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ORIGINAL ARTICLE
Year : 2016  |  Volume : 4  |  Issue : 3  |  Page : 119-122

Retinopathy of prematurity: Incidence, prevalence, risk factors, and outcomes at a tertiary care center in Telangana


1 Department of Ophthalmology, Tulane University, New Orleans, LA, USA
2 Department of Neonatology, Dolphin Children's Hospital, Retina Services, Hyderabad, Telangana, India
3 Department of Anesthesia and Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
4 Anand Eye Institute, Hyderabad, Telangana, India

Date of Submission17-Mar-2015
Date of Acceptance12-Apr-2016
Date of Web Publication19-Sep-2016

Correspondence Address:
Ramesh S Ayyala
Department of Ophthalmology, Tulane University, 1430 Tulane Avenue., Box SL69, New Orleans, LA 70112
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2320-3897.190785

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  Abstract 

Aims: To evaluate the incidence of retinopathy of prematurity (ROP), prevalence of pre-and postnatal risk factors for development of ROP, and treatment outcomes among preterm infants admitted to the Neonatal Intensive Care Unit (NICU) of a tertiary care hospital located in Hyderabad. Materials and Methods: Retrospective chart review of all infants admitted to the NICU between 2008 and 2013, who met the criteria for ROP screening: (a) ≤34 weeks of gestation, (b) ≤1750 g of birth weight, (c) infants with significant risk factors including sepsis, respiratory distress syndrome, or long-term oxygen use. Treatment was offered to infants with Stage III ROP disease or Stage II in Zone II with plus disease. Qualified infants were treated with argon laser photocoagulation within 48 h of diagnosis. They were followed until the disease was successfully treated. Results: A total of 2910 infants were admitted to the NICU. Incidence of ROP was found to be 2.3% (n = 66), the majority of whom (71%) had Stage I ROP. Seventeen percent of the infants weighed <1000 g. The most prevalent prenatal risk factor was multiple gestations (17%). Prevalent postnatal risk factors included oxygen treatment (71%) and respiratory distress syndrome (58%). Twelve percent (8/66) of infants met the treatment threshold. Following argon laser, regression was observed in 100% of infants, with no recurrence with follow-up between 1 and 4 years after treatment. Conclusions: This is the first study to evaluate the incidence of ROP in Telangana. Argon laser photocoagulation appears to be effective in the treatment of infants in this population. We recommend screening infants ≤32 weeks of gestation and infants born ≤1700 g birth weight.

Keywords: Argon laser photocoagulation treatment, India, pre- and postnatal risk factors, retinopathy of prematurity, Telangana


How to cite this article:
Le C, Basani LB, Zurakowski D, Ayyala RS, Agraharam SG. Retinopathy of prematurity: Incidence, prevalence, risk factors, and outcomes at a tertiary care center in Telangana. J Clin Ophthalmol Res 2016;4:119-22

How to cite this URL:
Le C, Basani LB, Zurakowski D, Ayyala RS, Agraharam SG. Retinopathy of prematurity: Incidence, prevalence, risk factors, and outcomes at a tertiary care center in Telangana. J Clin Ophthalmol Res [serial online] 2016 [cited 2019 Nov 17];4:119-22. Available from: http://www.jcor.in/text.asp?2016/4/3/119/190785

Retinopathy of prematurity (ROP) is a significant cause of preventable blindness across both the developed and developing countries. Recent advancements in neonatal care have led to an increase in the survival of low birth weight infants, resulting in a rise of ROP incidence. Globally, ROP is estimated to affect more than 50,000 infants annually. In India, every year, 500 children are estimated to become blind from ROP.[1] While ROP may cause severe visual impairments, the condition fortunately carries a good prognosis, given early screening and management. Thus, an effective screening protocol is essential for timely detection and treatment of this avoidable disease.[2] Moreover, there is a disparity between the profiles of ROP infants in developing countries versus developed countries, and no unified screening guidelines exist for ROP in India. If current American and British screening guidelines for ROP infants were applied in India, a large proportion of Indian infants would be missed because heavier infants (>1500 g) are also at a risk for developing ROP.[3]

The aim of the study was to evaluate the incidence of ROP and treatment outcomes in the setting of a Neonatal Intensive Care Unit (NICU) at a tertiary care facility located in Hyderabad, India. The retina specialist from a local eye institute screened all infants determined to be at high risk for ROP by the neonatologists at the NICU. In addition, our research aimed to contribute to the current body of knowledge of ROP in the South Indian population and help facilitate development of unified screening guidelines in the country.


