Clinical and genetic studies for a cohort of patients with Leber congenital amaurosis.

PURPOSE: Leber congenital amaurosis (LCA) is a group of early-onset retinal degenerative disorders, resulting in blindness in children. This study aimed to describe the clinical and genetic characteristics of a cohort of patients with LCA and to investigate the retinal vascular characteristics in LCA patients. METHODS: Fifty-two children with LCA were included in the study. All patients underwent detailed ocular examinations. Electroretinography (ERG) was used to evaluate the retinal function. Optical coherence tomography (OCT) was used to assess the structure change of the retina for those patients who were able to cooperate very well. Panel-based next-generation sequencing was performed to identify pathogenic variants in genes associated with LCA. Diameters of the retinal vessels were measured using the EVision AI screening system with an artificial intelligence (AI) technique. An ultrasound Doppler was used to evaluate hemodynamic parameters, including peak systolic velocity (PSV), resistive index (RI), and pulsatility index (PI), in the ophthalmic, central retinal, posterior ciliary, carotid, and internal carotid as well as external carotid arteries in 12 patients aged from 3 to 14 years. RESULTS: We detected 75 pathogenic variants from ten genes of RPGRIP1, CEP290, GUCY2D, LCA5, AIPL1, CRB1, RPE65, CRX, RDH12, and TULP1, including 29 novel and 36 previously reported variants in 52 affected children with LCA, with the highest detective rate in RPGRIP1 (26.9%). Fundus appearance is diverse in patients with LCA, ranging from normal to severe peripheral or central retinopathy. Retinal vasculature was evaluated in 12 patients with different gene variants, showing narrowed arteries with an average diameter of 43.6 ± 3.8 µm compared to that of 51.7 ± 2.6 µm in the normal controls (P < 0.001, n = 12). Meanwhile, their hemodynamic parameters were changed as well in the ophthalmic artery (OA), with a decreased PSV (P = 0.0132, n = 12) and slightly increased PI (P = 0.0488, n = 12) compared to the normal controls. However, the hemodynamic parameters did not change significantly in the other vessels. CONCLUSIONS: Blood supply to the eyeball is predicted to be reduced in patients with LCA, presumably due to photoreceptor cell degeneration. The novel identified variants will expand the spectrum of variants in LCA-related genes and be useful for studying the molecular mechanisms of LCA.

Differences of ocular oscillations and neuro-retinal structures in patients with nystagmus caused by GPR143 and FRMD7 gene variants.

PURPOSE: Mutations of G protein-coupled receptor 143 (GPR143) and FERM domain containing 7 (FRMD7) may result in congenital nystagmus (CN) in the first 6 months of life. We aimed to compare the differences in ocular oscillations between patients with these two gene mutations as well as the functional and structural changes in their retinas and visual pathways. METHODS: Medical records were retrospectively reviewed to identify patients of congenital nystagmus with confirmed mutations in either GPR143 or FMRD7 genes from January 2018 to May 2023. The parameters of the ocular oscillations were recorded using Eyelink 1000 Plus. The retinal structure and function were evaluated using optical coherence tomography and multi-focal electroretinography (mERG). The visual pathway and optical nerve projection were evaluated using visual evoked potentials. The next-generation sequencing technique was used to identify the pathogenic variations in the disease-causing genes for CN. RESULTS: Twenty nystagmus patients of GPR143 and 21 patients of FMRD7 who had been confirmed by molecular testing between January 2018 and May 2023 were included. Foveal hypoplasia was detected only in patients with the GPR143 pathogenic variant. mERG examination showed a flat response topography in the GPR143 group compared to the FRMD7 group. VEP showed that bilateral amplitude inconsistency was detected only in the patients with GPR143 gene mutation. The amplitude and frequency of the ocular oscillations were not found to differ between patients with two different genetic mutations. CONCLUSIONS: Although the etiology and molecular mechanisms are completely different between CN patients, they may have similar ocular oscillations. A careful clinical examination and electrophysiological test will be helpful in making a differential diagnosis. Our novel identified variants will further expand the spectrum of the GPR143 and FRMD7 variants.

Clinical and genetic studies for a cohort of patients with congenital stationary night blindness.

