Magnetic Resonance Imaging Findings in Patients With Duane Retraction Syndrome.

BACKGROUND: Duane retraction syndrome (DRS) is known to relate to the absence of the abducens nucleus, with abnormal innervation of the lateral rectus (LR) muscle by branchesof the oculomotor nerve (CN III). The purposes of this study were to investigate the morphological characteristics of the oculomotor nerve (CN III), the abducens nerve (CN VI), and the extraocular muscles in patients with clinically diagnosed Duane retraction syndrome (DRS) using MRI. In addition, we assessed the association between ocular motility, horizontal rectus muscle volumes, and CN III/VI in patients with Duane retraction syndrome (DRS). METHODS: The study comprised 20 orthotropic control subjects (40 eyes) and 42 patients with Duane syndrome (48 eyes), including 20 patients with DRS Type I (24 eyes), 5 patients with DRS Type II (6 eyes), and 17 patients with DRS Type III (18 eyes). Three-dimensional (3D) T1/2 images of the brainstem and orbit were obtained to visualize the cranial nerves, especially the abducens (VI) and oculomotor (III) nerves, as well as extraocular muscles. RESULTS: Based on the clinical classification, among 42 patients, MRI showed that the abducens nerves (CN VI) on the affected side were absent in 24 of 24 eyes (100%; 20 patients) with Type I DRS and in 16 of 18 eyes (88%; 16 patients) with Type III DRS. However, CN VI was observed in 6 of 6 eyes (100%; 5 patients) with Type II DRS and in 2 of 18 eyes (11%) with Type III DRS. CN III was observed in all patients. The oculomotor nerves on the affected side were thicker than those on the nonaffected contralateral side in DRS Type I ( P < 0.05) and Type III ( P < 0.05), but not in DRS Type II. Smaller LR and larger MR volumes were shown in the affected eye than that in the nonaffected eye in DRS Types I and III. Based on the presence or absence of CN VI, there was a tendency for thicker oculomotor nerves in the affected eye than in the nonaffected eye in the absence groups ( P < 0.05). However, no significant difference was found in the present group. In the CN VI absence groups, similar results were found in the affected eyes than in the nonaffected eyes as in DRS Types I and III. In addition, the presence of CN VI was correlated with better abduction ( P = 0.008). The LR and MR volumes have positive correlations with the oculomotor nerve diameter in the affected eye. However, there was no correlation between the range of adduction/abduction and the LR/MR ratio in patients with or without an abducens nerve. CONCLUSIONS: Different types of DRS have different characteristic appearances of CN VI and CN III on MRI. Horizontal rectus muscles have morphological changes to adapt to dysinnervation of CN VI and aberrant innervation of CN III. Thus, these neuroimaging findings may provide a new diagnostic criterion for the classification of DRS, improving the comprehension of the physiopathogenics of this disease.

Predicting Risk Factors for Consecutive Esotropia Failed with Conservative Therapy.

Purpose: To investigate risk factors predisposing to the failure of nonsurgical treatment of consecutive esotropia.Methods: A retrospective review was carried out for all cases diagnosed as having developed consecutive esotropia who following surgical correction of intermittent exotropia between 2013 and 2018 and have failed to conservative treatment. Performing 1:2 case-control match, control subjects were randomly selected from patients who underwent surgeries for intermittent exotropia during the same period but did not develop consecutive esotropia. Various factors were examined for assessing the risks for the failure of nonsurgical intervention in the treatment of consecutive esotropia.Results: A total of 270 patients were enrolled in the study. Ninety cases were diagnosed as consecutive esotropia and 180 as controls. Univariate analysis showed significant association of consecutive esotropia for ineffective nonsurgical treatment with age of the patient at the onset of exotropia, age of the patient at the time of surgery, amblyopia, preoperative deviation, the type of surgical procedure, and the vertical components combined with exotropia (p<0.01).To further explore potential risk factors of consecutive esotropia, conditional logistic regression model was applied. Patients aged below 3 years old at the time of surgery and bilateral lateral rectus recession were shown in conditional logistic regression analysis to be significantly associated with higher incidence of consecutive esotropia (p<0.01).Conclusion: The presence of an early age (below 3 years old) at surgery and bilateral symmetric procedure may be associated with a high risk of consecutive esotropia who failed with conservative therapy. Systematic preoperative examination, close supervision, suitable surgical approach could be optimized to reduce the risk of consecutive esotropia.

