Publications by authors named "Loh-Shan Leung"

Introduction: This study examines a set of oculomotor measurements, or "oculometric" biomarkers, as potential early indicators of visual and visuomotor deficits due to retinal toxicity in asymptomatic Systemic Lupus Erythematosus (SLE) patients on long-term hydroxychloroquine (HCQ) treatment. The aim is to identify subclinical functional impairments that are otherwise undetectable by standard clinical tests and to link them to structural retinal changes.

Methods: We measured oculomotor responses in a cohort of SLE patients on chronic HCQ therapy using a previously established behavioral task and analysis technique.

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Bietti crystalline dystrophy (BCD) is a rare heritable retinal disease characterized by crystal deposition primarily in the retina. It is associated with atrophy of the retinal pigment epithelium (RPE) and is caused by variants in CYP4V2 , which encodes a cytochrome P450 hemethiolate protein superfamily member. CYP4V2 is involved in the selective hydrolysis of saturated medium chain fatty acids, and patients with BCD demonstrate abnormalities in fatty acid metabolism, including abnormal lipid profiles and the accumulation of the pathogenic crystals within the RPE, which leads to the visual pathologies characteristic of BCD.

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Aim: To describe and correlate electroretinographic responses with clinical and angiographic findings in retinal vasculitis (RV).

Methods: Medical records of patients with diagnosis of RV at a tertiary eye centre from December 2017 to May 2021 were reviewed. Cases in which fluorescein angiography (FFA) and full field electroretinography (ffERG) were done within 1 month were included.

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Purpose: This article reports the case of a 21-year-old woman with both hypertensive retinopathy and Purtscher-like retinopathy in association with C3 glomerulopathy.

Observations: The patient was referred for bilateral painless vision loss with posterior pole cotton wool spots, optic disc edema, and confluent retinal whitening suggesting a mixed picture of hypertensive retinopathy, with initial blood pressure 236/152, and Purtscher-like retinopathy. She was subsequently diagnosed with C3 glomerulopathy which likely caused her severe hypertension and which likely occurred alongside Purtscher-like retinopathy due to a shared pathogenesis of complement dysregulation.

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Purpose: To report a patient who developed a cancer associated retinopathy (CAR) like syndrome in the setting of pembrolizumab and lenvatinib combination therapy for metastatic endometrial carcinoma. Symptoms resolved with normalization of objective functional tests following cessation of medications.

Observations: A 52-year-old female with history of endometrial carcinoma, managed with pembrolizumab infusions and daily oral lenvatinib treatment for 18 months, presented to a tertiary eye center with complaints of nyctalopia, photosensitivity and photopsia.

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Intracameral cefuroxime has been associated with postoperative macular edema and sub-retinal fluid. To date, nearly all published cases are attributed to errors in antibiotic dilution, leading to administration of supratherapeutic doses. We report three cases of postoperative macular edema and subretinal fluid following a standard dose of 1 mg/0.

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Purpose: To compare dilated smartphone-based imaging with a nonmydriatic, tabletop fundus camera as a teleophthalmology screening tool for diabetic retinopathy (DR).

Methods: This was a single-institutional, cross-sectional, comparative-instrument study. Fifty-six patients at a safety-net hospital underwent teleophthalmology screening for DR using standard, nonmydriatic fundus photography with a tabletop camera (Nidek NM-1000) and dilated fundus photography using a smartphone camera with lens adapter (Paxos Scope, Verana Health).

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Purpose Of Review: This review aims to discuss retinal diseases that may masquerade as neurological causes of vision loss and highlights modern ophthalmic ancillary testing that can help to establish these diagnoses.

Recent Findings: Retinal diseases with signs and symptoms overlapping with neurological causes of vision loss include central serous chorioretinopathy, retinal ischemia, acute macular neuroretinopathy, Acute zonal occult outer retinopathy (AZOOR) complex diseases, paraneoplastic retinopathy, retinal dystrophy, and toxic retinopathy. Diagnosis is facilitated by electrophysiologic studies and multimodal ophthalmic imaging including optical coherence tomography and fundus autofluorescence imaging.

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Background And Objective: To characterize the burden of eye disease and the utility of teleophthalmology in nursing home patients, a population with ophthalmic needs not commensurate with care received.

Patients And Methods: Informed consent was obtained from 78 California Bay Area skilled nursing facility patients. Near visual acuity (VA) and anterior/posterior segment photographs were taken with a smartphone-based VA app and ophthalmic camera system.

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Purpose: To determine if final visual acuity (VA) is affected by duration of macular detachment (DMD) within the first week of macula-off retinal detachment (RD).

Methods: This is a retrospective study of eyes that underwent repair within 7 days with vitrectomy or vitrectomy with scleral buckle for macula-off RD at Stanford University Hospital between 1 May 2007 and 1 May 2017. A generalised linear model was constructed using DMD, postoperative lens status, preoperative VA, patient age and surgeon as the independent variables and the final VA as the dependent variable.

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Photodynamic Therapy-Induced Macular Hole.

Ophthalmic Surg Lasers Imaging Retina

April 2018

A 72-year-old female with neovascular macular degeneration refractory to anti-vascular endothelial growth factor injections underwent photodynamic therapy and subsequently developed a macular hole (MH) associated with vitreomacular traction. After a period of observation, the MH enlarged. Pars plana vitrectomy was performed, and the MH was closed successfully.

