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        west china medical publishers
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        find Keyword "Vision" 41 results
        • An improved Vision Transformer model for the recognition of blood cells

          Leukemia is a common, multiple and dangerous blood disease, whose early diagnosis and treatment are very important. At present, the diagnosis of leukemia heavily relies on morphological examination of blood cell images by pathologists, which is tedious and time-consuming. Meanwhile, the diagnostic results are highly subjective, which may lead to misdiagnosis and missed diagnosis. To address the gap above, we proposed an improved Vision Transformer model for blood cell recognition. First, a faster R-CNN network was used to locate and extract individual blood cell slices from original images. Then, we split the single-cell image into multiple image patches and put them into the encoder layer for feature extraction. Based on the self-attention mechanism of the Transformer, we proposed a sparse attention module which could focus on the discriminative parts of blood cell images and improve the fine-grained feature representation ability of the model. Finally, a contrastive loss function was adopted to further increase the inter-class difference and intra-class consistency of the extracted features. Experimental results showed that the proposed module outperformed the other approaches and significantly improved the accuracy to 91.96% on the Munich single-cell morphological dataset of leukocytes, which is expected to provide a reference for physicians’ clinical diagnosis.

          Release date:2023-02-24 06:14 Export PDF Favorites Scan
        • The interpretation of recommendation statement of US Preventive Services Task Force for vision screening in children aged 6 months to 5 years old

          Release date:2018-01-20 10:08 Export PDF Favorites Scan
        • Expression of alternatively spliced mRNA isoforms of the NMDA-R1 in the visual cortex of strabismic amblyopic cats

          Purpose To identify the expression of alternatively spliced mRNA isoforms of the NMDA-R1 in the visual cortex of strabismic cats. Methods Two pai rs of normal and strabismic cats were used.The amblyopic cats had been made monocularly esotropic (by tenotomy) at the age of weeks,resulting in behavioral am blyopia.Animals were sacrificed about 6 months by intraperitoneal administration of Nembutal.Cryostat sections of fresh,frozen central visual cortex of the ats were cut to 20 micron thickness.A series of digoxygenin-labelled oligonucle otide probes basing on the human gene sequence were used for ISH.Control probes included sense oligonucleotides and short segment probes which were adjacent to ,but did not,span the splice junctions.A computer-assisted systematic morphometric ounting procedure was used to enumerate hybridising cells. Results The number of positive cells expressing NMDA-R1 mRNA in t he strabismic amblyopic cats was decreased,notably in layer IV of visual cortex (P<0.0001).The pattern of isoform expression varied between normal and strabismic amblyopic cats with decreased numbers of 1-a,1- b and 1-1 isoforms and apparently increased expression of 1-3 P <0.0001),whereas no significant difference was found for the 1-2 and 1-4 isoforms (P>0.05). Conclusion Transcriptional inhibition of NMDA-R1 mRNA and of specifie isoforms may underlie the change in receptor expression.Alternatively,preferentialloss of neurones bearing particular NMDA-R1 isoforms and compensation with a proportional increase in cells expressing other isoforms may occurr during the critical period of visual plasticity. (Chin J Ocul Fundus Dis,2000,16:71-138)

          Release date:2016-09-02 06:05 Export PDF Favorites Scan
        • Visual function before and after photodynamic therapy of subfoveal choroidal neovascularization in age-related macular degeneration

          Objective To evaluate the visual function before and after photodynamic therapy(PDT) in patients with subfoveal choroidal neovascularization ( CNV) caused by age-related macular degeneration (AMD). Methods Twenty-five consecutive patients (34 eyes) treated with PDT (verteporfin) for subfoveal CNV in age-related macular degeneration diagnosed by fluorescein angiography (FFA), indocyanine green angiography (ICGA) and optical coherence tomography (OCT). Visual function including best corrected visual acuity, contrast sensitivity frequency, binocular function, confusion, stereo-vision, color vision, metamorphopsis and central scotoma were examed before photodynamic therapy and 1 week, 1 month, 3 month after photodynamic therapy. The follow-up time varied from 3 months to 2 years (mean 7.6 months). Results The changes of visual function at the 3rd month after photodynamic therapy revealed improving in 13 eyes (38.24%), without any change in 17 eyes (50.00%), and decreasing in 6 eyes (17.65%). Visual acuity with logMRA improved after photodynamic therapy, but without statistic difference. All spatial contrast sensitivity improved. Contrast sensitivity for spatial frequencies 5 cycles per degree (cpd) was better after photodynamic therapy with significant difference (P=0.045).Binocular function, fusion function, stereo function and color vision were slightly improved without statistic difference. Conclusion Damage of visual function in macular degeneration is many-sided. The treatment of PDT for exudative AMD can improve part visual function. (Chin J Ocul Fundus Dis,2004,20:289-291)

