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Year : 2020  |  Volume : 64  |  Issue : 4  |  Page : 398-401  

Retinopathy of prematurity in a level II neonatal care unit of a district of West Bengal: A retrospective analysis of 5 years

1 Professor, Department of Neonatology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
2 Assistant Professor, Department of Neonatology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
3 Consultant, Department of Ophthalmology, Calcutta Medical Research Institute, Kolkata, West Bengal, India
4 Clinical Tutor, Department of Ophthalmology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
5 Medical Officer in-Charge, Special Newborn Care Unit, MR Bangur Hospital, Kolkata, West Bengal, India

Date of Submission10-Jul-2019
Date of Decision02-Jun-2020
Date of Acceptance05-Sep-2020
Date of Web Publication11-Dec-2020

Correspondence Address:
Anindya Kumar Saha
Department of Neonatology, Institute of Post Graduate Medical Education and Research, 244, A.J.C Bose Road, Kolkata - 700 020, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijph.IJPH_336_19

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Retinopathy of prematurity (ROP), particularly severe ROP is a health concern. The study is aimed to ascertain the magnitude, profile, and outcome of ROP over 5 years at a level II neonatal unit in a district of West Bengal. From 2012 to 2016, a total of 691 newborns with birth weight (BW) <2000 g and/or gestational age < 35 weeks of a district level II neonatal care unit were screened for ROP. Retrospective analysis of these screened babies was performed using the principles of descriptive and inferential statistics. Overall, 38.5% of newborns had any stage ROP and13.2% severe ROP. Two-thirds of babies with severe ROP were <1250 g of BW. About 16.2% of the ROP cases suffered from aggressive posterior ROP (APROP). Oxygen and prematurity were found as significant risk factors. Substantially high occurrence of severe ROP and APROP warrants appropriate measures. Timely screening and intervention with referral to the neonatal ROP unit can improve the scenario.

Keywords: Aggressive posterior retinopathy of prematurity, newborn, oxygen, preterm, retinopathy of prematurity

How to cite this article:
Mukherjee S, Saha AK, Das P, Sen D, Bhar S. Retinopathy of prematurity in a level II neonatal care unit of a district of West Bengal: A retrospective analysis of 5 years. Indian J Public Health 2020;64:398-401

How to cite this URL:
Mukherjee S, Saha AK, Das P, Sen D, Bhar S. Retinopathy of prematurity in a level II neonatal care unit of a district of West Bengal: A retrospective analysis of 5 years. Indian J Public Health [serial online] 2020 [cited 2022 Aug 12];64:398-401. Available from:

Retinopathy of prematurity (ROP) is a known complication of prematurity and one of the major preventable causes of blindness. Severe ROP may account for up to 40% of total childhood blindness.[1] The excessive and unmonitored use of oxygen in the premature newborn was found to be the major causative factor of ROP. Currently, India is going through the phase of an ROP epidemic and accounts for a large share of the global estimate of ROP-related childhood blindness.[2],[3],[4]

The facility-based newborn care has been expanded with >500 functional level II neonatal care units in 622 districts of India. However so far, there is a dearth of available reports on the actual ROP status of the huge number of newborns treated in the newly expanding level II neonatal units in India. Blended and titrated oxygen delivery with proper respiratory support is not always available in level II units and there is also a lack of trained ophthalmologists and infrastructure of ROP screening and treatment in such small units both in public and private sectors. This is enhancing the risk of severe ROP and the possibility of childhood blindness in near future.[5],[6] The real magnitude of such severe ROP among Indian newborns is still unknown. With this background, this study is aimed to ascertain the magnitude, profile and outcome of ROP, including severe ROP over 5 years at a single level II neonatal unit in a district hospital of West Bengal.

This was a descriptive study with retrospective analysis for a period of 5 years from January 2012 to December 2016 on ROP in preterm newborns admitted in a thirty-bedded level II neonatal unit at a district semi-urban hospital in West Bengal. The unit was functioning as satellite unit of another level III neonatal unit of a nearby medical college with the facility of ROP screening and treatment.

The infants with birth weight (BW) <2000 g and/or gestational age (GA) at birth <35 weeks were referred to the said level III neonatal care unit. The admitted babies who fitted with this protocol during the period of 2012-2016, were eligible for inclusion in the present study. Babies who were born with major congenital malformations or died or referred to other hospitals for medical reasons other than ROP or dropped out from the screening schedule before complete screening or treatment were excluded from the study.

ROP screening was done by two ophthalmologists. The procedure was assisted by trained optometrists and was performed in the presence of one neonatologist and neonatal nurse. The first screening was performed at 21 days of the postnatal age.

