Management of Retinopathy of Prematurity in a Neonatal Unit
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[Downloaded free from http://www.jcnonweb.com on Thursday, October 31, 2019, IP: 181.64.200.181] Review Article Management of Retinopathy of Prematurity in a Neonatal Unit: Current Approach Hussain Parappil1,2, Anant Pai3, Nazla Abdelmonem Mahmoud1, Mohammad Ayman AlKhateeb1,2, Hilal Al Rifai1,2, Maha Mohammed El Shafei3 1 Department of Neonatology, Retinopathy of prematurity (ROP) is a blinding morbidity affecting preterm Women’s Wellness and infants. It currently represents the leading preventable cause of childhood blindness Research Centre, Hamad Medical Corporation, worldwide. Most data indicate an increasing incidence of ROP disease in both 2Department of Pediatrics, industrialized countries and in the developing world. There are neither symptoms Abstract Weill Cornell Medical of ROP nor can a specific visual behavior in a preterm infant herald a concern for College, 3Department of ROP. Hence, an effective screening is essential for prompt diagnosis of ROP. The Ophthalmology, Hamad available evidence suggests that the majority of premature infants who go blind Medical Corporation, Doha, from ROP do so due to screening failure. Timely screening of premature infants at Qatar risk is as important as early treatment in the management of ROP. The screening protocol at each neonatal intensive care unit (NICU) should be evidence‑based, should be based on preferences of neonatologists, ophthalmologists, and NICU nurses. All at‑risk infants should be identified and receive adequate dilated retinal examinations at appropriate times. Appropriate screening and follow‑up guidelines and timely treatment protocols need to be implemented in every NICU by pediatricians and ophthalmologists to reduce the ROP‑related blindness in the community. The ultimate goals of treatment of ROP are prevention of retinal detachment or scarring and optimization of visual outcome. The standard treatment involves ablation of peripheral avascular retina preferably by indirect retinal laser photocoagulation when the ROP progresses to a stage which needs intervention since vascular endothelial growth factors (VEGF) are known to play a major role in ROP pathogenesis and its progression, injection of anti‑VEGF drugs intravitreally has been found to be effective in arresting the ROP disease process. This newer emerging pharmacotherapeutic option has the potential to improve Received: 10th October, 2018 treatment outcomes. Revision: 07th June, 2019 Accepted: 30th July, 2019 Keywords: Anti‑vascular endothelial growth factor intravitreal injection, Publication: 04th October, 2019 blindness, laser treatment, retinopathy of prematurity, screening Introduction two‑thirds of whom live in developing countries.[6] etinopathy of prematurity (ROP) is a blinding ROP is the cause of blindness in about 50,000 of these [7] R morbidity affecting preterm infants. It is a children. significant clinical problem and currently represents ROP is a condition of the developing retinal vascular the leading preventable cause of childhood blindness system; the incidence and severity of ROP are highly worldwide.[1,2] The prevalence varies by population correlated with the degree of prematurity at birth.[8,9] though is estimated overall between 10% and 25%[3‑5] and incidence between approximately 50% and 70% Address for correspondence: Dr. Hussain Parappil, [1,4] Department of Neonatology, Women’s Wellness and Research in infants weighing <1500 g at the time of birth. Centre, Hamad Medical Corporation, PB. No 3050, Doha, Qatar. According to the World Health Organization estimates, E‑mail: [email protected] there are 1.4 million[1] blind children worldwide, This is an open access article distributed under the terms of the Creative Commons Access this article online Attribution‑NonCommercial‑ShareAlike 4.0 License, which allows others to remix, Quick Response Code: tweak, and build upon the work non‑commercially, as long as the author is credited Website: and the new creations are licensed under the identical terms. www.jcnonweb.com For reprints contact: [email protected] DOI: How to cite this article: Parappil H, Pai A, Mahmoud NA, AlKhateeb MA, 10.4103/jcn.JCN_102_18 Al Rifai H, El Shafei MM. Management of retinopathy of prematurity in a neonatal unit: Current approach. J Clin Neonatol 2019;8:203‑11. © 2019 Journal of Clinical Neonatology | Published by Wolters Kluwer - Medknow 203 [Downloaded free from http://www.jcnonweb.com on Thursday, October 31, 2019, IP: 181.64.200.181] Parappil, et al.: Retinopathy of prematurity Nearly, all cases occur in neonates with a birth weight of Pathogenesis [9] below 1500 g and gestational age of below 32 weeks. The pathogenesis of ROP is a complex process, and ROP is a