  Materials and Methods Top


This retrospective study was approved by the Institutional Review Committee at all institutions involved. All infants admitted to the NICU were screened for ROP if they met the following criteria: (a) Presented at ≤34 weeks of gestation, (b) weighed ≤1750 g at birth, or (c) possessed other significant risk factors such as sepsis, respiratory distress syndrome (RDS), or long-term oxygen use. Screening was performed by a single retina specialist in the NICU under aseptic conditions, using an indirect binocular ophthalmoscope with a + 20 diopter lens. Our treatment threshold was Stage III ROP disease or Stage II in Zone II with plus disease. All infants who qualified were treated with laser photocoagulation within 48 h of diagnosis.

This is a retrospective study of all NICU admissions between March 2008 and December 2013 at a tertiary care center. Infants diagnosed with ROP were identified and any information that increased their risk of ROP development was recorded including low birth weight, gestational age, history of sepsis, history of blood transfusion, history of transient tachypnea of the newborn, apnea of prematurity, oxygen therapy, and respiratory support. Prenatal risk factors measured include multiple gestations and antenatal steroid use. The stage of ROP at the time of diagnosis, treatment intervention, and treatment outcomes were documented. Success of treatment was measured by regression of neo-vascularization and absence of recurrence.


  Results Top


A total of 2910 infants were admitted to the NICU between March 2008 and December 2013. Forty-two infants did not survive reflecting a mortality rate of 1.5%. Sixty-six infants admitted were diagnosed with ROP, demonstrating an incidence of 2.3%. Patients with ROP showed a male predominance (59% male, 41% female). All infants with ROP weighed <1750 g at birth, with 33% weighing between 1500 and 1750 g, 32% between 1000 and 1499 g, and 17% between 750 and 999 g. Mean gestational age was 31 weeks, ranging from 26 to 34 weeks. The average gestational age among infants with severe ROP requiring laser treatment was 28 weeks, ranging from 26 to 30 weeks' gestational age. ROP was most commonly seen in Zone III (68%) and Zone II was the second most common (26%). Only one case was noted to occur in Zone I, while in three cases, the zone was not recorded [Table 1].
Table 1: Demographics, incidence, prevalence and treatment outcomes among the study population

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The most prevalent postnatal risk factors among patients with ROP were RDS and use of oxygen therapy. Fifty-eight percent of patients with ROP experienced RDS and 71% needed oxygen therapy. Mean duration of oxygen therapy required was 5 days (range: 1–42 days). Thirty-two percent of patients required respiratory support via ventilation for an average of 3.5 days (range: 1 h–7 days). Thirty-six percent of infants with ROP were diagnosed with anemia of prematurity, while 26% of these infants required transfusion of packed red blood cells. Other significant postnatal risk factors noted were presence of sepsis (33%), transient tachypnea of the newborn (20%), apnea of prematurity (20%), patent ductus arteriosus (17%), hypoglycemia (15%), and neonatal seizures (6%).

Multiple gestations were the most common prenatal risk factor with a prevalence of 17% among infants with ROP. Antenatal steroids were used in 5% of infants who developed ROP.

