Day 2 :
Keynote Forum
Larry I. Benowitz,
Harvard Medical School, USA.
Keynote: Optic nerve regeneration: regulation by amacrine cells, nitric oxide, and zinc
Time : 09:30-10:10
Biography:
Larry Benowitz is a Professor of Surgery and Ophthalmology. His research interests involve understanding the mechanisms that underlie cell death and regenerative failure after CNS injury, and developing methods to preserve damaged neurons and promote the rewiring of neural circuitry.
Abstract:
Retinal Ganglion Cells (RGCs), the neurons that project visual information from the eye to the brain, cannot regenerate their axons once the optic nerve has been injured and soon begin to die. This failure has dire consequences for victims of traumatic or ischemic nerve damage or degenerative diseases such as glaucoma. Our lab and others have recently identified methods that enable some RGCs to regenerate axons from the eye to the brain, yet most RGCs go on to die and only a small fraction of surviving RGCs regenerate their axons. These findings imply the existence of other major suppressors of RGC survival and axon regeneration. We recently identified mobile zinc (Zn2+) one such factor. Within an hour after optic
nerve injury, Zn2+ increases dramatically in synaptic vesicles of amacrine cells (ACs), the inhibitory interneurons of the retina, then transfers slowly to injured RGCs. Zn2+ chelation leads to the persistent survival of many RGCs and to appreciable axon regeneration, with a therapeutic window of several days. New results show that Zn2+ elevation is induced by nitric oxide (NO), a gaseous signal that is generated in a small population of ACs via glutamate-dependent activation of the enzyme NO synthase-1 (NOS1). A novel fl uorescent NO sensor reveals that retinal NO levels increase within 30 minutes of optic nerve damage. NO or a derivative thereof probably liberates Zn2+ from proteins such as metallothioneins via nitrosylation of Zn2+- binding cysteine residues. Surprisingly, we also find that NO has a second, positive effect on optic nerve regeneration through a cGMP-dependent pathway. Besides eliminating Zn2+ accumulation in the retina, AC-specific deletion of NOS1 blocked the regeneration that would otherwise have occurred upon Zn2+ chelation. Conversely, elevation of NO with the NO donor DETANONOate or prevention of cGMP degradation was sufficient to induce axon regeneration. Thus, NO generated by NOS1 in a small population of ACs is responsible for the deleterious elevation of Zn2+ after optic nerve regeneration, but also exerts a positive effect on optic nerve regeneration via cGMP signaling.
Keynote Forum
Chih-Yu Chen
Keynote: Augmented superior rectus transposition with intraoperative botulinum toxin injection for large angle chronic six nerve palsy: A case report
Biography:
Chih-Yu Chen has completed his PhD at the age of 25 years from Taipei Medical University and had obtained his Master degree of Medical Science from National Taiwan University later. He is currently working in the field of Pediatric Ophthalmology and Strabismus at Taipei Municipal Wanfang Hospital (Managed by Taipei
Medical University), Taiwan.
Abstract:
A case of 54 years-old female patient, presented with 75 ΔPD esotropia, combined with obvious hypotropia of right eye in primary position. She was a case of right traumatic six nerve palsy for three years with chin-up and face turn to right. There was a filtration bleb on the upper limbus of right eye due to acute attack of PACG after the trauma. Augmented superior rectus transposition with intraoperative botulinum toxin injection of right medial rectus, combined with bilateral medial rectus muscle recessions. (od 6.5 mm, os 4.5 mm) on December 2017. Complete ptosis with lateral gaze limitation (-2) (od) and nasal limitation (-1) (ou) was found two weeks aft er the operation. Later, 18-20 PD exotropia (od) was found with slight hypertropia and ptosis (3+) aft er one month. Two months later, there was no exotropia or esotropia, just six prism-diopters hypertropia and slight degree of ptosis was found. Four months later, orthotropia in primary position and no more ptosis. A gain of 15 degree lateral gaze across the midline was achieved after the SRT surgery compared complete paralysis before the operation. There was a final exoshift of 75 prism-diopters and a successful outcome was achieved in this case. Augmented Superior Rectus Transposition (SRT) with intraoperative botulinum toxin injection maybe a selective method for the treatment of large angle chronic six nerve palsy.
- Neuroradiology
Session Introduction
Zhang Han
National Neuroscience Institute, Singapore
Title: Accidental intra-arterial injection of contrast of intracranial CTA
Biography:
Zhang Han is a Radiology Trainee in Singapore, Medical Doctor and Fellow of Royal College of Radiology (FRCR). He has special interest in neuroradiology and likes to collect rare but clinically significant radiology cases.
