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Fundus albipunctatus: review of the literature and report of a novel RDH5 gene mutation affecting the invariant tyrosine (p.Tyr175Phe).
Skorczyk-Werner, A, Pawłowski, P, Michalczuk, M, Warowicka, A, Wawrocka, A, Wicher, K, Bakunowicz-Łazarczyk, A, Krawczyński, MR
Journal of applied genetics. 2015;(3):317-27
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Abstract
Fundus albipunctatus (FA) is a rare, congenital form of night blindness with rod system impairment, characterised by the presence of numerous small, white-yellow retinal lesions. FA belongs to a heterogenous group of so-called flecked retina syndromes. This disorder shows autosomal recessive inheritance and is caused mostly by mutations in the RDH5 gene. This gene encodes the enzyme that is a part of the visual cycle, the 11-cis retinol dehydrogenase. This study is a brief review of the literature on FA and a report of the first molecular evidence for RDH5 gene mutation in a Polish patient with this rare disorder. We present a novel pathogenic RDH5 gene mutation in a 16-year-old female patient with symptoms of night blindness. The patient underwent ophthalmological examinations, including colour vision testing, fundus photography, automated visual field testing, full-field electroretinography (ERG) and spectral optical coherent tomography (SOCT). The patient showed typical FA ERG records, the visual field was constricted and fundus examination revealed numerous characteristic, small, white-yellowish retinal lesions. DNA sequencing of the RDH5 gene coding sequence (exons 2-5) enabled the detection of the homozygous missense substitution c.524A > T (p.Tyr175Phe) in exon 3. This is the first report of RDH5 gene mutation that affects the invariant tyrosine, one of the most conserved amino acid residues in short-chain alcohol dehydrogenases/reductases (SDRs), crucial for these enzymes' activity. The location of this substitution, together with its predicted influence on the protein function, indicate that the p.Tyr175Phe mutation is the cause of FA in our patient.
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MEK inhibitors: a new class of chemotherapeutic agents with ocular toxicity.
Duncan, KE, Chang, LY, Patronas, M
Eye (London, England). 2015;(8):1003-12
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Abstract
A new class of chemotherapeutic agents, MEK inhibitors, has recently been developed and is proving to be an effective treatment for a number of cancers. A pattern of ocular adverse events has followed these drugs through clinical trials and their association with retinopathy is only just beginning to be recognized. We present two cases of MEK inhibitor-associated retinopathy followed by a review of the current literature on ocular toxicity associated with MEK inhibitors. Patients undergoing treatment with MEK inhibitors appear to have high rates of multifocal serous retinal detachments as well as retinal vein occlusions. We present the first report of cystoid macular edema associated with MEK inhibitor use. The mechanism of these adverse events is still unclear though they seem to be related to oxidative stress and blood retinal barrier breakdown. Management of the ocular toxicity can range from observation to topical treatments or intravitreal injections. Fortunately most ocular adverse events appear to be self-limited and do not require discontinuing the MEK inhibitor. Discontinuation or decreased dosing of MEK inhibitors may be reserved for cases of severe sight-threatening ocular toxicity.
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Enhanced depth imaging optical coherence tomography features in a young case of primary hyperoxaluria Type 1.
Özişik, GG, Asena, L, Bulam, B, Güngör, SG
Retinal cases & brief reports. 2015;(1):92-4
Abstract
PURPOSE To describe the enhanced depth imaging optical coherence tomography findings in a very young case of Type 1 primary hyperoxaluria. METHODS Observational case report of a young patient who underwent clinical examination and enhanced depth imaging optical coherence tomography evaluation. RESULTS A 4-year-old boy with a history of Type 1 primary hyperoxaluria and resulting chronic renal failure was referred to us for ophthalmologic examination. There were no ocular symptoms when he was referred to us. Fundus examination showed deposition of calcium oxalate crystals at the posterior pole located symmetrically in both eyes. Enhanced depth imaging optical coherence tomography evaluation revealed hyperreflective structures, localized under the photoreceptor inner segment/outer segment junction, and over the retinal pigment epithelium, consistent with deposition of oxalate crystals. There were no oxalate crystals in the superficial retinal layers, and we observed no evidence of deposition of oxalate crystals in choroid with enhanced depth imaging optical coherence tomography. CONCLUSION We could not demonstrate any oxalate deposits in the choroid with enhanced depth imaging optical coherence tomography in this young case of primary hyperoxaluria Type 1. This may be related to the young age of our patient, and the amounts of the crystalline deposition may increase in the years ahead.
