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find Keyword "Vision" 40 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.

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  • Clinical features and visual function of recurrent neuromyelitis optica

    Objective To observe the clinical features and visual function of recurrent neuromyelitis optica (NMO). Methods Thirty-four patients with NMO were enrolled in this retrospective case series study. The patients included two males and 32 females. The average first onset age was (35.03plusmn;14.56) years old and the average recurrent rate were (4.24plusmn;2.45) times. The recurrent rate of optic neuritis (ON) ranged from two to 12 times. The recurrent rate of ON was two times in 15 eyes of 10 patients, ge;three times in 37 eyes of 24 patients. Vision acuity, direct ophthalmoscope, fundus pre-set lens examination, visual field and visual evoked potential (VEP) were evaluated. Clinical features were observed. The abnormal rate of optic nerve including optic edema and atrophy; abnormal rate of visual field including decreasing retinal sensitivity, central and paracentral scotoma, ring scotoma, half field defects, tunnel visual field, visual field centrality constriction; abnormal rate of VEP including Prolonged latent phase and/or decreasing amplitude of P100 wave from patients of first episode or recurrence was analyzed. Serum NMO-IgG was detected from 28 patients by indirect immunofluorescence technique to observe its positive rate. Results All patients were characterized by repeated episodes of ON and myelitis. The main clinical feature of ON was visual loss, and the main clinical features of myelitis included sensory disability, dyskinesia and vesicorectal disorder. Blindness rate was 41.67% after the first attack of ON, 33.33% after two relapses, and 64.86% after ge; three relapses. The difference of blindness rate between first attack and two episodes was not significant (chi;2=0.270,P=0.603). However, the blindness rate in patients having ge; three episodes was significantly higher than those having two episodes (chi;2=4.300,P=0.038). With recurrence rate increasing, the abnormal rate of the optic nerve (chi;2=6.750,P=0.034)and VEP(chi;2=6.990,P=0.030)increased. But the abnormal rate of visual field did not increase along with recurrent rate (chi;2=0.660,P=0.718). Seropositive rate of NMO-IgG did not differ significantly between patients with first attack ON and that with recurrent ON (chi;2=1.510,P=0.470). But the seropositive patients had significantly higher bilateral blindness rate than seronegative patients (chi;2=5.063,P=0.027). Conclusions NMO are characterized by recurrent ON and myelitis. Visual loss, sensory disability, dyskinesia and vesicorectal disorder are the main clinical features. With recurrence rate increasing, the blindness rate, abnormalities the optic nerve and the abnormity rate of VEP increase. Seropositive recurrent NMO patients have higher bilateral blindness rate than seronegative patients.

    Release date:2016-09-02 05:22 Export PDF Favorites Scan
  • Effects of local foveal photoreceptor defect on visual acuity

    Objective To observe the effects of local macular foveal photoreceptor defects on visual acuity.Methods Thirty-one patients (31 eyes) with photoreceptor defect in macular fovea (case group) diagnosed by spectral domain optical coherence tomography (SD-OCT) and 30 patients (30 eyes) age- and diopter- matched normal subjects (control group) were enrolled in this study. There were 22 eyes with full photoreceptor defects and 9 eyes with outer segment defects in case group. All subjects were examined for best corrected visual acuity (BCVA), slit-lamp microscopy, direct ophthalmoscope and SD-OCT. Independent sample t-test was used to compare central foveal thickness (CFT) between case group and control group. Difference of logMAR BCVA, CFT, maximum width and height of photoreceptor defects, defected area and residual retinal thickness in macular between patients with full photoreceptor defects and outer segment defects were also compared.Results The CFT of case group and control group were (225.32plusmn;19.70),(240.02plusmn;10.70) mu;m, the difference was not statistically significant (t=-1.96, P>0.05). In full photoreceptor defects and outer segment defects patients, the mean logMAR BCVA were 0.22plusmn;0.31, 0.32plusmn;0.43; the mean CFT were (224.09plusmn;20.57), (228.33plusmn;18.17) mu;m; the maximum width of photoreceptor defects were (131.32plusmn;108.18), (143.22plusmn;66.93) mu;m; the mean defected area were (0.022plusmn;0.054), (0.019plusmn;0.019) mm2; the mean maximum height of photoreceptor defects were (77.41plusmn;6.62), (44.89plusmn;4.26) mu;m; the mean residual retinal thickness were (87.00plusmn;20.31), (128.33plusmn;23.54) mu;m respectively. There was no statistical significance between full photoreceptor defects and outer segment defects patients in the mean logMAR BCVA, CFT, maximum width of photoreceptor defects and defected area (t=-0.76, -0.538, -0.305, 0.166; P>0.05), but there were significant difference in mean maximum width of photoreceptor defects and residual retinal thickness (t=12.72, -4.91;P<0.05). Conclusions The local photoreceptor defects in macular fovea can lead to decrease of visual acuity. The wider the photoreceptor defects, the worse the visual acuity.

