Hierarchically Porous W-Doped CoP Nanoflake Arrays as Highly Efficient and Stable Electrocatalyst for pH-Universal Hydrogen Evolution.

It is still challenging to develop high-efficiency and low-cost non-noble metal-based electrocatalysts for hydrogen evolution reaction (HER) in pH-universal electrolytes. Herein, hierarchically porous W-doped CoP nanoflake arrays on carbon cloth (W-CoP NAs/CC) are synthesized via facile liquid-phase reactions and a subsequent phosphorization process. The W-CoP NAs/CC hybrid can be directly employed as a binder-free electrocatalyst and delivers superior HER performance in pH-universal electrolytes. Especially, it delivers very low overpotentials of 89, 94, and 102 mV to reach a current density of 10 mA cm-2 in acidic, alkaline, and neutral electrolytes, respectively. Furthermore, it shows a nearly 100% Faradaic efficiency as well as superior long-term stability with no decreasing up to 36 h in pH-universal electrolytes. The outstanding electrocatalytic performance of W-CoP NAs/CC can be mainly attributed to the porous W-doped nanoflake arrays, which not only afford rich exposed active sites, but also accelerate the access of electrolytes and the diffusion of H2 bubbles, thus efficiently promoting the HER performance. This work provides a new horizon to rationally design and synthesize highly effective and stable non-noble metal phosphide-based pH-universal electrocatalysts for HER.

Self-assembled Co0.85Se/carbon nanowires as a highly effective and stable electrocatalyst for the hydrogen evolution reaction.

Self-assembled Co0.85Se/carbon nanowires, constructed by Co0.85Se nanoparticles homogenously embedded into carbon nanowires (Co0.85Se@CNWs), have been synthesized through a facile solvothermal reaction and selenylation process. Compared to the bare Co0.85Se NWs, the Co0.85Se@CNW hybrid demonstrates high efficiency and stability for HER. It has a small Tafel slope of 43.4 mV dec-1, a low onset potential of 138 mV vs. RHE, and a high cycling stability with more than 95% current retention after 1500 voltammetry cycles. The outstanding HER performance of Co0.85Se@CNWs is attributed to its unique particle-in-nanowire architecture, which not only prevents the Co0.85Se nanoparticles from aggregation, but also provides a highly conductive CNW matrix to promote the charge transfer in the electrocatalytic reaction, further enhancing the catalytic activity. This work provides a new strategy to rationally design transition metal-based selenide hybrids as highly effective and stable electrocatalysts for HER.

[Comparison of visual impairment caused by trachoma in China between 1978 and 2006].

OBJECTIVE: To understand the distribution of visual impairment caused by trachoma in China and provide evidences for evaluation of eliminating blinding trachoma in China in the mission of Vision 2020. METHODS: Sampling study. The results from the first year 1987 and second (year 2006) national sampling surveys of disabled persons were analyzed. Chi-square test was performed using SAS 9.30 to analyze the rates of visual impairment caused by trachoma in different groups. Unifactor and multifactor analyses were applied to analyze the relevance between visual impairment caused by trachoma and risk factors, including gender and age. RESULTS: The rate of visual impairment caused by trachoma was 102.01 persons/100 000 in 1987 and 17.62 persons/100 000 in 2006. The percentage of trachoma in all kinds of visual impairment was 14.25% in 1987 and 1.87% in 2006, and the difference was significant (F = 1 382.6, P < 0.01). Spatial aggregation was obvious in visual impairment caused by trachoma. H-aggregation areas included Hubei, Sichuan, Anhui, Shannxi, Guizhou, Hunan provinces and Chongqing Municipality. Survival time without trachoma between 1987 and 2006 was significantly different (F = 2 745.9, P < 0.01). The rate and risk of visual impairment caused by trachoma increased with age. Except the group of > 85 years, the rate of visual impairment caused by trachoma in all age groups in 1987 was significantly higher than that in 2006. The risk of visual impairment caused by trachoma in 1987 was 5.8 times that in 2006. If the other risk factors were not involved, the risk in 1987 was 8.75 times that in 2006. The risk in females was twice that in males. CONCLUSION: Both, the rate and risk of visual impairment caused by trachoma were significantly reduced in China. Impressive progresses were achieved in trachoma prevention and control.