Model of a Support Vector Machine to Assess the Functional Cure for Surgery of Intermittent Exotropia.

In this paper the optimum timing for the postoperative functional cure of basic intermittent exotropia is explored based on support vector machine (SVM). One hundred and thirty-two patients were recruited in this prospective cross-sectional study with 6 months of follow-up. Examinations included angle of deviation, central and peripheral fusion, controllability, and near and distance stereopsis. Influencing factors of postoperative alignment and stereopsis were analyzed with a chi-squared test and univariate and multivariate logistic regression analyses. At 6 months post-operation, there were 84 successful procedures for the angle of deviation, with 4 overcorrections and 44 undercorrections. The success rate was 63.6%. The angle of deviation on postoperative day 1 was the only significant associated factor. One hundred and thirty patients had normal near stereoacuity, 60 had normal distance stereoacuity according to a Functional Visual Analyzer assessment, and 108 had normal stereoacuity as assessed by the Frisby Davis Distance (FD2) stereotest. The age of onset and preoperative distance stereoacuity with FD2 were the influencing factors of postoperative distance stereopsis restoration. The accuracy of this method of SVM was 82.1%. The angle of deviation for distance on postoperative day 1 was the only significant factor that correlated with alignment at 6 months post-operation, and the model of SVM was useful to determine the optimal time of the postoperative functional cure.

Comparison of surgical outcomes between bilateral recession and unilateral recession-resection in moderate-angle intermittent exotropia.

PURPOSE: To compare postoperative drift after bilateral lateral rectus recession (BLR) and after unilateral recession combined with medial rectus resection (R&R) in children with primary moderate-angle intermittent exotropia. METHODS: The medical records of children with intermittent exotropia in the range of 25Δ-50Δ who underwent BLR or R&R from July 2015 to September 2016 were reviewed retrospectively. Outcomes were classified according to postoperative angle of deviation at distance as overcorrection (esophoria or -tropia of >5Δ), success (esophoria or -tropia of ≤5Δ to exophoria/tropia of ≤10Δ), or recurrence (exophoria or -tropia of >10Δ). Patients were examined on postoperative day 1 and at 6 weeks, 6 months, and 12 months. Sensory status was evaluated using the Titmus stereoacuity test. RESULTS: A total of 330 children were included (BLR, 175; R&R, 155). Exotropic drift was greater in the R&R group in the period between day 1 and 6 weeks and from 6 to 12 months (P <0.05). Surgical successful rates in each group were comparable: 57.7% in the BLR group and 60.6% in the R&R group (P > 0.05). However, higher overcorrection rates were noted in the BLR group at 6 and 12 months (16.6% vs 6.5 % at 12 months [P = 0.003]). There were more patients with deteriorated stereopsis after surgery in the BLR group (P = 0.025). CONCLUSIONS: In our study cohort, BLR was associated with more stable long-term ocular alignment and a higher rate of overcorrection than R&R. Postoperative day 1 overcorrection of <16Δ following R&R and of <10Δ following BLR were associated with relatively good results.

A Meta-Analysis of Choroidal Thickness Changes in Unilateral Amblyopia.

PURPOSE: To date, the topic of amblyopic changes remains controversial. Therefore, a systematic review and meta-analysis were carried out to evaluate choroidal changes in unilateral amblyopia. METHODS: Major literature databases were searched for amblyopia-relevant studies. Using enhanced depth imaging optical coherence tomography (EDI-OCT), the primary outcome parameters examined were subfoveal choroidal thickness (SFCT) and different choroidal thickness (CT) positions. Efficacy estimates were evaluated by weighted mean difference (WMD) and 95% confidence interval (CI) for choroidal-associated changes. We performed subgroup analysis and metaregression analysis to examine potential sources of heterogeneity. RESULTS: Eleven cross-sectional studies that included a total of 768 participants were identified. The amblyopic eye SFCT was thicker than that of the fellow and control (normal) eyes (WMDamblyopia versus fellow = 49.24, 95% CI of 30.22 to 68.27, p < 0.001; WMDamblyopia versus control = 54.51, 95% CI of 32.17 to 76.85, p < 0.001). There were no differences between the fellow and control eyes (WMD = 13.81, 95% CI of 1.16 to 28.77, p = 0.071). Subgroup and metaregression analyses indicated that the OCT type was the main source of heterogeneity. CONCLUSIONS: The CT in the amblyopic eyes was thicker than that in the fellow and control eyes.

