Binocular vision is the process of integrating visual information from the two eyes to form three-dimensional stereovision, which is the function of the advanced cognitive activities of the cerebral cortex. Strabismus produces visual diplopia and confusion because of the deviation of the ocular position. It leads to a series of binocular vision abnormalities including visual inhibition, abnormal retinal correspondence, and abnormal gaze, that seriously affect the formation and development of binocular vision function. Surgical treatment is the main option for correcting strabismus, but most patients cannot achieve normal binocular vision after surgery. The aim of treatment is not only to correct ocular position but also restore binocular vision. Restoration of binocular vision has a positive effect on reducing the recurrence rate of strabismus and improving the therapeutic effect of disease, even greatly improving quality of life for patients after surgery. Therefore, the restoration of binocular visual function should have a more important role in the treatment of strabismus and the early period after surgery is a prerequisite for establishing binocular vision function. At the same time, more attention should be paid to refractive correction and amblyopia treatment, methods should properly selected to promote the restoration of binocular vision.

Objective: To evaluate the repeatability of the Lea Symbols chart in vision examinations of preschool children. Methods: In this cross-sectional study, we included 250 children aged 42 through 78 months (61.9±10.3) from April to May 2017. All children completed comprehensive ophthalmological examinations and monocular assessment of visual acuity was performed in both eyes with the Lea Symbols chart. All visual acuity scores are presented in LogMAR units. Bland-Altman analysis, weighted Kappa test and correlation analysis were used to measure the reliability of repeated measurements between the two measurements. Results: The visual acuity (LogMAR) difference between test and retest thresholds  was between ±0.10 in 94.3% of eyes. Correlation between test and retest thresholds was 0.753 (P<0.001).  The mean difference in visual acuity (LogMAR) between test and retest was 0.014 in 139 preschool children  without refractive errors. A significant relationship was found between age and visual acuity in 139 preschool  children without refractive errors (rfirst=-0.335, P<0.001; rsecond=-0.424, P<0.001). Repeatability was not  associated with gender (P=0.197). Conclusions: The Lea Symbols chart provides a repeatable measure of  visual acuity in children 42 months and older. It is recommended for the clinical examination of children

Objective: To evaluate the results of a Toric intraocular lens (IOL) for correction of low preoperative astigmatism in cataract patients. Methods: In this prospective, case series study, 65 eyes (56 cataract patients) were enrolled from January to December 2016 from Eye Hospital, Wenzhou Medical University,all patients were divided into 2 groups: A Toric group (n=33) with implantation of a Toric IOL (Acrysof IQ Toric IOL, Alcon, SN6AT2 and SN6AT3); an IQ group (n=32) with implantation of a non-Toric IOL (Acrysof IQ IOL, Alcon, SN60WF). Uncorrected distance visual acuity (UDVA, LogMAR), best corrected distance visual acuity (CDVA, LogMAR), preoperative corneal astigmatism, residual refractive error, and the axis of the toric IOL were measured. UDVA and CDVA were measured preoperatively and 3 months after surgery. A vector analysis of postoperative residual astigmatism was performed and  compared between the groups. Data were statistically analyzed using an independent samples t test and  non-parametric rank sum test. Results: The preoperative CDVA was 0.39 in the Toric group and 0.30 in  the IQ group. At 3 months after surgery, the UDVA in the Toric group was 0.09, which was significantly  better than that in the IQ group (Z=-2.802, P=0.005). The median residual astigmatism in the Toric  group was 0.5 D, which was significantly smaller than that in the IQ group (1.00 D, Z=-3.636, P<0.001).  Vector analysis showed that the difference in the mean vector J0 between the Toric group and IQ group  was 0.11 D (t=1.456, P=0.151), and that of J45 was 0.11 D (t=1.998, P=0.050). Conclusions: Compared  with non-Toric IOLs, Toric IOLs (SN6AT2 and SN6AT3) are more efficient for the correction of low  corneal astigmatism (≤1.0 D)