    Release date:2016-09-02 05:26 Export PDF Favorites Scan
  • Causes of blindness and low vision of the people over 50 years old in Binhu Area of Wuxi City

    Objective To investigate the causes of blindness and low vision of the people over 50 years old in Binhu Area of Wuxi City. Methods Cluster sampling was used in randomly selected individuals over 50 years old in 28 villages. The oculopathy related to blindness and low vision of the people over 50 years old were analyzed. The vision acuity lt;0.05 was defined as blindness, while 0.05-0.3 was defined as low vision. SPSS 17.0 software was used to analyze the data. Results Totally 6150 individuals were examined. The bilateral blindness and low vision was found in 47 and 84 individuals, unilateral blindness and low vision was found in 201 and 214 individuals. Among 201 unilateral blindness individuals, there were 55 individuals have low vision in the other eye. In the 295 blind eyes, there are 116 eyes (39.32%) with cataract, 31 eyes (10.51%) with high myopia macular degeneration, and 28 (9.49%) eyes with atrophy eyeballs. In the 437 low vision eyes, there are 223 eyes (51.03%) with cataract, 41 (9.38%) eyes with high myopia macular degeneration, and 41 (9.38%) eyes with age-related macular degeneration. Conclusion Cataract is the first cause leading to blindness and low vision, followed by age-related macular degeneration, high myopia macular degeneration and atrophy eyeballs.

    Release date:2016-09-02 05:26 Export PDF Favorites Scan
  • Etiologies and vision outcomes of 367 inpatients with no light perception

    Objective To observe the etiologies and vision outcomes of inpatients with no light perception (NLP). Methods A total of 367 inpatients (430 eyes) with NLP in Zhongshan Ophthalmic Center were enrolled in this study. The visual acuity examination followed the international standard methods. NLP was detected by torch light in a dark room and the pupil light reflection state was also considered. The patients included 208 males (235 eyes) and 159 females (195 eyes). Sixtythree patients (126 eyes) were bilateral and 304 patients (304 eyes) were unilateral cases including 159 right eyes and 145 left eyes. The patients' ages ranged from 2.5 to 86.0 years, with a mean age of (40.85plusmn;18.03) years. All the patients were treated according to their diseases. The ratio of different eye disease and visual outcome were recorded and analyzed. Results Among 430 eyes, there were 157 eyes (36.5%) with optic neuritis, 68 eyes (15.8%) with uveitis, 54 eyes (12.6%) with retinal vascular disease, 35 eyes (8.1%) with ischemic optic neuropathy, 29 eyes (6.7%) with traumatic optic neuropathy, 28 eyes (6.5%) with optic atrophy, 18 eyes (4.2%) with trauma, 17 eyes (4.0%) with radiation optic neuropathy, 10 eyes (23%) with glaucoma, five eyes (1.2%) with retinal detachment, four eyes (0.9%) with compressive optic neuropathy, two eyes (0.5%) with orbital apex syndrome, two eyes (0.5%) with hysteria, and one eye (0.2%) with orbital cellulitis. After active treatment, 269 eyes (62.6%) remained NLP, 161 eyes (37.4%) got improved visual acuity, including light perception- 0.02 in 74 eyes (17.2%), ge;0.02-<0.05 in 25 eyes (5.8%), ge;0.05 -<0.1 in 14 eyes (3.3%), ge;0.1 -<0.3 in 11 eyes (2.6%) and ge;0.3 in 37 eyes (8.6%). Conclusions The main causes of nonsurgical and non-trauma NLP are retinal disease and optic neuropathy. Some patients with NLP may restore useful vision if they received prompt referral and active intervention.

