCLUSIONS: The authors have demonstrated a technique for noninvasive imaging and semiautomated detection and analysis of foveal capillaries. In comparison with other studies, their method yielded lower capillary densities than histology but similar results to the current clinical gold standard, fluorescein angiography. The increased field of view of the DCAO instrument opens up new possibilities for high-resolution noninvasive clinical imaging of foveal capillaries.
|
|
| 27. |
|
|
| 28. |
|
|
| 29. |
- Popovic, Zoran, 1966, et al.
(författare)
-
Resolution, separation of retinal ganglion cells, and cortical magnification in humans
- 2001
-
Ingår i: Vision Research. - 0042-6989. ; 41:10-11, s. 1313-1319
-
Tidskriftsartikel (refereegranskat)abstract
- We present direct comparisons of resolution thresholds and quantitative estimates of retinal ganglion cell separation in humans with reported functional magnetic resonance imaging estimates of the human linear cortical magnification factor. Measurements of resolution thresholds (MAR), retinal ganglion cell (GC) densities, and linear cortical magnification factor (M) values were taken from the literature. Out objective was to analyse the apparent overrepresentation of human central vision in the visual cortex and to determine whether the cause of this is an effect of the uneven distribution of GC in the retina and:or that central GC have more devoted cortical area per cell, The reserved amount of cortical distance per retinal unit, i.e. the product of M on the one hand and effective GC separation. MAR, and GC receptive field separation on the other. indicates an overrepresentation of the fovea and immediately surrounding retina in the human striate cortex due to an increase in devoted cortical distance per central GC or resolution unit. This cannot be explained by lateral displacement of foveal ganglion cells nor by peripheral scaling, but rather by an additional magnification in the retino-cortical pathway. (C) 2001 Elsevier Science Ltd. All rights reserved.
|
|
| 30. |
|
|
| 31. |
- Popovic, Zoran, 1966, et al.
(författare)
-
The relation between resolution measurements and numbers of retinal ganglion cells in the same human subjects
- 2005
-
Ingår i: Vision Research. - : Elsevier BV. - 0042-6989. ; 45:17, s. 2331-2338
-
Tidskriftsartikel (refereegranskat)abstract
- Limiting factors of resolution have previously only been investigated by using resolution data and retinal ganglion cell spacing data from different individuals. We report on our unique opportunity to study the intra-individual relationship in three human subjects between retinal ganglion cell separations and resolution thresholds, measured with high-pass resolution perimetry. Our data show that resolution is directly proportional to half the midget population, in accordance with the hypothesis that a dichotomous midget ON/OFF population mediates resolution. (c) 2005 Elsevier Ltd. All rights reserved.
|
|
| 32. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
Arrested foveal development in preterm eyes: Thickening of the outer nuclear layer and structural redistribution within the fovea
- 2017
-
Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 58:12, s. 4948-4958
-
Tidskriftsartikel (refereegranskat)abstract
- © 2017 The Authors. Purpose: The aim of this study was to define landmarks to better characterize foveal microstructure in normal subjects and in preterms with or without signs of immaturity, and to report on thickness changes of outer foveal layers following analysis of optical coherence tomography (OCT) B-scan images. Methods: Selected eyes from eight young adults with a history of prematurity (24-33 weeks of gestation) and five controls were imaged using conventional and directional OCT. Retinal layer thickness analysis was performed at selected temporal eccentricities defined by the individual distance between two landmarks for each case, the foveal center and the foveal rim. Results: The use of a foveal center and foveal rim landmark transformation enabled comparisons of interindividual B-scans at corresponding landmark positions in both controls and preterms. We found a 20% shorter foveal center to foveal rim distance in preterms with an immature fovea than in controls. Reflectometric and manual segmentation measurements showed increased thickness of inner retinal layers and photoreceptor cell body and outer plexiform layers centrally, but no observable change of photoreceptor inner and outer segment thickness. Conclusions: Our landmark-based analysis of OCT images using reflectometry and manual segmentation provides complementary findings in comparisons of normal and immature foveal structures. We show a central thickness increase in the outer nuclear layer, outer plexiform layer, and postreceptor layers in preterms with signs of arrested foveal development. We found no indication of abnormal photoreceptor inner or outer segment development in preterms.
