Browsing by Author "Lam, Byron L."

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    Metastatic paraganglioma presenting as ajunctional scotoma
    (Elsevier, 2021-12-31) Khodeiry, Mohamed M.; Lind, John T.; Pasol, Joshua; Lam, Byron L.; Lee, Richard K.; Ophthalmology, School of Medicine
    Purpose: To report a unique case of metastatic paraganglioma presenting as a junctional scotoma. Observations: A 38-year-old Caucasian man with a history of abdominal paraganglioma presented with minimally blurred vision 20/25 visual acuity in the left eye. The patient was found to have a junctional scotoma upon visual field testing. Cranial MRI revealed a large peri-clival mass compressing the pre-chiasmal optic nerves and other loci of metastatic disease. Intracranial masses, including metastases, can present with a relatively intact central acuity and nonspecific visual symptoms. Conclusions and importance: To the best of our knowledge, this is the first report of metastatic paraganglioma causing a junctional scotoma. In cases with junctional scotoma, careful neuro-ophthalmic assessment and imaging are of paramount importance, even in patients with excellent visual acuity.
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    Pharmacotherapy of retinal disease with visual cycle modulators
    (Taylor & Francis, 2018) Hussain, Rehan M.; Gregori, Ninel Z.; Ciulla, Thomas A.; Lam, Byron L.; Ophthalmology, School of Medicine
    Introduction: Pharmacotherapy with visual cycle modulators (VCMs) is under investigation for retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), Stargardt macular dystrophy (SMD) and nonexudative age-related macular degeneration (AMD), all blinding diseases that lack effective treatment options. Areas covered: The authors review investigational VCMs, including oral retinoids, 9-cis-retinyl-acetate (zuretinol) and 9-cis-β-carotene, which restore 11-cis-retinal levels in RP and LCA caused by LRAT and RPE65 gene mutations, and may improve visual acuity and visual fields. Therapies for SMD aiming to decrease accumulation of toxic Vitamin A dimers and lipofuscin in the retina and retinal pigment epithelium (RPE) include C20-D3-vitamin A (ALK-001), isotretinoin, VM200, emixustat, and A1120. Mouse models of SMD show promising data for these treatments, though proof of efficacy in humans is currently lacking. Fenretinide and emixustat are investigational VCMs for dry AMD, though neither has been shown to reduce geographic atrophy or improve vision in human trials. A1120 prevents retinol transport into the RPE and may spare the side effects typically seen in VCMs (nyctalopia and chromatopsia) per mouse studies. Expert opinion: Oral VCMs may be feasible treatment options for degenerative retinal diseases based on pre-clinical and some early clinical studies. Further trials are warranted to assess their efficacy and safety in humans.
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    Stargardt macular dystrophy and evolving therapies
    (Taylor & Francis, 2018) Hussain, Rehan M.; Ciulla, Thomas A.; Berrocal, Audina M.; Gregori, Ninel Z.; Flynn, Harry W.; Lam, Byron L.; Ophthalmology, School of Medicine
    Introduction: Stargardt macular dystrophy (STGD1) is a hereditary retinal degeneration that lacks effective treatment options. Gene therapy, stem cell therapy, and pharmacotherapy with visual cycle modulators (VCMs) and complement inhibitors are discussed as potential treatments. Areas covered: Investigational therapies for STGD1 aim to reduce toxic bisretinoids and lipofuscin in the retina and retinal pigment epithelium (RPE). These agents include C20-D3-vitamin A (ALK-001), isotretinoin, VM200, emixustat, and A1120. Avacincaptad pegol is a C5 complement inhibitor that may reduce inflammation-related RPE damage. Animal models of STGD1 show promising data for these treatments, though proof of efficacy in humans is lacking. Fenretinide and emixustat are VCMs for dry AMD and STGD1 that failed to halt geographic atrophy progression or improve vision in trials for AMD. A1120 prevents retinol transport into RPE and may spare side effects typically seen with VCMs (nyctalopia and chromatopsia). Stem cell transplantation suggests potential biologic plausibility in a phase I/II trial. Gene therapy aims to augment the mutated ABCA4 gene, though results of a phase I/II trial are pending. Expert opinion: Stem cell transplantation, ABCA4 gene therapy, VCMs, and complement inhibitors offer biologically plausible treatment mechanisms for treatment of STGD1. Further trials are warranted to assess efficacy and safety in humans.