1. Six Years and Counting: Restoration of Photopic Retinal Function and Visual Behavior Following Gene Augmentation Therapy in a Sheep Model of CNGA3 Achromatopsia. Ron Ofri et al. Human Gene Therapy, 2018.
Achromatopsia results in complete or incomplete colour blindness, extreme sensitivity to light and very low visual acuity due to dysfunction of the cones, the photoreceptors responsible for distinct vision of shapes and colours.The authors of this study had already described a phenomenon of 'day-blindness' (inability to see clearly in bright light) in a sheep model in 2010 in vivo caused by a mutation in the stop codon of the CNGA3 gene. Following this discovery, the researchers started a large-scale CNGA3 achromatopsia gene therapy. In this study, the authors evaluated the long-term efficacy and safety results of the treatment. The study showed a significant long-term improvement in cone function, up to six years after a single treatment. This long duration confirms the safe and stable nature of AAV5 gene therapy in the ovine achromatopsia model.https://www.liebertpub.com/doi/10.1089/hum.2018.076
Computational systems biology approach to identify novel pharmacological targets for diabetic retinopathy. Platania CBM et al. Biochem Pharmacol, 2018.
Diabetic retinopathy has been included by the World Health Organisation (WHO) in the list of priority eye diseases. To date, only proliferative diabetic retinopathy can be treated with authorised drugs, such as anti-VEGF agents and steroids, and with this in mind, it is necessary to identify new drug targets for the treatment of this disease. The search for new drugs now makes use of systems and computational biology techniques to identify new pharmacological targets for complex diseases with multifactorial aetiology and wide and variable symptomatology. A team of Italian researchers used systems biology to identify new drug targets for diabetic retinopathy. The team studied the complexity of the disease through the analysis of transcriptomics data extracted from the Gene Expression Omnibus Dataset repository (GEO). The researchers analysed the GEO datasets using an enrichment-information approach, which provided as output a series of complex gene networks and gene pathways. Analysis of these networks identified genes and biological pathways related to inflammation, fibrosis and G-protein-coupled receptors potentially involved in disease development. This analysis provided new clues to novel pharmacological targets useful for treating diabetic retinopathy.https://www.ncbi.nlm.nih.gov/pubmed/30222965
Corneal Endothelial Cell Density in Uveal Coloboma Associated with Microcornea. Dhakal R et al. Cornea, 2018.
Coloboma is a congenital anomaly that leads to abnormal development of the eye or eyelid and may involve the choroid, iris, retina, lens, cornea and optic disc. Coloboma can occur in isolation or can be part of other diseases (genetic or neurological). This study evaluated the relationship between endothelial cell density (ECD) and mean corneal diameter (MCD) in eyes with uveal coloboma associated with microcornea. The authors performed corneal endothelial cell imaging by specular microscopy on 22 eyes diagnosed with uveal coloboma associated with microcornea. The study revealed that eyes with congenital uveal coloboma associated with microcornea had an increased ECD, probably due to the reduced posterior corneal surface area.https://www.ncbi.nlm.nih.gov/pubmed/30222717
Selective permeability of mouse blood-aqueous barrier as determined by 15N-heavy isotope tracing and mass spectrometry. Pan Liu et PNAS September 4, 2018.
The aqueous fluid of the eye is composed of proteins from the blood circulation and ocular production. The main filter between the blood bed and the intraocular fluid is the blood-aqueous barrier. The authors of this study developed a system to target the selectivity of the blood-water barrier using nitrogen-15-labelled serum proteins as tracers. After systemic injection of the labelled serum onto normal nitrogen-14 mice, the labelled proteins that entered the aqueous fluid were measured by mass spectrometry. This new quantitative method allowed the authors to detect dynamic redistribution patterns of approximately 500 serum proteins from both healthy eyes and eyes recovering from injury. The authors reported that inhibitory complement proteins cross the blood-brain barrier of an injured eye and not a healthy eye.http://www.pnas.org/content/115/36/9032
Association of Cadmium and Lead Exposure With the Incidence of Contrast Sensitivity Impairment Among Middle-aged Adults. Ada J.Paulsen et al. JAMA Ophthalmol. September 13, 2018.