|
|
| 33. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
Declining visual acuity in healthy eyes with age. Calculation of loss of retinal ganglion cells in the elderly and old
- 2004
-
Ingår i: Investigative Ophthalmology & Visual Science. - 0146-0404. ; 45
-
Konferensbidrag (refereegranskat)abstract
- Purpose: To investigate the change in visual acuity in eyes without clinical signs of any disease from 70 to 88 years. An additional aim is to calculate the corresponding loss of retinal ganglion cells or functional channels. We find it important to specifically analyze the rate of change after 70 years of age where most previous studies only present scarce data. Methods: We used recently published population data of visual acuity (VA) in healthy eyes of subjects (n=104) from 70 to 88 years of age. An eye was defined as healthy when there were no clinical signs of disease. Loss of retinal ganglion cells or functional channels was predicted from changes of VA by using previously established relationships between cell separations in the retina and spatial resolution. Results: The rate of VA decline above 70 years of age is accelerated compared to previously published data on the decline between 30 and 69 years; 0.09 log MAR/10 years and 0.03 log MAR/10 years, respectively. The calculated annual loss of functional channels corresponding to the VA change is 0.65% before 70 years and 2.0% after 70 years of age. Conclusions: Even though morphological studies have shown only limited age related losses of cells involved in the visual processing of spatial resolution our analysis shows an accelerated decline of visual acuity after 70 years of age in eyes without obvious disease.
|
|
| 34. |
|
|
| 35. |
|
|
| 36. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
Morphometric study of the displacement of retinal ganglion cells subserving cones within the human fovea
- 1999
-
Ingår i: Graefes Archive for Clinical and Experimental Ophthalmology. - 0721-832X. ; 237:12, s. 1014-1023
-
Tidskriftsartikel (refereegranskat)abstract
- Background: A study was carried out to measure the displacement of retinal ganglion cells subserving the cones within the human fovea. Methods: Four human retinas were examined along the nasal or vertical hemi-meridians. Total displacement was estimated by adding the displacement due to fibres of Henle and bipolar cells, measured as the lateral extension of the Henle fibres and of the obliquely running fibre bundles within the inner nuclear layer, respectively. Results: At the foveal border (0.5-0.8 mm or 1.8-2.9 deg eccentricity) the mean offset due to fibres of Henle and mean total lateral displacement was at a maximum of 0.32+/-0.03 mm and 0.37+/-0.03 mm, respectively. A steep decrease of displacement was found outside the foveal border out to an eccentricity of 2.0-2.5 mm. We were able to plot displacement along the vertical meridian in relation to eccentricity with good correlation between three eyes. The data were used to establish different mathematical functions describing the relation between eccentricity and displacement. These functions were applied to previously presented data on densities of retinal ganglion cells and cones. Conclusions: The present estimates of displacement within the human central fovea offer the possibility of analysis of quantitative relations between cones and retinal ganglion cells. Our data provide predictive guidance by establishing that vitreo-retinal procedures causing damage to retinal ganglion cells up to 1 mm from the foveal centre could have implications for loss of information generated within the fovea.
|
|
| 37. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
Quantitative estimations of foveal and extra-foveal retinal circuitry in humans
- 1999
-
Ingår i: Vision Research. - 0042-6989. ; 39:18, s. 2987-2998
-
Tidskriftsartikel (refereegranskat)abstract
- For an understanding of the basis for psychophysical measurement of visual resolution, quantitative morphological studies of retinal neuronal architecture are needed. Here we report on cell densities and retinal ganglion cell:cone ratio (RGC:C) from the foveal border to the peripheral retina (34 degrees eccentricity). Quantitative estimates of RGC and C densities were made using a modified disector method in three vertically sectioned human retinae and were adjusted for RGC displacement. In agreement with our previous data on humans, we found an RGC:C ratio close to 3 at 2-3 degrees eccentricity. Outside the foveal border, the ratio declined to 1.0 at 7.5 degrees eccentricity and to 0.5 at eccentricities larger than 19 degrees. Center-to-center separation of C and RGC in addition to center-to-center separation of estimated 'receptive fields' was calculated at corresponding locations along the superior and inferior hemimeridians. The center-to-center separation of estimated 'receptive fields' was found to be more closely related to resolution thresholds from the fovea to 19 degrees eccentricity than was the separation of RGC and C. On the basis of these quantitative estimates, models for neural circuitry involved in central and peripheral spatial vision can be discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.
