China is a highly populated country. At the present time， over 13 million people have been identified with low vision. The real number of people with low vision is not clear but might be much higher. If we take the average prevalence of low vision in other countries for a reasonable estimate， the number of people with low vision in China would approach 20 million. To provide rehabilitation services to people with low vision， China has established a low vision rehabilitation service system in its National Development Plan since 1991 under the administration of China Disabled Persons′ Federation （CDPF）， a unique system in China that has played a very important role in the development of rehabilitation services in the country. However， present facilities for low vision rehabilitation in China are still far from adequate. The well established resource centres for low vision rehabilitation devices in the CDPF system are not the responsibility of the institutes providing full service to the public for vision rehabilitation but delivering certain types of vision aid devices to qualified registered disabled persons who already have a prescription for the device. So the system functions only with the availability of other types of vision rehabilitation providers. Unfortunately， the latter are very rare at the present time. Apparently， this has become the major obstacle for the establishment of a functional vision rehabilitation system in the country. Considering the possible resources that might be used， it is suggested that the possible， practical， reliable and probably the easiest solution is to open low vision clinics within the eye care units of medical institutions. Policies that support this practice are urgently needed. Other factors， such as the lack of professional training and public awareness， and the lack of quality devices， etc.， are all much less likely to be the major obstacles that hinder the development of a functional low vision rehabilitation service system in China.

Objective To investigate the prevalence and related factors of visual impairment in patients with diabetes mellitus. Methods Based on health records， type 2 diabetes patients from Beijing Desheng Community Health Center were enrolled into a cross-sectional investigative study. Visual acuity and the anterior segment of the eyes were checked. Two-field 45-degree color fundus images were taken through an undilated pupil. The retinal changes were graded using the Scottish Diabetic Retinopathy Grading System （2003）. Data collection was secured with Epidata. Data were analyzed using a t test， rank sum test， chi-square test and logistic regression analysis. Results A total of 720 patients were enrolled and 519（72.1%） participated in the survey. Thirty-four patients presented with a visual acuity of less than 0.3 in both eyes. Among them， at least one eye in 20 patients improved to no less than 0.3 with correction. The best visual acuity of the other 14 patients remained less than 0.3. The main reason for their visual impairment was diabetic retinopathy （42.9%）. Among all the participants， there were 73（14.1%） with ungraded images and 141（27.2%） with some diabetic retinopathy. In all， 150 patients （28.9%） needed to be referred to ophthalmologists due to vision threatened by diabetic retinopathy or ungraded images. The risk factors of visual impairment in diabetes patients through logistic regression analysis include diabetic duration， body mass index and diabetic retinopathy. Conclusion The main reason for visual impairment among diabetes patients was diabetic retinopathy. Screening for visual problems in the community might be one of the important strategies for the prevention of blindness among diabetes patients.

Objective To evaluate the reliability and validity of the Mars numeral contrast sensitivity test and to explore whether it can be used in the examination of contrast sensitivity in low vision patients. Methods This was a prospective comparative study. Eighty-three subjects （83 eyes） were divided into two groups： a normal vision group, 40 young adults without significant eye diseases whose habitual vision was better than 0.8, and a low-vision group, 43 low-vision patients whose better eye’s visual acuity ranged from 0.05 to 0.3. Subjects were tested with their corrected visual acuity. ①The first examiner randomly selected three Mars numeral contrast sensitivity charts and recorded the contrast sensitivity scores after testing. ②Subjects were tested randomly by the first examiner with one of three forms of the Mars numeral contrast sensitivity charts and the Mars letter contrast sensitivity charts. The contrast sensitivity scores were recorded for each test. ③The second examiner used the same procedure used by the first examiner to test subjects and record contrast sensitivity scores. Repeatability and reproducibility were assessed based on intersession within-subject standard deviations （Sw）， precision （1.96Sw）， coefficient of variation （CVw）， and intraclass correlation coefficient （ICC）. The agreement between the Mars numeral contrast sensitivity test and the Mars letter contrast sensitivity test was evaluated by Pearson correlation analysis， ICC and Bland-Altman analysis. Results Repeatability and reproducibility： the Mars numeral contrast sensitivity test showed excellent repeatability and reproducibility， with a lower 1.96Sw， CVw， and high ICC values （higher than 0.75）. Agreement between the Mars numeral contrast sensitivity test and the Mars letter contrast sensitivity test： there was excellent agreement between the two tests based on a high correlation （r=0.995， P<0.01）， high ICC （0.997）， and narrow 95% LoA confidence intervals （-0.053，0.092）logCS. Conclusion The Mars Numeral Contrast Sensitivity Test can be used for low-vision testing based on its high reliability and validity.

