Retina

Bujakowska KM, Liu Q, Pierce EA. Photoreceptor Cilia and Retinal Ciliopathies. Cold Spring Harb Perspect Biol 2017;9(10)Abstract
Photoreceptors are sensory neurons designed to convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, with analogous structures to those present in other nonmotile cilia. Deficient morphogenesis and/or dysfunction of photoreceptor sensory cilia (PSC) caused by mutations in a variety of photoreceptor-specific and common cilia genes can lead to inherited retinal degenerations (IRDs). IRDs can manifest as isolated retinal diseases or syndromic diseases. In this review, we describe the structure and composition of PSC and different forms of ciliopathies with retinal involvement. We review the genetics of the IRDs, which are monogenic disorders but genetically diverse with regard to causality.
Huang X, Zhou G, Wu W, Ma G, D'Amore PA, Mukai S, Lei H. Editing VEGFR2 Blocks VEGF-Induced Activation of Akt and Tube Formation. Invest Ophthalmol Vis Sci 2017;58(2):1228-1236.Abstract

Purpose: Vascular endothelial growth factor receptor 2 (VEGFR2) plays a key role in VEGF-induced angiogenesis. The goal of this project was to test the hypothesis that editing genomic VEGFR2 loci using the technology of clustered regularly interspaced palindromic repeats (CRISPR)-associated DNA endonuclease (Cas)9 in Streptococcus pyogenes (SpCas9) was able to block VEGF-induced activation of Akt and tube formation. Methods: Four 20 nucleotides for synthesizing single-guide RNAs based on human genomic VEGFR2 exon 3 loci were selected and cloned into a lentiCRISPR v2 vector, respectively. The DNA fragments from the genomic VEGFR2 exon 3 of transduced primary human retinal microvascular endothelial cells (HRECs) were analyzed by Sanger DNA sequencing, surveyor nuclease assay, and next-generation sequencing (NGS). In the transduced cells, expression of VEGFR2 and VEGF-stimulated signaling events (e.g., Akt phosphorylation) were determined by Western blot analyses; VEGF-induced cellular responses (proliferation, migration, and tube formation) were examined. Results: In the VEGFR2-sgRNA/SpCas9-transduced HRECs, Sanger DNA sequencing indicated that there were mutations, and NGS demonstrated that there were 83.57% insertion and deletions in the genomic VEGFR2 locus; expression of VEGFR2 was depleted in the VEGFR2-sgRNA/SpCas9-transduced HRECs. In addition, there were lower levels of Akt phosphorylation in HRECs with VEGFR2-sgRNA/SpCas9 than those with LacZ-sgRNA/SpCas9, and there was less VEGF-stimulated Akt activation, proliferation, migration, or tube formation in the VEGFR2-depleted HRECs than those treated with aflibercept or ranibizumab. Conclusions: The CRISPR-SpCas9 technology is a potential novel approach to prevention of pathologic angiogenesis.

