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Abstract
Purpose To identify and compare the profile of retinopathy of prematurity (ROP) in premature babies in urban and semiurban neonatal intensive care units (NICUs).
Methods A prospective study of babies admitted to NICUs of two urban and seven semiurban centres. They were <36 weeks of gestational age and were subjected to fundus photography with a RetCam shuttle camera. Photos and NICU details were uploaded on a secure website. Photographs were read by a single observer. Infants were followed till retinal vascularisation was complete, or 45 weeks post conceptional age. Babies developing severe ROP were lasered.
Results 500 babies were screened (243, urban group; 257, semiurban group). Incidence of ROP in the urban and semiurban groups was 16.5% (40) and 14.8% (38) respectively. Mean gestational age was 30.90 weeks and 31.53 weeks respectively. Mean birth weight was 1344 g and 1375 g respectively. 28 babies were lasered, 15 and 13 from each group respectively. There was no statistically significant difference between any of the parameters compared. Level of significance was fixed at 0.05.
Conclusions The magnitude of the burden of ROP is comparable between urban and semiurban NICUs stressing the need for effective screening strategies in semiurban and rural areas as well.
- Telemedicine
- Epidemiology
- Retina
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Introduction
Reports suggest 4–5% of all blindness in India is due to childhood blindness.1 In India 1 in 1000 children are blind.2–4 Retinopathy of prematurity (ROP) is one of the leading causes of childhood blindness in premature infants in both the developed and developing worlds. However, ROP though a potentially blinding condition has a very good prognosis with timely screening and correct treatment.5 The incidence of ROP in India is reported at 24–47%.6–9 It is also well recognised that the profile of the ROP babies in developing countries is much different from that in developed countries. In developing countries relatively older and heavier babies are also likely to develop ROP, thus increasing the burden of babies that need to be screened.6 ,8 ,10–12 Presently, most of the information we have about incidence and profile of these ROP babies in India have come out of studies conducted in tertiary centres in big cities. However, recently there is evidence to suggest that the rural ROP burden may be comparable to that of the urban population.13
With the improvement in neonatal care services many level 2 nurseries have mushroomed across semiurban and rural parts of India and with it many premature babies are surviving in these areas. Unfortunately there is a paucity of ROP care givers in these areas as most of the vitreo-retinal surgeons and paediatric ophthalmologists practise in bigger cities. In fact, paediatric ophthalmology is still not a well-established separate subspecialty in India.4 ,14 ,15 Hence babies treated in these neonatal intensive care units (NICUs) are not being subjected to screening for ROP. Hence the paradox, more babies need to be screened with fewer resources.
A logical solution for this problem would be telemedicine. With the advent of wide angle photography and telemedicine, the screening for ROP can be done remotely with good accuracy.16 ,17 The ‘Vittala ROP Project’ is one such project which utilises wide angle fundus photography and telemedicine to provide screening for ROP in level 3 and level 2 NICUs in six districts of Karnataka. Here we analyse ROP in 500 babies screened in these six districts.
This study aims to compare the incidence and profiles of ROP babies screened in two urban centres and seven semiurban centres across Karnataka.
Aims
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To identify the incidence of ROP in premature babies born in six districts of Karnataka.
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To compare the characteristics of ROP in premature babies being treated in a metropolitan city with those cared for in smaller towns.
Materials and methods
This is a prospective study of premature babies screened in six districts of Karnataka between April 2010 and October 2011. Our study covered two NICUs located in Bangalore city (urban) and seven located in rural/semiurban areas (Districts of Davangere, Hassan, Uttara Kannada, Shimoga and Gadag). The inclusion criteria were babies born at gestational age less than 36 weeks. The babies were subjected to fundus photography with a RetCam shuttle (Clarity Medical Systems, Pleasanton, California, USA) camera as part of a routine screening programme. The photographs were taken by trained technicians, after full pupillary dilatation with 0.4% tropicamide and 2.5% phenylephrine. Ten fields were taken in each eye which included the posterior pole and 360° retinal periphery and uploaded onto a secure website with the help of an indigenously developed software. The software is designed on open source technologies using the LAMP (Linux, Apache, MySQL and PHP) technologies. The data base structure allows for storage of multiple images per screening visit. The visit records are segregated by NICU and treating doctor, ensuring patient confidentiality. A dashboard-based mechanism shows the tasks at hand like patients needing diagnosis, patients due for review etc. The system is hosted in a shared server. The system can be accessed from any internet- enabled device without any downloads needed.