Of the 66 infants who developed ROP, only eight presented with severe enough disease warranting laser photocoagulation in both eyes (6 females, 2 males). The average gestation age of these patients was 28 weeks (range: 26–20 weeks). All infants were born under 1400 g (range: 760–1320 g). All the eight infants required oxygen therapy for an average of 10 days (range: 4–28 days). One half required respiratory support with an average length of 6 days on ventilation therapy (range: 4–8 days). Other postnatal risk factors included anemia requiring blood transfusion (7/8), presence of a patent ductus arteriosus (4/8) and sepsis (4/8) [Table 2] and [Figure 1].
Table 2: Comorbidities among the study population as a whole and among those that required treatment for ROP

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Figure 1: Incidence of comorbidities among the study population

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All laser photocoagulation treatments were successful, with follow-up examinations performed between 1 and 4 years after the procedure. All infants demonstrated regression of neo-vascularization of the retina and absence of recurrence during the last follow-up visit. In one case, vitreous hemorrhage was noted at the 3-month follow-up visit, and the patient underwent a repeat photocoagulation treatment. Following the second treatment, regression of neo-vascularization was observed without evidence of recurrence.


  Discussion Top


Severe ROP is a debilitating disease, which left untreated, may lead to permanent visual loss, resulting in decreased quality of life for the individual as well as a significant financial burden on the individual and the community.[1],[4] In India, approximately, 1 in 1000 children is blind, and the incidence of ROP is reported between 24% and 47%.[5] Our study discovered the incidence of ROP among preterm infants admitted to the NICU of a tertiary care children's hospital to be much lower at 2.3%. This lower value may be due to the small sample size of our study as well as a result of the patient population at the NICU. This particular NICU is in collaboration with an eye institute and abides by strict oxygen therapy and ROP screening guidelines, which is likely responsible for the low incidence of ROP development. The hospital is an urban institution that serves predominantly un-insured patients of an average income group. As a result of these factors, many infants born at this facility presented with less prenatal risk factors and subsequently, an overall reduced incidence of disease.

The American and British guidelines recommend screening for ROP for all infants born weighing ≤1500 g or present at ≤30 weeks gestational age. The guidelines further recommend that infants with birth weight of 1500–2000 g who experience an unstable course requiring cardiorespiratory support should also be screened.[6]

All infants who developed ROP in our study weighed <1,750 g at birth. The majority of the infants had a birth weight between 1500 and 1750 g (33%). The second most common range was 1000–1499 g (32%). All the eight infants who required laser photocoagulation treatment had a birth weight under 1500 g and 75% of these were between 750–999 g. In addition, the overall average gestational age was 31 weeks (range: 26–34 weeks). The average gestational age of those infants requiring laser photocoagulation was 28 weeks (range: 26–30 weeks). Our data demonstrate that if the American guidelines were used among the Indian population, many ROP cases would remain undiagnosed.

Our data suggest an overall ROP male predominance of 59%, and a female predominance, 6 out of 8, among infants with severe ROP requiring laser photocoagulation. No gender predominance in ROP has been documented before.

Previous studies suggest that the use of antenatal steroids decrease the severity of ROP.[7] Our study found only three cases of ROP among infants subjected to antenatal steroids. Two of these infants did not require laser treatment, while one exhibited severe ROP necessitating laser photocoagulation treatment. In addition, studies have identified intraventricular hemorrhage (IVH) as an independent risk factor for the development of severe ROP.[8],[9] Our study found only three cases of IVH among the infants who developed ROP, all of whom developed only Stage I disease and did not warrant laser photocoagulation intervention. Our research too contains small sample size to comment on this potential phenomenon. More studies are recommended to further evaluate the relationship between antenatal steroids and history of IVH with the development of ROP.

We found the incidence of ROP among multiple gestations to be 17%. The cryotherapy for ROP study showed the likelihood of developing threshold ROP disease to be 36% greater in multiple gestation births.[10] A larger sample size of infants resulting from multiple gestations needs to be done to confirm this hypothesis.

The most prevalent postnatal risk factors among patients with ROP are RDS (58%) and use of oxygen therapy (71%). Thirty-six percent of infants with ROP were diagnosed with anemia of prematurity, with 26% of these infants requiring transfusion of packed red blood cells. Other significant postnatal risk factors noted were presence of sepsis (33%), transient tachypnea of the newborn (20%), apnea of prematurity (20%), patent ductus arteriosus (17%), hypoglycemia (15%), and neonatal seizures (6%). The prevalence of these postnatal risk factors has not been clearly outlined in previous studies.