Modeling Radiometric Uncertainty for Vision with Tone-Mapped Color Images.

To produce images that are suitable for display, tone-mapping is widely used in digital cameras to map linear color measurements into narrow gamuts with limited dynamic range. This introduces non-linear distortion that must be undone, through a radiometric calibration process, before computer vision systems can analyze such photographs radiometrically. This paper considers the inherent uncertainty of undoing the effects of tone-mapping. We observe that this uncertainty varies substantially across color space, making some pixels more reliable than others. We introduce a model for this uncertainty and a method for fitting it to a given camera or imaging pipeline. Once fit, the model provides for each pixel in a tone-mapped digital photograph a probability distribution over linear scene colors that could have induced it. We demonstrate how these distributions can be useful for visual inference by incorporating them into estimation algorithms for a representative set of vision tasks.

Complement factor H polymorphism in age-related maculopathy in the Chinese population: the Beijing Eye Study.

PURPOSE: The purpose of this study was to analyze the association between the Y402H polymorphism in the complement factor H and soft drusen of the macula as part of age-related maculopathy in the Chinese population. METHODS: In the population-based Beijing Eye Study, the participants underwent a detailed ophthalmic examination including fundus photography. All fundus photographs were graded using the Wisconsin Grading System. Of 515 subjects with soft drusen in the macula, 208 (40.4%) subjects had blood samples taken and were thus eligible for the present study. These subjects were compared with 140 randomly selected control subjects from the Beijing Eye Study matched for age, sex, and rural versus urban area with the study group. The analysis of the genotype was performed by allele-specific digestion of polymerase chain reaction products. RESULTS: Dividing the study group into subjects with bilateral soft drusen and unilateral soft drusen showed a significant association between the Y402H polymorphism in the complement factor H gene and the study group with bilateral soft drusen with an odds ratio of 2.29 (95% confidence interval, 1.06-4.95). CONCLUSION: Also in the Chinese population, soft drusen as part of age-related maculopathy are associated with the Y402H polymorphism in the complement factor H gene despite a markedly lower frequency of C allele in the Chinese population than in white populations.

A population-based study of visual impairment among pre-school children in Beijing: the Beijing study of visual impairment in children.

PURPOSE: To evaluate the prevalence and causes of visual impairment among Chinese children aged 3 to 6 years in Beijing. DESIGN: Population-based prevalence survey. METHODS: Presenting and pinhole visual acuity were tested using picture optotypes or, in children with pinhole vision < 6/18, a Snellen tumbling E chart. Comprehensive eye examinations and cycloplegic refraction were carried out for children with pinhole vision < 6/18 in the better-seeing eye. RESULTS: All examinations were completed on 17,699 children aged 3 to 6 years (95.3% of sample). Subjects with bilateral correctable low vision (presenting vision < 6/18 correctable to >or= 6/18) numbered 57 (0.322%; 95% confidence interval [CI], 0.237% to 0.403%), while 14 (0.079%; 95% CI, 0.038% to 0.120%) had bilateral uncorrectable low vision (best-corrected vision of < 6/18 and >or= 3/60), and 5 subjects (0.028%; 95% CI, 0.004% to 0.054%) were bilaterally blind (best-corrected acuity < 3/60). The etiology of 76 cases of visual impairment included: refractive error in 57 children (75%), hereditary factors (microphthalmos, congenital cataract, congenital motor nystagmus, albinism, and optic nerve disease) in 13 children (17.1 %), amblyopia in 3 children (3.95%), and cortical blindness in 1 child (1.3%). The cause of visual impairment could not be established in 2 (2.63%) children. The prevalence of visual impairment did not differ by gender, but correctable low vision was significantly (P < .0001) more common among urban as compared with rural children. CONCLUSION: The leading causes of visual impairment among Chinese preschool-aged children are refractive error and hereditary eye diseases. A higher prevalence of refractive error is already present among urban as compared with rural children in this preschool population.

[Short hairpin RNA targeting vascular endothelial growth factor effectively inhibits expression of vascular endothelial growth factor in human retinal pigment epithelium].