The babies who were screened in this protocol during the period of 2012–2016 were included in the present study. The oxygen therapy used in the treating unit was unblended, and there was no provision of noninvasive or invasive respiratory support in the treating unit. Usually, the critically sick babies in need of respiratory support more than oxygen were referred to the various level III neonatal care units.

ROP screening was performed as per standard guidelines. ROP was classified as Stage I, Stage II, Stage III, with or without plus disease, and aggressive posterior ROP (APROP) according to the international classification of ROP.[7] The follow-up frequency was based on the severity and rate of progression of the disease and continued until the regression of ROP or full vascularization of retina.[8] The therapy was also decided as per the early treatment of ROP guidelines.[8] The eyes were treated using Argon green laser (514 nm) photoablation with laser indirect ophthalmoscope. The intravitreal anti-vascular endothelial growth factor was also used in some cases but as an adjuvant, to laser therapy as decided by the ophthalmologist. We defined severe ROP as those cases who were candidate for treatment for ROP according to the same guideline.[8]

The data on incidence, distribution, and development of various stages of ROP, the onset of worst stage ROP in any of the eyes, laser or intravitreal injection therapy, and anatomical outcome of severe ROP were prospectively documented and preserved at ROP unit of the level III neonatal care unit and subsequently recorded for this study. Informed consent had been obtained from parents before the ROP screening procedure and before any therapeutic intervention. The data on the basic demographics of the screened population, significant maternal, perinatal, and neonatal risk factors such as oxygen utilization, history of sepsis (clinical/culture positive) or pneumonia or meningitis, bronchopulmonary dysplasia, requirement of blood transfusions were collected retrospectively from the hospital records.

Data collected was summarized by descriptive statistics, mean and standard deviation for normally distributed numerical variables, median and interquartile range for nonparametric data and counts and percentages for categorical data. Key variables were expressed with 95% confidence interval (CI). Continuous variables were evaluated by Student's t-test or Mann–Whitney U tests depending on the skewness of the data. Categorical variables were compared using Chi-square test. Risk factors for ROP have been analyzed by univariate and multivariate analysis. Statistical analysis was performed using the Statistical Package for the Social Science software version 18 (Chicago, USA: SPSS Inc., 2009).

The approval for this study was granted by the Institutional ethics committee (IPGME and R/IEC/2018/573 dated September 29, 2018)

Out of the total eligible 1225 neonates, only 691 preterm infants could be screened for ROP during the study period and data for those babies were analyzed. The mean BW (± standard deviation [SD]) and mean GA at birth (±SD) of the population screened were 1338 (±303) g and 32.5 (±2.8) weeks. Among the study infants, 510 (73.8%) babies were born vaginally, 374 (54.1%) babies were male and the number of extremely low BW babies (ELBW) (<1000 g BW) was 91 (13.1%). Oxygen was required in 122 babies (17.6%) for more than 3 days. The requirement of transfusion and occurrence of any infection like clinical sepsis or meningitis or pneumonia were found in 57 (8.2%) and 212 (30.6%) babies, respectively. The magnitude of ROP in respect to BW and gestation is depicted in [Table 1]. The proportion of severe ROP was 34.2% (91/266) among all ROP cases. Among all ROP babies, 43 infants (16.2%) had suffered from APROP, almost half of the severe ROP cases. Three-fourth of the severe ROP cases were <32 weeks, whereas two-third of severe ROP cases was <1250 g BW mark. Of all APROP cases, almost 80% occurred <1500 g BW. The number of babies diagnosed with Stage I, Stage II, Stage III ROP, staged ROP with plus disease and APROP, in any eye, was 96 (13.9%), 92 (13.3%), 45 (6.5%), 43 (6.2%), and 42 (6.1%), respectively. Plus disease and APROP were diagnosed at an average of 54.8 (±16.9) and 31.3 (±11.3) postnatal days of life, respectively. The average corrected GA of detection of APROP was 34.1 (±1.9) weeks and for plus disease, it was 36.7 (±2.5) weeks.
Table 1: Magnitude and profile of retinopathy of prematurity among the screened neonates in the neonatal care unit over a period of 5 years (n=691)

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All the severe ROP babies (91) were treated with laser photoablation, with intravitreal anti VGEF therapy used in 22 babies. Among the babies required treatment, 43 (47.2%) babies suffered from APROP, 46 (52.8%) babies suffered from staged ROP (Stage II or III) with or without plus disease. Severe ROP babies required treatment at an average of 44.8 days of age and at mean postconceptional age of 36 weeks. ROP regressed completely in 85 babies (93.4%) with treatment. Only six babies had the unfavorable outcome of retinal detachment of which five babies had APROP and only one baby suffered from Stage II ROP with plus disease.