|
|
| 38. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
Structural consequences of arrested foveal development in preterms with persisting signs of immaturity
- 2020
-
Ingår i: Eye. - : Springer Science and Business Media LLC. - 0950-222X .- 1476-5454. ; 34, s. 1077-1085
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose To evaluate the impact of structural changes in a limited sample of adult preterms with foveal immaturity from optical coherence tomography (OCT) B-scan images and to estimate layer displacement and changes in areal and volume magnification within the inner fovea. Subjects and methods Layer thickness was measured in conventional and directional OCT scans from eight preterms with different degrees of foveal immaturity (24–33 weeks of gestation, 22–33 years of age) and five controls (20–33 years of age). We obtained reflectivity profiles of the outer plexiform layer (OPL) and manual segmentation data of the inner nuclear layer (INL) and the combined ganglion cell layer (GCL) and inner plexiform layer (IPL) at specified eccentricities from 300 to 900 µm. Displacement of cumulative thickness curves of preterms compared with that of the controls was used to estimate retardation of layer displacement. Changes in areal magnification and layer thickness were used to construct a structural model of redistribution within the fovea of preterms. Results Retardation of centrifugal layer displacement of OPL and all inner retinal layers (IRL) was marked in both preterm groups with foveal immaturity, whereas retardation was marginal in the preterm group without clinical signs of immaturity. Retarded displacement within the IRL and OPL had a major impact on available space within the central fovea. Conclusions A marked retardation of displacement was demonstrated for all IRL within the immature fovea of preterms with decreased areal and volume magnification and reduced space available for synaptic communication coupled to the degree of immaturity.
|
|
| 39. |
- Sjöstrand, Johan, 1936, et al.
(författare)
-
The decline in visual acuity in elderly people with healthy eyes or eyes with early age-related maculopathy in two Scandinavian population samples
- 2011
-
Ingår i: ACTA OPHTHALMOLOGICA. - 1755-375X. ; 89:2, s. 116-123
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study aimed to analyse the decline in visual acuity (VA) during normal ageing in two Scandinavian population samples of subjects aged ≥ 70 years and to study the age-specific decline in VA in eyes with early age-related maculopathy (ARM). METHODS: We carried out a cross-sectional analysis of data pertaining to VA in the better eye in one population sample from Oulu (OU), Finland (aged 70-82 years) and a second population sample from Gothenburg (GG), Sweden (aged 82 or 88 years). The change in VA with age was evaluated in healthy eyes (OU, n = 119; GG, n = 40) and in eyes with early ARM (OU-ARM, n = 22; GG-ARM, n = 114) using linear regression or logistic regression. The results were compared with those of previous reports. RESULTS: Our population samples showed a significant decrease with age in VA in healthy eyes in subjects aged ≥ 44 years using both statistical models. Comparisons with previous reports demonstrated a homogeneity in the decline in VA with age. On average, 0.3 logMAR are lost from middle age up to 88 years, presumably as a result of physiological ageing. In early ARM, the rate of age-specific decline in VA more than doubled and the prevalence of VA < 0.5 markedly increased. CONCLUSIONS: Visual acuity in healthy eyes declines with age from middle age onwards. The decrease in VA possibly accelerates in subjects aged > 70 years, although no significant evidence for this was found. An age-specific decline in VA is shown in eyes with early ARM. These results are important for the evaluation of age-specific treatment results.
|
|
| 40. |
|
|
| 41. |
- Thaung, Jörgen, 1965, et al.
(författare)
-
Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging.
- 2009
-
Ingår i: Optics express. - 1094-4087. ; 17:6, s. 4454-67
-
Tidskriftsartikel (refereegranskat)abstract
- We present analysis and preliminary laboratory testing of a real-time dual-conjugate adaptive optics (DCAO) instrument for ophthalmology that will enable wide-field high resolution imaging of the retina in vivo. The setup comprises five retinal guide stars (GS) and two deformable mirrors (DM), one conjugate to the pupil and one conjugate to a plane close to the retina. The DCAO instrument has a closed-loop wavefront sensing wavelength of 834 nm and an imaging wavelength of 575 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using one adjustable iris, and images the Hartmann patterns of multiple reference sources on a single detector. Zemax simulations were performed at 834 nm and 575 nm with the Navarro 99 and the Liou- Brennan eye models. Two correction alternatives were evaluated; conventional single conjugate AO (SCAO, using one GS and a pupil DM) and DCAO (using multiple GS and two DM). Zemax simulations at 575 nm based on the Navarro 99 eye model show that the diameter of the corrected field of view for diffraction-limited imaging (Strehl >or= 0.8) increases from 1.5 deg with SCAO to 6.5 deg using DCAO. The increase for the less stringent condition of a wavefront error of 1 rad or less (Strehl >or= 0.37) is from 3 deg with SCAO to approximately 7.4 deg using DCAO. Corresponding results for the Liou-Brennan eye model are 3.1 deg (SCAO) and 8.2 deg (DCAO) for Strehl >or= 0.8, and 4.8 deg (SCAO) and 9.6 deg (DCAO) for Strehl >or= 0.37. Potential gain in corrected field of view with DCAO is confirmed both by laboratory experiments on a model eye and by preliminary in vivo imaging of a human eye.
|
|
| 42. |
- Thaung, Jörgen, 1965, et al.