OBJECTIVE: To design shRNA targeted to human vascular endothelial growth factor (VEGF) and to evaluate the effect of VEGF. shRNA on expression of VEGF in human retinal pigment epithelium (RPE) cells in vitro. METHODS: Human RPE cells were isolated with enzyme-assisted microdissection. The cells were identified by immunohistochemical method with antibody to cytokeratin and S-100. Plasma DNA was identified via restriction enzyme EcoRI and SamI. shRNAs (P1, P2) specific for human VEGF were designed. DNA expression vector is pSilencer 4.1-CMV of Ambion company. P3 is negative control nonspecific shRNA. There are 5 groups. Group 1: VEGF in cultured human RPE exposed to 100 micromol/L CoCl2 30 h; Group 2: VEGF in cultured human RPE in normal culture medium; Group 3, 4, 5: VEGF in cultured human RPE exposed to 100 micromol/L CoCl2 30 h after P1, P2, P3 transfection, respectively. VEGF level in conditioned media was measured by Western blot. RESULTS: The cells in culture could be stained with both cytokeratin and S-100 antibodies. The length of two fragment was 3.3 kb and 1.6 kb, respectively, which indicated that the extraction and purification were successful. The expression of VEGF in RPE was increased significantly (P < 0. 001) in group 1 as compared with group 2. Hypoxia-induced upregulation of human VEGF is halted by siRNA application in vitro (P < 0. 001 and P < 0. 001 in group 3 and 4 compared with group 1, respectively). shRNAs targeted hVEGF effectively and specifically inhibited hypoxia-induced VEGF levels in human RPE. The level of VEGF was reduced 65.9% and 52.4% in groups 3 and 4, respectively. There was no difference between group 5 and 1 (P = 0. 147). There was no difference of beta-actin production in RPE cells among groups. CONCLUSIONS: Delivery of shRNA can be used in vitro to target specific RNAs of VEGF and to reduce the level of the specific protein product (VEGF) in the targeted cells (human RPE). This work established the basis for the using of RNA interference in studies of retinal biology and for the treatment of a variety of retinal angiogenic diseases, especially the choroidal neovascularization.

Prevalence and risk factors of lens opacities in urban and rural Chinese in Beijing.

OBJECTIVE: To determine the prevalence of lens opacities in the elderly Chinese population in an urban and a rural region of Beijing. DESIGN: Population-based cross-sectional study. PARTICIPANTS: The study included 4439 subjects of 5324 subjects invited to participate (response rate, 83.4%). The subjects were divided into a rural part (1973 subjects [44.4%]) and an urban part (2466 subjects [55.6%]). The study was limited to participants age 40 and older, and the mean age was 56.2+/-10.6 years (range, 40-101 years). METHODS: Nuclear, cortical, and posterior subcapsular lens opacities were assessed based on standardized slit-lamp photographs of the lens using a modification of the grading score of the Age-related Eye Disease Study (AREDS). MAIN OUTCOME MEASURES: Grading score of the AREDS. RESULTS: Lens data were provided for 4378 subjects (98.6%) of 4439 persons examined, which consisted of 8724 eyes. Prevalence of any cataract surgery was 1.3% (95% confidence interval [CI]: 1.0-1.7), which was statistically independent of gender (P = 0.51; odds ratio [OR]: 0.86; 95% CI: 1.00-1.34), rural area versus urban region (P = 0.25), and level of education (P = 0.84). Prevalence of any nuclear lens opacity was 82.0% (95% CI: 80.8-83.2); prevalence of any cortical lens opacity was 10.3% (95% CI: 9.4-11.3); and prevalence of any posterior subcapsular opacity was 4.3% (95% CI: 3.7-4.9). If grade 2 of nuclear lens opacity was considered to be normal, prevalence of nuclear cataract was 50.3% (95% CI: 48.8-51.8), and the overall prevalence of any cataract was 53.1% (95% CI: 51.6-54.6), increasing from 6.5% (95% CI: 5.2-7.8) in those subjects 40 to 49 years of age to 52.3% (95% CI: 47.4-55.3) in those who were 50 to 59 years of age, and to 97.8% (95% CI: 96.4-99.2) in those 70 years and older (P<0.001). Frequencies of any cortical cataract and any subcapsular posterior cataract were 10.3% (95% CI: 9.4-11.3) and 4.3% (95% CI: 3.7-4.9), respectively. CONCLUSIONS: Cataracts are common among adult Chinese residents in Beijing, with age as the most important associated factor. In view of the relatively low rate of cataract surgery performed so far, one may expect a marked increase in the number of cataract surgeries to meet the visual needs of the growing elderly population in China.

