Dr. Ashok Kanakamedala
K16863Dr.Madhu Kumar R, Dr. Pradeep Sagar, Dr. Bhargavi
Lakshmi Kanakamedala
THE INCIDENCE OF RETINOPATHY OF PREMATURITY AT A TERTIARY HOSPITAL IN ANDHRA PRADESH
Ashok K, Madhu kumar, Bhargavi Lakshmi, Pradeep
ABSTRACT:
Purpose: To study the incidence and risk factors of retinopathy of prematurity (ROP) and to assess the outcome of laser photocoagulation.
Methods: A retrospective review of premature babies admitted in NICU from May 2015 to May 2016, with a gestational age of 32 weeks or less at birth and a birth weight of 1500 g or less was made. Sick infants were included even if they were older and heavier. ROP screening was done in 200 cases from the fourth postnatal week and was followed up.
Results: The incidence of ROP was 19.5%. Most common maternal risk factor was pregnancy induced hypertension (17.9%). Low birth weight (LBW) and respiratory distress syndrome (RDS) (89.7%) were the most common risk factors in infants. 56.4% of ROP cases underwent laser photocoagulation. All the cases that underwent laser regressed.
Conclusion: In our study a very high proportion of cases underwent laser compared to previous studies. The outcome of laser was good. The most common risk factors were LBW and RDS.
Department of Retina, Sankara Eye Hospital, Guntur, Andhra Pradesh
Correspondence to: Dr. Ashok K, Department of Retina, Sankara Eye Hospital, Guntur, Andhra Pradesh, India. E-mail: dr.ashok83@gmail.com
INTRODUCTION:
Retinopathy of prematurity (ROP), characterized by abnormal development of retinal vasculature, is an important and preventable cause of childhood blindness1. It is estimated that ROP is the cause of 50,000 cases of childhood blindness in the world every year2. According to the available data, there has been an increase in the incidence of ROP in developing countries, cause of which was considered to be higher survival rates in extremely premature babies3. A high concentration of supplemental oxygen therapy was previously thought to be the major risk factor for development of ROP4,5. However, there are many reports that ROP has been observed in patients without oxygen therapy6. Low birth weight (BW) and low gestational age (GA) are well-known risk factors for ROP7,8.
The criteria for ROP screening have been well determined in industrialized countries, but the available data suggests that blindness from ROP varies from region to region3. According to many studies performed in various parts of the world, it has been recognized that ROP screening in each region has its own characteristics and a single screening program cannot suit all regions9.
PURPOSE:
To study the incidence,risk factors of retinopathy of prematurity (ROP) and to assess the outcome of laser photocoagulation.
METHODS:
This is a retrospective cross sectional review which included premature babies who were referred for ROP screening, admitted in NICU from May 2015 to May 2016, with a gestational age of 32 weeks or less at birth and a birth weight of 1500 g or less. Babies ˃32 weeks and ˃1500 grams were screened if the babies were sick as per paediatricians advice. ROP screening was done from the fourth postnatal week and within four weeks if the baby was ≤30 weeks and was followed up accordingly.
Data on birth weight, gestational age, postconceptional age was noted. Maternal risk factors like (pregnancy induced hypertension, gestational diabetes) and baby risk factors like (respiratory distress syndrome, sepsis) were also noted in the history. Babies in whom media opacity (not related to ROP) precluding fundus visualization disease, loss to follow-up were excluded from the study.
The pupils were dilated by application of tropicamide 0.5% and phenylephrine 1%, and the patients were examined by a single retina specialist using a binocular indirect ophthalmoscope with 20 D lens. A sterile lid speculum and a scleral depressor were routinely used.
ROP was classified according to the international classification of ROP and follow-up schedules were designed in accordance with suggestions of the American Academy of Pediatrics, American Academy of Ophthalmology and American Association for Pediatric Ophthalmology and Strabismus10.Treatment plans were based on recommendations of the Early Treatment of ROP cooperative group11.
RESULTS:
During the period of 1 year, 200 babies were screened. Male babies screened were 110, and female babies were 90. Gestational age (GA) of babies ranged from 26 weeks-38 weeks (meanGA-33wks). Birth weight (BW) of the babies range from 1kg-3.5kg (meanBW-2.25kg). Incidence of ROP was 19.5% (39 babies) in our study. Different stages of ROP seen are as shown in the table1. In the babies diagnosed to have ROP the gestational age ranged from 26weeks- 37weeks (with 30% being more than 32 weeks). Birth weight ranged from 1kg-2kg (with 25.6% being more than 1.5kg). Most common maternal risk factor for ROP was pregnancy induced hypertension in 7 patients (17.9%) followed by gestational diabetes in 2 cases (5.1%). The most common neonatal risk factors for ROP was respiratory distress syndrome in 35 babies (89.7%) followed by sepsis in 5 cases (12.8%). 22 patients (56.4%) diagnosed to have ROP underwent laser photocoagulation. All the cases that underwent laser regressed.
TABLE1:
| ROP(stage) | NO. (%) |
| Stage 1 | 5 (12.8%) |
| Stage 2 | 16 (41%) |
| Stage 3 | 18 (46.2%) |
| Stage 4 | 0 |
| Stage 5 | 0 |
DISCUSSION:
ROP is considered to be a preventable cause of childhood blindness especially if diagnosed and treated at an appropriate time. The incidence of ROP in premature infants in our study was 19.5%. In developed countries, the reported incidence of ROP ranges from 19.3% to 25% (12,13). Likewise in India, the incidence of ROP depends on the region of study and ranges from 20% to 47.3% (14,15). In the current study the incidence of ROP is almost same as other studies performed in India. As reported by Palmer, et al.(16), incidence and severity of ROP was closely related to lower birth weight and lower postconceptional age, as was seen in our study.
There are varying screening criteria described by different authors. Vinekar,et al.(17)suggested that the scenario in developing countries is quite different. Larger and gestationally ‘older’ infants are more likely to develop ROP compared to their counterparts in Western countries. Hence, the application of Western screening guidelines for developing countries has been questioned by Jalali, et al(18). As a higher cut off limit, they recommended screening babies born at<37 weeks gestation and/or birthweight <2000g in the presence of a high sickness score, in order to prevent missing any infant with threshold ROP.
So, we feel that all babies with birthweight less than 1500g and gestation ≤32 weeks should be routinely screened. Infants with birthweight between 1500-2000g and gestational age more than 32 weeks should be screened at the discretion of the neonatologist, depending on other risk factors during the course of stay in the NICU.
Many risk factors have been reported to predispose to the development of ROP. In our study the most common maternal risk factor noted was pregnancy induced hypertension seen in 17.9% followed by gestational diabetes in 5.1%. Most common neonatal risk factors were respiratory distress syndrome in 89.7% followed by sepsis in 12.8%. Oxygen therapy was not found to influence the development of ROP in our study.
56.2% of the babies who developed ROP underwent laser photocoagulation. All the babies who underwent laser had regressed ROP. Ng, et al.(19) and Connolly, et al.(20) have reported that long term structural and functional outcome using laser was superior to that obtained with cryotherapy. Laser obviates the need for general anesthesia and hardly has any complications. The higher rate of treatment required in our study is because our NICU is a tertiary referral center where sick babies are usually referred.
CONCLUSION:
ROP screening guidelines should vary according to the region. The most common risk factors were low birth weight, lower gestational age and respiratory distress syndrome and pregnancy induced hypertension. In our study a very high proportion of cases underwent laser compared to previous studies. The outcome of laser was good.
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