Retina

Retina Publications

Choi HJ, Wang R, Jakobs TC. Single-Cell Dissociation and Characterization in the Murine Retina and Optic Nerve. Methods Mol Biol 2018;1695:311-334.Abstract
Recent technological advances have extended the range of analytic tools to very small samples. It is now possible to assay the transcriptome, and in some cases even the proteome, of single cells reliably. This allows addressing novel questions, such as the genotype/phenotype relationships of single neurons, heterogeneity within individual cells of the same type, or the basis of differential vulnerability to injury. An important prerequisite for these kinds of studies is the ability to isolate well-defined individual cells without contamination by adjacent tissue. In the retina and optic nerve, cells of different types and functions are closely intermingled, limiting the use of standard methods such as laser capture microdissection. Here, we describe a simple method to isolate morphologically intact cells from the retina and the optic nerve and discuss considerations in recognizing and isolating different cell types after dissociation.
Sun D. Visualizing Astrocytes of the Optic Nerve. Methods Mol Biol 2018;1695:269-286.Abstract
Astrocytes make up approximately 30% of all the cells in the mammalian central nervous system. They are not passive, as once thought, but are integral to brain physiology and perform many functions that are important for normal neuronal development and metabolism, synapse formation, synaptic transmission, and in repair following injury/disease. Astrocytes also communicate with neurons, blood vessels, and other types of glial cells. Astrocytes within the optic nerve head region play a key role in glaucomatous axon degeneration. In this chapter, we describe ways in which astrocytes of the optic nerve head can be visualized, beginning with basic immunohistochemical staining methods, to single-cell dye injections and then to transgenic animals. We will also discuss the pros and cons of each method. Many of the methods were initially developed to visualize brain astrocytes; in some cases, the method has translated well to astrocytes of the optic nerve, and in others, it remains unclear.
Carvalho LS, Xiao R, Wassmer S, Langsdorf A, Zinn E, Pacouret S, Shah S, Comander JI, Kim L, Lim L, Vandenberghe LH. Synthetic adeno-associated viral vector efficiently targets mouse and non-human primate retina in vivo. Hum Gene Ther 2018;Abstract
Gene therapy is a promising approach in the treatment of inherited and common complex disorders of the retina. Preclinical and clinical studies have validated the use of adeno-associated viral vectors (AAV) as a safe and efficient delivery vehicle for gene transfer. RPE and rods, and to a lesser extent, cone photoreceptors can be efficiently targeted with AAV. Other retinal cell types however are more challenging targets. The aim of this study was to characterize the transduction profile and efficiency of in silico designed, synthetic Anc80 AAVs for retinal gene transfer. Three Anc80 variants were evaluated for retinal targeting in mice and primates following subretinal delivery. In the murine retina Anc80L65 demonstrated high level of RPE and photoreceptor targeting with comparable cone photoreceptor affinity compared to other AAVs. Remarkably, Anc80L65 enhanced transduction kinetics with visible expression as early as day 1 and steady state mRNA levels at day 3. Inner retinal tropism of Anc80 variants demonstrated distinct transduction patterns of Müller glia, retinal ganglion cells and INL neurons. Finally, murine findings with Anc80L65 qualitatively translated to the Rhesus macaque in terms of cell targets, levels and onset of expression. Our findings support the use of Anc80L65 for therapeutic subretinal gene delivery.
Fernandez-Godino R, Bujakowska KM, Pierce EA. Changes in extracellular matrix cause RPE cells to make basal deposits and activate the alternative complement pathway. Hum Mol Genet 2018;27(1):147-159.Abstract
The design of efficient therapies for age-related macular degeneration (AMD) is limited by our understanding of the pathogenesis of basal deposits, which form between retinal pigment epithelium (RPE) and Bruch's membrane (BrM) early in disease, and involve activation of the complement system. To investigate the roles of BrM, RPE and complement in an AMD, we generated abnormal extracellular matrix (ECM) using CRISPR-edited ARPE-19 cells. We introduced to these cells the p.R345W mutation in EFEMP1, which causes early-onset macular degeneration. The abnormal ECM binds active complement C3 and causes the formation of basal deposits by normal human fetal (hf)RPE cells. Human fetal RPE (hfRPE) cells grown on abnormal ECM or BrM explants from AMD donors show chronic activation of the alternative complement pathway by excessive deposition of C3b. This process is exacerbated by impaired ECM turnover via increased matrix metalloproteinase-2 activity. The local cleavage of C3 via convertase-independent mechanisms can be a new therapeutic target for early AMD.