treatable, vascular proliferative disorder that it is incompletely understood. It is related to the affects the incompletely vascularized retina in premature interruption of the normal pattern of retinal vascular [8] neonates. Neonates with ROP are prone to develop development with ensuing pathologic changes. visual complications, both structural and functional in In simplistic terms, ROP is characterized by two long terms. Structural complications include refractive phases:[16] errors and strabismus, whereas functional complications • Phase 1: This is also called as vasoconstrictive include visual dysfunction from mild to severe, even phase. It is characterized by delayed physiologic complete blindness, reduced contrast sensitivity, visual retinal vascular development and vasoattenuation. field defects, and abnormal color vision and perception.[10] This phase occurs during exposure to high Most data indicate an increasing incidence of ROP oxygen levels. Here is suppression of the normal anterior‑ward vascularization of the retina, and there disease as industrialized countries report increased is downregulation of vascular endothelial growth incidence by approximately 10‑fold since the 1990s.[11] factor (VEGF)[17] In the most severe stages of the disease retinal traction • Phase 2: This is a vasoproliferative phase and detachment develop leading to permanent characterized by intravitreal neovascularization. blindness.[12] Recent work demonstrates the rates of This secondary phase occurs during the shifting severe, treatment‑worthy, ROP rose from 1.7 to 14.8/1000 from oxygen to room air, and it involves dilatation preterm infants between the years 1990 and 2011.[11] and tortuosity of the existing larger vessels with The National Eye Institute reports that approximately neovascularization and proliferation of new vessels 1100–1500 infants will develop ROP requiring treatment into the vitreous. This is assumed to be due to the each year in the US and approximately 400–600 will sudden surge in VEGF levels. become legally blind from ROP.[13] Thus, ROP is an increasing and significant clinical problem. Classification of Retinopathy of When it was first described in 1942 by Terry,[14] this Prematurity disease was not commonly seen, and hence had little In the past, there were several classifications of ROP interest, but 10 years later, it became a major problem which led to much confusion among pediatricians, to all pediatricians and ophthalmologists. It now affects neonatologists, and ophthalmologists. To resolve thousands of children worldwide.[15] The introduction this issue, a committee for ROP classification was of neonatal intensive care units (NICUs) in Europe formed in 1984, which proposed an international and the United States during the 1940s and 1950s led classification of ROP (ICROP) by dividing the retina to the unmonitored supplemental oxygen in preterm into three zones, extending from posterior to anterior and low birth weight infants. This resulted in the first retina and describing the extent of ROP in clock‑hours epidemic of ROP. This epidemic ceased following the of involvement.[18] The retinal changes are divided implementation of controlled oxygen administration. into stages of severity. However, with the advances However, advances in neonatal care led to the survival in retinal imaging techniques, a revised ICROP of premature neonates with increasingly low gestational classification was put forth which described the zones ages and low birth weights. This had led to the so‑called better.[19] “second epidemic” of ROP. More recently, ROP is Zones again emerging as a major cause of pediatric blindness Three concentric zones, centered on the retina, define and visual impairment in the developing world and the anteroposterior location of retinopathy [Figure 1]. middle‑income countries of Latin America, Eastern • Zone I: With optic disc as the center, and twice the Europe, and Asia where cases of ROP are increasingly distance from the disc to fovea, the circle formed being reported. Rates of this potentially blinding disease is Zone I. Using a 25 or 28 diopter (D) condensing requiring treatment also tend to be higher in middle‑ and lens, when the nasal edge of the optic disc is kept at low‑income countries suggesting that babies are being one edge, the temporal field of view is Zone I extent exposed to risk factors which are, to a large extent, being • Zone II: It starts from the edge of Zone I and extends controlled in industrialized countries. This phenomenon till the anterior edge of retina (also called as ora is considered as the “third ROP epidemic.”[7] Hence, it serrata) nasally, with a corresponding area temporally is imperative that every pediatrician and neonatologist • Zone III: Zone III is the remaining crescent of retina should know how to address