BACKGROUND: Congenital stationary night blindness (CSNB) is an inherited retinal disorder. Most of patients have myopia. This study aims to describe the clinical and genetic characteristics of fifty-nine patients with CSNB and investigate myopic progression under genetic cause. RESULTS: Sixty-five variants were detected in the 59 CSNB patients, including 32 novel and 33 reported variants. The most frequently involved genes were NYX, CACNA1F, and TRPM1. Myopia (96.61%, 57/59) was the most common clinical finding, followed by nystagmus (62.71%, 37/59), strabismus (52.54%, 31/59), and nyctalopia (49.15%, 29/59). An average SE of -7.73 ± 3.37 D progressed to -9.14 ± 2.09 D in NYX patients with myopia, from - 2.24 ± 1.53 D to -4.42 ± 1.43 D in those with CACNA1F, and from - 5.21 ± 2.89 D to -9.24 ± 3.16 D in those with TRPM1 during the 3-year follow-up; the TRPM1 group showed the most rapid progression. CONCLUSIONS: High myopia and strabismus are distinct clinical features of CSNB that are helpful for diagnosis. The novel variants identified in this study will further expand the knowledge of variants in CSNB and help explore the molecular mechanisms of CSNB.

Novel pathogenic variants of SLC38A8 gene and literature review.

PURPOSE: This study aimed to analyze the clinical and genetic characteristics of 6 Chinese patients with foveal hypoplasia (FH) caused by the variants of solute carrier family 38 member 8 (SLC38A8), and to describe the genotype and phenotype of SLC38A8 variants from previous literature. METHODS: All subjects underwent comprehensive ophthalmic examinations. Optical coherence tomography (OCT) was performed to evaluate the structural grade of FH. Pathogenic variants of SLC38A8 gene were identified using panel-based next-generation sequencing and direct Sanger sequencing techniques. Further, all previously reported cases of SLC38A8 variants were re-analyzed together with the novel ones identified in this study. RESULTS: Nystagmus and FH were present in 6 patients with variants of SLC38A8 gene, accompanied by a normal anterior segment. Grade 4 FH was identified in 4 patients. A total of 12 variants of SLC38A8 gene were identified, including 9 novel variants. Systematical analysis revealed that half of the variants (30/60) were missense, the majority of which (23/30) were distributed in the transmembrane (TM) domains. Grade 4 FH was detected in the majority of patients (66%, 23/35). There was no statistical difference in the clinical features between the subgroups of patients with 0, 1 and 2 missense variants. CONCLUSION: Severe arrest of foveal development was identified in patients with variants of SLC38A8. This study provides a brief summary of the clinical and genetic characteristics of the pathogenic SLC38A8 variants, which is helpful in the differentiation diagnosis of FH.

Alterations of large-scale functional network connectivity in patients with infantile esotropia before and after surgery.

BACKGROUND: Growing evidences have indicated neurodevelopmental disorders in infantile esotropia (IE). However, few studies have analyzed the characteristics of large-scale functional networks of IE patients or their postoperative network-level alterations. METHODS: Here, individuals with IE (n = 32) and healthy subjects (n = 30) accomplished the baseline clinical examinations and resting-state MRI scans. A total of 17 IE patients also underwent corrective surgeries and completed the longitudinal clinical assessments and resting-state MRI scans. Linear mixed effects models were applied for cross-sectional and longitudinal network-level analyses. Correlation analysis was performed to assess the relationship between longitudinal functional connectivity (FC) alterations and baseline clinical variables. RESULTS: In cross-sectional analyses, network-level FC were apparently aberrant in IE patients compared to controls. In longitudinal analyses, intra- and internetwork connectivity were observed with significant alterations in postoperative IE patients compared to the preoperative counterparts. Longitudinal FC changes are negatively correlated to the age at surgery in IE. CONCLUSIONS: Obviously, altered network-level FC benefiting from the corrective surgery serves as the neurobiological substrate of the observed improvement of stereovision, visuomotor coordination, and emotional management in postoperative IE patients. Corrective surgery should be performed as early as possible to obtain more benefits for IE in brain function recovery.

Clinical analysis of eye movement-based data in the medical diagnosis of amblyopia.