Heiferman MJ, Rahmani S, Jampol LM, Nesper PL, Skondra D, Kim LA, Fawzi AA. ACUTE POSTERIOR MULTIFOCAL PLACOID PIGMENT EPITHELIOPATHY ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina 2017;37(11):2084-2094.Abstract
PURPOSE: To investigate choroidal involvement in acute posterior multifocal placoid pigment epitheliopathy (APMPPE). METHODS: A retrospective observational case series using multimodal imaging including optical coherence tomography (OCT) angiography. RESULTS: Five patients with APMPPE were included. In most acute lesions, OCT angiography revealed outer retinal and retinal pigment epithelium (RPE) hyperreflective lesions with attenuated OCT signal in the underlying choroid, but careful examination allowed us to identify a single lesion with decreased choriocapillaris flow outside the signal attenuation. Optical coherence tomography angiography obtained after healing of lesions revealed areas of hypointense circular flow voids clustered in groups surrounded by either isointense or hyperintense signal background. Point-by-point evaluation revealed these flow voids did not correspond to areas of RPE thickening or focal pigmentary changes. Larger hypointense lesions were observed and did correlate with pigmentary changes. CONCLUSION: Our case series demonstrates choriocapillaris flow abnormalities in acute APMPPE extending beyond the OCT lesions, and distinct residual vascular abnormalities in healed APMPPE lesions on OCT angiography. Our findings support a primary ischemic insult to the photoreceptors and RPE, but choriocapillaris flow abnormalities could be secondary to (OCT invisible) retinal and RPE involvement. The lack of understanding of the etiology along with the inability to visualize most of the choroid in acute lesions precludes definite conclusions about the true pathogenesis of APMPPE.
Fu Z, Gong Y, Liegl R, Wang Z, Liu C-H, Meng SS, Burnim SB, Saba NJ, Fredrick TW, Morss PC, Hellstrom A, Talukdar S, Smith LEH. FGF21 Administration Suppresses Retinal and Choroidal Neovascularization in Mice. Cell Rep 2017;18(7):1606-1613.Abstract

Pathological neovascularization, a leading cause of blindness, is seen in retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration. Using a mouse model of hypoxia-driven retinal neovascularization, we find that fibroblast growth factor 21 (FGF21) administration suppresses, and FGF21 deficiency worsens, retinal neovessel growth. The protective effect of FGF21 against neovessel growth was abolished in adiponectin (APN)-deficient mice. FGF21 administration also decreased neovascular lesions in two models of neovascular age-related macular degeneration: very-low-density lipoprotein-receptor-deficient mice with retinal angiomatous proliferation and laser-induced choroidal neovascularization. FGF21 inhibited tumor necrosis α (TNF-α) expression but did not alter Vegfa expression in neovascular eyes. These data suggest that FGF21 may be a therapeutic target for pathologic vessel growth in patients with neovascular eye diseases, including retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration.

Witkin AJ, Chang DF, Jumper MJ, Charles S, Eliott D, Hoffman RS, Mamalis N, Miller KM, Wykoff CC. Vancomycin-Associated Hemorrhagic Occlusive Retinal Vasculitis: Clinical Characteristics of 36 Eyes. Ophthalmology 2017;124(5):583-595.Abstract

PURPOSE: To expand understanding of presentation, diagnosis, and outcomes of hemorrhagic occlusive retinal vasculitis (HORV). DESIGN: Retrospective case series. PARTICIPANTS: Thirty-six eyes of 23 patients. METHODS: The American Society of Cataract and Refractive Surgery (ASCRS) and the American Society of Retina Specialists (ASRS) formed a joint task force to define clinical characteristics of HORV and to study its prevalence, cause, treatment, and outcomes. An online registry was established on both societies' web sites. Surveys were e-mailed to members of both societies soliciting cases of suspected HORV. A literature search was performed to uncover additional cases. MAIN OUTCOME MEASURES: Historical data including intraoperative characteristics, images, treatment regimens, and visual and anatomic outcomes. RESULTS: Characteristic findings of HORV included unremarkable postoperative day 1 undilated examination, delayed-onset painless vision loss, mild anterior chamber and vitreous inflammation, sectoral retinal hemorrhages in areas of ischemia, and predilection for venules and peripheral involvement. Based on predetermined diagnostic criteria, 36 eyes of 23 patients were diagnosed with HORV. All eyes received intraocular vancomycin via intracameral bolus (33/36), via intravitreal injection (1/36), or through the irrigation bottle (2/36). Patients sought treatment with HORV 1 to 21 days after surgery or intravitreal injection. Visual results usually were poor: 22 of 36 eyes (61%) had 20/200 or worse visual acuity and 8 of 36 eyes (22%) had no light perception (NLP). Neovascular glaucoma developed in 20 of 36 eyes (56%). Seven eyes received additional intravitreal vancomycin after surgery; 5 of these 7 eyes had NLP visual acuity at the most recent examination. Three eyes received intravitreal corticosteroids and had final visual acuities of 20/40, 20/70, and hand movements. CONCLUSIONS: Hemorrhagic occlusive retinal vasculitis is a rare, potentially devastating condition that can develop after cataract surgery or intraocular injection. All cases in this series were associated with intraocular vancomycin. Disease course and findings suggest that HORV is caused by a delayed hypersensitivity reaction to vancomycin. Early treatment with corticosteroids likely is beneficial. Subsequently, anti-vascular endothelial growth factor injections and panretinal photocoagulation are important to prevent neovascular glaucoma, a common complication. Avoidance of additional intravitreal vancomycin is recommended if HORV is suspected.