Data regarding the gestational age, birth weight, sex, type of delivery and history of delivery of twins were recorded. Other neonatal risk factors such as oxygen supplementation, mechanical ventilation, blood transfusion, exchange transfusion, sepsis and apnoea were captured on the software. The photographs were read by a single observer (KRM) and reported within 24 h. ROP was classified as per the revised International Classification of Retinopathy of Prematurity.18 The technician visited the NICUs every week on a fixed day and took fundus pictures with the same camera. Infants were followed up till the retinal vascularisation was complete or till 45 weeks post conceptional age. Infants who had no ROP were followed up every 2 weeks. Infants in whom ROP was detected were followed every week or earlier as the severity demanded. Babies progressing to severe ROP were treated with laser photocoagulation as per the Early Treatment of Retinopathy of Prematurity (ETROP) guidelines.19 Laser treatment was delivered by a diode laser retinal photocoagulator (Carl Zeiss, Jena, Germany).
Inclusion criteria
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Premature babies born at less than 36 weeks of gestation.
Exclusion criteria
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Babies born at more than 36 weeks of gestation
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Babies’ parents not consenting for screening
Statistical methods used
Mann–Whitney U test was applied to compare the two groups when the data were continuous as in gestational age and birth weight. The χ2 test was applied when the variables were categorical (location, ROP, laser, compliance and gender). SPSS (V.15) was used for the data analysis. Level of significance was fixed at 0.05. The study was approved by the institutional review board of Vittala International Institute of Ophthalmology. An informed oral consent was taken from the parents before each screening and a written consent before any laser procedure.
Results
During the period between April 2010 and October 2011, 512 infants were photographed with the help of a RetCam shuttle, out of which 500 babies satisfied the inclusion criteria with a mean gestational age of 32.13 weeks and a mean birth weight of 1576.7 g. Of 500 babies, 243 belonged to the urban cohort and 257 to the semiurban cohort. Overall incidence of ROP was 15.6% (78) and it was not significantly influenced by gender, type of delivery or twin pregnancies. Incidence of ROP in the urban cohort was 16.5% (40) and in the semiurban cohort it was 14.8% (38). There was no statistically significant difference in the incidence of ROP in the two groups (urban and rural/semiurban) (p=0.606). The mean gestational age (in weeks) and the mean birth weight (in grams) of the babies that developed ROP were compared. There was no statistically significant difference between the two groups with respect to gestational age or birth weight (table 1) Comparison of the incidence of ROP in Zone I, Zone II and Zone III in the urban and semiurban cohorts showed no statistical significance (p=0.519). The details are summarised in table 2.
Comparison of the gestational age and birth weight between the two cohorts
Zone-wise comparison of incidence of retinopathy of prematurity in urban and semiurban cohorts
Out of 78 babies that developed ROP, 28 babies required laser; 15 (37.5%) belonged to the urban cohort and 13 (34.2%) to the semiurban cohort. There was no statistically significant difference in the incidence of severe ROP between the urban and semiurban cohorts (p=0.762).
Discussion
Close to 72% of the population of India resides in rural areas and it is safe to assume that 70% of the new births are happening in rural parts of India.20 The present ROP scenario in India is largely described by studies coming out of urban NICUs, which paint a bleak picture of the problem ahead.6–9 Recently there is evidence emerging that the incidence of ROP in rural NICUs could be comparable to the published incidence of ROP in urban studies which is not comforting.13 To the author's knowledge this is the first comparative study of the incidence and profile of ROP babies in the urban and rural NICUs of India.