Contrast sensitivity (CS) is an important indicator of visual function that greatly affects all activities of daily living. Understanding, therefore, the risk factors for CS impairment would be helpful in preventing visual function impairment. In this study, researchers at the University of Wisconsin-Madison analysed the incidence and factors associated with CS by analysing a cohort of 1,983 subjects who had no CS impairment at the start of the investigation.The researchers found that factors associated with increased risk included cadmium level in the highest quintile, older age, larger waist circumference, and the presence of multiple plaque sites; male gender and alcohol consumption correlated with reduced risk. The study found no correlation between lead levels and increased risk of CS. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2702298
Autologous Transplantation of the Neurosensory Retina for Refractory Macular Holes.Ming-yu Wu et al. J Clin Exp Ophthalmol
This article reports the clinical case of a 51-year-old woman who presented with a retinal detachment with a large macular hole. The patient underwent vitrectomy via pars plana with autologous neurosensory retina transplantation. Fundus examination revealed that the retinal attachment was consistent with the macular hole. Optical coherence tomography showed that the free neurosensory flap was consistent with the retina and that the margins of the macular hole were healed Long-term follow-up will be necessary to determine whether the transplanted neurosensory retina has visual function. https://www.omicsonline.org/open-access/autologous-transplantation-of-the-neurosensory-retina-for-refractory-macular-holes-2155-9570-1000739-104107.html
7. The Role of Stereopsis and Binocular Fusion in Surgical Treatment of Intermittent Exotropia. Maria Cristina Fernandez-Ruiz et al. J Clin Exp Ophthalmol, 2018.
Intermittent exotropia (XT) is the most common form of strabismus, affecting approximately 1% of the population. The clinical severity of this disorder is determined by several factors representing fusional ability, particularly control of deviation and stereopsis. This study sought to identify, through the use of specific parameters, the appropriate time to surgically intervene on intermittent esotropia (XT). The authors performed a thorough retrospective review of the medical records of 95 patients aged between 3 and 17 years who underwent surgical management for intermittent XT. The study concludes that worsening stereopsis and/or proximity of controls, used as parameters to determine the appropriate time for surgery, do not predict better outcomes. https://www.omicsonline.org/open-access/the-role-of-stereopsis-and-binocular-fusion-in-surgical-treatment-ofintermittent-exotropia-2155-9570-1000742-103337.html
8.Visual acuity outcomes in cytomegalovirus retinitis: early versus late diagnosis. Ausayakhun S. et al. Br J Ophthalmol.
The aim of this study is to determine whether early dilated fundus examination in cytomegalovirus (CMV) retinitis leads to better visual outcomes, especially in geographic areas where there is a shortage of HIV care and patients receive a late diagnosis of retinitis.The authors of the study demonstrated that patients screened early, after a low CD4 count, exhibited better vision than patients screened late. Routine early screening of patients with CD4 counts below 100 cells/mm3 can detect the disease early and prevent vision loss. https://bjo.bmj.com/content/early/2018/09/10/bjophthalmol-2018-312191.long
9. Changes in the optic nerve head induced by horizontal eye movements. Lee WJ et al. PLoS One, 2018.
This prospective observational study analysed the effect of eye movement on the optic nerve head (ONH) in 52 healthy subjects aged 20 to 40 years using swept-source optical coherence tomography (SS-OCT) and then measured the degree of change in ONH.The authors identified significant morphological changes in the ONH, both in abduction and adduction, which were also associated with the mean axial length (AXL). According to the authors, considering these morphological changes as physical properties allows a better understanding of the biomechanical characteristics of ONH. https://www.ncbi.nlm.nih.gov/pubmed/30226883
10.Genome-Wide Association Study Identifies a Susceptibility Locus for Comitant Esotropia and Suggests a Parent-of-Origin Effect. Sherin Shaaban et al. Investigative Opthalmology & Visual Science, 2018.
This study investigated genetic variants that confer an increased susceptibility to exotropia. The researchers conducted a genome-wide association study (GWAS) in which they found an association of esotropia with a single, differentially methylated polymorphism located within intron 1 (non-coding genetic region) of the WRB (tryptophan rich basic protein) gene located on chromosome 21. https://iovs.arvojournals.org/article.aspx?articleid=2697346
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Dr. Carmelo Chines
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