Timing-dependent LTP and LTD in mouse primary visual cortex following different visual deprivation models.

Visual deprivation during the critical period induces long-lasting changes in cortical circuitry by adaptively modifying neuro-transmission and synaptic connectivity at synapses. Spike timing-dependent plasticity (STDP) is considered a strong candidate for experience-dependent changes. However, the visual deprivation forms that affect timing-dependent long-term potentiation(LTP) and long-term depression(LTD) remain unclear. Here, we demonstrated the temporal window changes of tLTP and tLTD, elicited by coincidental pre- and post-synaptic firing, following different modes of 6-day visual deprivation. Markedly broader temporal windows were found in robust tLTP and tLTD in the V1M of the deprived visual cortex in mice after 6-day MD and DE. The underlying mechanism for the changes seen with visual deprivation in juvenile mice using 6 days of dark exposure or monocular lid suture involves an increased fraction of NR2b-containing NMDAR and the consequent prolongation of NMDAR-mediated response duration. Moreover, a decrease in NR2A protein expression at the synapse is attributable to the reduction of the NR2A/2B ratio in the deprived cortex.

Resolution of hypertropia with correction of consecutive horizontal deviation.

BACKGROUND: To study the resolution of hypertropia in patients who undergo horizontal deviation surgery for consecutive esotropia or consecutive exotropia. METHODS: We retrospectively reviewed the records of 23 patients with consecutive esotropia or exotropia who had concomitant vertical tropia. All patients had had surgery for horizontal deviation that required further surgery to correct consecutive horizontal strabismus and had a minimum of six months of postoperative follow-up. All patients were noted to have vertical deviation greater than 5 prism diopters (PD) in primary position on preoperative examination. Patients underwent corrective surgery for horizontal strabismus without surgical manipulation of the vertical extraocular muscles. The exclusion criteria were coexisting oblique muscle dysfunction, manifest or latent dissociated vertical deviation, and extraocular muscle palsy. RESULTS: The mean preoperative vertical deviations were 7.6 ± 2.3 PD for distance and 7.3 ± 2.3 PD for near. All patients had resolution of vertical deviation in all fields of gaze despite surgical correction only being made to horizontal extraocular muscles. No patients had measureable vertical tropia during six months of follow-up. CONCLUSION: We propose that measureable hypertropia unrelated to oblique muscle dysfunction, dissociated vertical deviation, or paretic/mechanical muscle that coincides with consecutive horizontal deviation can be resolved with horizontal muscle surgery alone. Therefore, it may not be necessary to perform vertical surgery to correct coincident vertical deviation in patients with consecutive horizontal deviation. More research is needed in the form of prospective clinical trials to determine whether vertical surgery has any utility for these patients.

Comparison of augmented and nonaugmented modified Knapp procedure for the treatment of nonrestrictive double elevator palsies.

PURPOSE: To compare surgical results of augmented and nonaugmented modified Knapp procedure, for the treatment of nonrestrictive double elevator palsies (DEP). METHODS: The medical records of patients with congenital DEP were reviewed retrospectively. Patients were divided into three treatment groups: standard transposition (group A), Foster transposition (group B), and resection transposition (group C). Pre- and postoperative vertical deviation in primary position, ocular motility, and binocular vision were compared. RESULTS: Thirty patients were enrolled. The pre- and postoperative deviations in group A were 34.7Δ ± 8.6Δ and 6.5Δ ± 6.5Δ; in group B, 38.6Δ ± 14.6Δ and 5.7Δ ± 9.3Δ; and in group C, 43.1Δ ± 10.3Δ and 8.5Δ ± 6.1Δ. The corrected vertical deviation of group B (32.9Δ ± 5.7Δ) and group C (34.6Δ ± 5.0Δ) were greater than that of group A (28.1Δ ± 3.6Δ; P = 0.03, 0.002). The pre- and postoperative measures of upgaze in group A were -3.7 and -1.8; in group B, -4.0 and -1.3; and in group C, -3.6 and -2.0. The average improved upgaze in group B (2.6 ± 0.5) was statistically significantly better than that in group A (1.9 ± 0.6) and group C (1.5 ± 0.5; P = 0.03, 0.002). There was no significant difference in the surgical effect on downgaze in three groups (P > 0.05). The surgical outcome was satisfactory in 19 (63.3%) patients with preoperative vertical devation of ≤40Δ. CONCLUSIONS: All transpositions are reasonably effective in treating vertical deviations of <35Δ without obviously limiting downgaze in DEP. Augmented procedures could correct greater vertical deviation of 30Δ-40Δ. The Foster transposition demonstrates the strongest effect in improving upgaze.

