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- Abdalla Elsayed, Maram E.A., et al.
(författare)
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Sickle cell retinopathy. A focused review
- 2019
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 0721-832X .- 1435-702X. ; 257:7, s. 1353-1364
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Forskningsöversikt (refereegranskat)abstract
- Purpose: To provide a focused review of sickle cell retinopathy in the light of recent advances in the pathogenesis, multimodal retinal imaging, management of the condition, and migration trends, which may lead to increased prevalence of the condition in the Western world. Methods: Non-systematic focused literature review. Results: Sickle retinopathy results from aggregation of abnormal hemoglobin in the red blood cells in the retinal microcirculation, leading to reduced deformability of the red blood cells, stagnant blood flow in the retinal precapillary arterioles, thrombosis, and ischemia. This may be precipitated by hypoxia, acidosis, and hyperosmolarity. Sickle retinopathy may result in sight threatening complications, such as paracentral middle maculopathy or sequelae of proliferative retinopathy, such as vitreous hemorrhage and retinal detachment. New imaging modalities, such as wide-field imaging and optical coherence tomography angiography, have revealed the microstructural features of sickle retinopathy, enabling earlier diagnosis. The vascular growth factor ANGPTL-4 has recently been identified as a potential mediator of progression to proliferative retinopathy and may represent a possible therapeutic target. Laser therapy should be considered for proliferative retinopathy in order to prevent visual loss; however, the evidence is not very strong. With recent development of wide-field imaging, targeted laser to ischemic retina may prove to be beneficial. Exact control of intraoperative intraocular pressure, including valved trocar vitrectomy systems, may improve the outcomes of vitreoretinal surgery for complications, such as vitreous hemorrhage and retinal detachment. Stem cell transplantation and gene therapy are potentially curative treatments, which may prevent retinopathy. Conclusions: There is lack of evidence regarding the optimal management of sickle retinopathy. Further study is needed to determine if recent progress in the understanding of the pathophysiology and diagnosis of sickle retinopathy may translate into improved management and outcome.
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- Al Oreany, Abdulaziz Abdulrahman, et al.
(författare)
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Congenital stationary night blindness with hypoplastic discs, negative electroretinogram and thinning of the inner nuclear layer
- 2016
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 0721-832X .- 1435-702X. ; 254:10, s. 1951-1956
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe congenital stationary night blindness (CSNB) with negative electroretinogram, hypoplastic discs, nystagmus and thinning of the inner nuclear layer (INL). Methods: Retinal structure was analyzed qualitatively with spectral domain optical coherence tomography and wide field imaging. Retinal function was evaluated with full-field electroretinography (ffERG). Molecular genetic testing included next-generation sequencing (NGS) of the known genes involved in CSNB. Results: Patients presented with CSNB presented with nystagmus, high myopia, hypoplastic discs and negative ffERG with no measurable rod response. The retinas appeared normal and automated segmentation of retinal layers demonstrated a relative reduction of thickness of the INL. There was no significant change in the ffERG after prolonged 2 hour dark adaptation compared to standard 30 minute dark adaptation. Affected family members harboured the homozygous 1-bp deletion c.2394delC in exon 18 of the TRPM1 gene, whereas their unaffected parents were heterozygous carriers. Conclusions: This data expands the genotype and phenotype spectrum of CSNB. The lack of improvement of rod responses after prolonged dark adaptation, together with thinning of the INL, is compatible with postreceptoral transmission dysfunction in the bipolar cells. Such knowledge may prove useful in future development of treatment for outer retinal dystrophies, using opsin genes to restore light responses in survivor neurons in the inner retina.
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- Andréasson, Sten, et al.
(författare)
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Cone implicit time as a predictor of visual outcome in macular hole surgery.
- 2014
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 1435-702X .- 0721-832X. ; 252:12, s. 1903-1909
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether preoperative retinal function measured by full-field ERG and multifocal ERG is correlated to postoperative visual acuity after macular hole surgery.
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- Aring, Eva, 1959, et al.
(författare)
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Visual fixation development in children.
- 2007
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Ingår i: Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv für klinische und experimentelle Ophthalmologie. - : Springer Science and Business Media LLC. - 0721-832X .- 1435-702X. ; 245:11, s. 1659-65
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The ability to keep steady fixation on a target is one of several aspects of good visual function. However, there are few reports on visual fixation during childhood in healthy children. METHODS: An infrared eye-tracking device (Orbit) was used to analyse binocular fixation behaviour in 135 non-clinical participants aged 4-15 years. The children wore goggles and their heads were restrained using a chin and forehead rest, while binocularly fixating a stationary target for 20 s. RESULTS: The density of fixations around the centre of gravity increased with increasing age (p < 0.01), and the time of fixation without intruding movements increased with increasing age (p = 0.02), while intruding saccades decreased with increasing age (p < 0.01). The number of blinks and drifts did not differ between 4 and 15 years, and there were no significant differences with regard to gender or laterality in any of the investigated variables. No nystagmus was observed. CONCLUSION: This study establishes values for visual fixation behaviour in a non-clinical population aged 4-15 years, which can be used for identifying children with fixation abnormalities.