Abstract:
Intracranial Computed Tomography Angiography (CTA) is widely used for evaluation of intracranial vascular disease. Intravenous contrast is used. Accidental intra-arterial injection of contrast is rare and results in odd imaging outcome. A 48 year old man presented with incoherent and was unable to stand without assistance. CT brain showed acute left parieto-temporal lobe intra-parenchymal haematoma. And subsequent CTA showed an Arteriovenous Malformation (AVM) in left temporal region as the culprit lesion. The patient underwent left temporal AVM resection, clot evacuation and cranioplasty. The fi rst postsurgical CTA was done 1 day after surgery with the contrast injected via a left cubital intra-venous plug. The coverage was from vertex to skull base. On arterial phase, there was enhancement of the left distal vertebral artery, left cerebellum, basilar artery, bilateral Posterior Cerebral Arteries (PCA) and bilateral posterior cerebral circulation with no contrast in bilateral anterior and middle circulations and very little contrast in right cerebellum. The radiographer said that the backflow was very strong when connecting the injector to the left cubital intra-venous plug. Deduction of intra-arterial injection of contrast was made. The contrast refl uxed via the left subclavian artery into the left vertebral artery, which caused the eff ect of selective left vertebral angiogram on arterial phase. The ward doctor checked the plug, which occluded already and was removed. A new intra-venous plug was inserted and tested and another CTA was done 6 hours later. Expected opacifi cation of the anterior, middle and posterior cerebral arteries was achieved on arterial phase. This case illustrates the imaging outcome of an intracranial CTA with accidental intra-arterial injection of contrast. Although this situation is rare, good knowledge of anatomy is required to deduce the cause and whole process. Intra-venous plug must always be checked carefully before injection of contrast.
Lina Raffa
King Abdulaziz University Hospital, Saudi Arabia
Title: Visual function, ocular morphology and growth – Children born moderate-to-late preterm
Biography:
Lina Raffa is a Saudi Ophthalmologist, holds both Swedish and European Board certifi cations, as well as a PhD degree from the University of Gothenburg. She
has graduated from the Faculty of Medicine at King Abdulaziz University in 2007. She further completed her Residency training in parallel with her PhD studies at Sahlgrenska University Hospital in Gothenburg and obtained Swedish and European Boards of Ophthalmology in 2015. Later, she completed her Pediatric Ophthalmology Fellowship at University of Montreal and another Fellowship at Dalhousie University in Halifax, Canada.
Abstract:
In the past, researchers have closely studied both systemic and Ophthalmological complications associated with extreme preterm birth. Moderate-to-Late Preterm (MLP) infants have become the fastest-growing subgroup of preterm infants in the last decade. To date, very few studies have focused on the ophthalmological aspects of this particular subset of MLP children. The aim of our project was to investigate the development of ocular morphology and visual function in children born MLP. In a prospective population based study conducted in 2002-2004, 247 potentially eligible children (110 girls and 137 boys) born MLP [Gestational Age (GA) 32-36 weeks] participated in the neonatal study. None of the participating children had a previous history of ROP. At 5.5, 8, 10 and 12 years of age, 78, 50, 33 and 22 children, respectively who were still included in the study took part in sub-studies that focused on orthoptic evaluation, ocular morphology, visual function and electrophysiology in both MLP and sex and age-matched controls. Based on our fi ndings, being born MLP is associated with increased ocular morbidity and may require greater ophthalmic surveillance than full-term counterparts. Auxological data at birth, especially birth weight, seems to be an important risk indicator when establishing an ophthalmological diagnosis in preschool MLP children, and visual acuity outcome was positively correlated to GA. Good catch-up growth favoured proper development of ocular growth and morphology. Our results show that fundus morphology, Visual Evoked Potential (VEP) and full-fi eld Electroretinography (ff -ERG) responses are also aff ected in the MLP group.
Vicuna C Jessie Lin
National Institute Of Ophthalmology, Peru
Title: Pediatric ophthalmology and Ultrasound Biomicroscopy (UBM): A world to discover
Biography:
Vicuna C Jessie Lin is the Founder of the Society of Ocular Echography in Venezuela. She is the Ophthalmologist and Specialist in Cornea, Anterior Segment, Ocular Trauma and Ocular Sonography in National Institute of Ophthalmology.