[Apply of RetCam â ¡ and color Doppler imaging in persistent hyperplastic primary vitreous].

OBJECTIVE: To observe the manifestations of RetCam Ⅱ and color Doppler imaging (CDI) in a retrospective case series of persistent hyperplastic primary vitreous (PHPV). METHODS: Retrospective study. The medical records of 9 eyes/9 patients with PHPV went through RetCamⅡ and CDI from 2009 to 2014. RESULTS: There were 6 young boys and 3 young girl in this study, age from 2 months to 5 years. All the patients were born at full term. 9 eyes had complication (cataract). The manifestations of RetCam Ⅱ: There were pale in optic disc. There were white fibre rod connected with optic disc, then prolonged to vitreous cavity, connected with posterior lens capsule. CDI showed arterial blood stream signal in band-shaped echogenic structure within vitreous cavity, prolonged to lens from the optic disc, or showed funnel-shaped echogenic mass at the posterior surface of lens and anterior of vitreous body, adhered to ciliary body, lens and the optic disc. CONCLUSIONS: PHPV is congenital ocular anomalies because of a failure of primary vitreous and the hyaloids vascular system to regress. It manifests as unilateral and boys. We diagnosis PHPV by RetCamⅡ and CDI.

Effects of Bilateral Superior Oblique "Hang-Back" Recession in Treatment of A-pattern Strabismus with Superior Oblique Overaction.

PURPOSE: To investigate the efficacy and safety of bilateral hang-back recession of superior oblique (SO) muscles in the treatment of A-pattern strabismus with superior oblique overaction (SOOA). METHODS: Thirty-one (31) patients (62 eyes) with A-pattern horizontal deviation and SOOA underwent hang-back recession of SO and retrospective analysis of the surgical amount of hang-back recession of SO, preoperative and postoperative A-pattern, ocular motility, and corrected objective torsion. Patients were evaluated before and 6 to 9 months after surgery. RESULTS: The average A-pattern horizontal deviation was 27.58 ± 11.47 prism diopters (PD) before surgery and 3.48 ± 3.70 PD after surgery (n=31, P<0.05). The mean corrected A-pattern was horizontal deviation 24.10 ± 10.32 PD. The average scale of SOOA on a scale of +1 to +4 was +3.05 ± 0.80 before surgery and +0.42 ± 0.50 after surgery in 62 eyes (P<0.05). The mean corrected objective torsion was 4.91° ± 4.53°. The surgical amount of SO hang-back recession ranged from 4 to 10 mm (mean: 7.62 ± 1.18 mm), which was related to the preoperative A-pattern and corrected A-pattern. There were no surgical complications. CONCLUSIONS: SO hang-back recession is a safe and efficient option for A-pattern caused by SOOA.

SPP2 Mutations Cause Autosomal Dominant Retinitis Pigmentosa.

Retinitis pigmentosa (RP) shows progressive loss of photoreceptors involved with heterogeneous genetic background. Here, by exome sequencing and linkage analysis on a Chinese family with autosomal dominant RP, we identified a putative pathogenic variant, p.Gly97Arg, in the gene SPP2, of which expression was detected in multiple tissues including retina. The p.Gly97Arg was absent in 800 ethnically matched chromosomes and 1400 in-house exome dataset, and was located in the first of the two highly conserved disulfide bonded loop of secreted phosphoprotein 2 (Spp-24) encoded by SPP2. Overexpression of p.Gly97Arg and another signal peptide mutation, p.Gly29Asp, caused cellular retention of both endogenous wild type and exogenous mutants in vitro, and primarily affected rod photoreceptors in zebrafish mimicking cardinal feature of RP. Taken together, our data indicate that the two mutations of SPP2 have dominant negative effects and cellular accumulation of Spp-24 might be particularly toxic to photoreceptors and/or retinal pigment epithelium. SPP2 has a new role in retinal degeneration.

