Tackling blindness due to Retinopathy of Prematurity (ROP) in low and middle income countries.

The history of Retinopathy of Prematurity must be as old as the history of the survival of premature infants. Retinopathy of Prematurity (ROP), previously termed as Retrolental Fibroplasia, is a vaso proliferative condition of Retina which is one of the major causes of childhood blindness and visual morbidity in the surviving premature infants. ROP is one of the priority diseases of Vision 2020 and ranks fifth among all other causes of childhood blindness in the world.1,2 It has a well-established classification system, the natural history of the disease is known, signs develop within 3-4 weeks after birth with rapid progression. In around 70% of these infants, the condition resolves without treatment. 20-30% of cases progress to sight threatening ROP that need treatment. 

 

Two epidemics of ROP have been described in industrialized countries. It was during the 1940s and 1950s in these countries where ROP was first noticed as a significant cause of blindness among infants. At that time, the survival rate of premature babies increased due to the use of supplemental unrestricted oxygen. That era was known as the “first epidemic.3 Thereafter, blindness from ROP diminished with the restriction of oxygen, but there was an increase in mortality rates and cerebral palsy. The “second    epidemic” started in the 1970s as neonatal care improved over time with use of mechanical ventilation and better modalities of monitoring oxygen supplementation and improved control of neonatal and perinatal complications. Lower weight preterm babies survived in 1980s and blindness from ROP re- emerged.

Over the last 10-15 years, it has become clear that ROP is making its mark again as a major cause of blindness among the newborn in low and middle income countries like Latin America, Eastern Europe, South Asia and Southeast Asia. These countries are expanding their neonatal care but have insufficient knowledge on ROP, setting the stage for a “third epidemic.”4 The unnecessary blindness from ROP can be controlled through 2 broad approaches: a) excellent neonatal care, and b) detecting and treating infants who develop the severe stages of the disease. The World Health Organization estimates that there are 15 million preterm births per year (born at <37 weeks). Risk of ROP is more in those born at <32 weeks gestational age and birth weight <1.5 Kg. Only preterm babies cared for in neonatal intensive care units develop ROP. In most of our South Asian countries, with rapidly developing neonatal intensive care systems and limited health resources, blindness due to ROP has recently emerged as an increasing problem in bigger premature  infants as well.

Common reasons why infants in these countries become blind from ROP include:

  • The unit in which they are treated lacks services for the detection and/or treatment of ROP
  • The infant exceeds birth weight criteria for examination and hence is not screened for ROP
  • The examination and treatment aren’t carried out effectively
  • The baby is exposed to excess oxygen due to lack of or poor oxygen saturation measuring techniques.

 

The strategies for management of ROP must be approached with an all-inclusiveness of Family Health Division, Child Health Division and integration of screening program for premature babies. Foremost is primary prevention of preterm births, the causes of which are multifactorial. It has been shown that reducing teenage pregnancies, preventing multiple births (i.e. in vitro fertilization), and avoiding unnecessary caesarian sections may reduce premature births. Improvement of neonatal care with specific interventions that decrease infection and use oxygen more judiciously can reduce the risk. Current modalities, such as the use of

1) blenders (systems that deliver oxygen in varying amounts); and

2) probes/monitors (measure blood oxygen levels) account for better oxygen monitoring. Periodic training of staffs on the importance of neonatal life.

Tele-screening with RetCam (wide field digital fundus camera) by a non-ophthalmologist5 may offer a viable solution for timely detection of treatable ROP, especially in areas where a trained ophthalmologist is not available. 

 

The advantages of a RetCam are the following: it can take images to track change over time and is useful for educating staff and    counselling parents. The camera is portable and can be used in more than one unit. Yet, the device does not provide a substitute for a trained ROP screener. It is a form of documentation that still needs interpretation by an ophthalmologist. The challenge of its use is that the report must be fed back to the screener within 48 hours in case treatment is urgent. This requires a 24/7 real time access to remote experts. Since ROP is not present at birth, but develops during the first few weeks of life, the first screening examination should take place no later than 30 days after birth. Follow-up screening is often needed, and may be done after the baby has been discharged from the neonatal unit. All babies who develop the sight-threatening stages of ROP must be treated urgently: within 48–72 hours. Peripheral retinal ablation with Diode Green or Infra-Red laser is still a gold standard for the treatment of ROP. However, aggressive posterior ROP and ROP in Zone 1 are less responsive to laser6 and require intra-vitreal injection of Anti-Vascular Endothelial Growth Factor (Bevacizumab 0.625 mg, Avastin; Genentech) or (Ranibizumab 0.2 mg, Lucentis; Novartis) as a single dose. Pediatric retinal surgery is required for progression to Stage 4 or 5. Lens-sparing vitrectomy (LSV) is the most exciting recent innovation used for most cases of Stage 4 ROP with a good outcome. Nearly 74% of anatomic and 63% of successful visual outcomes have been reported in Indian population with LSV for Stage 4 ROP.7

 

Infants with ROP may have an increased risk for other pathologies, such as high myopia, squint, and cortical brain damage. They need regular follow up so these problems can be detected and managed. Hence, good relationships among parents, pediatricians, and other caregivers have to be instituted. Tertiary prevention involves rehabilitation in order to restore function, with special education so that these children will integrate soonest with the regular education system and be able to mix with normally sighted children. Moreover, support services must be made accessible to families afflicted with a visually disabled child. Thus, there is a need to develop and strengthen eye facilities, specifically for low vision care.