          Release date:2016-09-02 05:58 Export PDF Favorites Scan
        • Analysis of the causes of visual loss after silicone oil removal

          Objective To investigate the causes of visual loss and failure of treatment after intraocular silicone oil removal. Methods Retrospective clinical analysis of the causes of loss of visual acuity of 15 eyes after silicone oil removal in patients with complicated retinal detachment which were successfully treated with vitreous and retinal microsurgery. Results Among the 15 eyes,retina failed to reattach in 11 eyes,secondary glaucoma occurred in 2 eyes and corneal opacity appeared in another two eyes.All of them were resulted in total loss of vision. Conclusion Retinal redetachment was the leading cause of final visual loss in the failing 15 cases(15 eyes) after intraocular silicone oil removal,and secondary glaucoma and corneal decompensation may also be the causes of visual loss. (Chin J Ocul Fundus Dis, 1999, 15: 230-231)

          Release date:2016-09-02 06:07 Export PDF Favorites Scan
        • The effect of form deprivation on the morphology of retinal ganglion cells in mice

          ObjectiveTo investigate the effects of form deprivation on the morphology of different types of RGC in mice.MethodsSixty B6.Cg-Tg (Thy1-YFP) HJrs/J transgenic mice were randomly assigned to form-deprived group (n=28) and control group (n=32). The right eyes of mice in the form-deprived group were covered by an occluder for 2 weeks as experimental eyes. The right eyes of mice in the control group were taken as control eyes. Before and 2 weeks after form deprivation, the refraction and ocular biometrics were measured; RGC were stained with Bra3a antibody and counted; the morphology of RGC was reconstructed with Neuroexplore software after immunohistochemical staining. The data was compared among experimental eyes, fellow eyes and control eyes by one-way analysis of variance.ResultsTwo weeks after form deprivation, the axial myopia was observed in the experimental eyes (refraction: F=15.009, P<0.001; vitreous chamber depth: F=3.360, P=0047; ocluar axial length: F=5.011, P=0013). The number of RGC in central retina of the experimental eyes was decreased compared with the fellow eyes and the control eyes (F=4.769, P=0.035). The reconstructed RGC were classified into 4 types according to their dendritic morphology. Form deprivation affected all 4 types of RGC but in a different way. Among them, 3 types of RGC were likely contribute to form vision perception. Form deprivation increased the dendrite branches in these types of ganglion cells. However, form deprivation decreasd dendrite segment numbers in both eyes and the intersection and length insholl analyse type 4 ganglion cells which were morphologically identified as ipRGC.ConclusionForm deprivation distinguishingly affects the morphology of different types of RGC, indicating that form vision and non-form vision play different role in myopia development.

          Release date:2019-11-19 09:24 Export PDF Favorites Scan
        • Correlation of foveal avascular zone size with visual acuity and metamorphopsia in idiopathic macular epiretinal membrane eyes using optical coherence tomography angiography

          Objective To analyze the correlation of foveal avascular zone (FAZ) size with visual acuity and metamorphopsia in idiopathic macular epiretinal membrane (IMEM) eyes. Methods This is a cross-sectional study, including 43 patients (43 eyes) with IMEM (IMEM group) and 35 health subjects (35 eyes) as control group. The best corrected visual acuity (BCVA) was measured using the international standard visual acuity chart, and the results were converted to the logarithm of the minimum angle of resolution (logMAR) visual acuity. The severity of metamorphopsia was measured using M-charts. The FAZ areas were estimated with optical coherence tomography angiography (OCTA) in both the superficial and deep capillary plexus layers. The central macular thickness (CMT) was assessed with spectral-domain optical coherence tomography. There was no difference of logMAR BCVA and CMT between two groups (Z=?7.379, ?7.560; P<0.001). The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between FAZ areas and visual acuity as well as metamorphopsia. Results The FAZ area in superficial and deep capillary plexus in IMEM group were smaller than those in control group (t=?30.316, ?27.606; P<0.001). In IMEM group, the mean M-score was 0.41±0.32; the horizontal and vertical M-score were 0.49±0.40 and 0.32±0.29, respectively. The horizontal M-score was higher than vertical M-score with the significant difference (Z=?2.000, P=0.046). In IMEM group, the FAZ area in superficial capillary plexus correlated inversely with metamorphopsia (r=?0.709, P<0.001); the FAZ area in deep capillary plexus correlated inversely with metamorphopsia and BCVA (r=?0.533, ?0.838; P<0.001). Conclusions The FAZ areas are significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ areas are correlated with metamorphopsia, and deep FAZ area is also correlated with BCVA.