Objective To study the effectiveness of 2 different low vision aids for reading rehabilitation： the aspheric optical aid and the portable electronic aid； to provide guidelines for visual rehabilitation. Methods This was a prospective case-control study. Thirty students were selected from the Peiying Vocational School to participate in the study. Subjects read material under 3 conditions： no low visual aid （NL）， the new aspheric optical low vision aid （NA） and the portable electronic low vision aid （PE）. The reading order was randomly established before the test. A voice recorder was used to record and measure reading distance when subjects read the material. After each trial， students were asked which low vision aid was better. Reading duration， reading distance， reading speed， line changing time and error rate were calculated. Finally， SPSS 13.0 software was used to analyze the data from the trials in a one-way ANOVA. Results There were significant differences in reading duration（4.35±2.82 min vs. 7.27±4.50 min vs. 10.71±3.09 min， F=4.60， P<0.01）， reading distance （7.44±4.40 cm vs. 13.38±7.07 cm vs. 20.97±6.84 cm， F=11.21， P<0.01）， reading speed （35.64±24.01 words/min vs. 49.41±24.96 words/min vs. 65.59±20.03 words/min， F=13.77， P<0.01）， line changing time （1.52±1.13 s vs. 2.24±1.25 s vs. 3.42±0.94 s， F=7.40， P<0.01） and error rate （10.34±11.01% vs. 5.84±3.61% vs. 5.26±2.72%， F=1.79， P=0.03） under the 3 conditions. PE was significantly superior to NA in reading duration （P<0.0167）， reading distance （P<0.0167）， and reading speed （P<0.0167）. NA was significantly superior to NL in reading duration （P<0.0167）， reading distance （P<0.0167）， and reading speed （P<0.0167）. PE was not significantly superior to NA （P>0.0167） and NA was not significantly superior to NL in error rate （P>0.0167）. However， PE was significantly superior to NL （P<0.0167）. PE took significantly longer than NL （P<0.0167） and NA （P<0.0167） for line changing time. NA took significantly longer than NL for line changing time （P<0.0167）. Conclusion Low vision aids are very helpful for low vision students in reading， and the portable electronic low vision aid was superior to the new aspheric low vision aid in reading rehabilitation.

Objective To compare the effectiveness of the newly designed continuous-focus electronic low vision aids with optical low vision aids in low vision rehabilitation. Methods In a prospective case-control study， 19 low vision patients and 14 blind patients used the optical low vision aids and the newly designed continuous-focus electronic low vision aids， respectively， while testing near visual acuity and reading newspapers. Near visual acuity， reading speed and reading duration were recorded and compared using a paired t test. Results The difference in near visual acuity was significant （t=-2.392， P＜0.05） for all patients when optical low vision aids were compared to near continuous-focus electronic aids. For blind patients and low vision patients， the difference in near visual acuity was also significant （t=-7.433， -8.721， P＜0.01）. The difference in reading speed was significant （t=-4.290， -6.728， P＜0.01） for all patients and blind patients when using optical low vision aids and near continuous-focus electronic low vision aids. The difference was not statistically significant for low vision patients alone （t=-1.534， P＞0.05）. For all patients， whether blind or low vision patients， the difference in reading duration was statistically significant （t=-8.211， -6.137， -6.007， P＜0.01） when using the optical low vision aids and near continuous-focus electronic low vision aids. Conclusion The newly designed continuous-focus electronic low vision aid is more effective in improving patients′ near visual acuity and reading ability.