Prevalence of visual impairment among adults in China: the Beijing Eye Study.

PURPOSE: To estimate the prevalence and distribution of blindness and low vision in Northern China. DESIGN: Population-based cohort study. METHODS: The Beijing Eye Study included 4438 subjects with an age of 40+ years. Mean age was 56.2 +/- 10.6 years (range, 40 to 101 years). RESULTS: Forty-three (1.0%) individuals had low vision (<20/60 and >/=20/400 best-corrected vision), and 17 (0.4%) individuals were blind (best-corrected visual acuity in the better-seeing eye <20/400). Low vision/blindness were significantly associated with age (P < .001), myopic refractive error (P < .001), and level of educational background (P = .035). It was not associated with gender (P = .76) and rural vs urban area (P = .88). CONCLUSIONS: Blindness or low vision affects approximately one in 100 Chinese older than 40 years. An estimated 4.1 million Chinese older than 40 years have low vision, and an estimated 1.6 million Chinese older than 40 years are blind.

Frequency of under-corrected refractive errors in elderly Chinese in Beijing.

PURPOSE: The aim of the study was to evaluate the prevalence of under-corrected refractive error among elderly Chinese in the Beijing area. METHODS: The population-based, cross-sectional, cohort study comprised 4,439 subjects out of 5,324 subjects asked to participate (response rate 83.4%) with an age of 40+ years. It was divided into a rural part [1,973 (44.4%) subjects] and an urban part [2,466 (55.6%) subjects]. Habitual and best-corrected visual acuity was measured. Under-corrected refractive error was defined as an improvement in visual acuity of the better eye of at least two lines with best possible refractive correction. RESULTS: The rate of under-corrected refractive error was 19.4% (95% confidence interval, 18.2, 20.6). In a multiple regression analysis, prevalence and size of under-corrected refractive error in the better eye was significantly associated with lower level of education (P<0.001), female gender (P<0.001), and age (P=0.001). CONCLUSIONS: Under-correction of refractive error is relatively common among elderly Chinese in the Beijing area when compared with data from other populations.

Refractive error in urban and rural adult Chinese in Beijing.

PURPOSE: To evaluate refractive error and its demographic associations in an urban and rural population in northern China. DESIGN: Epidemiological study. PARTICIPANTS: The Beijing Eye Study is a population-based cohort study in northern China including 4439 subjects. Excluding pseudophakic and aphakic patients, the present study involved 4319 subjects. It was divided into a rural part (1905 [44.1%] subjects) and an urban part (2414 [55.9%] subjects). Mean age was 55.85+/-10.33 years (range, 40-90). METHODS: Standardized ophthalmologic examination. For statistical analysis, the spherical equivalent was converted to binary variables, and logistic regression was used to investigate the association with continuous or categorical independent variables. MAIN OUTCOME MEASURE: Refractive error. RESULTS: Mean refractive error measured -0.33+/-2.22 diopters (D) (range, -20.88 to +7.88). Myopia of >-0.50 D, -1.0 D, >-6.0 D, and >-8 D, respectively, occurred in 22.9% (95% confidence interval [CI], 21.7-24.2), 16.9% (95% CI, 15.8-18.0), 2.6% (95% CI, 2.2-3.1), and 1.5% (95% CI, 1.1-1.9) of the subjects, respectively. Myopic refractive error was associated significantly with younger age (P<0.001), urban region (vs. rural region) (P<0.001), higher educational background (P<0.001), higher degree of nuclear cataract (P<0.001), decreasing uncorrected visual acuity (UCVA) (P<0.001), decreasing best-corrected visual acuity (BCVA) (P<0.001), and female gender (P<0.001). Prevalence of high myopia (myopic refractive error >-8 D) was associated with age (P<0.001), female gender (P = 0.020), urban region (P = 0.023), and lower BCVA (P<0.001). Mean anisometropia was 1.09+/-2.03 D (median, 0.38; range, 0-22.0). Prevalence of anisometropia of > or =1 D was associated significantly with age (P<0.001), refractive error (P<0.001), BCVA (P<0.001), and region (P<0.001). Mean astigmatic error measured 0.62+/-0.90 D (median, 0.25; range, 0-7.50). Astigmatism of > or =1 D was associated significantly with age (P<0.001), lower UCVA (P = 0.003), lower BCVA (P<0.001), urban area (P<0.001), and degree of cortical cataract (P = 0.027). CONCLUSIONS: As in other population-based studies on Chinese, myopia was more prevalent in younger subjects. Myopia was associated with urban region, educational background, female gender, decreasing visual acuity, and nuclear cataract. If longitudinal studies confirm the association of refractive error with age, refractive surgery may achieve emmetropia only for a limited time.

