TY  - CHAP
M1  - Book, Section
TI  - Retinopathy of Prematurity and Ophthalmologic Issues
A1  - Malcolm, William F.
Y1  - 2015
N1  - 
T2  - Beyond the NICU: Comprehensive Care of the High-Risk Infant
AB  - Retinopathy  of  prematurityDefinitionRetinopathy  of  prematurity  (ROP)  is  an  eye  disease  that  affects  the  blood  vessels  and  neurons  of  the  incompletely  developed  retina  in  infants  born  preterm.Normal  retinal  vascular  growth  and  development  is  suppressed  after  premature  birth  as  the  infant  enters  an  environment  that  is  missing  factors  provided  by  the  mother  and  that  has  higher  oxygen  levels  than  in  utero.Abnormal  vascular  shunting  and  neovascularization  may  occur  as  the  retina  reacts  to  subsequent  hypoxia.This  pathological  process  may  stop  and  spontaneously  regress  without  treatment  in  milder  cases  or  lead  to  progressive  retinal  traction  and  detachment,  resulting  in  vision  loss  in  more  severe  cases.IncidenceROP  is  a  leading  cause  of  potentially  preventable  childhood  blindness  in  developed  countries.Each  year,  ROP  affects  approximately  14,000  to  16,000  premature  infants  in  the  United  States.Approximately  1100  to  1500  of  these  infants  will  develop  ROP  severe  enough  to  require  treatment  and  400  to  600  infants  will  become  legally  blind  from  ROP.Two  large  multicenter  studies  have  reported  on  the  natural  history  of  ROP  in  premature  infants  weighing  <1251  g  at  birth.  Similar  rates  of  ROP  were  found  between  the  two  studies  that  involved  infants  born  15  years  apart.Cryotherapy  for  Retinopathy  of  Prematurity  (CRYO-ROP)  Study  (1986-1987):  4099  infants  with  a  mean  birthweight  (BW)  of  954  g  and  mean  gestational  age  (GA)  of  27.9  weeks;  65.8%  developed  any  ROP;  27.1%  developed  prethreshold  ROP;  6%  developed  threshold  ROP  requiring  treatment.The  Early  Treatment  for  Retinopathy  of  Prematurity  (ETROP)  Study  (2000-2002):  6998  infants  with  a  mean  BW  of  907  g  and  mean  GA  of  27.4  weeks;  68%  developed  any  ROP;  36.9%  developed  prethreshold  ROP;  8%  developed  type  1  ROP  requiring  treatment.PathophysiologyRetinal  vascularization  begins  at  the  optic  nerve  at  16  weeks'  GA  and  is  completed  by  40  weeks'  GA.  Infants  born  prematurely,  thus,  have  incompletely  vascularized  retinas.The  degree  of  immaturity  reflects  the  susceptibility  of  the  retina  to  loss  of  factors  provided  by  the  mother  and  the  relative  hyperoxia  of  the  extrauterine  environment.ROP  is  a  biphasic  disease  consisting  of  an  initial  phase  of  vessel  growth  cessation  and  loss  followed  by  a  second  phase  of  vessel  proliferation  (Figure  23-1).Phase  1  occurs  from  birth  to  approximately  30  to  32  weeks'  postmenstrual  age  (PMA).  The  extrauterine  environment  is  relatively  hyperoxic,  causing  vaso-obliteration  of  the  developing  retinal  vessels  and/or  cessation  of  vessel  growth.  As  the  retina  matures,  metabolic  demands  increase  and  the  peripheral  avascular  retina  becomes  hypoxic,  leading  to  the  second  neovascular  phase  of  ROP.Phase  2  begins  at  approximately  32  to  34  weeks'  PMA.  The  hypoxic  retina  stimulates  release  of  oxygen-regulated  angiogenic  factors  such  as  vascular  endothelial  growth  factor  (VEGF)  and  erythropoietin,  leading  to  abnormal  growth  of  fibrovascular  tissue  at  the  junction  of  the  vascularized  and  nonvascularized  retina.Risk  factorsBirth  characteristics  that  reflect  the  degree  of  retinal  vascular  development  and  susceptibility  to  insult.GA  and  BW  correlate  with  the  level  of  retinal  immaturity.  Younger  GA  and  lower  BW  are  key  risk  factors  for  the  development  of  ROP.  In  the  CRYO-ROP  and  ETROP  studies,  the  incidence  of  any  ROP  increased  to  81.6%  to  82.5%  in  infants  weighing  <1000  g  at  birth.Other  birth  characteristics  with  an  increased  risk  of  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - accesspediatrics.mhmedical.com/content.aspx?aid=1105545289
ER  -