Amblyopia is an abnormal visual processing-induced developmental disorder of the central nervous system that affects static and dynamic vision, as well as binocular visual function. Currently, changes in static vision in one eye are the gold standard for amblyopia diagnosis. However, there have been few comprehensive analyses of changes in dynamic vision, especially eye movement, among children with amblyopia. Here, we proposed an optimization scheme involving a video eye tracker combined with an "artificial eye" for comprehensive examination of eye movement in children with amblyopia; we sought to improve the diagnostic criteria for amblyopia and provide theoretical support for practical treatment. The resulting eye movement data were used to construct a deep learning approach for diagnostic and predictive applications. Through efforts to manage the uncooperativeness of children with strabismus who could not complete the eye movement assessment, this study quantitatively and objectively assessed the clinical implications of eye movement characteristics in children with amblyopia. Our results indicated that an amblyopic eye is always in a state of adjustment, and thus is not "lazy." Additionally, we found that the eye movement parameters of amblyopic eyes and eyes with normal vision are significantly different. Finally, we identified eye movement parameters that can be used to supplement and optimize the diagnostic criteria for amblyopia, providing a diagnostic basis for evaluation of binocular visual function.

Diversity of clinical phenotypes in a cohort of Han Chinese patients with PAX6 variants.

The PAX6 gene plays an important role in ocular development. Mutations of the PAX6 gene may result in a series of ocular abnormalities, including congenital aniridia, anterior segment dysgenesis (ASD), progressive corneal opacification, glaucoma, and hypoplasia of the fovea and optic nerve, leading to reduced visual acuity and even blindness. This study aimed to describe the diversity of clinical features caused by PAX6 pathogenic variants in 45 Han Chinese patients from 23 unrelated families. All patients underwent detailed clinical assessment. Genetic testing was performed to identify pathogenic variations in the PAX6 gene by next-generation sequencing, minigene splicing assay, RT-qPCR, and long-range PCR. Twenty pathogenic variations were detected in the PAX6 gene from 12 pedigrees and 11 sporadic patients, of which 12 were previously reported and 8 were novel. The clinical phenotypes obtained as a result of the PAX6 gene mutations were complicated and vary among patients, even among those who carried the same variants. Genetic testing is helpful for differential diagnosis. Our genetic findings will expand the spectrum of pathogenic variations in the PAX6 gene. PAX6 pathogenic variants not only cause defects in ocular tissues, such as the iris and retina, but also lead to maldevelopment of the whole eye, resulting in microphthalmia.

Thicknesses of the retina and choroid in children with retinitis pigmentosa.

PURPOSE: To compare the retinal thicknesses (RT) and choroidal thicknesses (CT) in retinitis pigmentosa (RP) children with those of healthy children using enhanced depth imaging (EDI) optical coherence tomography (OCT). The RT and CT in different genetic subgroups of autosomal dominant RP (ADRP) and X-linked inheritance RP (XLRP) were further studied to investigate the characteristics of retinal and choroidal changes in the early stages of RP. METHOD: A retrospective analysis was performed on a group of patients with RP who underwent EDI-OCT. Thirty-two children (64 eyes) with RP and 28 age- and refraction-matched healthy children (56 eyes) were included in the study. Seven of the 32 RP children (14 eyes) had X-linked inheritance RP, and 10 (20 eyes) had autosomal dominant inheritance RP. RT and CT were measured by optical coherence tomography and compared between the 32 children with RP and 28 controls and between 7 XLRP and 10 ADRP children. RESULT: Among the 32 children with RP, there were 18 males and 14 females with an average age of 6.6 ± 2.4 years. The mean RT was smaller in the RP group than in the control group at all of the locations. The mean temporal CT was smaller in the RP group (243.76 ± 60.82 µm) than in the control group (275.23 ± 40.92 µm) (P = 0.001), while there was no significant thinning on the foveal or nasal side. The best-corrected visual acuity of the XLRP group (0.40 ± 0.19) was worse than that of the ADRP group (0.68 ± 0.21) (P = 0.001), but the disease duration was the same (P = 0.685). The mean foveal RT was smaller in the XLRP group (173.85 ± 22.87 µm) than in the ADRP group (192.20 ± 9.70 µm) (P = 0.003), while there was no significant thinning at the other locations we studied. The mean temporal CT was smaller in the XLRP group (211.21 ± 69.41 µm) than in the ADRP group (274.45 ± 57.91 µm) (P = 0.007); CT measurements in XLRP children showed a more severe reduction on the temporal side. CONCLUSION: The choroid in RP children was preferentially smaller on the temporal side of the macula, and retinal thinning was relatively extensive. Children with RP have strong clinical and genetic heterogeneity. The XLRP children demonstrated greater RT reduction at the fovea and greater CT reduction at the temporal side of the macula than the ADRP children. Our findings also provide evidence that the changes in thicknesses may be indicative of the greater severity of XLRP versus ADRP in the early stage.