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- Barth, Henrik, et al.
(författare)
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A cross-linked hyaluronic acid hydrogel (Healaflow(®)) as a novel vitreous substitute
- 2016
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Ingår i: Graefe's Archives for Clinical and Experimental Ophthalmology. - : Springer. - 0721-832X .- 1435-702X. ; 254:4, s. 697-703
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Vitrectomy requires the substitution of the natural vitreous, as well as tamponading of retinal breaks. Clinically available alternatives such as gas and silicone oil have side effects such as inflammation, secondary glaucoma, cataract, and a need for head posturing. In this study, a hydrogel of cross-linked sodium hyaluronic acid (Healaflow(®)) is evaluated for use as a novel vitreous substitute.Methods: A combined 25-20-gauge pars plana vitrectomy with posterior vitreous detachment was performed in the right eye of twelve pigmented rabbits, with subsequent injection of approximately 1 ml Healaflow(®). Clinical evaluation, measurement of intraocular pressure (IOP), and full-field ERG were performed postoperatively. The rabbits were sacrificed at different time-points between 42 and 105 days. After enucleation, the eyes were examined macroscopically, photographed, and prepared for histological examination with routine microscopy and immunohistochemistry.Results: Healaflow(®) was successfully used with standard surgical procedures and remained translucent but did lose most of its viscosity during the postoperative period. One rabbit was lost due to unrelated causes. In two eyes iatrogenic partial retinal detachments were seen, and in two eyes significant cataract developed due to intra-operative complications. ERG-recordings revealed no toxic effect on rod or cone function. Routine microscopy and immunohistochemistry demonstrated normal morphology with some Müller cell activation (up-regulation of glial acidic fibrillary protein, GFAP) compared to unoperated eyes and no significant DNA-fragmentation (TUNEL-assay).Conclusions: Healaflow® did not affect retinal morphology or function negatively during long-term use as a vitreous substitute, making it highly interesting in this setting. An estimated retention time of a few weeks suggests potential for use as a short-term tamponade. Future work will include an increased ratio of cross-linking to prolong the structural integrity of the gel.
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- Barth, Henrik, et al.
(författare)
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A new model for in vitro testing of vitreous substitute candidates
- 2014
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Ingår i: Graefe's Archives for Clinical and Experimental Ophthalmology. - Hedidelberg, Germany : Springer. - 0721-832X .- 1435-702X. ; 252:10, s. 1581-1592
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe a new model for in vitro assessment of novel vitreous substitute candidates.Methods: The biological impact of three vitreous substitute candidates was explored in a retinal explant culture model; a polyalkylimide hydrogel (Bio-Alcamid (R)), a two component hydrogel of 20 wt.% poly (ethylene glycol) in phosphate buffered saline (PEG) and a cross-linked sodium hyaluronic acid hydrogel (Healaflow (R)). The gels where applied to explanted adult rat retinas and then kept in culture for 2, 5 and 10 days. Gel-exposed explants were compared with explants incubated under standard tissue culture conditions. Cryosections of the specimens were stained with hematoxylin and eosin, immunohistochemical markers (GFAP, Vimentin, Neurofilament 160, PKC, Rhodopsin) and TUNEL.Results: Explants kept under standard conditions as well as PEG-exposed explants displayed disruption of retinal layers with moderate pyknosis of all neurons. They also displayed moderate labeling of apoptotic cells. Bio-Alcamid (R)-exposed explants displayed severe thinning and disruption of retinal layers with massive cell death. Healaflow (R)-treated explants displayed normal retinal lamination with significantly better preservation of retinal neurons compared with control specimens, and almost no signs of apoptosis. Retinas exposed to Healaflow (R) and retinas kept under standard conditions showed variable labeling of GFAP with generally low expression and some areas of upregulation. PEG-exposed retinas showed increased GFAP labeling and Bio-Alcamid (R)-exposed retinas showed sparse labeling of GFAP.Conclusions: Research into novel vitreous substitutes has important implications for both medical and surgical vitreoretinal disease. The in vitro model presented here provides a method of biocompatibility testing prior to more costly and cumbersome in vivo experiments. The explant culture system imposes reactions within the retina including disruption of layers, cell death and gliosis, and the progression of these reactions can be used for comparison of vitreous substitute candidates. Bio-Alcamid (R) had strong adverse effects on the retina which is consistent with results of prior in vivo trials. PEG gel elicits reactions similar to the control retinas whereas Healaflow (R) shows protection from culture-induced trauma indicating favorable biocompatibility.
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