To evaluate the long-term clinical effect of cataract phacoemulsification combined with astigmatism in patients implanted with AcrySof IQ ReSTOR Toric MIOLs. Methods: This was a prospective analysis. Fifty patients (82 eyes) underwent cataract phacoemulsification combined with astigmatism correction with IOL implants in Oilfield General Hospital of Daqing. The patients were followed up for 1 year to assess uncorrected distance visual acuity (UDVA, LogMAR), uncorrected intermediate visual acuity (UCIVA, LogMAR), uncorrected near visual acuity (UNVA, LogMAR), best corrected distance visual acuity (BCDVA, LogMAR), best corrected intermediate visual acuity (BCIVA,LogMAR), best corrected near visual acuity (BCNVA, LogMAR), defocus curve, contrast sensitivity (CS), total eye aberrations, estimated residual astigmatism and analysis of axis deviation of the artificial IOL, and spectacle independence preoperatively and 3 months, 6 months, and 1 year postoperatively. Data were analyzed by repeated measured analysis of variance. Results: Postoperative vision was better than preoperative vision and the difference was statistically significant (F=26.39, P<0.001; F=13.68, P<0.001; F=12.90, P<0.001). At 6 months after the operation, the uncorrected distance visual acuity was close to 0, and visual acuity with +1.2 - -4.0 D defocus could reach more than 0.3. Under glare conditions, contrast sensitivity was best during the day and was worst at night 1 year after the operation and the difference was statistically significant. Residual astigmatism at 1 year was significantly reduced compared to baseline (0.24±0.15 D vs 1.56±0.38 D, t=3.31, P=0.023), and was not a statistically significant difference from the preoperative anticipated residual astigmatism (t=2.31, P=0.102). At 1 year, the mean IOL axis rotation was 3.12°±1.51°. All the patients independent of spectacle. Conclusions: The AcrySof IQ ReSTOR Toric astigmatic MIOL provides satisfactory full vision, visual quality, predictability, and good rotational stability for cataract patients.

To investigate the role of dopamine D4 receptor (D4R) in the development of normal refraction and form-deprivation myopia (FDM) by applying D4R agonist PD-168077 and D4R antagonist L-745870 in mice. Methods: This was an animal experimental study. Four-week-old C57BL/6 mice were raised either in a visually normal environment or subjected to FDM by covering one eye with vision obstructing goggles while the other eye served as the normal control. Both groups were divided into sub-groups including vehicle and drug groups (D4R agonist PD-168077: 1 mg/kg/day and 10 mg/kg/day; D4R antagonist L-745870: 1 mg/kg/day and 10 mg/kg/day). They were intraperitoneally injected daily for two weeks. ERG was measured in normal enviroment mice on postnatal day 35. Refraction, corneal curvature radius, and ocular axial components were measured in all animals prior to and after each experiment. Statistical analyses were performed by a paired t test, one-way ANOVA, and repeated measurement ANOVA. Results: Normal refractive development was not affected by D4R agonist PD-168077 treatment. On the other hand, the D4R antagonist L-745870 enhanced normal refractive development towards hyperopia at a dose of 10 mg/kg (P=0.047) with no significant changes in other biometric parameters. PD-168077 increased the ERG OPs amplitude under scotopic conditions at an intensity of -0.699 log cdsm-2 (P=0.04), while L-745870 had no significant effect on the a-wave, b-wave, or summed OPs amplitudes under scotopic and photopic conditions. The development of FDM was promoted by PD-168077 treatment (P=0.004), with increases in both vitreous chamber depth and axial length. In contrast, D4R antagonist L-745870, inhibited FDM (P<0.001), with a shortened vitreous chamber depth and axial length. No significant changes in anterior chamber depth, lens thickness or corneal curvature radius were observed. Conclusions: D4R is activated or inactivated had no significant effects on normal refractive development in mice. In contrast, in a form-deprived environment, D4R is activated enhance while D4R inactivated inhibit FDM development, suggesting D4R activation enhances while D4R inactivation inhibits the development of myopia in mice.