A previous study from Maharashtra, India looked at the most common causes for childhood blindness in 1712 children in special schools, who were blind or severely visually impaired.21 Disorders of the globe were found to be the most common causes. But what was surprising was that there was not a single case of blindness due to ROP or its sequelae. The reasons postulated by the authors for this was that most babies with ROP had other disabilities and hence may not have reached these institutions. Also most of the children in their group were above 10 years and ROP is most frequently seen in early childhood.
Initially it was thought that ROP like diabetes was a disease of the developed nations, but now that myth has been shattered and we are looking at an epidemic of ROP in developing nations. After the initial reports of ROP in India which naturally came out of the big tertiary paediatric and eye hospitals there was a hope that this phenomenon was predominantly restricted to large level 3 nurseries due to the high survival rate of very small babies in these nurseries.
Surprisingly, we noted that there was nothing separating the babies surviving in smaller NICUs in the semiurban and rural areas of Karnataka with respect to the incidence of ROP, mean gestational age, mean birth weight and the incidence of severe ROP warranting laser therapy. However, what was noticed was that there appeared to be an increased risk to develop Zone 1 disease in the semiurban cohort (six when compared to three) which was not statistically significant. This finding echoes the recent observations of increased incidence of aggressive ROP in a rural NICU in India.13
What this study suggests is that the burden of ROP is real and it is comparable between the rural and urban population of India. Thus we need to have a uniform screening strategy for ROP which needs to be instituted in all NICUs. What is also true is that there is a large deficit of available paediatric eye care specialists in India and the few who are practising are in large tertiary care eye hospitals situated in big cities.22
Though the gap in terms of available screening facilities and the desired facilities is quite wide, this can be significantly narrowed with the effective use of telemedicine. Telescreening for severe disease in ROP has already been proved to be effective and efficient.16 In fact, the time required for an ophthalmologist to make a telemedical ROP diagnosis is significantly less than that for an ophthalmoscopic diagnosis.23 With smart amalgamation of information technology and retinal photography by trained technicians we have been able to provide ROP screening facilities to remote areas of Karnataka where no such facility previously existed. It has been our experience that the quality of photographs is not a limiting factor in the diagnosis of ROP. Since the software is based on an open source technology and the data are hosted on the web, the cost of maintenance of data is drastically brought down. Since the data can be accessed from any internet-enabled device it could be adopted into any telescreening programme anywhere in the world. The initial investment on the RetCam and its insurance, a vehicle to transport it and the development of the customised software was US$125 000 and the monthly running expenses of this programme is about US$1500 costing us around US$18–20 per screening.
Conclusions
The burden of ROP seems to be evenly distributed across the urban and rural areas of Karnataka emphasising the need for an effective screening programme encompassing the entire ‘at risk’ population. However, uneven distribution of technical expertise poses the greatest challenge. Remote screening with the help of teleophthalmology promises to be a good option to achieve this goal of universal screening in developing countries.
Acknowledgments
The authors thank the Vittala ROP team of technicians and drivers for helping photograph these babies from remote areas on a weekly basis, the NICU staff from the different NICUs, Mr S K Rao for software and technical support and Mrs Mariamma Philips from the statistics department of NIMHANS (National Institute of Mental Health and Neuro Sciences) for her help with statistical analysis.
References
Footnotes
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Contributors KRM, PRM, NB, NHS were involved in designing the study. KRM, DS, MN were involved in data compilation and analysis. KRM, DS and MN were involved in drafting the manuscript.
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Competing interests None.
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Ethics approval IRB of Vittala International Institute of Ophthalmology.
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Provenance and peer review Not commissioned; externally peer reviewed.
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Data sharing statement Additional unpublished data are available in the Vittala ROP project database which is available to Vittala International Institute of Ophthalmology.