Objective To investigate the binocular accommodative function of patients with intermittent exotropia. Methods Seventy-six patients aged 18 to 40 years with intermittent exotropia and 40 normal controls were recruited for a prospective case control study. Accommodative responses in dominant and nondominant eyes were tested using MEM （monocular estimate method） dynamic retinoscopy. The testing measured positive relative accommodation/negative relative accommodation （PRA/NRA） and deviation to a 40 cm target with binocular viewing. The data were analyzed by a nonparametric test， t-test and correlation analysis. Results During binocular viewing at the 40 cm target， the accommodative response was asymetric between the two eyes in patients with intermittent exotropia. Forty-eight of the dominant eyes （63%） showed an accommodative lead. Sixty-two of the nondominant eyes （81%） showed an accommodative lag. The mean accommodative response in the dominant and nondominant eyes in patients and normal control dominant eyes were -0.32±0.57 D， +0.36±0.44 D and +0.34±0.28 D， respectively. The accommodative response was asymetric in patients between dominant and nondominant eyes （Z=-7.01， P<0.01）. There was significant difference between the dominant eyes in patients and normal controls （Z=-6.36， P<0.01）. The accommodative responses in the dominant eyes were significantly correlated with the angle of exotropia （r=-0.67， P<0.01）. The mean PRA was -4.03±0.82 D in patients and -3.09±0.74 D in normal controls （t=6.05， P<0.01）. The mean NRA was +1.96±0.56 D in patients and +2.23±0.34 D in normal controls （t=-2.82， P<0.01）. Conclusion During binocular viewing at the near target， the accommodative response in patients with intermittent exotropia was asymetric between dominant and nondominant eyes with a hyperactive response in the dominant eye.

Objective To evaluate the efficacy of using immunosuppressive agents and surgery for refractory Mooren′s ulcer combined with necroscleritis. Methods In a retrospective study， 7 patients who were diagnosed with refractory Mooren′s ulcer combined with necroscleritis between January 2004 and July 2011 at Shandong Eye Hospital were included. The treatment for the patients was determined by the following principles： first， oral cyclosporin A and prednisone were administered for half a year based on the condition， glucocoreicoid eye drops and cyclosporin A eye drops were used four times daily and reduced according to the condition； second， when the corneal ulcer area was smaller than half the area of the cornea， lamellar keratoplasty was performed； and when the area of the scleral necrosis was less than 1/4 quadrant， scleral neoplasty was performed； the remaining patients underwent conjunctival flap surgery. Patients were followed up twice a month for 3 months， once a month for 1 year and every two months thereafter. Results Three eyes were treated with conjunctival flap， and these 3 eyes recovered ocular surface stabilization. No recurrence was observed in these 3 patients during the follow-up period. The other 4 eyes were treated by lamellar keratoplasty combined with scleral neoplasty. In these patients， recurrence was discovered in 1 patient who had stopped using the systemic drugs. Scleral neoplasty was performed again on this patient， and postoperative medications were continued. No recurrence was observed. No significant complications related to drug use were observed in any patient during the study period. Conclusion The treatment of immunosuppresive agents and surgery are effective in patients with refractory Mooren′s ulcer combined with necroscleritis. Using systemic and partial immunosuppresive agents can effectively decrease the incidence of recurrence.

Objective To observe the effect of Puerarin on human fetal scleral fibroblasts′（HFSFs） proliferation and expression of collagen type I （COL1A1） following exposure to extremely low frequency electromagnetic field （ELF-EMFs）. Methods Experiment study. HFSFs were cultured and divided into control groups and radiation groups， which were exposed to 0.2 mT ELF-EMFs. The radiation groups were divided into groups of different puerarin concentrations （0.0， 0.1， 1.0， 10.0 µmol/L）. The proliferation of HFSFs under different exposure time （0， 12， 24， 48 hours） and under different final puerarin concentrations were detected by MTT skills. The expressions of COL1A1 mRNA and protein of all these groups were detected by real-time PCR and Western-Blot. Single factor analysis of variance was first used to determine whether there was difference among these groups， LSD-t was then used to figure out which groups had significant difference. And the difference between two groups are analysed by independent sample t test. Results There was significant difference between different radiating time in radiations groups （F=4.560， P<0.05）， and the proliferation of HFSFs （A490） of radiation groups was inhibited after exposed to 0.2 mT ELF-EMFs for 24 hours （t=5.000， P<0.01） with shrinking protein expression of COL1A1 （t=7.956， P<0.01） and decreasing mRNA expression （t=17.364， P<0.01）. However， Puerarin （1.0 µmol/L） enhanced HFSFs′ proliferation activity （P<0.01） and 0.1 µmol/L increased the protein expression of COL1A1 （P<0.05） and its mRNA expression （P<0.05）. The effects were more obvious under higher-concentration of puerarin（1.0， 10.0 µmol/L）. Conclusion ELF-EMFs inhibited the proliferation of HFSFs and expression of COL1A1， but puerarin can reverse these changes， suggesting that puerarin play a postive role in sclera remodeling.

