Publications by authors named "Chan Choi Mun"

Inherited retinal degeneration (IRD) is a heterogeneous group of genetic disorders of variable onset and severity, with vision loss being a common endpoint in most cases. More than 50 distinct IRD phenotypes and over 280 causative genes have been described. Establishing a clinical phenotype for patients with IRD is particularly challenging due to clinical variability even among patients with similar genotypes.

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Purpose: We describe an atypical presentation of an 11-year-old female with enhanced S-cone syndrome (ESCS).

Methods: Case report. The patient underwent a thorough ophthalmic examination and investigations such as colour fundus photography, optical coherence tomography, fundus autofluorescence, fluorescein and indocyanine angiography, an electroretinogram and genetic testing.

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Article Synopsis
  • The paper looks at how inherited retinal diseases (IRD) are diagnosed and treated in the Asia-Pacific region.
  • They surveyed 36 centers about their practices, including how they collect patient information and provide help for low vision.
  • The results showed there are important gaps, like many centers not having a database for patients, not enough genetic counselors, and a need for better support for low-vision rehabilitation.
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Background: Planned gene therapies for retinitis pigmentosa (RP) depend on viable photoreceptors for efficacy. Understanding disease severity at presentation, and drivers that influence time to presentation is important when planning interventions. We examined features that influence RP severity at initial presentation.

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Purpose: To describe the early experiences of patients with neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) whose treatment was switched to faricimab from other anti-vascular endothelial growth factor (VEGF) agents.

Methods: This is a prospective cohort of eyes with nAMD and PCV that were previously treated with anti-VEGF agents other than faricimab. We evaluated visual acuity (VA), central subfield thickness (CST), macular volume (MV), pigment epithelial detachment (PED) height, and choroidal thickness (CT) after one administration of faricimab.

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(1) Purpose: -associated retinal degeneration (-RD) is a phenotypically diverse disease that often evades diagnosis, even by experienced retinal specialists. This may lead to inappropriate management, delayed genetic testing, or inaccurate interpretation of genetic testing results. Here, we illustrate the phenotypic diversity of -RD using a series of representative cases and compare these to other conditions that closely mimic -RD.

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Purpose: The study aimed to describe the phenotypic features of retinitis pigmentosa (RP) associated with the previously described EYS C2139Y variant in Singaporeans and establish the importance of this variant as a prevalent cause of RP among East Asians.

Methods: A clinical phenotyping and exome-sequencing study was conducted on consecutive patients with nonsyndromic RP. Epidemiological analysis was performed using Singaporean and global population-based genetic data.

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Objective: To assess the economic impact of inherited retinal disease (IRD) among Singaporeans.

Methods: IRD prevalence was calculated using population-based data. Focused surveys were conducted for sequentially enrolled IRD patients from a tertiary hospital.

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Background: Ongoing trials for retinitis pigmentosa (RP) are genotype-specific, with most trials conducted on European cohorts. Due to genetic differences across diverse ancestries and populations, these therapies may not be efficacious in East Asians.

Materials And Methods: A literature search was conducted from 1966 to September 2022 for cohort studies on East Asian populations reporting on non-syndromic RP genotypes and variants.

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Background: To evaluate the ability of handheld chromatic pupillometry to reveal and localise retinal neural dysfunction in diabetic patients with and without diabetic retinopathy (DR).

Methods: This cross-sectional study included 82 diabetics (DM) and 93 controls (60.4 ± 8.

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Objective: To evaluate the pattern of vision loss and genotype-phenotype correlations in WFS1-associated optic neuropathy (WON).

Design: Multicenter cohort study.

Methods: The study involved 37 patients with WON carrying pathogenic or candidate pathogenic WFS1 variants.

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Inherited retinal diseases (IRDs) are a heterogenous group of orphan eye diseases that typically result from monogenic mutations and are considered attractive targets for gene-based therapeutics. Following the approval of an IRD gene replacement therapy for Leber's congenital amaurosis due to mutations, there has been an intensive international research effort to identify the optimal gene therapy approaches for a range of IRDs and many are now undergoing clinical trials. In this review we explore therapeutic challenges posed by IRDs and review current and future approaches that may be applicable to different subsets of IRD mutations.

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Purpose: To evaluate whether optical coherence tomography (OCT) can determine polypoidal lesion (PL) perfusion in polypoidal choroidal vasculopathy eyes after 12 months of aflibercept monotherapy. Polypoidal lesion perfusion status, assessed by indocyanine green angiography, is an important anatomical outcome in polypoidal choroidal vasculopathy management.

Methods: Post hoc data from a prospective randomized, open-label, study in eyes with polypoidal choroidal vasculopathy undergoing monotherapy with aflibercept evaluated PL perfusion status based on indocyanine green angiography (gold standard) and OCT features from baseline to 12 months.

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: Mutations in the RCC1 and BTB domain-containing protein 1 () gene have been implicated in a rare form of retinal dystrophy. Herein, we report the clinical features of a 45-year-old Singaporean-Chinese female and her presymptomatic sibling, who each possesses compound heterozygous mutations in . Expression of in patient-derived cells was evaluated.