[The prevalence and its effective factors of primary angle-closure glaucoma in defined populations of rural and urban in Beijing].

OBJECTIVE: To investigate the prevalence of primary angle-closure glaucoma (PACG) of urban and rural residents in Beijing, China. A quantitative comparison was made based on the data collected from this epidemiological survey. We also identify some of the most typical risk factors associated with PACG. METHODS: Glaucomatous screening examination was applied to specific age group populations (aged 40 and older) in the defined district of Beijing and its remote rural county, from June to October, 2001. There are 4451 subjects in all, 1980 rural subjects and 2471 urban subjects, 1939 males and 2512 females. The screen and diagnostic methods used in this survey included van Herick methods and gonioscopy examination to estimate the peripheral depth of the anterior chamber, visual acuity, intraocular pressure, refraction status, stereoscopic fundus photography, and threshold-related visual field tests. Subjects regarded as suspected glaucoma and glaucoma patients are reexamined with standard glaucomatous examination. RESULTS: The response rate of rural and urban population is 79.6% (1980/2488), 87.1% (2471/2836), respectively. The prevalence of PACG (in aged 40 years or older population) resulted from this survey was 1.2% (95% CI 0.9% - 1.5%). However, the prevalence was different between urban and rural residents, 1.1% (95% CI 0.8% - 1.4%) vs. 1.6% (95% CI 1.2% - 2.0%). The prevalence of PACG in female was more than that in male, 1.7% (95% CI 1.3% - 2.1%) vs.0.8% (95% CI 0.5% - 1.1%). A drastic increase in prevalence of PACG with age increase was identified in both survey sites, however, this increase in rural subjects (aged 60-69 years group) occurred ten years earlier than those from urban subjects (aged more than 70 years group). Compared to urban residents, rural residents showed higher prevalence of unilateral low vision (39.3% vs. 20.6%) and blindness (28.6% vs. 14.7%). This survey also confirmed that, as people aging, refraction status became hyperopia, the depth of peripheral anterior chamber became narrow. In the different age groups, female and male groups, the changes of refraction status and the depth of peripheral anterior chamber paralleled the prevalence of PACG. CONCLUSIONS: The prevalence of PACG was obviously different in different groups. This could due to several factors including gender, age, change of refraction status and chamber angle as well.

[Adeno-associated virus mediated delivery and expression of GDNF cDNA in cultured bovine iris pigment epithelial cells].

OBJECTIVES: To obtain transgenic bovine iris pigment epithelial cells (IPECs) by adeno-associated virus (AAV) mediated delivery of cDNA of glial cell-line derived neurotrophic factor (GDNF). METHODS: AAV-GDNF was titrated by slot blotting. Cultured bovine passage two IPECs were transfected using AAV-GDNF at dosage of MOI (multiplicity of infection) = 50, then were cultured in DMEM medium complemented with 3% FBS for 4 weeks with no change of medium. The expression of GDNF in culture medium was examined using ELISA test. By using the same methods, cultured passage two IPECs were transfected with AAV-GFP (green fluorescent protein) at dosage of MOI = 50, and then were cultured in DMEM medium complemented with 20% FBS. The expression of GFP in IPECs was examined using fluorescence microscope every 2 days after transfection. RESULTS: (1) GFP expression in IPECs could not be detected until 4 days after transfection. The positive GFP expression in IPECs reached fastigium in day 8 or 10. (2) According to the results of ELISA test, concentration of GDNF in the culture medium was (17.14 +/- 1.10) micro g/L. CONCLUSIONS: AAV-GDNF can effectively transfect cultured IPECs, and the transgenic cells show a high expression of GDNF.

[The prevalence and its screening methods of primary open angle glaucoma in defined population-based study of rural and urban in Beijing].

