Visual acuity chart is extremely important and a very useful tool in enrollment， recruitment， screening， ophthalmology clinic and scientific research. So far， the design of visual acuity chart has been more and more mature， and the core design has basically trended to be standard. However， people are still confused about the selection， design and application of visual acuity chart. This paper reviewed the development history， core design and practical problems of international and national visual acuity charts，in order to avoid the misunderstandings in selection and application of visual acuity chart effectively， and make it to be better used in the screening， ophthalmology clinic and scientific research.

To design a Chinese characters reading acuity chart with high and low contrast by selecting some Chinese sentences that have the equal legibility as the optotypes. Methods Experimental study. Choose the sentences with the same legibility as the optotypes by the following steps： ①Standardizing the sentences： the length of the sentence was got statistically by calculating collected the sentences on the daily reading materials； based on the junior middle school Chinese teaching materials and within 2500 most common Chinese characters， 95 sentences were constructed in Chinese with the same length of words， highly comparable syntactical structure and the same lexical and grammatical difficulty. ②Psychophysical experimental method： choose those university students， with the best corrected far and near visual acuity of 1.0 or better， normal amplitude， no uncomfortable complaints recently as volunteers. Sentences were statistically selected and standardized in these volunteers. The optotypes were selected following the rule of the minimum scope and the maximum intersection of the reading speed and the total strokes of the sentences. The principles of international universal visual chart design were applied in designing the Page layout. With high （100%） and low （10%） contrast. Results 52 sentences with the same legibility were selected after the firstly standardized sentences and secondly psychophysical experimental method； the Chinese characters reading acuity chart with high and low contrast was designed by following the principles of International universal visual chart design. Conclusion The high and low contrast Chinese characters reading acuity chart， with the equal legibility optotypes， were designed scientifically， which hoped to be used in measuring reading acuity and assessing reading behavior etc.

Objective To determine the cutoff point of visual acuity to screen refractive error or myopia in children. Methods This was a cross-sectional research. The database of the RESC （Refractive Error Study in Children） were used which were collected from October 2002 to January 2003. The examination included visual acuity measurement（ETDRs visual acuity chart）， auto refraction （ARK-30； Nidek Corp.） and ocular health examination. The definition of refractive error was SE≤-0.50 D， SE≥+2.00 D or cylinder power ≤-1.00 D. The sensitivity， specificity， and predictive values were calculated using each patient as a case； a receiver operator curve was plotted. Myopia was defined as： spherical equivalent （SE）≤-0.50 D or SE≤-0.75 D or SE≤-1.00 D. Results The data of 3 715 cases 7-15 years old subjects′ were analyzed. A satisfactory sensitivity/specificity profile was obtained which show 0.625 was the cutoff point for refractive error. The sensitivity， specificity， positive and negative predictive values were 71.7%， 93.3%， 92.9%， 72.9%， respectively. And 0.5 was the best cutoff point under three different myopia definitions. The sensitivity for SE≤-0.50 D， -0.75 D or -1.00 D were 66.3%， 73.5%， 80.7%， respectively. The specificity were 94.3%， 94.0% and 93.5%， respectively. The positive predictive values were 89.7%， 88.0% and 86.3%， and the negative predictive values were 78.9%， 85.4%， 90.5%. Conclusion 0.625 is advised to screen refractive error， while 0.5 is advised to screen potential myopia subjects who aged 7 to 15.