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Purpose: To compare the efficacy of aflibercept using a personalised versus fixed regimen in treatment-naïve participants with polypoidal choroidal vasculopathy (PCV).

Design: A 52-week, randomised, open-label, non-inferiority, single-centre study that included participants with symptomatic PCV. Participants were randomised (3:1 ratio) to receive either personalised (n=40) or fixed 8-weekly treatment regimen (n=13).

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Purpose: To describe the 12-month outcomes of treatment-naïve eyes with choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) after initiation of intravitreal anti-vascular endothelial growth factor (VEGF) monotherapy or combination therapy with verteporfin photodynamic therapy (PDT).

Design: A 12-month single-center, retrospective, comparative, nonrandomized cohort study.

Participants: Patients with AMD or PCV who initiated intravitreal anti-VEGF therapy during 2015.

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Importance: Wide-field optical coherence tomographic angiography (OCTA) may provide insights to peripheral capillary dropout in eyes with diabetic retinopathy (DR).

Objective: To describe the diagnostic performance of wide-field OCTA with and without large vessel removal for assessment of DR in persons with diabetes.

Design, Setting, And Participants: This case-control study was performed from April 26, 2018, to April 8, 2019, at a single tertiary eye center in Singapore.

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Background: While the aetiology of age-related macular degeneration (AMD)-a major blinding disease-remains unknown, the disease is strongly associated with variants in the complement factor H (CFH) gene. CFH variants also confer susceptibility to invasive infection with several bacterial colonizers of the nasopharyngeal mucosa. This shared susceptibility locus implicates complement deregulation as a common disease mechanism, and suggests the possibility that microbial interactions with host complement may trigger AMD.

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Purpose: To assess the ability of optical coherence tomography (OCT) alone and in combination with OCT angiography (OCTA) to differentiate polypoidal choroidal vasculopathy (PCV) from neovascular age-related macular degeneration, as compared to fluorescein angiography and indocyanine green angiography.

Methods: This is a cross-sectional study. All participants had a standardized history, clinical examination including measurement of best-corrected visual acuity, slit-lamp biomicroscopy, and indirect fundus examination, and underwent standardized imaging (color photography, fluorescein and indocyanine green angiography, OCT, and OCTA) after predefined protocols.

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Importance: Since the advent of optical coherence tomography angiography (OCT-A), nonexudative neovascularization has been described in the fellow eyes of unilateral exudative age-related macular degeneration (AMD). However, there is limited literature describing the natural course and optimal management of these lesions.

Objective: To determine the incidence of fellow eye involvement in patients presenting with unilateral typical AMD or polypoidal choroidal vasculopathy and to evaluate the patterns of OCT-A changes within 6 months before the onset of exudative changes, especially focusing on nonexudative neovascularization.

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Polypoidal choroidal vasculopathy (PCV), a subtype of age-related macular degeneration (AMD) more frequently seen in East Asians, has both common and distinct clinical manifestations with typical neovascular AMD (tAMD). We aim to examine the extent to which common genetic variants are shared between these two subtypes. We performed the meta-analysis of association in a total of 1062 PCV patients, 1157 tAMD patients and 5275 controls of East Asian descent from the Genetics of AMD in Asians Consortium at the 34 known AMD loci.

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Choroid thinning occurs in age-related macular degeneration (AMD). However, it remains unclear whether the reduction is due to reduction in choroidal vessels or shrinkage of choroidal stroma, or both. The purpose of this study was to evaluate the changes of the choroidal vascular and stromal area in 118 patients with typical AMD (t-AMD) and polypoidal choroidal vasculopathy (PCV) over a 12-month period.

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Purpose: To compare changes in optical coherence tomography angiography in eyes with polypoidal choroidal vasculopathy after treatment with anti-vascular endothelial growth factor monotherapy or combined with photodynamic therapy.

Methods: This is a longitudinal case-controlled study. The authors performed optical coherence tomography angiography at baseline and Month 3 in patients with treatment-naive polypoidal choroidal vasculopathy undergoing monotherapy (n = 10) or combination therapy (n = 13).

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Purpose: To investigate the influence of choroidal vascular hyperpermeability (CVH) and choroidal thickness on treatment outcomes in eyes with polypoidal choroidal vasculopathy (PCV) undergoing anti-vascular endothelial growth factor monotherapy or combination therapy of photodynamic therapy and anti-vascular endothelial growth factor injections.

Methods: The authors performed a prospective, observational cohort study involving 72 eyes of 72 patients with polypoidal choroidal vasculopathy (mean age 68.6 years, 51% men) treated with either monotherapy (n = 41) or combination therapy (n = 31).

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Purpose: To determine the prevalence of subclinical nonexudative neovascularization and associated choroidal vascular changes in the fellow eyes of patients presenting with unilateral typical exudative AMD (tAMD) or polypoidal choroidal vasculopathy (PCV) using indocyanine green angiography (ICGA) and swept-source (SS) optical coherence tomography angiography (OCT-A).

Methods: We recruited patients presenting with tAMD or PCV in a prospective clinical study. The diagnosis in the presenting eye was determined based on clinical, fluorescein angiography (FA), and ICGA findings.

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