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Background And Objective: To compare pneumatic retinopexy (PR) and scleral buckle for the repair of primary rhegmatogenous retinal detachment.

Patients And Methods: Retrospective analysis of 90 patients undergoing surgery for primary rhegmatogenous retinal detachment, with 46 patients undergoing PR compared with 44 patients undergoing scleral buckle procedure (SBP).

Results: Both groups had similar baseline characteristics.

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Purpose: To report rapid onset of retinal toxicity in a series of patients followed on high-dose (1000 mg daily) hydroxychloroquine during an oncologic clinical trial studying hydroxychloroquine with erlotinib for non-small cell lung cancer.

Design: Retrospective observational case series.

Methods: Ophthalmic surveillance was performed on patients in a multicenter clinical trial testing high-dose (1000 mg daily) hydroxychloroquine for advanced non-small cell lung cancer.

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CNS neurons change their connectivity to accommodate a changing environment, form memories, or respond to injury. Plasticity in the adult mammalian retina after injury or disease was thought to be limited to restructuring resulting in abnormal retinal anatomy and function. Here we report that neurons in the mammalian retina change their connectivity and restore normal retinal anatomy and function after injury.

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Purpose: To evaluate the effect of intravitreal triamcinolone acetonide (TA) on healing of retinal photocoagulation lesions using drug and laser dosing typically employed in clinical practice.

Methods: Laser burns with a 267-μm retinal beam size at 532-nm wavelength were applied to 40 eyes of Dutch belted rabbits. Barely visible to intense lesions were produced with pulses of 5, 10, 20, and 50 milliseconds and power of 175 mW.

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Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), is widely used for the treatment of macular edema associated with central retinal vein occlusion (CRVO). The authors present a series of three patients with CRVO who suffered apparent macular infarction within weeks of intravitreal administration of bevacizumab. Of the nearly 200 patients undergoing intravitreal injections of bevacizumab for this indication over a surveillance period of 3 years, this event occurred in three patients.

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Background And Objective: The 577-nm (yellow) laser provides an alternative to the 532-nm (green) laser in retinal photocoagulation, with potential benefits in macular treatment and through ocular opacities. To assess relative risk of thermomechanical rupture of Bruch's membrane with yellow laser in photocoagulation, the therapeutic window, the ratio of threshold powers for mild coagulation and rupture, was measured.

Materials And Methods: Retinal coagulation and rupture thresholds, visualized ophthalmoscopically, were measured with 577- and 532-nm lasers using 10- to 100-ms pulses in 34 rabbit eyes.

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Macular edema is a common cause of visual loss in patients with retinal vein occlusions. Ozurdex(®), a dexamethasone intravitreal implant, has been shown in randomized controlled trials to reduce macular edema and improve visual acuity in patients with either branch retinal vein occlusions or central retinal vein occlusions. It was approved in the United States in 2009.

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Decreasing the pulse duration helps confine damage, shorten treatment time, and minimize pain during retinal photocoagulation. However, the safe therapeutic window (TW), the ratio of threshold powers for thermomechanical rupture of Bruch's membrane and mild coagulation, also decreases with shorter exposures. Two potential approaches toward increasing TW are investigated: (a) decreasing the central irradiance of the laser beam and (b) temporally modulating the pulse.

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Purpose: Subthreshold retinal phototherapy demonstrated clinical efficacy for the treatment of diabetic macular edema without visible signs of retinal damage. To assess the range of cellular responses to sublethal hyperthermia, expression of the gene encoding a 70 kDa heat shock protein (HSP70) was evaluated after laser irradiation using a transgenic reporter mouse.

Methods: One hundred millisecond, 532 nm laser exposures with 400 μm beam diameter were applied to the retina surrounding the optic nerve in 32 mice.

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Purpose: To evaluate the safety, selectivity, and healing of retinal lesions created using a continuous line scanning laser.

Methods: A 532-nm Nd:YAG laser (PASCAL) with retinal beam diameters of 40 μm and 66 μm was applied to 60 eyes of 30 Dutch-belted rabbits. Retinal exposure duration varied from 15 μs to 60 μs.

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A 28-year-old woman presented with a 2-week history of right upper eyelid swelling and intermittent frontal headaches. CT demonstrated an ill-defined superior right orbital mass with adjacent right frontal bone erosion and undeveloped frontal sinuses. The orbital biopsy revealed tissue strongly positive for CD1a and S100, diagnostic of Langerhans cell histiocytosis.

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It has been nearly a century since Jules Gonin performed the first intervention for rhegmatogenous retinal detachment, trans-scleral cautery, achieving successful outcomes in close to 50% of his cases. With the introduction of alternative surgical approaches in the last half-century, including Charles Schepens' scleral buckle technique and Robert Machemer's pars plana vitrectomy, the surgical success rates have risen to close to 90%. Nonetheless, despite dramatic progress in the success of reattachment surgeries, reasonable disagreement exists as to which approach (or combination of approaches) is the best form of surgical intervention for patients with rhegmatogenous retinal detachments.

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