Objective To evaluate new logMAR visual acuity chart′s test-retest reliability and concordance with “C” logarithm visual acuity chart. Methods This was a cross-sectional study. Measurements using two versions of each chart design were obtained on the right eye of 48 high school students. The test-retest reliability was analyzed by intraclass correlation coefficient （ICC） and Cronbach′s Alpha coefficients， and Bland-Altman plots were used to compare the agreement between the two charts. Results The Cronbach′s Alpha coefficients of “C” logarithm visual acuity chart was more than 0.8， and the ICC was near 0.9. For the new logMAR visual acuity chart， the Cronbach′s Alpha coefficients was near 0.8， and the ICC was more than 0.75. The Bland-Altman plots displayed relatively good agreement between the two charts. The 95％ limits of agreement were 0.173 to -0.133 logMAR and 0.198 to -0.116 logMAR for the test and retest measurements respectively. Conclusion In healthy eyes， the new logMAR visual acuity chart has high test-retest reliability and good concordance with Landolt C logarithmical visual acuity chart.

Objective To conduct research on the relationship between LCD visual acuity chart display accuracy and LCD display pixel size. Methods Standard control and measurement methods were used to assess the LCD-related parameters of the new standard logarithmic visual acuity chart relative to the national standard （GB11533-2011）. A comparative study of optotype sizes versus permissible errors in the LCD chart was done. Results The LCD visual acuity chart was fully compliant for brightness， width， whiteness， and lighting requirements （GB11533-2011）. For liquid crystal display precision， a 0.27 mm pixel size can accurately test distance visual acuity ≤5.0； a 0.1245 mm pixel size can accurately test distance visual acuity ≤5.2； a 0.077 mm pixel size can accurately test distance visual acuity ≤5.3. Conclusion Select the appropriate distance and LCD display pixel size to more accurately test visual acuity.

Objective To evaluate the effects of perceptual learning on visual acuity and contrast sensitivity function in juveniles and adults with amblyopia. Methods In this prospective self-control study， 18 anisometropic amblyopes were recruited，the amblyopic eyes were trained in contrast detection near the pre-training cut-off spatial frequency. Patients were followed up for 3-6 months. Changes in the best corrected visual acuity and contrast sensitivity function and pattern visual evoked potentials and stereoacuity were measured. Data were analyzed using t test and correlation analysis. Results The amblyopic eyes had more profound changes in the visual acuity and contrast threshold （at all spatial frequencies） than the non-amblyopic fellow eyes （t=2.731， P<0.05； t=5.108， P<0.01； t=3.700， P<0.01）. No difference was found in the mean 60"， 30"， 15" P100 latency and amplitude in both eyes after the treatment. Eight patients showed improvement in steroacuity （average 420"）. The improved visual acuity was retained at 6 months in some patients. Conclusion Perceptual learning can improve the visual function of juvenile and adult amblyopia.

Objective To described methods and outcomes of a sutureless technique for partial excision of symptomatic overhanging bleb and reported the histopathological findings. Methods A retrospective case series of 10 eyes of 9 patients who underwent trabeculectomy. A sutureless partial excision procedure was offered to 10 eyes with overhanging blebs. Data on age， sex， presenting symptoms， glaucoma types， type of prior filtration surgery， pre- and post- best corrected visual acuity， pre- and post- excision intraocular pressure （IOP）， bleb morphology， corneal surface， complications of excision， ultrasonic biomicroscopy images and histopathological imaging were collected. The length of follow up ranged from 4 months to 5 years. Data were analyzed using paired t test. Results The length of follow up was （28.8±19.8） months. Before the surgical excision， Ultrasonic biomicroscopy imagings showed that the bleb tissues were tightly attached to the cornea and some parts of the blebs were fluid-filled. Successful excision of the overhanging bleb was achieved for all the cases. There was satisfactory control of IOP and the cornea remained clear. No case of recurrent overhanging bleb was found in the period of follow-up. This surgical technique did not lead to leakage， hypotony， and endophthalmitis during the period of follow up. Histopathological examination showed that the excised tissues mainly consisted of fibrous connective tissue and corneal epithelial tissue embedded with cyst-like structures. Conclusion Sutureless partial excision of the overhanging blebs seems to be a simple and safe means that helps in revising the blebs， relieving discomfort， and ensuing IOP control.