To measure the choroidal thickness (ChT) of adolescents and correlate the ChT with elevation at high altitude areas. Methods: A cross-sectional study. Between May 13, 2015 and June 10, 2015, 674 students lived at the altitude of 1 535 meters (group A), 1 917 meters (group B) and 2 936 meters (group C) were examine. CirrusTM HD-OCT 4000 scanner was used to measure ChT at 7 locations: Fovea and 750, 1 500, and 2 250 μm nasal (N) and temporal (T) to the fovea. Monocular data were used for analysis. Continuous variables were analyzed using univariate analysis of variance, and categorical variables were compared using the chi-square test. Results: A total of 624 participants (624 eyes) were included, and group A, B, and C was 172, 242, and 210 cases, respectively. There was no difference in age, gender, spherical equivalent, keratometry, anterior chamber depth, and axial length among three groups. The mean ChTs at the location of T2250, T1500, T750, Fovea, N750, N1500, N2250 in the group C were 283±61, 291±59, 298±63, 302±62, 282±61, 246±62, and 215±58 μm, respectively, which were thicker than the group A and B ( all P<0.05), there was no difference between group A and group B. Between the participants aged 7-14 years with emmetropia or mild myopia, the ChT in the group C were thicker than the group A and B (all P<0.05). There was no difference between group A and group B. Among the participants with moderate myopia, there was no difference in three groups. Among the participants aged 15-19 years, the ChT in the group C were thicker than the group B (all P<0.05). Conclusions: The ChT was significantly different in adolescents lived in different high altitude areas. ChT increased with elevation increasing, which was marked between the participants aged 7-14 years with emmetropia or mild myopia, and was unremarkable for the participants aged 15-19 years with moderate myopia. Key words: choroidal thickness; high altitude; optical coherence tomography; adolescents; ametropia

Objective: To statistically analyze human resource allocation and service delivery for low vision in tertiary medical institutions in mainland China, and to provide a basis for the development of low vision medical rehabilitation work. Methods: All tertiary medical institutions providing ophthalmic services participated in an online survey in 2015. Descriptive statistics were used for data collection and statistical analysis was performed on staffing and service provisions for low vision in tertiary medical institutions. Results: Among 1 508 tertiary medical institutions surveyed, 559 institutions provided medical rehabilitation service(37.07%), while 949 did not provide this service (62.93%). There was a significant difference in providing low vision rehabilitation services of medical institutions at all levels (χ2=61.94, P<0.001). Among those institutions providing services, 338 institutions had low vision clinics (60.47%) with an annual average of 964 outpatient visits. There were 2 993 professionals working in low vision medical rehabilitation, with 1.98 ophthalmologists, 0.46 nursing staff, 0.41 technicians, and 0.22 support staff in each institution. Functional vision rehabilitation training for children, community education and publicity and typoscope prescriptions were the main services provided by tertiary institutions. Conclusions: A trained staff qualified to provide low vision services in tertiary medical institutions needs to be accumulated and strengthened. Human resources are quite sparse and the group talent hierarchy is imperfect. Low vision care is characterized by the low number of service clinics with programs consisting of a single treatment that can not meet the
comprehensive service needs of low vision patients in mainland China.

To discuss the correlation between the peripapillary retinal nerve fiber layer (RNFL) thickness and the visual field mean defect in different periods of pseudoexfoliation glaucoma (PXG). Methods: This was a clinical case control study. In the study, samples were selected consecutively from patients who were hospitalized in the Glaucoma Department of the First Hospital of Shijiazhuang from January 2013 to January 2018. The PXG group included 97 eyes of 97 patients who were divided into an early PXG group (28 eyes), a medium PXG group (27 eyes), and a late PXG group (42 eyes). The normal control group consisted of 32 eyes of 32 people who were matched for age, gender and refractive error. All subjects underwent spectral domain optical coherence tomography (SD-OCT) scans to measure peripapillary RNFL thickness in every quadrant. The SD-OCT and the visual field measurements among the different groups were compared using analysis of variance, and the correlation between the average RNFL thickness and visual field defects were analyzed with a Pearson correlation. Results: The average RNFL thickness in the normal control group, and the early, medium and late PXG groups was 104±11 μm, 92±14 μm, 82±12 μm, and 54±18 μm, respectively. The difference between the 4 groups in nasal, nasal superior, temporal superior, temporal, temporal inferior, nasal inferior quadrants and the average RNFL thickness were all statistically significant (F=24.38, 36.40, 47.84, 8.70, 95.46, 54.75, 82.28, all P<0.001). The differences between the normal control group and the early PXG group in the temporal superior, temporal inferior, and nasal inferior quadrants and the average RNFL thickness were statistically significant (all P<0.05). The differences between the normal control group and the medium PXG group in the nasal, nasal superior, temporal superior, temporal inferior, and nasal inferior quadrants and the average RNFL thickness were statistically significant (all P<0.05). The differences in RNFL thickness between the normal control group and the late PXG group in every quadrant were statistically significant (P<0.001). The average RNFL thickness was positively correlated with visual field mean differences in the medium PXG group and the late PXG group (r=0.404, P=0.037; r=0.582, P<0.001). Conclusions: The average peripapillary RNFL thickness is positively correlated with visual field mean differences in the medium and late PXG eyes. The changes of peripapillary RNFL thickness can be monitered by SD-OCT, which can be used as an important reference index for the status and follow-up of PXG.

