|Year : 2012 | Volume
| Issue : 3 | Page : 277-281
Screening for retinopathy of prematurity in South of Iran
Mehrdad Afarid, Hamid Hosseini, Bagher Abtahi
Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran
|Date of Web Publication||3-Jul-2012|
Assistant Professor of Ophthalmology, Department of Ophthalmology, Poostchi Research Center, Shiraz
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Purpose: The purpose of this study is to report the screening data for retinopathy of prematurity (ROP) at a screening center in Southern Iran.
Materials and Methods: A chart review was performed of all screened neonates who were referred to Poostchi screening center affiliated to Shiraz University of Medical Sciences from February 2006 to January 2010. Statistical analysis of data was performed with the Chi-square and independent t-test where appropriate. A P < 0.05 was considered statistically significant.
Results: Of 787 infants referred, 293 (37.2%) had some form of ROP and 77 cases (9.8%) had plus disease, only 6 (2%) patients progressed to advanced ROP stages 4 and 5. The mean gestational age (GA) of patients with ROP (ROP group) was statistically significantly lower at 29.46 ± 2.31 weeks compared to patients without ROP (non-ROP group) (31.56 ± 2.03 weeks) (P < 0.05). The mean GA of patients with plus disease was statistically significantly lower at 28.92 ± 2.18 weeks compared to patients without plus disease (30.98 ± 2.30 weeks) (P < 0.05). The mean birth weight in the ROP group was statistically significantly lower at 1248.46 ± 301.75 g compared to the non-ROP group (1485.79 ± 268.66 g) (P < 0.05). The mean birth weight of patients with plus disease was statistically significantly lower at 1207.92 ± 334.79 g compared to patients without plus disease (417.99 ± 293.19 g) (P < 0.05). There was no difference in the occurrence of ROP or plus disease between single or multiple births, normal vaginal delivery, and caesarian section and between clomiphene users and nonusers (P > 0.05, all cases).
Conclusion: Greater cooperation between ophthalmologists, neonatologists, gynecologists, and health policy makers is necessary to optimize ROP screening programs. Data from this study can be used by health policy makers for implementation of health programs. These programs must include screening guidelines and effective coordination among the screening centers, antenatal, obstetric, and neonatal care services.
Keywords: Childhood Blindness, Retinopathy of Prematurity, Retinopathy of Prematurity Screening
|How to cite this article:|
Afarid M, Hosseini H, Abtahi B. Screening for retinopathy of prematurity in South of Iran. Middle East Afr J Ophthalmol 2012;19:277-81
|How to cite this URL:|
Afarid M, Hosseini H, Abtahi B. Screening for retinopathy of prematurity in South of Iran. Middle East Afr J Ophthalmol [serial online] 2012 [cited 2020 Jun 2];19:277-81. Available from: http://www.meajo.org/text.asp?2012/19/3/277/97922
| Introduction|| |
Retinopathy of prematurity (ROP) is a leading cause of blindness in premature infants and affects approximately 80% of premature infants with birth weight less than 1000g. 
Over the last decade, neonatal care has improved, which had contributed to an increasing population of survivors in neonatal intensive care units (NICUs) today. ,,
ROP is an important cause of blindness in middle-income countries.  Control of childhood blindness is a priority of the World Health Organization's (WHO) VISION 2020 programs.  The mission of these programs is to eliminate the main causes of preventable and treatable blindness as a public health issue by the year 2020.
ROP is a preventable cause of childhood blindness.  Infants in Iran are considered at high risk of severe visual loss due to ROP. , In the last few years, new NICUs have been added in Iran and it is expected that the incidence of ROP will increase further. However, currently treatment centers for ROP in Iran are rare. In Shiraz, a city in Southern Iran, there is a ROP screening center that is part of a tertiary eye clinic which was opened in 2006.
The aim of this study is to report data from this screening center in Shiraz, to provide preliminary statistics on ROP in Southern Iran. These data may be pertinent to the development of public health policy and for the prevention of visual morbidity due to ROP.
| Materials and Methods|| |
This retrospective study was initiated after the approval from the Shiraz Institutional Review Board (IRB). A chart review was performed of all screened neonates who were referred from February 2006 to January 2010 to Poostchi screening center affiliated to Shiraz University of Medical Sciences. Parental or guardian consent was sought prior to ophthalmic examination and completion of charts.