Objective To compare the outcomes of using fresh and glycerin-cryopreserved corneal tissue in treating purulent keratitis with deep anterior lamellar keratoplasty. Methods This was a retrospective case series study. Thirty-two patients （32 eyes） with purulent keratitis successfully underwent deep anterior lamellar keratoplasty （DALK） in Shandong Eye Hospital from January 2011 to August 2012. Based on the method for preserving corneal tissue， all patients were divided into a fresh corneal tissue （FCT） group （13 cases） and a glycerin-cryopreserved corneal tissue （GCCT） group （19 cases）. Data on donor， complications， graft status and visual outcome were collected. An independent samples t test analysis was used to analyze the data. Results The amount of time for the epithelium graft to heal in the FCT group and GCCT group were 3.8±2.2 d and 7.3±2.7 d （t=-3.764， P<0.05）. The amount of time for the graft edema to disappear in the FCT group and GCCT group were 5.7±2.6 d and 10.4±3.0 d （t=-4.348， P<0.01）. In the follow-up phase， 3 cases of graft epithelium defects occurred in the GCCT group and were healed with symptomatic treatment. After the surgery， the best corrected visual acuity （BCVA） of 23 patients （excluding cataract and congenital amblyopia） improved to 20/63-20/25， the mean BCVAs of the FCT and GCCT groups were 0.25±0.12 logMAR and 0.28±0.17 logMAR， respectively （t=-1.428， P>0.05）. Conclusion When glycerin-cryopreserved corneal tissue is used to treat purulent keratitis in DALK， the amount of time for the epithelium to heal and corneal edema to disappear took longer than with fresh corneal tissue. If potential or actual complications in GCCT group were treated in a timely and reasonable manner， similar outcomes would be obtained as for the FCT group.

Objective To explore the difference and agreement in the measurement of central anterior chamber depth（CACD） and peripheral anterior chamber depth（PACD） in the acute primary angle-closure glaucoma（APACG） between Sirius triaxial anterior system and ultrasound biomicroscopy（UBM）. Methods Prospective control study. Forty eyes of 40 APACG patients were selected，respectively， using Sirius triaxial anterior system and UBM measuring CACD and PACD. Paired samples t-test and Pearson linear correlation for statistical analysis， and application of Bland-Altman analysis to evaluate the two methods of measurement consistency. Results The CACD values measured by Sirius triaxial anterior system and UBM were （1.87±0.30）mm and （1.98±0.30）mm，PACD values were （0.61±0.21）mm and （0.56±0.21）mm， respectively， indicating a significant difference （t=-6.533， 2.432， P＜0.05）； and a significant linear correlation between them （r=0.944， 0.796， P＜0.05）. Sirius triaxial anterior system and UBM measurement of CACD value， and PACD value difference were -0.10±0.10 mm， 0.05±0.14 mm respectively， 95% limits of agreement were （-0.30， 0.09）mm和（-0.22， 0.32）mm. Conclusion Sirius anterior system and UBM show good agreement in the measurement of ACD in patients with APACG， the two instruments can be replaced.

Objective To analyze the relationship between near fusional range and ametropic correction on myopic children before and after ametropic correction and to predict horizontal binocular balance. Methods This was a cross-sectional study. The near positive and negative fusional vergence and horizontal binocular balance among 60 myopic children before and after ametropic correction were measured and binocular symptoms were predicted. In addition， myopic children were classified according to refractive error： Group A，-0.50 to -1.00 D， 20 cases； Group B，-1.25 to -2.00 D， 20 cases； Group C， -2.25 to -3.00 D， 20 cases. Another 30 emmetropic children were chosen as a control group. Data were analyzed using a one-way ANOVA and chi-square test. Results There were significant differences among the refractive groups for the uncorrected near positive fusional range （F=85.88， P<0.01）， but there was no significant difference in the negative fusional range in Group A（F=1.48， P>0.05）. The fusional range decreased in uncorrected myopia to +12.50 to -15.89 △. The binocular vision of the uncorrected group was significantly imbalanced compared to the emmetropic children （?字2=47.27， P<0.01）. Conclusion Without correction， the effects of low myopia on near fusional range are detectable， especially on near positive fusional vergence. In addition， the imbalance in binocular vision increase noticeably.