[See the strabismus and amblyopia research development trend from the twelfth World Congress of strabismus].

The International strabismus association conference has a history of fifty years until now. It's the most influential academic communication forum for the worldwide doctors and related scientists or technical carers in strabismus and amblyopia area. The conference gathered the top-level experts. The latest clinical/research achievements of strabismus, amblyopia in the field of binocular vision and ocular motility have been showed. The breakthroughs in the etiology study of incomitant strabismus have been and are being transformed into new therapeutic concepts and techniques. Re-adjust the competition between dominant and amblyopic eye using binocular stimulation methods may overcome the existing defects of monocular occlusion therapy, expand new interventional methods to treat amblyopia, and represent the future trends of amblyopia therapy. In this paper, we will introduce the main contents of the XII ISA meeting and spread knowledge of strabismus/amblyopia promoting directions in order to provide reference ideas for the clinicians and research colleagues in this field.

[Hot topics in treatment of intermittent exotropia].

Intermittent exotropia is the most common type of exotropia, and also is one of the most difficult types of strabismus to deal with. Surgery is the main choice of treatment and non-surgical treatment is used only under certain indications. Long-term outcomes of the surgery for intermittent exotropia are related to many factors, such as age, course of the disease, perceptual state of visual cortex, timing of surgery, types of intermittent exotropia, the surgical methods, preoperative measurements of exodeviations, target angle of surgery, postoperative treatment of overcorrection or undercorrection, and so on. It is significant to pay attention to these issues to improve success rate of the surgeries. In this paper, recent progress of clinical studies of intermittent exotropia were reviewed to arouse the attentions of domestic ophthalmologist to the standardization of diagnosis and treatment of intermittent exotropia.

[The developmental switch of visual cortex NMDA receptor NR2 subunits and its implications for visual plasticity].

Many forms of synaptic plasticity require NMDA-type glutamate receptors (NMDAR). These tetrameric receptors consist of two obligatory NR1 subunits and two regulatory subunits, usually a combination of NR2A and NR2B. In the neonatal visual cortex NR2B-containing NMDAR predominate, after thatvisual experience facilitates a developmental switch in which NR2A levels increase relative to NR2B. In this review, it puts emphasis on the role and the regulation of this shift as well as the effect on synaptic plasticity.

Knocking Down Snrnp200 Initiates Demorphogenesis of Rod Photoreceptors in Zebrafish.

Purpose. The small nuclear ribonucleoprotein 200 kDa (SNRNP200) gene is a fundamental component for precursor message RNA (pre-mRNA) splicing and has been implicated in the etiology of autosomal dominant retinitis pigmentosa (adRP). This study aims to determine the consequences of knocking down Snrnp200 in zebrafish. Methods. Expression of the Snrnp200 transcript in zebrafish was determined via whole mount in situ hybridization. Morpholino oligonucleotide (MO) aiming to knock down the expression of Snrnp200 was injected into zebrafish embryos, followed by analyses of aberrant splicing and expression of the U4/U6-U5 tri-small nuclear ribonucleoproteins (snRNPs) components and retina-specific transcripts. Systemic changes and retinal phenotypes were further characterized by histological study and immunofluorescence staining. Results. Snrnp200 was ubiquitously expressed in zebrafish. Knocking down Snrnp200 in zebrafish triggered aberrant splicing of the cbln1 gene, upregulation of other U4/U6-U5 tri-snRNP components, and downregulation of a panel of retina-specific transcripts. Systemic defects were found correlated with knockdown of Snrnp200 in zebrafish. Only demorphogenesis of rod photoreceptors was detected in the initial stage, mimicking the disease characteristics of RP. Conclusions. We conclude that knocking down Snrnp200 in zebrafish could alter regular splicing and expression of a panel of genes, which may eventually trigger rod defects.

C2 rs547154 polymorphism and polypoidal choroidal vasculopathy susceptibility: a meta-analysis.