Clinical and genetic studies of 17 Han Chinese pedigrees and 31 sporadic patients with blepharophimosis-ptosis-epicanthus inversus syndrome.

Purpose: To investigate the molecular pathogenesis of a large group of Han Chinese patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), and to evaluate the correlation between the phenotype and genotype for these patients. Methods: Seventy-six affected individuals, including 45 patients from 17 pedigrees and 31 sporadic patients, were recruited with their family members. All participants underwent complete clinical examinations and were classified as having type I or II based on whether they had premature ovarian failure. The patients' genomic DNA was extracted. A genetic test was performed with direct sequencing of the coding regions of the forkhead transcriptional factor 2 (FOXL2) gene. Variations were analyzed using online databases and programs. Genotype-phenotype correction was investigated. Results: Seventy-six affected and 75 unaffected individuals underwent clinical evaluations and genetic testing. Only one family was diagnosed with type I; the others could not be classified because of a lack of female patients or a definite history of premature ovarian failure. Twenty-seven variations were identified, including 12 novel and 15 previously reported variations. Six variations were detected repeatedly in different nonconsanguineous pedigrees. Four indel variations, located in the alanine/proline-rich region of the FOXL2 gene, presented with a relatively higher frequency. Two rare double variations were detected in two sporadic patients. FOXL2 gene variations were not detected in five sporadic patients. The phenotype varied among different families and patients, although they carried the same variations. Conclusions: We identified 12 novel variations in the FOXL2 gene that would expand the spectrum of the FOXL2 variation database. In addition, we found that the alanine/proline-rich region is a variation hotspot in the FOXL2 gene. The genotype-phenotype correlation is not easy to establish due to clinical and genetic heterogeneity.

Clinical features and genotypes of six patients from four families with horizontal gaze palsy with progressive scoliosis.

Background: Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare disorder mainly involved in ocular movement and spinal development. It is caused by a roundabout guidance receptor 3 (ROBO3) gene mutation. This study aimed to describe the clinical features of six patients with HGPPS and investigate the corresponding ROBO3 gene mutations. Methods: Patients underwent detailed clinical and imaging examinations. Whole-exome sequencing was performed to detect nucleotide variations in the disease-causing genes of HGPPS. Results: Six pathogenic variants were detected in the ROBO3 gene from six patients with HGPPS, including two novel compound heterozygous mutations, c.1447C > T (p.R483X) and c.2462G > C (p.R821P); c.1033G > C (p.V345L) and c.3287G > T (p.C1096F); a novel homozygous indel mutation, c.565dupC (p.R191Pfs*61); and a known missense mutation, c.416G > T (p.G139V). Patients with HGPPS had horizontal conjugated eye movement defects and scoliosis with variable degrees, as well as flattened pontine tegmentum and uncrossed corticospinal tracts on magnetic resonance imaging. Conclusion: Our genetic findings will expand the spectrum of ROBO3 mutations and help inform future research on the molecular mechanism of HGPPS.

Case report: Exotropia in waardenburg syndrome with novel variations.

Background: Waardenburg syndrome (WS) is a rare genetic disorder characterized by congenital sensorineural hearing loss and pigmentary abnormalities of the hair, skin and eyes. However, exotropia is rarely reported. The purpose of this study is to describe the clinical characteristics of three sporadic patients with WS and congenital exotropia and to investigate the disease-causing genes for them. Methods: Patients underwent detailed physical and ocular examinations. Ocular alignment and binocular status were evaluated. DNA was extracted and whole exome sequencing was performed to detect the pathogenic variations in the disease-causing genes for WS. Cloning sequencing was carried out for those indel variations. Results: Three unrelated patients were diagnosed with Waardenburg syndrome and congenital exotropia. Four novel variants, including c.136delA (p.I46Sfs*64) and c.668G>T (p.R223L) in PAX3, c.709dupC (p.Q237Pfs*119) in COL11A2, c.426G>A (p.W142X) in SOX10 gene, were detected in this study. Conclusion: Simultaneous presence of congenital exotropia and WS in our patients is suggested that WS could be involved in malfunction in the multiple nerve systems. Our genetic study will expand the mutation spectrum of PAX3, COL11A2 and SOX10 genes, and is helpful for further study on the molecular pathogenesis of WS.

The Relationship between the Aqueous VEGF Level and the Severity of Type 1 Retinopathy of Prematurity.