All the eight infants who presented with severe ROP necessitating laser photocoagulation intervention required oxygen therapy and half required respiratory support. Other significant postnatal risk factors among these infants include anemia requiring blood transfusion (7/8), presence of patent ductus arteriosus (4/8), and sepsis (4/8). These results underscore the importance of screening infants with these specific risk factors since they were highly associated with severe disease.

Following laser photocoagulation, patients were followed up between 1 and 4 years after the procedure. All the eight patients demonstrated a regression of neo-vascularization of the retina, supporting the need for rapid treatment intervention to preserve vision.


  Conclusion Top


This is the first study to identify the incidence of ROP in the state of Telangana. While it is well documented that the prevalence of ROP is correlated with gestational age and birth weight, these factors are not the only risk factors for ROP.[9] Our study outlines the prevalence of pre- and postnatal risk factors for the development of ROP and highlights the need to develop refined screening guidelines to better assess the Indian population. In addition, we found that treating threshold ROP with argon laser photocoagulation appears to be very effective in this population. The data collected from this investigation should be combined with other assessments of ROP in South India to help construct and validate a unified screening protocol. We recommend screening infants ≤32 weeks of gestation and infants born ≤1750 g birth weight in India. We also stress the importance of strict oxygen therapy guidelines and transfusion practices to decrease the incidence of ROP.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Gilbert C. Retinopathy of prematurity: A global perspective of the epidemics, population of babies at risk and implications for control. Early Hum Dev 2008;84:77-82.  Back to cited text no. 1
    
2.
Patwardhan SD, Azad R, Gogia V, Chandra P, Gupta S. Prevailing clinical practices regarding screening for retinopathy of prematurity among pediatricians in India: A pilot survey. Indian J Ophthalmol 2011;59:427-30.  Back to cited text no. 2
[PUBMED]  Medknow Journal  
3.
Vinekar A, Dogra MR, Sangtam T, Narang A, Gupta A. Retinopathy of prematurity in Asian Indian babies weighing greater than 1250 grams at birth: Ten year data from a tertiary care center in a developing country. Indian J Ophthalmol 2007;55:331-6.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
4.
Mets MB. Childhood blindness and visual loss: An assessment at two institutions including a “new” cause. Trans Am Ophthalmol Soc 1999;97:653-96.  Back to cited text no. 4
    
5.
Murthy KR, Murthy PR, Shah DA, Nandan MR, S NH, Benakappa N. Comparison of profile of retinopathy of prematurity in semi urban/rural and urban NICUs in Karnataka, India. Br J Ophthalmol 2013;97:687-9.  Back to cited text no. 5
    
6.
Fierson WM; American Academy of Pediatrics Section on Ophthalmology; American Academy of Ophthalmology; American Association for Pediatric Ophthalmology and Strabismus; American Association of Certified Orthoptists. Screening examination of premature infants for retinopathy of prematurity. Pediatrics 2013;131:189-95.  Back to cited text no. 6
    
7.
Higgins RD, Mendelsohn AL, DeFeo MJ, Ucsel R, Hendricks-Munoz KD. Antenatal dexamethasone and decreased severity of retinopathy of prematurity. Arch Ophthalmol 1998;116:601-5.  Back to cited text no. 7
    
8.
Watts P, Adams GG, Thomas RM, Bunce C. Intraventricular haemorrhage and stage 3 retinopathy of prematurity. Br J Ophthalmol 2000;84:596-9.  Back to cited text no. 8
    
9.
Rao KA, Purkayastha J, Hazarika M, Chaitra R, Adith KM. Analysis of prenatal and postnatal risk factors of retinopathy of prematurity in a tertiary care hospital in South India. Indian J Ophthalmol 2013;61:640-4.  Back to cited text no. 9
[PUBMED]  Medknow Journal  
10.
Palmer EA, Flynn JT, Hardy RJ, Phelps DL, Phillips CL, Schaffer DB, et al. Incidence and early course of retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group. Ophthalmology 1991;98:1628-40.  Back to cited text no. 10
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]


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