Screening criteria at this center were gestational age (GA) below or equal to 32 weeks, birth weight below or equal to 2000g, and poor general conditions (more than 1 week admission in NICU, and receiving more than 90% oxygen in NICU, acute respiratory distress syndrome, and other poor general conditions according to the diagnosis of a neonatologist). Patients referred with one of the above criteria were accepted for the screening program and a follow-up chart was completed that included the name, GA, birth weight, gender, method of delivery, multiparity, causes of prematurity (premature rupture of membrane, premature labor pains, eclampsia or preeclampsia, or other causes according to the history or medical notes during the pregnancy), medication used by the mother during or before pregnancy, use of clomiphene, and results of eye, the ophthalmic examination according to the international classification of ROP. The first examination was performed after 20−30 days post-partum or 31−32 weeks postmenstrual age. Indirect ophthalmoscopy on both eyes of all patients under local anesthesia was performed by a vitreoretinal specialist and ROP grading and treatment was based on the international committee on classification of acute ROP and early treatment of ROP criteria. , All pupils were dilated with topical cyclomydril (0.2% cyclopentolate and 1% phenylephrine).
All data of infants screened for ROP were retrieved from medical records and entered into a specially designed questionnaire. Data were analyzed on the GA, birth weight, gender, route of delivery, multiparity, cause of prematurity (as described above), medication used by mother during or before pregnancy (did or did not use clomiphene), and the results of the ophthalmic examination according to the international classification of ROP.  Data were analyzed using the program SPSS 15 (IBM Corp., Armonk, NY, USA). The Chi-square and independent t-tests were used for statistical analysis. A P value less than 0.05 was considered statistically significant.
| Results|| |
In this study, 1148 premature infants were assessed during the study period 2006−2010. The medical records of all 1148 infants were retrieved and 361 infants were excluded from the study because they did not meet the screening criteria or the medical charts were incomplete. The study cohort comprised 787 infants including 389 (49.4%) males and 398 (50.6%) females.
The mean GA was 30.87 ± 2.37 weeks (range, 23−38 weeks). The mean birth weight was 1397 ± 303.776 g (range, 600−2100 g) and 555 (70.5%) of the infants were single and 232 (29.5%) were multiparous. There was normal vaginal delivery in 221 (28.1%) cases and 566 (71.9%) infants were delivered via cesarean section (CS). Of the mothers, 171 (21.7%) had a history of clomiphene consumption during pregnancy.
Retinopathy of prematurity and characteristics
In the study cohort, 293 (37.2%) had a stage of ROP and 77 cases (9.8%) had plus disease (ROP group). Of the infants with ROP, 36% were males and 38.4% were females (P = 0.477).
The mean birth weight in the ROP group was 1248.46 ± 301.75 g, and 1485.79 ± 268.66 g for those without ROP (non-ROP group). The difference in birth weight between groups was statistically significant (P = 0.000). The mean GA of the ROP group was 29.46 ± 2.31 weeks, and 31.56 ± 2.03 weeks for the non-ROP group. The difference in GA between groups was statistically significant (P = 0.000). In the ROP group, 33.4% had stage 1, 48.8% had stage 2, 15.7% had stage 3, and 2% had stage 4−5 ROP [Figure 1].
ROP was present in 73.3% of infants with GA ≤ 28 weeks, 40.6% of infants with GA of 29−31 weeks, and 18.3% of infants with GA ≥ 32 weeks ( P ≤ 0.000) [Figure 2]. ROP was present in 75% of infants with birth weight ≤ 1000 g, 53.3% of infants with birth weight of 1001−1250 g, 34.6% of infants with birth weight of 1251−1500 g, and 16.7% of infants with birth weight > 1500 g (P = 0.000) [Figure 3].
ROP was present in 33.9% of infants whose mothers used clomiphene and in 38.1% of infants whose mothers did not use clomiphene. This difference was not statistically significant (P = 0.31).
ROP occurred in 42.5% of infants whose mothers underwent normal vaginal delivery and 35.2% of infants delivered via CS, and 35.3% of single infants and 41.8% of multiple infants had ROP (P = 0.086) [Table 1]. There was no statistically significant difference in the occurrence of ROP between delivery methods and single or multiparous births.
|Table 1: Findings of the study in retinopathy of the prematurity (ROP) group and no ROP group|
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Retinopathy of prematurity plus disease
Plus disease was present in 77 (9.8%) infants of whom 10.3% were males and 9.3% were females (P = 0.641). The mean GA was 28.92 ± 2.18 weeks for patients with plus disease and 30.98 ± 2.30 weeks for patients without plus disease. The difference in GA was statistically significant (P = 0.000). The mean birth weight was 1207.92 ± 334.79 g for patients with plus disease and 1417.99 ± 293.19 g for patients without plus disease (P = 0.000). Plus disease was present in 22.6% of infants with GA ≤ 28 weeks, 11.4% of infants with GA 29−31 weeks and 7% of infants with GA ≥ 32 weeks. Plus disease was present in 27.3% of infants with birth weight ≤ 1000 g, 11.4% of infants with birth weight 1001−1250 g, 9.2% of infants with birth weight 1251−1500 g, and 3.6% with birth weight >1500 g (P = 0.00) [Figure 3] [Table 2].
|Table 2: Findings of the study in the plus disease group and no plus disease group|
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Plus disease was present in 8.8% of single infants and 12.1% of multiparous births (P = 0.163).