To analyze the intraoperative frozen section diagnosis of eyelid tumors with modified Mohs surgery. Methods: This was a retrospective case study. Forty-four patients who had surgical treatment for eyelid tumors with an intraoperative frozen section technique from September 2014 to May 2018 in Qingdao Eye Hospital were included in the study. The eyelid tumors and the margin of the tumors were sectioned for frozen section diagnosis. Results: In 44 cases of eyelid tumors, 43 had a confirmed diagnosis, and 31(70%) had malignant tumors, including basal cell carcinoma in 22 cases (50%), meibomian gland carcinoma in 5 cases (11%), squamous cell carcinoma in 2 cases (5%) and in situ carcinoma in 2 cases (5%). Twelve cases were diagnosed with benign lesions, including 5 cases of varus follicular keratosis, 3 cases of seborrheic keratosis, 2 cases of chronic inflammation, and 1 case of eyelid abscess and 1 case of amyloidosis. Only one case could not be confirmed during surgery, and metastatic renal cell carcinoma was confirmed by paraffin section. In malignant tumors, the suspected tumor cells in the margin of the resection were found in 3 cases, and extended resections were performed until no tumor cells could be found. Postoperative follow-up showed there was no recurrence of eyelid tumors in any patients. Conclusions: Intraoperative frozen section with surgical treatment can rapidly evaluate the malignancy of eyelid tumors and the margin of resection, which can help clinical surgeons choose the scope of surgical resection for precision surgery.

To analyze a modified methylene blue staining technique applied during the surgical removal of complex orbital dermoid cysts, and to evaluate clinical outcomes of the novel procedure. Methods: We previously reported on the modified methylene blue staining technique used during surgical removal of complex orbital dermoid cysts, and retrospectively reviewed medical records of patients who had undergone the modified staining procedure from June 2014 to December 2017 in Eye & ENT Hospital of Fudan University. Results: Eight patients (8 eyes) were recruited, including seven primary cases and one recurrent case identified at the first visit. All lesions were in the superotemporal region of the orbit, with one lesion that formed a skin fistula and one lesion that extended into the temporal fossa. Clinical manifestations included diplopia (2 cases), global deviation (5 cases) and proptosis (6 cases). During surgery, modified methylene blue staining facilitated visualization and complete resection of the cysts. Follow-up duration was 2.9 years on average. CT scans showed no recurrence, and no patients complained of diplopia or global deviation. Based on histopathologic study, two cases were epidermoid cysts and six cases were dermoid cysts. Conclusions: A modified methylene blue staining technique, which facilitates visualization and complete removal of cyst walls, will play an important role in the surgical treatment of complex orbital dermoid cysts.

After corneal refractive surgery, the measurement of intraocular pressure is underestimated because central corneal thickness and corneal biomechanical properties are changed during the operation. Accurately evaluating intraocular pressure after corneal refractive surgery has an important clinical significance. The evaluation of postoperative intraocular pressure measurements should take tonometer, central corneal thickness, corneal hysteresis and corneal resistance factors into consideration. This article reviews the intraocular pressure measurements and influencing factors after corneal refractive surgery.