Thanos A, Todorich B, Hypes SM, Yonekawa Y, Thomas B, Randhawa S, Drenser KA, Trese MT. RETINAL VASCULAR TORTUOSITY AND EXUDATIVE RETINOPATHY IN A FAMILY WITH DYSKERATOSIS CONGENITA MASQUERADING AS FAMILIAL EXUDATIVE VITREORETINOPATHY. Retin Cases Brief Rep 2017;11 Suppl 1:S187-S190.Abstract

PURPOSE: To report a novel presentation of dyskeratosis congenita masquerading as familial exudative vitreoretinopathy. METHODS: Observational case series involving single family and literature review. RESULTS: A brother and sister were diagnosed with familial exudative vitreoretinopathy at ages 4 and 2, respectively. Both patients were managed with laser photocoagulation. Eight years after the initial presentation, both siblings developed pancytopenia secondary to bone marrow failure. Laboratory work-up revealed severely shortened telomere length in both patients, and genetic testing revealed a missense mutation in the gene that encodes the reverse transcriptase component of telomerase, confirming the diagnosis of dyskeratosis congenita. The father of both children was a carrier of the same mutation, who exhibited marked retinal vascular tortuosity of the second-order vessels. CONCLUSION: Dyskeratosis congenita is a severe multisystem disorder, which should be considered in cases of pediatric exudative retinopathies with concurrent signs and/or symptoms of bone marrow failure.

Phadikar P, Saxena S, Ruia S, Lai TYY, Meyer CH, Eliott D. The potential of spectral domain optical coherence tomography imaging based retinal biomarkers. Int J Retina Vitreous 2017;3:1.Abstract

BACKGROUND: Biomarker", a merged word of "biological marker", refers to a broad subcategory of medical signs that objectively indicate the state of health, and well-being of an individual. Biomarkers hold great promise for personalized medicine as information gained from diagnostic or progression markers can be used to tailor treatment to the individual for highly effective intervention in the disease process. Optical coherence tomography (OCT) has proved useful in identifying various biomarkers in ocular and systemic diseases. MAIN BODY: Spectral domain optical coherence tomography imaging-based biomarkers provide a valuable tool for detecting the earlier stages of the disease, tracking progression, and monitoring treatment response. The aim of this review article is to analyze various OCT based imaging biomarkers and their potential to be considered as surrogate endpoints for diabetic retinopathy, age related macular degeneration, retinitis pigmentosa and vitreomacular interface disorder. These OCT based surrogate markers have been classified as retinal structural alterations (macular central subfield thickness and cube average thickness); retinal ultrastructural alterations (disruption of external limiting membrane and ellipsoid zone, thinning of retinal nerve fiber layer and ganglion cell layer); intraretinal microangiopathic changes; choroidal surrogate endpoints; and vitreoretinal interface endpoints. CONCLUSION: OCT technology is changing very quickly and throughout this review there are some of the multiple possibilities that OCT based imaging biomarkers will be more useful in the near future for diagnosis, prognosticating disease progression and as endpoint in clinical trials.