Objective To evaluate the effects of chronic alcoholism on visual function in rats and the protective effects of ebselen. Methods In this experimental study， the models were based on chronic alcohol feeding. Rats were divided randomly into 3 groups： control group， ethanol group and ethanol+ebselen group （drug group）. Visual function was assessed by FERG and FVEP. Data were analyzed using ANOVA. Results The latencies of the a-wave and b-wave of FERG were obviously prolonged in the ethanol group compared to the control group （F=4.161， 3.664， P<0.05）， while no differences were found between the drug group and control group （P>0.05）. The amplitude of the b-wave decreased in the ethanol and drug groups compared to the control group （F=3.312， P<0.05）. For FVEP， the latencies of the N1 and P1 waves were prolonged and the amplitude of the N1-P1 wave obviously decreased in the ethanol group compared to the control group （F=7.940， 5.0707， 3.874， P<0.05）， while no differences were found between the drug group and control group （P>0.05）. Conclusion The damage to the visual system from chronic alcoholism can be prevented by an antioxidant. Thus， it can be inferred that oxidative stress plays a significant role in the damage from chronic alcoholism in the central nervous system.

Objective To evaluate monochromatic aberrations （MA） with intraocular lenses （IOLs） using a model eye and Hartmann-Shack aberrometry for measurement． Methods This was a prospective study. Part I： There were 5 different IOL refractive powers （Alcon， SA60AT， +10 D， +15 D， +20 D， +25 D and +30 D）． Part II： There were three different +20 D IOLs （SA60AT； Akreos Adapt， Bausch & Lomb； AR40e， AMO）． IOLs were tested in a fluid-filled model constructed to replicate the optical conditions of a pseudophakic human eye at different wavelengths of 436， 486， 525， 546， 589， 660 and 710 nm． Those images were caught by CCD and analyzed in MATLAB． A single-factor analysis of variance and Pearson correlation analysis were used for statistical evaluation. Results Part I： Positive correlations were found between IOL refractive power and aberrations for spherical aberrations （SA， Z12， r=0.599， P<0.05）， vertical coma （VC， Z7， r=0.817， P<0.05） and horizontal coma （HC， Z8， r=0.488， P<0.05）． There was no correlation between IOL refractive power and root mean square of total higher-order aberration （RMSh， r=0.007， P>0.05）． No correlation was found between wavelength and aberrations for SA （r=-0.213， P>0.05）， VC （r=-0.074， P>0.05）， HC （r=0.021， P>0.05） and RMSh （r=-0.322， P>0.05）． Part II： There was a significant difference among the 3 IOLs in aberrations， SA （F=74.637， P<0.05）， HC （F=6.719， P<0.05） and RMSh （F=11.768， P<0.05）． There was no difference in VC （F=1.295， P>0.05）． AR40e had the least SA， HC and RMSh of the three IOLs． There was no correlation between wavelength and aberrations for SA （r=0.007， P>0.05）， VC （r=-0.312， P>0.05）， HC （r=-0.238， P>0.05） and RMSh （r=0.246， P>0.05）． Conclusion The MA of IOLs can be evaluated in this model eye. This is useful for an improvement in the optical quality of IOLs and also could be a better choice for patients．

Objective To verify the accuracy of the results of special visual measurement instruments for heterphoric testing. Methods In this cross-sectional study， fifty healthy students served as subjects. The degree of heterphoria was measured by a special visual measurement instrument， the Maddox rod and a synoptophore. A one-way ANOVA and paired t test were used to calculate the data. Results ①The Maddox rod and synoptophore measured the highest amounts of esophoria， accounting for 38% and 34%； hyperphoria was the least， accounting for 2% and 4%. Measurements with the special visual measurement instrument found the highest amounts of esophoria plus hyperphoria， accounting for 36%； orthophoria was found the least， accounting for 4%. ②Esophoria values measured in order from the most to the least were the Maddox rod， measurement instrument and synoptophore （F=3.18， P<0.05）. There was a significant difference between the Maddox rod and synoptophore （P<0.05）， but there were no significant differences between the Maddox rod and measurement instrument and the measurement instrument and the synoptophore （P>0.05）. Exophoria values measured from high to low were the Maddox， synoptophore and inspection instrument. There were no significant differences among the three methods （F=0.83， P>0.05）. Hyperphoria values measured from high to low were the measurement instrument， Maddox rod and synoptophore （F=6.34， P<0.05）. There were significant differences between the measurement instrument and synoptophore and the Maddox rod and synoptophore （P<0.05）， but there was no significant difference between the measurement instrument and Maddox rod （P>0.05）. ③The dominant eye′s value was higher than the nondominant eye′s in esophoria， exophoria and hyperphoria， but only the Maddox rod measured a significant difference in esophoria （t=2.74， P<0.01）. Conclusion There were differences in the degree of heterphoria measured by the three instruments， but there was no significant difference between the measurement instrument and Maddox rod.