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High-altitude retinopathy--case report.
Wilczyński, M, Kucharczyk, M, Filatow, S
Klinika oczna. 2014;(3):180-3
Abstract
High-altitude retinopathy is one of altitude-related illnesses. Its signs include high-altitude retinal hemorrhages, dilated vessels and peripapillary hyperemia. Increased intracranial pressure seems to be the main cause of all high-altitude diseases including high-altitude retinopathy, cerebral oedema and high-altitude pulmonary oedema. We present the case of high-altitude retinopathy in a 35-year-old woman who reported decreased vision in her right eye, scotomas and high-altitude retinopathy after ascending to more than 7000 meters above sea level. The associated optical coherence tomography findings, fundus photography and literature review are presented. High-altitude retinopathy is an important multifactorial condition of unknown mechanism and etiology, which significantly impacts human vision. Climbing high mountains can cause retinopathy in otherwise healthy people and may lead to permanent sequelae such as retinal nerve fiber layer and optic nerve defects. These symptoms, however, may resolve without causing any permanent damage to the retina. Conservative treatment may help to relieve them. With increasing popularity of mountaineering, ophthalmologists should be prepared to diagnose and treat high-altitude retinopathy.
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Hydroxychloroquine retinopathy after short-term therapy.
Phillips, BN, Chun, DW
Retinal cases & brief reports. 2014;(1):67-9
Abstract
PURPOSE To report an unusual case of hydroxychloroquine toxicity after short-term therapy. METHODS Observational case report. RESULTS A 56-year-old woman presented to the Ophthalmology Clinic at Walter Reed Army Medical Center (WRAMC) with a 6-month history of gradually decreasing vision in both eyes. The patient had been taking hydroxychloroquine for the preceding 48 months for the treatment of rheumatoid arthritis. Examination of the posterior segment revealed bilateral "bull's eye" macular lesions. Fundus autofluorescence revealed hyperfluorescence of well-defined bull's eye lesions in both eyes. Optical coherence tomography revealed corresponding parafoveal atrophy with a loss of the retinal inner segment/outer segment junction. Humphrey visual field 10-2 white showed significant central and paracentral defects with a generalized depression. The patient was on a standard dose of 400 mg daily, which was above her ideal dose. The patient had no history of kidney or liver dysfunction. There were no known risk factors but there were several possible confounding factors. The patient was started on high-dose nabumetone, a nonsteroidal antiinflammatory drug, at the same time she was started on hydroxychloroquine. She also reported taking occasional ibuprofen. CONCLUSION Retinal toxicity from chloroquine has been recognized for decades with later reports showing retinopathy from long-term hydroxychloroquine (Plaquenil) use for the treatment of antiinflammatory diseases. Hydroxychloroquine is now widely used and retinal toxicity is relatively uncommon. However, it can cause serious vision loss and is usually irreversible. The risk of hydroxychloroquine toxicity rises to nearly 1% with a total cumulative dose of 1,000 g, which is ∼5 years to 7 years of normal use. Toxicity is rare under this dose. For this reason, the American Academy of Ophthalmology has revised its recommendations such that annual screenings begin 5 years after therapy with hydroxychloroquine has begun unless there are known risk factors. This case report confirms the need for a baseline examination and annual ophthalmologic screening for patients taking hydroxychloroquine at a dose higher than the recommended dosage. It is also reasonable to consider annual examinations in patients taking high-dose nonsteroidal antiinflammatory drugs from the initiation of the medication.