Previous studies have indicated the association between C2 rs547154 polymorphism and polypoidal choroidal vasculopathy (PCV) risk, while the results are controversial and inconsistent. Herein, we perform a meta-analysis to gain a precise estimation of the association using 5 eligible studies involving 4076 subjects, of which 1220 were PCV cases, 1073 were age-related macular degeneration (AMD) cases and 1783 were controls. Allelic frequencies of C2 rs547154 polymorphism between PCV and AMD were also compared. Both crude and adjusted odds ratios (OR) with their 95% confidence interval (CI) were included to assess the strength of the association. The pooled OR in random-effect model for allele T versus G was 0.64 (95% CI, 0.52-0.80; p < 0.0001), for genotype TG versus GG was 0.65 (95% CI, 0.52-0.83; p, 0.0004), and for genotype TT + TG versus GG was 0.64 (95% CI, 0.51-0.80; p, 0.0002). No difference in allelic frequency was observed between PCV and AMD (OR, 0.86; 95% CI, 0.64-1.16; p, 0.32). Sensitivity analysis proved the robustness of our data. No significant ethnic divergence was suggested by subgroup analysis, and no publication bias was detected via Egger's test. In conclusion, our data indicate that C2 rs547154 polymorphism plays a protective role in the development of PCV.

Targeted next-generation sequencing reveals novel EYS mutations in Chinese families with autosomal recessive retinitis pigmentosa.

EYS mutations demonstrate great genotypic and phenotypic varieties, and are one of the major causes for patients with autosomal recessive retinitis pigmentosa (ARRP). Here, we aim to determine the genetic lesions with phenotypic correlations in two Chinese families with ARRP. Medical histories and ophthalmic documentations were obtained from all participants from the two pedigrees. Targeted next-generation sequencing (NGS) on 189 genes was performed to screen for RP causative mutations in the two families. Two biallelic mutations in EYS, p.[R164*];[C2139Y] and p.[W2640*];[F2954S], were identified in the two families, respectively. EYS p.R164* and p.F2954S are novel alleles associated with RP, while p.C2139Y and p.W2640* are known mutations. Crystal structure modeling on the protein eyes shut homolog encoded by the EYS gene revealed abnormal hydrogen bonds generated by p.C2139Y and p.F2954S, which would likely affect the solubility and cause significant structural changes of the two mutated proteins. In conclusion, our study expands the genotypic spectrums for EYS mutations, and may provide novel insights into the relevant pathogenesis for RP. We also demonstrate targeted NGS approach as a valuable tool for genetic diagnosis.

Molecular genetic testing in clinical diagnostic assessments that demonstrate correlations in patients with autosomal recessive inherited retinal dystrophy.

IMPORTANCE: Inherited retinal dystrophies (IRDs) are a group of retinal degenerative diseases presenting genetic and clinical heterogeneities, which have challenged the genetic and clinical diagnoses of IRDs. Genetic evaluations of patients with IRD might result in better clinical assessments and better management of patients. OBJECTIVE: To determine the genetic lesions with phenotypic correlations in patients with diverse autosomal recessive IRD using next-generation sequencing. DESIGN, SETTING, AND PARTICIPANTS: A cohort of 20 Chinese families affected with autosomal recessive IRD were recruited (with data on their detailed family history and on their clinical condition). To identify disease-causing mutations in the patients, the targeted sequence capture of IRD-relevant genes using 2 in-house-designed microarrays, followed by next-generation sequencing, was performed. Bioinformatics annotation, intrafamilial cosegregation analyses, in silico analyses, and functional analyses were subsequently conducted for the variants identified by next-generation sequencing. MAIN OUTCOMES AND MEASURES: The results of detailed clinical evaluations, the identification of disease-causing mutations, and the clinical diagnosis. RESULTS: Homozygous and biallelic variants were identified in 11 of the 20 families (55%) as very likely disease-causing mutations, including a total of 17 alleles, of which 12 are novel. The 17 alleles identified here include 3 missense, 6 nonsense, 4 frameshift, and 4 splice site mutations. In addition, we found biallelic RP1 mutations in a patient with cone-rod dystrophy, which was not previously correlated with RP1 mutations. Moreover, the identification of pathogenic mutations in 3 families helped to refine their clinical diagnoses. CONCLUSIONS AND RELEVANCE: In this study, to our knowledge, many mutations identified in those known loci for autosomal recessive IRD are novel. Specific RP1 mutations may correlate with cone-rod dystrophy. Genetic evaluations with targeted next-generation sequencing might result in a better clinical diagnosis and a better clinical assessment and, therefore, should be recommended for such patients.