Costela FM, Kajtezovic S, Woods RL. The Preferred Retinal Locus Used to Watch Videos. Invest Ophthalmol Vis Sci 2017;58(14):6073-6081.Abstract
Purpose: Eccentric viewing is a common strategy used by people with central vision loss (CVL) to direct the eye such that the image falls onto functioning peripheral retina, known as the preferred retinal locus (PRL). It has been long acknowledged that we do not know whether the PRL used in a fixation test is also used when performing tasks. We present an innovative method to determine whether the same PRL observed during a fixation task was used to watch videos and whether poor resolution affects gaze location. Methods: The gaze of a group of 60 normal vision (NV) observers was used to define a democratic center of interest (COI) of video clips from movies and television. For each CVL participant (N = 20), we computed the gaze offsets from the COI across the video clips. The distribution of gaze offsets of the NV participants was used to define the limits of NV behavior. If the gaze offset was within this 95% degree confidence interval, we presumed that the same PRL was used for fixation and video watching. Another 15 NV participants watched the video clips with various levels of defocus blur. Results: CVL participants had wider gaze-offset distributions than NV participants (P < 0.001). Gaze offsets of 18/20 CVL participants were outside the NV confidence interval. Further, none of the 15 NV participants watching the same videos with spherical defocus blur had a gaze offset that was decentered (outside the NV confidence interval), suggesting that resolution was not the problem. Conclusions: This indicates that many CVL participants were using a PRL to view videos that differed from that found with a fixation task and that it was not caused by poor resolution alone. The relationship between these locations needs further investigation.
Roh M, Lee NG, Miller JB. Complications Assoicated with MIRAgel for Treatment of Retinal Detachment. Semin Ophthalmol 2017;:1-6.Abstract
MIRAgel (MIRA, Waltham, MA) is a hydrogel buckle that was introduced in 1979 as a new scleral implant for the treatment of retinal detachment. Long-term follow-up of more than 10 years revealed that the hydrolysis of the synthetic hydrophilic material leads to marked expansion of the substance, causing complications such as buckle extrusion and intrusion, eye motility disorder, cosmetic deformities, and periocular infections. Removal of the implant is the treatment of choice in cases with complications, but it is technically difficult due to the friability of the implant, severe scleral ectasia, and relatively high rate of redetachment after removal.
Bakthavatchalam M, Lai FHP, Rong SS, Ng DS, Brelen ME. Treatment of cystoid macular edema secondary to retinitis pigmentosa: A systematic review. Surv Ophthalmol 2017;Abstract
There are various treatments for cystoid macular edema (CME) secondary to retinitis pigmentosa (RP); however, the evidence for these treatments has not been previously systematically reviewed. Our review that includes 23 studies shows that oral carbonic anhydrase inhibitors (CAI) (including acetazolamide, methazolamide) and topical CAI (dorzolamide and brinzolamide) are effective first line treatments. In patients unresponsive to CAI treatment, intravitreal steroids (triamcinolone acetonide and sustained-release dexamethasone implant), oral corticosteroid (Deflazacort), intravitreal anti-vascular endothelial growth factor agents (ranibizumab and bevacizumab), grid laser photocoagulation, pars plana vitrectomy, or ketorolac were also effective in improving CME secondary to RP. Oral acetazolamide has the strongest clinical basis for treatment and was superior to topical dorzolamide. Rebound of CME was commonly seen in the long term, regardless of the choice of treatment. Oral acetazolamide should be the first line treatment in CME secondary to RP. Topical dorzolamide is an appropriate alternative in patients intolerant to adverse effects of oral acetazolamide. More studies are required to investigate the management of rebound CME.
Chou J, Daly MK. Reply. Retina 2017;37(10):e118.
Poon LY-C, Solá-Del Valle D, Turalba AV, Falkenstein IA, Horsley M, Kim JH, Song BJ, Takusagawa HL, Wang K, Chen TC. The ISNT Rule: How Often Does It Apply to Disc Photographs and Retinal Nerve Fiber Layer Measurements in the Normal Population?. Am J Ophthalmol 2017;184:19-27.Abstract
PURPOSE: To determine what percentage of normal eyes follow the ISNT rule, and whether ISNT rule variants may be more generalizable to the normal population. DESIGN: Cross-sectional study. METHODS: Setting: Institutional setting. STUDY POPULATION: Total of 110 normal subjects. OBSERVATION PROCEDURES: Neuroretinal rim assessments from disc photographs and retinal nerve fiber layer (RNFL) thickness measurements from spectral-domain optical coherence tomography. MAIN OUTCOME MEASURES: The percentages of subjects that obeyed the ISNT rule and its variants. RESULTS: The ISNT rule is only valid for 37.0% of disc photograph rim assessments and 43.8% of RNFL measurements. Deviation of the nasal sector from the expected ISNT pattern was a major cause for the ISNT rule not being obeyed for both rim and RNFL assessments. Specifically, 10.9% of subjects had wider nasal rims than the inferior rims, 29.4% had wider nasal rims than the superior rims, 14.7% had narrower nasal rims than the temporal rims, and 42.9% had thinner nasal RNFLs compared to the temporal quadrant. Exclusion of the nasal quadrant from the ISNT rule significantly increased the validity of ISNT variant rules, with 70.9% and 76.4% of disc photographs following the IST rule and the IS rule, respectively. Similarly, for RNFL thickness, 70.9% and 71.8% of patients followed the IST and IS rule, respectively. CONCLUSIONS: The ISNT rule is only valid for about a third of disc photographs and less than half of RNFL measurements in normal patients. ISNT rule variants, such as the IST and IS rule, may be considered, as they are valid in more than 70% of patients.