Haruta M, Arai M, Sueda J, Hirose T, Yamakawa R. Patching retinal breaks with Seprafilm for treating retinal detachments in humans: 9 years of follow-up. Eye (Lond) 2017;31(5):776-780.Abstract
PurposeTo describe the long-term surgical outcomes of four patients treated for retinal detachment using Seprafilm as a novel technique.MethodsRetinal breaks in four eyes were covered with Seprafilm using a transvitreal approach after cataract surgery, pars plana vitrectomy, fluid-air exchange, and laser photocoagulation. Neither long-standing gas nor silicone oil was used. The patients were not instructed to maintain a specific head positioning postoperatively.ResultsSuccessful retinal reattachment was achieved with a single surgery in all four eyes, and none developed proliferative vitreoretinopathy. The mean best-corrected visual acuity preoperatively and 9 years postoperatively were 20/97 and 20/33, respectively. The intraocular pressure increased several days postoperatively that lasted no longer than 2 weeks. Visual field defects either in the inferonasal or inferotemporal quadrant were detected postoperatively. The mean electroretinogram a- and b-wave amplitude ratios of the operated eyes to the fellow eyes were 0.68 and 0.64 preoperatively and 0.87 and 0.92 postoperatively, respectively. The mean corneal endothelial cell density was 2365 cells/mm(2) preoperatively and 2592 cells/mm(2) postoperatively.ConclusionCovering retinal breaks with Seprafilm may promote retinal reattachment without gas tamponade and postoperative head positioning. The visual outcomes 9 years postoperatively showed no apparent adverse effects of intraocular application of Seprafilm.
Gupta MP, Talcott KE, Kim DY, Agarwal S, Mukai S. Retinal findings and a novel TINF2 mutation in Revesz syndrome: Clinical and molecular correlations with pediatric retinal vasculopathies. Ophthalmic Genet 2017;:1-10.Abstract

BACKGROUND: Revesz syndrome is a telomere disorder in the dyskeratosis congenita (DKC) spectrum characterized by exudative retinopathy, bone marrow failure, neuroradiographic abnormalities, and integumentary findings. MATERIALS/METHODS: We report the ophthalmologic findings, documented by examinations under anesthesia with clinical photography and fluorescein angiography, as well as the systemic manifestations and genetic and molecular testing, in identical twins with Revesz syndrome, and compare and contrast these features to those of other pediatric retinal vasculopathies. RESULTS: Both twins exhibited widespread avascularity and anomalous vasculature of the retinal periphery, retinal telangiectasias, and exudation. One twin developed a combination exudative/tractional/rhegmatogenous retinal detachment, while the other exhibited a focal collection of buds of retinal neovascularization. Both twins developed bone marrow failure and were found to have cerebellar hypoplasia and widespread cerebral calcifications. Telomere testing in lymphocytes and granulocytes revealed telomere length less than the 1st percentile for age, and gene sequencing revealed a novel mutation in the TINF2 gene, resulting in the T284P TIN2 protein variant. CONCLUSIONS: We report ophthalmic findings in twins with Revesz syndrome due to a previously unreported mutation in TINF2 and propose that phenotypic and molecular overlaps between DKC spectrum disorders and pediatric retinal vasculopathies may reflect a shared pathophysiologic basis.

Chee YE, Eliott D. The Role of Vitrectomy in the Management of Fungal Endophthalmitis. Semin Ophthalmol 2017;32(1):29-35.Abstract

Fungal endophthalmitis is an important cause of vision loss worldwide with a large body of literature describing the treatment of the disease. The evidence supporting the use of pars plana vitrectomy in the management of fungal endophthalmitis is largely comprised of case reports and case series and demonstrates the important role of vitrectomy surgery. Vitrectomy can improve the likelihood of establishing the diagnosis, enhance the treatment of infection by removing fungal elements in the vitreous, aid in the removal of other inoculated intraocular structures, and is an important tool in the management of vision-threatening post-infectious sequelae like retinal detachment and epiretinal membrane.