PURPOSE: To analyze the relationship between the severity of type 1 retinopathy of prematurity (ROP) and the level of vascular endothelial growth factor (VEGF) in aqueous fluid. METHODS: The aqueous VEGF levels of 49 patients (88 eyes) with type 1 ROP were retrospectively analyzed. These eyes were categorized into three groups according to the severity of disease: aggressive retinopathy of prematurity (A-ROP), threshold of ROP (T-ROP), and type 1 pre-threshold ROP (P-T-1). The differences in aqueous VEGF levels among these three groups were compared. The relationship between the aqueous VEGF level and the retinal changes of ROP, including the vessel tortuosity in zone I, and the location and stage of the ROP lesions, were also analyzed. RESULTS: The aqueous VEGF level of the A-ROP group was the highest among the three groups, followed by those of the T-ROP and P-T-1 groups. The aqueous VEGF level was negatively correlated with the zone and the stage of the ROP diseases, while it was positively correlated with the venous tortuosity in zone I and had no relevance with the artery tortuosity in zone I. CONCLUSIONS: The aqueous VEGF level in A-ROP was the highest in type I ROP. The location of the ROP lesions and the venous tortuosity in zone I correlated with the aqueous VEGF level and could indicate the severity of ROP.

Abnormal developmental trends of functional connectivity in young children with infantile esotropia.

Previous studies have shown that functional networks are present at birth and change dynamically throughout infancy and early childhood. However, the status of functional connectivity is still poorly understood in patients with infantile esotropia (IE). The aim of this study is to investigate the developmental trends of functional connectivity in patients with IE during a critical period of growth and development. A total of 17 patients with IE (9 males and 8 females; mean age: 3.36 ± 2.03 years, age range: 0.67-6.36 years) and 20 healthy subjects matched for age and gender were recruited and underwent resting-state functional magnetic resonance imaging. The whole-brain functional network connectivity was analyzed for the IE group and healthy control group. A general linear model was applied to assess the group-age interaction in terms of the functional connectivity. The discrepancy between the two groups in functional connectivity trajectories was also quantified across age and exhibited by the quadratic parabolic model. There were significant group-age interactions between the visual network and the default mode network, the visual network and the sensorimotor network, the limbic network and the default mode network, and within the limbic network in the functional connectivity. A U-shaped tendency across age, with an "inflection point" ranging from 3.1 to 4.0 years of age was exhibited in the difference between functional connectivity trajectories of the IE patients and normal controls. Abnormality in functional network connectivity could present in IE patients at birth, exhibiting aberrant developmental patterns over time. An abnormal functional network could reduce the ability of the cortex in visual information processing, further reactivating the subcortical visual information processing system, which is probably the pathogenesis of IE. Three to four years after birth is the critical time window for children with IE to establish normal network connections in the brain. Early surgery during this period may be helpful for affected children to have an opportunity to approach the normal development trajectory as early as possible.

Nasal Transposition of the Split Lateral Rectus Muscle for Strabismus Associated With Bilateral 3rd-Nerve Palsy.

PURPOSE: To determine the success rate and complications associated with nasal transposition of the split lateral rectus muscle (NTSLR) for treating bilateral 3rd-nerve palsy. DESIGN: Retrospective, interventional case series. METHODS: An international, multicenter registry was used for the study. The study population was all patients with bilateral 3rd-nerve palsy treated with NTSLR. Sensorimotor evaluations were conducted before and 6 months after unilateral or bilateral NTSLR. Outcome measures were postoperative horizontal alignment ≤15 prism diopters (PD), intraoperative technical difficulties, and vision-threatening complications. The association of patient demographics and surgical technique with each outcome was analyzed using multivariable logistic regression. RESULTS: A total of 34 patients were included, with a median age of 46 years (interquartile range [IQR] = 25-54 years) at surgery. The most common etiologies were ischemic (29%), neoplastic (15%), and congenital (12%). NTSLR performed unilaterally with alternative surgery on the opposite eye (65%) resulted in a median postoperative exotropia of 18 PD (IQR = 7-35 PD), and when performed bilaterally (35%) resulted in postoperative exotropia of 14 PD (IQR = 5-35 PD). Success was achieved in 50% of cases, intraoperative technical difficulties were reported in 18%, and vision-threatening complications occurred in 21%. Attachment of the lateral rectus muscle ≥10 mm posterior to the medial rectus insertion was associated with increased vision-threatening complications (odds ratio = 9.0; 95% CI = 1.3-99). CONCLUSIONS: NTSLR can address the large-angle exotropia associated with bilateral 3rd-nerve palsy. Surgeons should be aware that posterior placement of the lateral rectus muscle may increase the risk of vision-threatening complications, particularly serous choroidal effusion.

