Retinopathy of prematurity – Present scenario By Rajesh Goyal, MS;AkshiAgarwal, DNB;Manish Sharma, MS;Mukesh Sharma, MD,DNB

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Editor                                   Dr Sudhir Singh   Advisors Prof. P.K Mathur Dr  Pavan Shorey   Editorial Board Dr Anshoo Choudhary Dr Arun Kshetrapal Dr L S Jhala Dr Mayank Agrawal Dr Mukesh Sharma Dr Sandeep Arora Dr Sonu Goel Dr Subodh Saraf Dr Sukesh Tandon Dr Sunil Gupta Dr Suresh Kumar Pandey Dr Swati Tomar Dr Virendra Agrawal   Retinopathy of prematurity – Present scenario   Rajesh Goyal, MS;AkshiAgarwal, DNB;Manish Sharma, MS;Mukesh Sharma, MD,DNB Article Code RJO20110113 Corresponding Author Dr. Rajesh Goyal 21/278 Madhyam Marg ,Mansarovar JAIPUR (RAJ) Ph : 01415130011,9414551929 E Mail: dr.goyalrajesh@gmail.com   IntroductionRetinopathy of Prematurity (ROP) is a bilateral proliferative retinopathy, occurring in premature infants1  with low birth  weight who have been exposed to high concentration of oxygen. Previously this disease was known as retrolental fibroplasia. WHO Vision 2020 programme has recognized ROP as an important cause of childhood blindness2. Worldwide 50,000 children are blinded by ROP each year3. Indian studies shows an ROP incidence of 20 to 46%4,5in babies screened. As more advanced neonatal centers continue to save smaller premature babies the incidence of ROP is on rise, and has become an important cause of childhood blindness across the world. Pathogenesis Retinal vessels extend up to nasal edge of retina by eighth month of gestation, but temporal retina  becomevascularised by about a month after birth. These immature vessels are prone to damage in the presence of oxygen which leads to vasoconstriction   specially  in premature infants. As a result retinal arteries and veins are obliterated, inciting a phase of neovascularisation (Hypoxia induces VEGF production which induces neovascularisation )6,7,8. Due to neovascularisation, there occurs formation of fibrovascular tissue in the vitreous which may cause tractional retinal detachment and may give the appearance of pseudoglioma   International Classification of Retinopathy of Prematurity9 : International Classification of Retinopathy of Prematurity uses a number of parameters to describe the disease. They  are  location  of  disease  into  zones (1, 2, 3), the circumferential extent of disease based on clock hours (1-12), the severity of disease (Stage 1 to 5) and presence or absence of plus disease. Zones : Zone I :    Is the posterior zone of retina, defined as circle with a radius extending from optic nerve to double the distance to the macula. Zone II :   A circle is drawn with the optic disc as centre and disc to nasal oraserrata as the radius. Area between zone I and this boundary constitute zone II.   ZONES OF ROP Zone III :  Temporal arc of retina left beyond the radius of zone II is zone III. Stages : Stage I :   A discrete line of demarcation separates the anterior, immature avascular retina from mature vascularised retina posteriorly.   Stage II :  Demarcation line is transformed into elevated ridge separating the avascular and vascular retina.   Stage III : Fibrovascular tissue develops at the ridge with extraretinalneovascularisation extending into the vitreous Stage IV :      Sub total retinal detachment. Stage V : Total retinal detachment.   Plus Disease10 Refers to presence of tortuous dilated vessels at posterior pole with any stage of ROP. Plus disease signifies the tendency to progression. Extent of involvement : Denoted by clock hours of retinal involvement in particular zone. Threshold Disease Refers to stage III plus disease involving 5 continuous or 8 discontinuous clock hours. Differential Diagnosis Advanced stages of ROP are differentiated from other causes of leukocoria. Most important differential diagnosis includes:- Exudative viteroretinopathy which is a genetic disorder that disrupts the retinal vascularisation in full term infants. Persistent hyperplastic primary vitreous that can cause tractional retinal detachment. Prognosis In 80% cases ROP resolves spontaneously with restoration of normal vascularisation of retina, while the rest develops sequeale such as myopia, temporal viteroretinal fibrosis with dragging of disc, partial or extensive retrolentalfibrovascular tissue, secondary angle closure glaucoma and total retinal detachment. Management Prophylaxis  : Once the condition has fully developed, visual prognosis is poor and treatment is relatively ineffective. So prophylaxis is most important which includes :- 1.      Screening :- American screening guidelines11 recommend screening in babies < 1.5 kg. birth weight or < 32 weeks gestational age or higher in case of unstable babies considered high risk to develop ROP by neonatologist. They suggest first screening to be done at 31 weeks PCA(post conceptional age ) or 4 weeks after birth, whichever is later. Indian expert group12  suggest screening babies < 1.5 Kg. birth weight or < 34 weeks gestational age or higher in case of unstable babies, considered high risk to develop ROP by neonatologist. They recommend first screening to be done at 31 weeks PCA or 4 weeks after birth, whichever is earlier. 2.      Level of PaO2in  the umbilical  artery  should  be  monitored  between 50-100 mm. Hg being regarded as unlikely to produce constriction of immature retinal vessels. 3.      Premature newborn should not be placed in incubator with an O2 concentration of more than 30%. Treatment Early treatment of ROP is both efficacious  and economically desirable 13. Current treatment strategy is guided by The Early Treatment for Retinopathy of Prematurity Cooperative Group (ETROP)14 Study.  ETROP Group divides these eyes into 2 categories :- Type I ROP defined as : A.           Zone I, any stage ROP with plus disease or B.           Zone I, stage 3 ROP without plus disease or C.           Zone II, stage 2 or 3 ROP with plus disease. Type II ROP defined as : A.           Zone I, stage 1 or 2 ROP without plus disease or B.           Zone II, stage 3 ROP without plus disease. Type I ROP requires prompt treatment while type II ROP is regularly followed up and considered for treatment only if it progress to type I or threshold ROP. Treatment in Different Stages Stage I & II    –  Weekly examination is recommended. Stage III         –  Threshold disease should be treated by cryo and laser. Stage IV        –  Scleral buckling + cryo or laser. Stage V         –  Viteroretinal surgery need to be carried out. New treatment modalities such as vascular endothelial growth factor(VEGF) blocking antibodies are being assessed15,16 .Efficient management of apnea and sepsis may be crucial in further monitoring the risk of ROP17. So in conclusion it is best to run effective screening programmes to ensure early detection and timely treatment in children with ROP. As ROP progresses treatment outcome gets poor. So spreading awareness is vital to tackle this preventable cause of childhood blindness. Disclaimer The Rajasthan Journal Of Ophthalmology An Official Publication Of The Rajasthan Ophthalmological Society
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