Objective To study the choroidal thickness of the macula subfovea using enhanced depth imaging spectral-domain optical coherence tomography （EDI-OCT） before dilation， after dilation， the following day after dilation. Methods Prospective clinical study. Fifty-eight patients （116 eyes） were dilated with tropicamide eye drops. All patients were examined with EDI-OCT before dilation， after dilation and the following day after dilation. Then， the eyes were scanned with a 8.8 mm scan line in the horizontal and vertical directions. Finally， the subfoveal choroidal thickness and the retinal thickness of the fovea were measured. Data were analyzed using independent t test and paired t test. Results Choroidal thickness after dilation was thinner than before dilation. The difference was statistically significant （right eye： t= 4.305， P＜0.01； left eye： t=5.007， P＜0.01）. Choroidal thickness after dilation was thinner than that measured the next day after dilation， and the difference was statistically significant （right eye： t=-3.237， P＜0.01； left eye： t=-3.011， P＜0.01）. However， the difference between choroidal thickness before dilation and the next day after dilation was not statistically significant （right eye： t=-0.300， P＞0.05； left eye： t=-0.333， P＞0.05）. There was no significant difference between binocular retinal values measured before dilation， after dilation， or the following day after dilation. Conclusion The choroid becomes thinner after using tropicamide eye drops when measured by EDI-OCT， which is noninvasive and intuitive to observe the subtle changes in living tissue after drug use.

Objective To study the clinical management methods and their effects on capsular contraction syndrome. Methods This was a retrospective study. Thirty-one patients （31 eyes） with capsular contraction syndrome were treated by Nd∶YAG laser or surgery. Twenty-two eyes were treated by Nd∶YAG laser only including 17 eyes that underwent 3 incisions and 5 eyes that underwent 2 incisions at first but had 4 incisions later because the initial results were not ideal. Nine eyes were treated by surgery. Visual acuity was tested and slit-lamp was used to observe the size of the transparent area of the capsularhexis hole， the condition of the anterior and posterior capsules， and the intraocular lenses （IOLs） position postoperatively. Complications were also noted postoperatively and whether or not there were subjective symptoms such as glare or monocular diplopia. Patients were followed up for 3-6 months. Results Uncorrected visual acuity and best corrected visual acuity improved postoperatively. Glare or monocular diplopia disappeared postoperatively. The capsular contraction was relieved in the surgically treated eyes. The sizes of the transparent zones of the capsularhexis holes were bigger. IOLs stayed centrally and stable. The main postoperative complications were high intraocular pressure and slight iritis. Conclusion  Both Nd∶YAG laser treatment and surgery for capsular contraction syndrome are effective， economical and safe.

Early treatment diabetic retinopathy study （ETDRS） charts was designed for vision research， which incorporated features of the original Bailey-Lovie charts. Compared with Snellen chart. The design of ETDRS chart is much more scientific and reasonable， accuracy and repeatability is better， but it takes more time； the logMAR testing results of ETDRS chart can be used directly in statistics. low vision can be quantified and evaluated reliably by the ETDRS chart， by changing the viewing distance to 4， 2， 1 meter， conversion of logMAR values in different testing distance is applicable. Due to discrepancy between theoretical and virtual testing values， it′s possible to exaggerate visual gain and loss， we should be cautious of converted values of different testing distance.

Periorbital infantile hemangiomas （IH） are the most common periorbital infantile vascular tumors. Accurate evaluation and emergency treatment are necessary due to its severe vision-threatening potential. The clinical features of periocular hemangiomas and therapeutic modalities are reviewed in this paper.