 

As with most public health interventions, evidenced-based health information through population researches would help in better  planning of public health approach, policy development, and       rehabilitative services for visually disabled children due to retinopathy of prematurity. Hence, any ROP program must be comprehensive in nature that needs to have good coverage, needs good information management system, constant coordination of screening and management, financial support for the equipment and training, and vigorous public awareness campaign in the country.

Tele-screening with RetCam (wide field digital fundus camera) by a non-ophthalmologist5 may offer a viable solution for timely detection of treatable ROP, especially in areas where a trained ophthalmologist is not available. 

 

The advantages of a RetCam are the following: it can take images to track change over time and is useful for educating staff and    counselling parents. The camera is portable and can be used in more than one unit. Yet, the device does not provide a substitute for a trained ROP screener. It is a form of documentation that still needs interpretation by an ophthalmologist. The challenge of its use is that the report must be fed back to the screener within 48 hours in case treatment is urgent. This requires a 24/7 real time access to remote experts. Since ROP is not present at birth, but develops during the first few weeks of life, the first screening examination should take place no later than 30 days after birth. Follow-up screening is often needed, and may be done after the baby has been discharged from the neonatal unit. All babies who develop the sight-threatening stages of ROP must be treated urgently: within 48–72 hours. Peripheral retinal ablation with Diode Green or Infra-Red laser is still a gold standard for the treatment of ROP. However, aggressive posterior ROP and ROP in Zone 1 are less responsive to laser6 and require intra-vitreal injection of Anti-Vascular Endothelial Growth Factor (Bevacizumab 0.625 mg, Avastin; Genentech) or (Ranibizumab 0.2 mg, Lucentis; Novartis) as a single dose. Pediatric retinal surgery is required for progression to Stage 4 or 5. Lens-sparing vitrectomy (LSV) is the most exciting recent innovation used for most cases of Stage 4 ROP with a good outcome. Nearly 74% of anatomic and 63% of successful visual outcomes have been reported in Indian population with LSV for Stage 4 ROP.7

 

Infants with ROP may have an increased risk for other pathologies, such as high myopia, squint, and cortical brain damage. They need regular follow up so these problems can be detected and managed. Hence, good relationships among parents, pediatricians, and other caregivers have to be instituted. Tertiary prevention involves rehabilitation in order to restore function, with special education so that these children will integrate soonest with the regular education system and be able to mix with normally sighted children. Moreover, support services must be made accessible to families afflicted with a visually disabled child. Thus, there is a need to develop and strengthen eye facilities, specifically for low vision care.

 

As with most public health interventions, evidenced-based health information through population researches would help in better  planning of public health approach, policy development, and       rehabilitative services for visually disabled children due to retinopathy of prematurity. Hence, any ROP program must be comprehensive in nature that needs to have good coverage, needs good information management system, constant coordination of screening and management, financial support for the equipment and training, and vigorous public awareness campaign in the country.

 

References:

  1. https://www.who.int/blindness/Vision2020_report.pdf
  2. C. Gilbert and A. Foster; Childhood blindness in the context of Vision 2020- the right to sight. Bull World Health Organ.2001; 79(3): 227–232.
  3. Ashton N, Ward B, Serpell G. Effect of oxygen on developing retinal vessels with particular reference to the problem of retrolental fibroplasia. Br J Ophthalmol. 1954; 38:397–432.
  4. Rajvardhan Azad, Claire Gilbert, et al. Retinopathy of Prematurity: How to prevent the third epidemics in developing countries. Review article, Asia Pac J Ophthalmol (Phila) 2020;9:440–448
  5. Vinekar A, Gilbert C, Dogra M, Kurian M, Shainesh G, Shetty B, et al. The KIDROP model of combining strategies for providing retinopathy of prematurity

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Dr. Sanyam Bajimaya
Dr. Sanyam Bajimaya

Dr Bajimaya is Asst. Professor, Cataract & Vitreo-Retina Surgeon of Tilganga Institute of Ophthalmology. Dr. Bajimaya completed his Vitreo-Retina fellowship from John A. Moran Eye Center, Utah, USA in 2012. His special interests include Cataracts, Vitreo-Retina and Pediatric Retina. Dr. Bajimaya is a Life Member of Nepal Ophthalmic Society (NOS), All India Ophthalmological Society (AIOS), and Asia Pacific Vitreo-Retina Society (APVRS). Currently, Dr. Bajimaya is holding the post of Council Member of APVRS and Secretary-General of Nepal Vitreo-Retina Society (NVRS). He has International Memberships from the American Academy of Ophthalmology (AAO). Dr. Bajimaya is an expert at Cataract surgery and Vitreo-Retina Specialty. He has been actively involved in training, teaching-learning, and research activities in the field of Cataract, Vitreo-Retinal disease, Diabetic Retinopathy and Pediatric Retina including Retinopathy of Prematurity (ROP).