          Release date:2018-01-17 03:16 Export PDF Favorites Scan
        • Epidemiological investigation of ocular fundus diseases in Tibetan above 40 in Maqin county, Qinghai Province

          Objective To investigate the morbidity of ocular fundus diseases in Tibetan above 40 in Maqin county, Qinghai Province. Methods A total of 2511 Tibetan above 40 in Maqin county, Qinghai Province were seelected by cluster sampling method. The sampling survey of ocular fundus diseases was performed on the individuals with indirect ophthalmoscope, and the results were compared with the domestic existing epidemiological data. Results Two hundred and thirty five (9.35%) cases were found to have abnormal ocular fundus, and the blindness rate due to the abnormal ocular fundus was 20.5% (80/391 eyes) which was lower than the blindness rate due to cataract (52.5%). Low vision and blindness led by ocular fundus diseases were found in 155 eyes (65.96%),including 74(47.74%) with age-related macular degeneration (AMD) and 23 (9.79%) with retinoangiopathy. Conclusions The morbidity of ocular fundus disorder is higher in high plateau than that in backland; AMD and retinoangiopathy are the main diseases leading to blindness. (Chin J Ocul Fundus Dis, 2006, 22: 321-323)

          Release date:2016-09-02 05:51 Export PDF Favorites Scan
        • Multifocal electroretinogram of the fellow eye in patients with unilateral retinal vein occlusion

          Objective To measure the macular function of the fellow eye in patients with unilateral retinal vein occlusion (RVO). Methods A total of 24 cases of unilateral RVO were diagnosed by fundus fluorescein angiography (FFA), and multifocal ERG (mfERG) was recorded by RETI scan. The mfERG data of 24 fellow eyes of those RVO patients, and 18 normal control eyes were analyzed and compared. The parameters included the amplitude density, latency of the P1 and N1 wave in 6 concentric circles and 4 quadrants of the mfERG graphics. Results The amplitude densities of P1 and N1 wave in first and second concentric circles of RVO fellow eyes were significantly lower than normal eyes (t=4.520, 2.147; P<0.05). There was no significant difference (P>0.05) of P1/N1 latency in any concentric circles or quadrants between RVO fellow eyes and normal eyes. Conclusion The central fovea of the RVO fellow eyes was functionally impaired.

          Release date:2016-09-02 05:43 Export PDF Favorites Scan
        • Preliminary observation of the therapeutic effects of vitrectomy on chronic and refractory Behcet′s disease

          Objective To evaluate the therapeutic effects of vitrectomy on chronic and refractory Behcet′s diseases. Methods The clinical data of 8 patients (10 eyes) with Behcet′s diseases from 0.5 to 3 years after vitrectomy were retrospectively analyzed. Pre-and post-operative visual acuity, control of inflammation after the surgery, and the recurrence were observed and analyzed. Both of the eyes were involved in all of the patients, including complete Behcet′s diseases in 5 and incomplete in 3. Results Vitreous opacity and liquefaction were found in all of the involved eyes, dark retina and thin retinal vessels were seen in most of the eyes, and vascular obstruction or sheath-like changes in different degrees were detected in some eyes. Improvement of visual acuity was observed in all of the eyes which had undergone the treatment after the operation. There was significant difference between the visual acuity before the surgery and at the 1st and 2nd week and the 1st and 6th month after the surgery. During the follow-up period, recurrence of the inflammation was found in 3 eyes within 1 month and in 6 eyes within 6 months; no recurrence was found in 4 eyes after the operation. No acute recurrence of inflammation was found after operation in the involved eyes. Conclusion Vitrectomy for chronic and refractory Behcet′s diseases may improve the visual acuity of the involved eyes, and the surgery is safe and effective. (Chin J Ocul Fundus Dis, 2005, 21: 357-359)

          Release date:2016-09-02 05:52 Export PDF Favorites Scan
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