Correlations of FRMD7 gene mutations with ocular oscillations.

Mutations in the FERM domain containing 7 (FRMD7) gene have been proven to be responsible for infantile nystagmus (IN). The purpose of this study is to investigate FRMD7 gene mutations in patients with IN, and to evaluate the nystagmus intensity among patients with and without FRMD7 mutations. The affected males were subdivided into three groups according to whether or not having FRMD7 mutations and the types of mutations. Fifty-two mutations were detected in FRMD7 in 56 pedigrees and 34 sporadic patients with IN, including 28 novel and 24 previous reported mutations. The novel identified mutations further expand the spectrum of FRMD7 mutations. The parameters of nystagmus intensity and the patients' best corrected visual acuity were not statistically different among the patients with and without identified FRMD7 mutations, and also not different among patients with different mutant types. The FERM-C domain, whose amino acids are encoded by exons 7, 8 and 9, could be the harbor region for most mutations. Loss-of-function is suggested to be the common molecular mechanism for the X-linked infantile nystagmus.

Differences in gene expression between the primary and secondary inferior oblique overaction.

Background: This study sought to define different adaptive changes in the molecular levels of the overacting inferior oblique muscle in primary and secondary inferior oblique overaction. Methods: The inferior oblique muscles of patients with congenital superior oblique palsy (SOP) and those of patients with congenital esotropia were collected during surgery. RNA-seq technology was performed to detect the differentially expressed genes (DEGs) between the two groups. A comprehensive analysis of the gene expression profiles was then conducted, including the identification of DEGs, a Gene Ontology (GO) analysis, and a gene set enrichment analysis (GSEA). Finally, a protein-protein interaction (PPI) network was constructed with Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape software. Results: We identified 221 DEGs, of which 104 were significantly upregulated and 117 were downregulated in the SOP group. Additionally, several isoforms of the myosin heavy chain (MyHC) gene were found to be significantly and differentially expressed in the SOP group, including 3 upregulated fast-twitch MyHC isoforms (i.e., MYH1, MYH4, and MYH13) and 1 downregulated slow-twitch MyHC isoform (i.e., MYH3). The GO analysis indicated that the upregulated DEGs were mainly enriched in the muscle system process and muscle contraction. The GSEA analysis revealed that the upregulated pathways of ribosome, proteasome, oxidative phosphorylation, fatty acid metabolism, viral myocarditis, and cardiac muscle contraction were enriched. Conclusions: Our findings provide insights into the different molecular changes of inferior oblique muscle overaction secondary to SOP and suggest the potential pathological mechanisms of inferior oblique overaction (IOOA) in SOP. The results suggest that upregulated fast-twitch MyHC isoforms and downregulated slow-twitch MyHC isoform in SOP may contribute to the increased force of its inferior oblique muscle.

Y-splitting medial rectus muscle and recession in treatment for convergence excess esotropia.

AIM: To evaluate the surgical outcome of medial rectus (MR) recession with Y-splitting procedure in treatment of esotropia with convergence excess. METHODS: Medical records were retrospectively reviewed for those patients who underwent surgical treatment for their convergence excess esotropia (CEET) between January 2018 and December 2020. Refractive error was examined by the equipment of the VS100 (Welch Allyn). The surgical approach was bilateral MR recession with Y-splitting. The amount of recession was calculated according to the deviation angle at distance. Ocular movement and ocular alignment at distance and near were evaluated pre- and post-operatively. Binocular sensory status was evaluated by the Bagolini striated glasses at near and distance, and by stereoacuity assessment at near using the Titmus test. RESULTS: Six patients with CEET were included in this study. Four of them were hyperopia and two of them were myopia. A mean of eso-deviation angle at distance had been changed from 27.3±13.02 prism diopters (PD) preoperatively to 1.83±1.60 PD postoperatively (P<0.05), while a mean of eso-deviation angle at near had been changed from 50.00±20.74 PD preoperatively to 6.83±0.98 PD postoperatively (P<0.05). Patients had obtained binocular vision postoperatively. CONCLUSION: The surgical approach of Y-splitting MR and recession is effective in treatment of CEET.