Plus disease was present in 10.9% of infants born with normal vaginal delivery and 9.4% of infants who were delivered through CS (P = 0.526). Plus disease was present in 10.5% of infants whose mothers used clomiphene and 9.6% of infants whose mothers did not use clomiphene (P = 0.712). Six (2%) patients had advanced stage (4 and 5) ROP.
Response to treatment
Laser therapy was performed on 74 neonates with plus disease and on three patients with stage 3, zone 1 ROP without plus disease. Laser therapy was performed on three patients with plus disease due to poor systemic health. All treated cases responded well to a single session of laser therapy except two neonates who needed additional laser therapy and other two neonates who progressed to stage 5. Deep vitrectomy was performed for three of six patients with stage 4−5 ROP with anatomical success in only one patient after 24 month follow-up.
| Discussion|| |
ROP is a significant cause of childhood blindness as the survival rate of premature infants increases.  Extremely low birth weight (<1500 g), very premature birth (GA < 28 weeks), and unrestricted oxygen supplementation are the dominant risk factors. , In industrialized countries blindness from ROP is now largely restricted to infants in the extremely low birth weight group (<1500 g). ,
Many studies have addressed the natural course and risk factors of ROP. ,,, However, causes of regression of ROP or progression to retinal detachment remain unclear.  Most cases of ROP begin at 31−32 weeks postmenstrual age and in infants with birth weight of <1500 g.  The results of our study concur with previous observations that low GA and low birth weight are two major risk factors for ROP. As a greater population of very low birth weight and extremely low birth weight babies survive due to advances in neonatal care, the risk of ROP is increased. , ROP is also more likely to occur in males in some studies;  however, the outcomes from our study indicate that the risk of ROP is the same for males and females.
Control of risk factors and performing regular screenings can lead to early identification and treatment of ROP. These are two main methods to control ROP-associated visual impairment or blindness. , It is essential to identify infants at risk for progression of ROP.
Guidelines for screening vary between ROP screening centers worldwide. ,,,,, Guidelines depend on the availability of human and material resources and the heath infrastructure to address the problem. Guidelines which include larger more mature infants will increase over-referrals and workload for ophthalmologists. Alternately including only smaller, less mature infants may miss some cases. The results of our study show that 37.2% of infants classified as at risk by our referral criteria (i.e. ≤32 weeks GA or 2000 g) had ROP and 73.3% of infants with GA ≤ 28 weeks developed ROP. The outcomes of our study are similar to other centers in India, Brazil, South Africa, Thailand, China, Sweden, and the United States. ,,,,,, For example, a study of infants in Sweden of GA ≤ 27 weeks showed that 72.7% had ROP which was very near to our results. 
Socioeconomic factors, distribution of screening centers, antenatal, obstetric and neonatal care programs, and physician knowledge about ROP and availability of expert ophthalmologists for screening and treatment programs are important factors for implementation of screening protocols and developing and implementing referral criteria. Some reports from other ROP screening centers in Iran indicated that major improvement in the referral criteria and processes is necessary in Iran. The Poostchi screening center is the first center in Southern Iran and as NICUs in Southern Iran improve, there needs to be a concomitant improvement in ROP centers for optimal implementation of an effective ROP screening protocol. This effort will require educating general ophthalmologists, neonatologists, and parents about prematurity and its complications.
In addition to setting up an effective ROP screening program, control of risk factors is important. In our study, only GA and birth weight were identified as associated risk factors but sex, multiparity, route of delivery, and use of clomiphene by the mother did not show a significant association with ROP or progression to plus disease. An evaluation of all the possible risk factors of ROP was beyond the scope of the resources available to us. Other studies must be done in Iran to determine other risk factors in this region.
ROP can be decreased by reducing prematurity and low birth weight through improved antenatal and obstetric care and by better neonatal care.  To achieve optimal outcomes, better cooperation between ophthalmologists, neonatologists, gynecologists, and health policy experts is necessary.
In conclusion, the results of our study can be used by public health policy planners for the implementation of an effective screening program. In addition, other major stakeholders in the multidisciplinary approach can use this data for the coordination of the programs. These programs must include screening guidelines, appropriate distribution and contribution of screening centers, antenatal, obstetric, and neonatal care programs.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]