Vodopivec I, Cestari DM, Rizzo JF. Management of Transient Monocular Vision Loss and Retinal Artery Occlusions. Semin Ophthalmol 2017;32(1):125-133.Abstract

Acute transient or permanent retinal occlusive disease requires prompt medical attention and can be an ophthalmological emergency. Central retinal artery occlusion leads to permanent and severe monocular visual loss in the majority of patients. Transient monocular vision loss leaves no permanent deficits, but requires the same level of clinical vigilance, as it portends possible future adverse events, including loss of vision and stroke. Acute treatment options remain limited, and secondary prevention of cerebral ischemic events is the mainstay of management. This article reviews the current evidence for managing patients with retinal ischemia.

Eliott D, Stryjewski TP, Andreoli MT, Andreoli CM. SMOKING IS A RISK FACTOR FOR PROLIFERATIVE VITREORETINOPATHY AFTER TRAUMATIC RETINAL DETACHMENT. Retina 2017;37(7):1229-1235.Abstract
PURPOSE: To determine the incidence of retinal redetachment due to proliferative vitreoretinopathy after open-globe trauma in smokers and nonsmokers. METHODS: A total of 892 patients comprising 893 open-globe injuries, in whom 255 eyes were diagnosed with a retinal detachment, and 138 underwent surgical repair were analyzed in a retrospective case-control study. Time to redetachment was examined using the Kaplan-Meier method and analysis of risk factors was analyzed using Cox proportional hazards modeling. RESULTS: Within one year after retinal detachment surgery, 47% (95% CI, 39-56%) of all 138 repaired retinas redetached because of proliferative vitreoretinopathy. Being a smoker was associated with a higher rate of detachment (adjusted hazard ratio 1.96, P = 0.01). As shown in previous studies, the presence of proliferative vitreoretinopathy at the time of surgery was also an independent risk factor for failure (adjusted hazard ratio 2.13, P = 0.005). Treatment with vitrectomy-buckle compared favorably to vitrectomy alone (adjusted hazard ratio 0.58, P = 0.04). Only 8% of eyes that redetached achieved a best-corrected visual acuity of 20/200 or better, in comparison to 44% of eyes that did not redetach (P < 0.001). CONCLUSION: Proliferative vitreoretinopathy is a common complication after the repair of retinal detachment associated with open-globe trauma, and being a smoker is a risk factor for redetachment. Further study is needed to understand the pathophysiologic mechanisms underlying this correlation.
Shaikh M, Miller JB, Papakostas TD, Husain D. The Efficacy and Safety Profile of Ocriplasmin in Vitreomacular Interface Disorders. Semin Ophthalmol 2017;32(1):52-55.Abstract

Vitreomacular adhesion (VMA) describes the adhesion of the posterior hyaloid face to the inner retina in any part of the macula. This can arise after incomplete separation of the posterior vitreous cortex from the macula during vitreous liquefaction. While the VMA may resolve spontaneously, a strong and persistent adhesion can lead to a variety of anatomical changes, including vitreomacular traction (VMT) and macular hole (MH). Both conditions can present with metamorphopsia and decreased vision. In cases of symptomatic VMT and full-thickness macular hole, pars plana vitrectomy has long been the standard of care. However, due to the possible surgical complications and need for postoperative care, many have searched for non-surgical options via pharmacologic vitreolysis. Ocriplasmin (Jetrea, Thrombogenics USA, Alcon/Novartis EU) is a recombinant protease approved in October 2012 for the treatment of symptomatic vitreomacular adhesion (VMA). There have been conflicting views on the safety of Ocriplasmin with changes in the ellipsoid zone seen on OCT and changes seen on ERG indicating photoreceptor damage. This publication reviews the efficacy and safety of ocriplasmin injection for VMA based on previously published data.

Hansen RM, Moskowitz A, Akula JD, Fulton AB. The neural retina in retinopathy of prematurity. Prog Retin Eye Res 2017;56:32-57.Abstract

Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP.

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