    Release date:2016-09-02 05:26 Export PDF Favorites Scan
  • Visual acuity of patients of proliferative diabetic retinopathy after vitreoretinal surgery

    Objective To observe the visual acuity of different stages of proliferative diabetic retinopathy (PDR) eyes after vitrectomy and analyze the risk factors of blindness.Methods A total of 384 eyes of 300 patients underwent vitrectomy for PDR were followed up. All cases were divided into three groups according to different stage of PDR (stage Ⅳ, stageⅤ and stage Ⅵ), the effect of vitrectomy were compared among these groups.Results The final visual acuity increased in 271 eyes (70.6%), among them there were 171 eyes (85.5%) in stage Ⅳ-Ⅴ, and 100 eyes (54.3%) in stage Ⅵ, and there was statistical difference between these two groups(chi;2=44.78,P<0.05). 82.8% of early-treated and 64.6% of middle/late-treated stage Ⅵ patients had postoperative visual acuity above 0.05 (chi;2=4.861,P<0.05). 39.5% (131 eyes) of 332 eyes with diabetic blindness was still blind after surgery. Conclusion Visual acuity can be improved in the majority of PDR eyes after vitrectomy, early prevention and early treatment are the keys to avoid diabetic blindness.

    Release date:2016-09-02 05:40 Export PDF Favorites Scan
  • Examination of full-field flash electroretinogram for retinal functi on of patients with retinopathy of prematurity

    Objective To observe the retinal function of infa nts with retinopat hy of prematurity (ROP). Methods A total of 78 infants (156 ey es) aged from 4-5 months underwent full-field flash electroretinogram (ERG) examination. The am p litude and implicit time of a-and b-wave of ERG were detected to evaluate the i nfants' retinal function. Seventy-eight infants (156 eyes) included 33 healthy a nd full-term infants (66 eyes), 25 healthy premature children (50 eyes), and 20 infants (40 eyes) with ROP. Results Obvious ERG waveforms were recorded in all the fullterm and healthy premature children. Amplitude of combined b-wave wa s 388.7 mu;V in full-term infants and 336.7 mu;V in healthy premature children, whi c h was 64.4% and 55.6% of that of the healthy adults respectively. In infants wit h ROP, ERG was nonrecordable in 20 eyes (50%); amplitude of combined b-wave was 183.8 mu;V in the other 20, whose implicit time delayed obviously compared with that of fullterm infants. The amplitude of ERG of healthy premature infants de c reased significantly compared with that of the full-term infants. Conclusions Retina keeps growing after birth. ERG of healthy full-term chi ldren is not as developed as those of adults. The progress of retinal maturation in infants with ROP is slower than that in the full-term infants. ERG examination is an effecti ve method in evaluating retinal function of infants with ROP.

    Release date:2016-09-02 05:46 Export PDF Favorites Scan
  • Characteristics of electroretinograms in preterm infants

    Objective To investigate the degree of retinal developmen t in pret erm infants and compare the electroretinograms between preterm and fullterm in fants. Methods Flash electroretinogram (ERG) were obtained wit h contact lens el ectrodes in one eye from ten preterm infants (10 eyes) and twenty full-term inf a nts (20 eyes) in seven days after birth. The rod cell, cone cell, maximal combi nation, oscillatory potentials, and 30 Hz flicker responses were recorded. Results Compared with the full-term infants, the implicit time of rod cell respon s e (t=3.216,P=0.003) was longer and the amplitudes were lower (t=6.0 50,P=0.000) in the preterm infants; the difference of implicit time of maximal response was not significant (t=0.465,P=0.650; t=1.068,P=0.295), while th e amplitudes dec reased (t=6.584, P=0.000; t=6.649, P=0.000). The a- and b-wav e implicit time of cone response was not differed much between the two groups (t=0.077, P=0.939; t=0.935,P=0.358); the amplitudes was obvious lower in preterm group (t =3 .417,P=0.002;t=6.310,P=0.000); the difference of implicit t ime of 30 Hz flic ker betw een the two groups was not significant (t=3.745,P=0.001). The difference of b/a value of maximal combination response was not obvious between the two groups ( t=0.215, P=0.831). Conclusions The development of retinal function is slower in preterm infants than that in full-term ones.

    Release date:2016-09-02 05:46 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
  • 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
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