OBJECTIVE: The purpose of the study is to determine the prevalence of primary open-angle glaucoma (POAG) in persons aged 40 or above in Beijing, China. METHODS: From June 2001 to October 2001, the screening population was identified by a door-to-door census in five metropolitan resident areas in the north of Beijing and three villages in a county south to Beijing. The screening included visual acuity, frequency doubling perimetry (FDP, C-20 screening program), non-contact tonometry, slit lamp microscopy, anterior chamber depth (Van Herick method), and fundus photography. The suspect glaucoma and definite glaucoma patients were asked to have an examination of Octopus 1-2-3 perimetry (G1X TOP threshold program), repeat tonometry, gonioscopy and fundus stereo-photography at Beijing Tongren Hospital. RESULTS: There were 4451 subjects who were examined at the study sites. The response rates in rural and urban were 79.58% and 87.13%, respectively. In this 40 years-old or above population, the prevalences of POAG were 1.97% in rural men, 2.07% in urban men, 1.04% in rural women and 1.42% in urban women. In this study, 92.30% POAG patients in rural and 87.30% POAG patients in urban were new diagnosed cases. The prevalence of POAG increased with age and the change was exponential. In 50% POAG patients first IOP measurement was less than 21 mm Hg (1 mm Hg = 0.133 kPa). The prevalence of monocular eye blindness was 15.40% and 10.90% in rural and urban, respectively. CONCLUSIONS: Owing to use fundus photography and integrated evaluation of optic disc, it is possible to diagnose in earlier stage of POAG. This study identifies more patients with POAG than any previous population-based studies of China, and is similar to other studies of Asia such as in India and Singapore. The reason of lower POAG prevalence in rural women than in urban may be that the anterior chamber depth of rural women is shallower than that of urban women. It may cause difficult to differentiate the chronic primary angle closure glaucoma from POAG at screening sites, so the part POAG patients may be included in primary angle closure glaucoma patients.

[Prevalence of low vision and blindness in defined populations in rural and urban areas in Beijing].

OBJECTIVE: To investigate the prevalence and causes of low vision and blindness in Beijing residents aged 40 and over. METHODS: 4,451 residents aged 40 and over in 3 rural communities and 5 urban communities in Beijing underwent eye examination, including examination of distant and near visual acuity (VA), best corrected distant and near VA, pinhole VA, and visual field, slit lamp biomicroscopy, and dilated ocular examination in the form of in-home survey by defined population-based sampling. The medical history was surveyed too. The data were analyzed based on the criteria of the World Health Organization. RESULTS: The general prevalence rates of low vision and blindness were 0.99% (95% CI: 0.70-1.28) and 0.39% (95% CI: 0.21-0.57) respectively. The prevalence rate of low vision in females was 1.45%, 2.23 times that of males (0.65%) (OR: 1.97, 95% CI: 1.00-3.95). The prevalence rate of low vision of rural residents was 1.76%, 2.89 times that of urban residents (0.61%) (OR: 2.93, 95% CI: 1.43-6.11). The prevalence rate of blindness in females was 0.64% and 0.37% in males. The prevalence rate of blindness of rural residents was 1.06%, 2.04 times that of the urban residents (0.52%) (OR: 3.77, 95% CI: 1.41-10.62). The 3 major causes of blindness were cataract (37.50%), glaucoma (29.20%), and high myopic macular degeneration (8.30%). The prevalence of blindness increased with age. CONCLUSION: The prevalence rates of low vision and blindness are higher in the rural areas. Cataract, glaucoma, and high myopic macular degeneration are the major causes of blindness. The prevalence of low vision and blindness are influenced by age, sex; area, health care level, educational level, and environmental factors.

[The application of digital photography with retroillumination for lens in cataract study].