Wang JC, Finn AP, Grotting LA, Sobrin L. Acute Zonal Occult Outer Retinopathy Associated With Retrobulbar Optic Neuritis. J Neuroophthalmol 2017;37(3):287-290.Abstract
A 17-year-old girl presented with unilateral retrobulbar optic neuritis as well as bilateral funduscopic findings and outer retinal dysfunction suggestive of acute zonal occult outer retinopathy (AZOOR). Fundus autofluorescence abnormalities, visual field loss, and electroretinographic changes were supportive of bilateral AZOOR. MRI was consistent with the diagnosis of clinically isolated syndrome (CIS), which is defined as a central nervous system demyelinating event that may herald the onset of multiple sclerosis (MS). While AZOOR previously has been linked to MS and demyelinating white matter lesions in the brain, our case seems unique due to concurrent development of AZOOR and retrobulbar optic neuritis as a CIS.
Lundgren P, Hård A-L, Wilde Å, Löfqvist C, Smith LEH, Hellström A. Implementing higher oxygen saturation targets reduced the impact of poor weight gain as a predictor for retinopathy of prematurity. Acta Paediatr 2017;Abstract
AIM: This study evaluated poor weight gain as a risk factor for infants who required treatment for retinopathy of prematurity (ROP), by comparing those born before and after the implementation of higher oxygen saturation (SpO2 ) targets at the Queen Silvia Children's Hospital, Gothenburg, Sweden. METHODS: We compared infants born at less than 31 weeks, who were screened and, or, treated for ROP: 127 in 2011-2012 when SpO2 targets were 88-92% and 142 in 2015-2016 when they were 91-95%. The subjects were reviewed for birth characteristics, weekly weight and ROP treatment. Data were analysed using the weight, insulin-like growth factor-1, neonatal, ROP (WINROP) prediction tool. RESULTS: The 2011-12 infants who needed ROP treatment (12.6%) had significantly poorer postnatal weight gain than those who did not, but this was not seen in the treated (17.6%) and non-treated ROP groups in 2015-2016. WINROP sensitivity decreased from 87.5% in 2011-12 to 48% in 2015-2016. CONCLUSION: After the SpO2 target range was increased from 88-92% to 91-95%, postnatal weight gain was no longer a significant risk factor and WINROP lost its ability to predict ROP requiring treatment. Risk factors clearly change as neonatal care develops. This article is protected by copyright. All rights reserved.
Tsikata E, Vercellin Verticchio AC, Falkenstein I, Poon LY-C, Brauner S, Khoueir Z, Miller JB, Chen TC. Volumetric Measurement of Optic Nerve Head Drusen Using Swept-Source Optical Coherence Tomography. J Glaucoma 2017;26(9):798-804.Abstract
PURPOSE: To describe new software tools for quantifying optic nerve head drusen volume using 3-dimensional (3D) swept-source optical coherence tomography (SS-OCT) volumetric scans. MATERIALS AND METHODS: SS-OCT was used to acquire raster volume scans of 8 eyes of 4 patients with bilateral optic nerve head drusen. The scans were manually segmented by 3 graders to identify the drusen borders, and thereafter total drusen volumes were calculated. Linear regression was performed to study the relationships between drusen volume, retinal nerve fiber layer thickness, and Humphrey visual field mean deviation. RESULTS: In the 8 study eyes, drusen volumes ranged between 0.24 to 1.05 mm. Visual field mean deviation decreased by ∼20 dB per cubic millimeter increase in drusen volume, and the coefficient of correlation of the linear regression was 0.92. In this small patient series, visual field defects were detected when drusen volume was larger than about 0.2 mm. CONCLUSIONS: Software tools have been developed to quantify the size of OHND using SS-OCT volume scans.

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