Objective To evaluate the changes in visual acuity and reaction times at different contrast levels in myopic patients before and after sub-Bowman′s keratomileusis （SBK）. Methods This was a prospective self-control study. A total of 20 patients （40 eyes） who had undergone SBK were enrolled in this study. LogMAR contrast visual acuity and reaction times were measured by the multi-functional visual acuity tester （MFVA-100） at 4 contrast levels （100%， 25%， 10%， 5%） with a dark background in a dark environment before surgery and 1 month and 3 months after surgery. Data were analyzed using ANOVA and SNK. Results At the same room illumination， logMAR values gradually increased as contrast levels decreased. The postoperative logMAR values at 100% and 25% contrasts were significantly lower than preoperative values （q=4.722， 5.167， P<0.05； q=3.000， 3.217， P<0.05）， but the differences were not significant at 10% and 5% contrast levels （F=1.647， 1.382， P>0.05）. Reaction time increased with decreases in contrast levels. The postoperative reaction times became shorter at contrast levels of 100%， but were longer at 25%， 10% and 5% contrast levels. The differences were not significant （F=0.484， 0.049， 1.073， 0.637， P>0.05）. Conclusion After SBK， the logMAR values at 100% and 25% contrast levels were reduced， but there were no significant differences at 10% and 5% contrast levels. The surgery has no effect on reaction times at the 4 contrast levels. Myopic patients can acquire good contrast visual acuity in a dark environment after SBK. Contrast visual acuity and reaction time may be used as one of the bases to evaluate the effects of the surgery.

Objective To evaluate the treatment for filamentary keratitis guided by laser scanning confocal microscopy （LSCM） and high-definition optical coherence tomography （HD-OCT）. Methods This was a prospective case series study. The study included 76 eyes from 70 patients who presented with filamentary keratitis at the Shandong Eye Institute and Hospital between January 2009 and January 2011. LSCM was performed on the diseased cornea and inflammatory cells were counted. HD-OCT was performed the depth of filaments. On the basis of etiological status， individual treatments were carried out according to the filament structure to ensure that the appropriate combination and dose of anti-inflammatories， proliferation inhibitors， mucolytic agents or combinations for removing the filaments were used. Results The approximate structure of the filaments was observed in vivo with LSCM and HD-OCT. The depth and width of the filaments′ core was shown simultaneously. The density of inflammatory cells could be detected clearly and the structure of the filament varied in different patients. Twelve eyes had inflammatory cell counts <5/ visual field， 26 eyes had ≥5/ to >10/ visual field＞inflammatory cell counts， 38 eyes had inflammatory cell counts ≥10/ visual field. At 1 month after individual treatment based on etiological status， a 100% cure rate was achieved. The cornea recovered without scarring as shown by HD-OCT. No recurrence was observed at the 12-month follow-up. Conclusion LSCM combined with HD-OCT is an effective and rapid method to guide the treatment of filamentary keratitis. It provides valuable and objective information that is required in selecting individual therapeutic regimens to treat filamentary keratitis.

Presbyopia is a leading cause of reduced visual function and life quality of people more than 40 years old. The mechanism of presbyopia is still not clear. There are some limitations in the traditional glasses treatment， and safe and effective surgical treatments have not yet been developed. Unfortunately， there are no useful standard animal models and measurement methods for presbyopia research until now. This article reviews current advances in experimental research on presbyopia.

Fenofibrate， which is a peroxisome proliferator-activated receptor α （PPARα） agonist， has beneficial effects on lipid profiles that include lowering triglycerides and increasing high-density lipoprotein cholesterol， and reducing coronary vascular events in large clinical trials. Results from recent clinical trials suggest a role for fenofibrate in reducing the progression and/or inducing regression in mild-to-moderate nonproliferative diabetic retinopathy （DR）. The role of fenofibrate in the pathogenesis of diabetic retinopathy is associated with its anti-inflammatory properties. The effect and mechanisms of fenofibrate in the pathogenesis of diabetic retinopathy are reviewed in this article.