OBJECTIVE: To evaluate the reliability of digital photography with retroillumination for lens as a tool to assess the degree of lens opacity, and to study the morphological features of some lens diseases using the digital images. METHODS: The cataract screener (Neitz CT-S) was connected to a computer capable of acquiring digital images of lens. The digital lens retroillumination and slit lamp images were collected in 64 eyes. Three independent separate examiners took three sets of different CT-S digital photographs in four cataract subjects. The area of lens opacification in the images was measured and analyzed using threshold adjustment in PhotoShop software and a customized program in Matlab software. RESULTS: The distinct digital images of lens cortical opacity, posterior subcapsular opacity and other lens diseases were obtained with CT-S computer digital photography, which images were much better than slit lamp sectional digital images. The sensitivity and specificity of measuring lens opacification with CT-S digital images were 90% and 94% respectively. However, the digital lens retroillumination images were not as sensitive as the slit lamp images for nuclear cataracts. The variation coefficients of lens opacity area in the three sets of CT-S digital images in the same subject, which were taken by the independent examiners, were from 2.23% to 10.86%. The cortical opacification in CT-S digital images was linear, cuniform or clustered aggregate shadow configuration. The posterior subcapsular opacification was discal vacuolar or granular appearance. CONCLUSIONS: The reproducibility of the CT-S digital images taken by the independent examiners is excellent. This technique can objectively show cortical or posterior subcapsular opacities, but nuclear cataracts.

[Evaluation of visual function following neodymium: YAG laser posterior capsulotomy].

OBJECTIVE: To probe into the clinical application of contrast sensitivity and glare sensitivity in evaluating visual function of posterior capsular opacification (PCO) and also investigate the visual function criterion in performing neodymium:yttrium aluminum garnet (Nd:YAG) laser posterior capsulotomy. METHODS: Measurements of visual acuity, contrast sensitivity and glare sensitivity were obtained from 73 pseudophakic eyes (67 cases) before and after Nd:YAG laser posterior capsulotomy and the results were analysed. The method of Nd:YAG laser surgery was posterior capsular circular resection. The diameter of capsular chip was 5 mm. The average energy of single pulse was (2.93 +/- 0.63) mJ and the mean total energy was (57.47 +/- 36.05) mJ. The average follow-up was (14 +/- 6) months. RESULTS: Visual acuity, contrast sensitivity curve and glare sensitivity curve improved in all cases postoperatively. Comparing the parameters of pre-laser and post-laser measurement, there was very significant difference (P < 0.01). The only postoperative complication was the laser spot in intraocular lens (IOL, 5 eyes, 6.8%). No retinal detachment, cystoid macular edema and dislocation of IOL were observed in this series. CONCLUSION: Contrast sensitivity and glare sensitivity can represent the visual function of PCO sensitively and completely. They can be regarded as evaluation criterion of surgical timing and effect of Nd:YAG laser posterior capsulotomy.

[Expression of mRNA for proteins involved in retinol metabolism in cultured bovine iris pigment epithelial cells in vitro].

OBJECTIVE: To assess the retinol metabolism of cultured bovine iris pigment epithelial (IPE) cells. METHODS: IPE cells were isolated from neonatal bovines with Hu's method, and were cultured. The total RNA of IPE cells was extracted by Trizol one step method. The specific primers for retinol-binding protein (RBP) and cellular retinaldehyde-binding protein (CRALBP) were designed according to their sequence from Genbank. The mRNA expression of these proteins in the IPE cells was analyzed by reverse transcription polymerase-chain reaction (RT-PCR). RESULTS: The extracted RNA from IPE cells of the second passage was ideal and had no degradation. RT-PCR analysis showed that RBP mRNA and CRALBP mRNA were expressed in cultured IPE cells in vitro. CONCLUSIONS: Similar to RPE cells, cultured IPE cells may have potential of transporting and metabolizing retinol.

Transplantation of corneal stem cells cultured on amniotic membrane for corneal burn: experimental and clinical study.

OBJECTIVE: To investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burns. METHODS: The proliferation and differentiation of corneal stem cells in vitro had been examined using colony-forming efficiency and immunohistochemistry. The stem cells had been cultured on amniotic membranes and transplanted to the limbal area for treating corneal burns. RESULTS: Corneal stem cells had a high proliferation capacity in primary and first passage, cytokeratin 3 was not expressed in primary culture but partly in first passage. The stem cells could proliferate to form cell layer on an amniotic membrane. When transplanted, stem cells could survive on limbus. After transplantation, ocular inflammation resolved, the cornea re-epithelialized, the stromal opacity reduced, the superficial neovascularity was lessened and the conjunctival fornix re-established. CONCLUSIONS: Ocular surface conditions could be improved by allograft of corneal stem cells cultured on amniotic membranes.