[Learn new version of Preferred Practice Pattern to further standardize the diagnosis and treatment of amblyopia].

The introduction of Preferred Practice Patterns (PPP) into China has given ophthalmologists in China more opportunities to acquaint themselves with international clinical guidelines for eye care, including its developing principles, methods and the application value. It had brought significant effects on the fast improvement of clinical eye care and standardization of diagnosis and treatment of eye diseases in China, and promoted the international academic exchanges. The 2nd Chinese version of PPPs translated by Prof. Jialiang Zhao was officially published in November, 2013. The new version of PPP for amblyopia adopted the newest standard for grading of evidence strength and recommendation assessment, and emphasizes the practicability based on evidence. New explanations of the definition of amblyopia are added according to the recent research progresses in amblyopia. The diagnostic criteria of best visual acuity for bilateral amblyopia at different ages is given with new specifications. Comprehensive and practical suggestions on the examination methods for amblyopia are provided from the qualitative assessment of visual acuity, the choice of eye chart, to the use of cycloplegic agents. In the aspect of the treatment of amblyopia, based on the findings of recent multi-central random controlled clinical trials, not only strong recommendations are provided, but also the insufficiency of evidence supporting for some choices of therapy is pointed out. The necessity of the follow-up evaluation after the cessation of the treatment of amblyopia is emphasized too. In the aspect of the prevention of amblyopia, the new amblyopia PPP points out the importance of the early-period screening of amblyopia, and that the healthcare insurance plans should cover timely screening, treatment, and monitoring for recurrence of amblyopia. This article deciphers the essential contents of the new version of Chinese PPP for amblyopia, and aims to promote the standardization of the diagnosis and treatment of amblyopia with our ophthalmic colleagues in China.

[Clinical investigation on AC/A ratio in intermittent exotropia coexisting with ametropia].

OBJECTIVE: To investigate AC/A ratio and coexisting ametropia in intermittent exotropia. To discuss the relation between AC/A ratio and the development of intermittent exotropia. METHODS: The medical records of 135 patients who had an exotropia were retrospectively reviewed. Patients were divided into 3 groups based on the type of ametropia: exotropia without ametropia (-0.50-+3.00 D between the age of 3-6 years old, -0.50-+2.00 D between the age of 7-40 years old) , exotropia coexisting with myopia (-0.50-7.75 D) and exotropia coexisting with hypermetropia ( ≥ + 3.00 D of 3-6 years old , ≥ + 2.00 D of 7 ∼ 40 years old). AC/A ratios of all patients were assessed using synoptophore method. Distance and near deviations were assessed using prism cover test. AC/A ratios and deviation angles of 3 groups were compared. The relationship between AC/A ratios and ametropia/age were investigated. RESULTS: There were obvious differences in AC/A ratios(2.686 ± 1.372, 1.773 ± 1.110, 4.581 ± 1.552, F = 36.323, P < 0.001) and in near deviation angles (44.473(Δ) ± 19.008(Δ), 53.621(Δ) ± 20.749(Δ), 34.455(Δ) ± 13.292(Δ), F = 8.762, P = < 0.001) between 3 groups of patients, no obvious differences were seen in distance deviation angles (40.333(Δ) ± 19.474(Δ), 44.052(Δ) ± 23.722(Δ), 35.590(Δ) ± 11.143(Δ), F = 1.444, P = 0.24). AC/A ratios were negative linear correlated with refractive powers for patients of intermittent extropia coexisting with myopia or with hypermetropia (r = 0.320, P = -0.469 and r = -0.046, P = 0.036, respectively) . A trend of decline with age was found for AC/A ratios only in patients of intermittent extropia without ametropia (r = -0.320, P = 0.019; r = -0.023, P = 0.865; r = 0.246, P = 0.296 for the other 2 groups, respectively). CONCLUSIONS: Myopia and hypermetropia, when coexisting with abnormally low or high AC/A ratio, can destroy the balance between extraocular muscles and induce exophoria to be manifest.