(författare)
-
Dual-conjugate adaptive optics instrument for wide-field retinal imaging
- 2008
-
Ingår i: Adaptive optics for industry and medicine, Proceedings of the sixth international workshop, National University of Ireland, Ireland 12-15 June 2007. - 1848161107 ; , s. 263-268
-
Konferensbidrag (refereegranskat)abstract
- To date only conventional single-conjugate adaptive optics (SCAO) systems are used to correct ocular aberrations. A major shortcoming of SCAO is the severely restricted corrected field of view. This can be solved with multi-conjugate adaptive optics (MCAO), a solution that is costly and gives bulky instruments. Another problem, especially in the study of the human eye, is unwanted light from parasitic source reflections and light from unwanted object regions. We present a dual-conjugate adaptive optics (DCAO) demonstrator that will enable wide field high resolution imaging of the human retina in vivo, implementing five retinal guide stars, two OKO micromachined membrane deformable mirrors; a 15 mm 37 channel pupil conjugate mirror, and a 40 mm 79 channel mirror conjugated to a plane in the vitreous body approximately 3 mm in front of the retina. The AO system runs with a closed-loop measurement wavelength of 835 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using only one adjustable iris, and a single camera to image the Hartmann patterns of multiple reference sources. Optical simulations in Zemax indicate an increase of the retinal isoplanatic patch from a radius of 0.5 degrees using SCAO to approximately 3.5 degrees or more using DCAO. The advantage of this is a clinically useful imaging area that is approximately 50 times the size of an SCAO system. This is corroborated by measurements on a model eye while performing SCAO, ground layer adaptive optics (GLAO), and DCAO correction.
|
|
| 43. |
- Thaung, Jörgen, 1965, et al.
(författare)
-
Evaluation of the effect of tinted night driving glasses on contrast sensitivity with and without glare
- 2001
-
Ingår i: Journal of Vision. ; 1:3, s. 456-456
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: To evaluate claims of contrast improvement by tinted night driving glasses (TNDG) during mesonic luminance conditions. Methods: Contrast sensitivity functions (CSF) were measured in two trained myopic subjects, aged 20 and 34 years, with no known eye disease and normal foveal fusion. Both were fully corrected and their accommodative abilities were 13D and 8D, respectively. CSF with and without glare, induced by a Fostec DCR® II Light with four fiberoptical branches, was measured with the Morphonome® 4.2.4 image psychophysics software at two spatial frequencies (3 and 23 cod). All measurements were done with the subjects wearing prescribed glasses, TNDG (Zeiss Clarlet 1.5 GOLD ET 015), and ophthalmic test lenses, with TNDG and test lenses beeing of equal dioptric value. Results: TNDG were found to perform better than prescribed glasses, especially subjectively. CSF was improved both with and without the presence of glare sources. However, no significant difference was found between TNDG and test lenses, neither with nor without glare. Conclusion: CSF was not significantly improved by tinted night driving glasses. Subjectively, the TNDG were prefered by both test subjects. Our findings indicate that at the higher spatial frequency the major improvements are due to the correction of night myopia.
|
|
| 44. |
|
|
| 45. |
- Venkataraman, Abinaya Priya, et al.
(författare)
-
Structural impact of arrested foveal development in children born extremely preterm without ROP at 6.5 years of age.
- 2023
-
Ingår i: Eye. - : Springer Science and Business Media LLC. - 0950-222X .- 1476-5454. ; 37:9, s. 1810-1815
-
Tidskriftsartikel (refereegranskat)abstract
- To characterize changes of foveal topography and microstructure of persisting foveal immaturity at 6.5 years of age in children born extremely preterm without retinopathy of prematurity (EPT-NoROP).Images from previous optical coherence tomography examinations of 37 EPT-NoROP and 92 control eyes were selected from a regional cohort of the EXPRESS (Extremely Preterm Infants in Sweden) study. Thickness of ganglion cell + inner plexiform layer (GCL+), outer nuclear layer (ONL), retinal thickness (RT) at the foveal centre (FC), foveal depth (FD) and RT at the foveal rim were evaluated.Layer thickness of GCL+, ONL and RT was increased at FC in the EPT-NoROP group. More than two-thirds had thickness values above the control limit (control mean+2SD) at FC (GCL+68%, ONL 76%, and RT 68%), and 50% had reduced FD compared to controls. All parameters showed a high correlation within the EPT-NoROP group, whereas no or weaker correlation was seen in control eyes. The EPT-NoROP sub-groups, divided based on the control limit, did not differ in terms of associated factors such as gestational age, birth weight, visual acuity, and refraction.Extreme prematurity without impact of ROP is associated with increased GCL+, ONL, and RT thickness at FC as well as reduced FD compared to full-term controls at age 6.5. This indicates that prematurity per se may have a profound effect on foveal anatomical maturation during the first months after birth. Our results suggest RT at FC to be a simple and useful measure of foveal anatomical immaturity.
|
|