In bivariate analysis, several factors were identified as potential risks for developing severe ROP [Table 2]. The lower GA at birth and smaller BW were found to be the most significant risk factors. Oxygen utilization for >3 days (odds ratio [OR] 5.04, CI 3.13–8.12), the requirement of blood transfusion (OR 5.13, CI 2.58–9.25), any one of the diagnosis like clinical sepsis or pneumonia or meningitis (OR 1.968, CI 1.254–3.087) were other significant contributing factors for developing severe ROP requiring treatment. In multivariable analysis, lower GA (OR 0.66, CI 0.56–0.78, P < 0.001) and oxygen use > 3 days (OR 0.30, CI 0.169–0.553, P < 0.001) were found as independent risk factors for developing severe ROP.
Table 2: Comparison between two groups of babies: Babies in whom retinopathy of prematurity not developed or spontaneously regressed versus babies with severe retinopathy of prematurity requiring treatment

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In this study, the authors have analyzed 5 years of ROP data (2012–2016) of a level II neonatal unit of a district hospital in Eastern India where 38.5% of infants had any stage ROP and 13% of the screened babies had severe ROP requiring treatment. Initial reports from rural Karnataka (2012–2014) recorded an ROP proportion of 34%–41% with 10%–12% proportion of severe ROP.[5],[6] One multicentric study from 17 neonatal intensive care units of the six districts of North Karnataka reported 24.5% ROP, but they observed only 4.5% severe ROP among.[9] This study, however, included multiple units and had only 4.2% of ELBW babies. However our study is unique as the population was selected from a single unit and had more (13.1%) of ELBW infants in the screened population. The inclusion of multiple units with heterogeneous levels of care and lesser ELBW population in the Karnataka study may have contributed for the lesser occurrence of ROP, including severe ROP than this study. High incidence of ROP ranging from 32% to 44% has been reported from other developing countries also.[10],[11]

We observed that 60%–70% of babies in the severe ROP group were <1250 g BW and 32 weeks of gestation. This study showed the risk of APROP was also high in the smaller babies of level II care units. Sixty percent of APROP cases were found in babies <1250 g here. Hence, APROP was not only the major contributor of severe ROP but also more prevalent among babies with less GA and smaller BW. This is in contrast with the previous reports[12],[13],[14] of APROP in babies with higher BW, where APROP occurred as a result of unrestricted use of a higher concentration of oxygen. This data are alarming because there is a large cohort of the surviving smaller and less mature infants, even from district level neonatal unit of India, who are now exposed to a higher risk of severe ROP. Not only this, our report also confirmed that, the APROP cases had been detected much earlier, even before 28 days in many cases. From this report, it is evident, ELBW babies, susceptible to develop APROP, should be screened at 3 weeks of life and before 34 weeks of postconceptional age. A similar observation was reported previously by Hungi et al.[5] also.

In the present study, we could successfully manage 93.4% of babies with severe ROP resulting in completely regressed ROP. Similar successful outcome was reported in earlier studies by Sanghi et al.[13] and Jalali et al.[15] This overall favorable outcome has only become possible because of early screening, close monitoring, and timely intervention by the ROP team of the level III neonatal unit as a result of proper linkage between the two units. The favorable outcome has proved that this model may be considered as a strategic intervention for decreasing ROP-related morbidities of the district level II neonatal units of our country.

Risk factors are well known for developing ROP.[16],[17] The effect of prematurity and prolonged oxygen use were found as independent risk factors for developing ROP. Hence, the prevention of premature birth and restricted and judicious use of blended oxygen only can be helpful in preventing ROP in level II neonatal units.

Being single-center study, the population is homogeneous and the treatment protocol, as well as the ROP screening, diagnosis, and treatment, are mostly uniform in nature. There are some limitations also in this study like it is a retrospective study and the dropout rate of RIOP screening was also high. We could not analyze the effect of other risk factors like the use of surfactant, prolonged use of continuous positive airway pressure, necrotizing enterocolitis, or symptomatic ductus arteriosus, as most of the sicker babies with the complicated course were transferred to higher center.

Substantially high proportion of severe ROP in the district hospital level II neonatal unit is alarming. Prematurity and prolonged oxygen are independent risk factors for it. The linkage of the district level II unit with an ROP unit of a tertiary care hospital is a sustainable solution for favorable outcome of ROP.

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Conflicts of interest

There are no conflicts of interest.

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  [Table 1], [Table 2]


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