Abstract:
Ophthalmological evaluation in children is very difficult when they present an ocular pathology such as: Corneal opacity, dysgenesis of the anterior segment, among others. Ultrasound imaging is valuable in eyes with opaque media to detect pathological changes of the posterior segment, but ultrasound biomicroscopy has been used widely to analyze corneal disease, cysts and tumors of the eye, lens implants and cataracts. This study allows the ophthalmologist and the surgeon to make the best decision and obtain an accurate diagnosis, obtaining direct visualization of the anterior segment. Ultrasound Biomicroscopy (UBM) is high frequency, 20 and 50 Mhz, ultrasound that penetrates 5-6 mm and has a resolution of 25 microns. UBM requires contact with the eye via a water bath or a clear shield interface, UBM can be used in infants under sedation with oral Chloral hydrate and what clinically, useful information it can provide UBM can be especially useful when corneal opacifi cation limits direct visualization of anterior segment structures. This technique can be used to assess the need for additional procedures prior to corneal transplantation, including cataract extraction, intraocular lens implantation, iris reconstruction, a glaucoma procedure. The potential and usefulness of the UBM was demonstrated as an accurate diagnostic procedure in ocular pathology with transparent and non-transparent media in children, diagnosing: Corneal diseases, dysgenesis of the anterior segment, cyst, tumors, plateau iris configuration, plateau iris syndrome, vitreous bands and/or traction affecting the anterior segment including the ciliary body, pars plana and peripheral retina.
Ambika MV Raman
Westminster Healthcare Pvt Ltd, India
Title: Prevalence of refractive errors among cerebral palsy kids
Biography:
Ambika MV Raman is currently working as a Senior Consultant Optometrist in Chennai, India. She has been a Faculty for low vision aids, visual optics, geriatric
optometry, and pediatric optometry. Dr. Ambika won prize for Best Performance in Low Vision Aids at SANKARA NARAYANAN.
Abstract:
Purpose: The purpose of the study is to understand the refractive status among the children with cerebral palsy and the need of appropriate spectacle correction to improve their quality of vision.
Method: Around 102 children from various special schools across Chennai, Tamil Nadu, India were recruited for the study with the appropriate consent from the concerned person. Children recruited in the study were in the age group of 9 months to 12 years. All the children were assessed for the vision using LEAs symbols and LEAs paddles based on their level of cognition. All the children were dilated with cyclopentolate 0.5% HCl and tropicamide. Routine static retinoscopy was performed both in dilated and undilated state. Aft ereliciting their refractive errors, children were corrected with spectacles considering their need.
Result: Totally 102 children were assessed, out of which 12% were normal (around 12 children), 69% were hyperopic (around 71 kids) and remaining 19% were myopic (around 19 children).
Conclusion: From the results, the cerebral palsy kids need periodic visual assessment and appropriate spectacle correction. Further studies are being done on assessing the accommodative status of the cerebral palsy children. On improving the quality of vision, quality of life of the cerebral palsy children can be improved.
Zhang Han
National Neuroscience Institute, Singapore
Title: Accidental intra-arterial injection of contrast of intracranial CTA
Biography:
Zhang Han is a Radiology Trainee in Singapore, Medical Doctor and Fellow of Royal College of Radiology (FRCR). He has special interest in neuroradiology and likes to collect rare but clinically signifi cant radiology cases.
Abstract:
Intracranial Computed Tomography Angiography (CTA) is widely used for evaluation of intracranial vascular disease. Intravenous contrast is used. Accidental intra-arterial injection of contrast is rare and results in odd imaging outcome. A 48 year old man presented with incoherent and was unable to stand without assistance. CT brain showed acute left parieto-temporal lobe intra-parenchymal haematoma. And subsequent CTA showed an Arteriovenous Malformation (AVM) in left temporal region as the culprit lesion. The patient underwent left temporal AVM resection, clot evacuation and cranioplasty. The fi rst postsurgical CTA was done 1 day after surgery with the contrast injected via a left cubital intra-venous plug. The coverage was from vertex to skull base. On arterial phase, there was enhancement of the left distal vertebral artery, left cerebellum, basilar artery, bilateral Posterior Cerebral Arteries (PCA) and bilateral posterior cerebral circulation with no contrast in bilateral anterior and middle circulations and very little contrast in right cerebellum. The radiographer said that the backflow was very strong when connecting the injector to the left cubital intra-venous plug. Deduction of intra-arterial injection of contrast was made. The contrast refl uxed via the left subclavian artery into the left vertebral artery, which caused the eff ect of selective left vertebral angiogram on arterial phase. The ward doctor checked the plug, which occluded already and was removed. A new intra-venous plug was inserted and tested and another CTA was done 6 hours later. Expected opacifi cation of the anterior, middle and posterior cerebral arteries was achieved on arterial phase. This case illustrates the imaging outcome of an intracranial CTA with accidental intra-arterial injection of contrast. Although this situation is rare, good knowledge of anatomy is required to deduce the cause and whole process. Intra-venous plug must always be checked carefully before injection of contrast.