| BackgroundRetinopathy of prematurity (ROP) is a proliferative vascular retinopathy, which occurs in low birth weight and premature infants. According to the World Health Organization (WHO), ROP is the main cause of blindness in children, with a prevalence of6%-18%in children with blindness. ROP has been recognized as one of the important factors bind to high income countries in "vision2020project" advocated by the world health organization (WHO).It is the second cause of children blindness in the United States. With the implement of intensive care technology in developed countries, more low body survivals. ROP will become a major factor of the blind causes of children in developing countries.In recent years, with the continuous development of our country medical treatment level, infants with low birth weight and premature mortality decline under new advances in pediatric first-aid and nursing. Meanwhile, the prevalence of ROP, and the amount of blind children due to ROP are also gradually increased.Since the exact pathogenesis of ROP is still unclear, the efficacy of surgery in the advanced stages of ROP is limited and variable. Even if retinal surgery appropriately repositions the detached retina, recovery of the patients’visual function remains limited. Therefore, early screening and an appropriate treatment for early ROP is vital to reduce the rate of blindness in low birth weight and premature infants. In2004, the ministry of health has issued "the premature treatment with oxygen and retinopathy prevention guide". Since then, many screening results from big hospitals (Level of Class III and Grade A) have been reported in China, but there is no reports from basic-level hospitals. So, we screened the retina of premature and low birth weight babies in the panyu district at Guangzhou with binocular indirect ophthalmoscope which incorporated with a video recordingsystem.The key of standardization of ROP screening is to set a reasonable and unified screening standard. There are more or less differences between the ROP screening standards around the world. In general, the screening standard of a country or region was set on the basis of the risk factors and the analysis of recognized results at local city. The ROP screening standard of China was put forward by the Chinese Medical Association in2004in the guideline "Guide and treatment for premature infants with oxygen and ROP prevention ". This standard is as the following:Ocular fundus screening for premature and low birth weight (less than2.0kg) infants, and the follow-up should be continued until the peripheral retinal becomes neovascularization. It is appropriate to expand the scope of ROP screening in those infants with serious disease. But Li Xiaoxin said that the screening standard of our country is inadequate on the basis of lack of enough time number of reliable epidemiological data. So we need continue to conduct relevant research, along with reasonable use of oxygen after ROP onset in the circumstance of a continuous correction nt the characteristics of ROP in our country.The ROP screening started late in China, and mainly concentrated in the large hospitals of developed areas. It is not well completed in most of Grade III hospitals, rather than the maternal and child health hospitals at the level of Grade II and the lower. Because the different object of ROP screening in various medical institutions of different regions and the different incidence rate among respective reports, it is difficult to evaluate the epidemiological characteristics of ROP in China. Treatment of premature infants in hospitals of Grade III is very difficult to be done due to far distance and high cost. Therefore, we should pay more attention to the screening of retinopathy of prematurity in the hospitals of grade two and below. The screening object, standard tool, its training and data analysis in all levels of hospital should be unified, in order to achieve a satisfactory epidemiological study. The accurate incidence, correct risk evaluation of ROP and the most appropriate screening criteria can be achieved based only on the reliable epidemiological research.In this study, binocular indirect ophthalmoscope with video was used for retinal screening of premature and low birth weight infants in the Panyu District of Guangzhou city. The results were analyzed in order to understand retina development of premature infants and the occurrence of retinopathy in Grade II hospitals and find a suitable method and a standard for screening retinopathy of prematurity at primary hospitals in our country, and to provide epidemiological data for multicenter study on retinopathy of prematurity screening in our country. To our knowledge, this study is the first report on retinopathy of prematurity screening amnong the grass-roots hospitals in China. The screening model will be a good reference for ROP screening in the other Grade II hospitals. The screening results of the premature infants are of great significance for preventive research and epidemiological screening in China. ObjectiveTo investigate the characteristics of the retinal development of premature infants in the secondary hospitals in China. To explore a suitable ROP screening method and standard for hospitals of basic level in China in order to provide epidemiological data for multicenter study on ROP screening.MethodsThis prospective study enrolled1270premature infants for ROP screening. The procedures were examined by using a computer-assisted imaging system of binocular indirect ophthaimoscope. The development of retina was observed and the fundus lesions were recorded and compared with other basic level hospitals in China. The relationship of birth weight, gestational age at birth or the number of embryos and the occurrence of ROP was analysed by chi-square test with SPSS software. It is regarded as statistically significance if the p value of difference is less than0.05.Results1. Normal performance of premature retina:Except the14cases with ROP patients,5cases had vitreous lesions,32cases had retinal hemorrhage,2cases had optic neuropathy patients. According to the research group, the corrected gestational age of1217cases with normal fundus is divided into32-36weeks,37-40weeks,41-46weeks, and greater than46weeks.There were133,603,388, and603premature infants in each group respectively. OPTIC CUPThe retinal developmentsuch as retinal vascularization and macular development is as follows:(1) the morphology of optic cup:In the1217normal infants, the optic cups od1016cases of premature infants (83.5%) showed waned, light color, unclear borders, optic cup is not obvious;. The optic cups of201cases are reddish, with clear border. The optic cup is not obvious.(2) Macular morphology:In the32-36weeks group with133cases of premature infants, the macular contour of105cases is not obvious, accounted for78.0%.14cases had clear macular outline (10.0%). The macular halo was ambiguously seen, the macular fovea did not see. The color of macular and peripheral retina did not change. In the37-40weeks group with603cases of premature infants, macular outline is obvious in587cases of premature infant, accounted for97.3%; macular anti halation is clearly visible in575cases, accounted for95.3%. In the41-46weeks group with388cases of premature infants, macular morphology changes obviously in352cases (90.7%),, the central part of retinal fovea presented obvious flake dark red or reddish brown, and formed a certain degree of sag with slope shape. A concave shape of macular center formed, without macular fovea reflex. In the greater than46weeks group with93cases of premature infants, macular fovea formation with visible foveal reflex presented in78cases (83.9%).(3) The morphological change of retinal vascularization:In the32-36weeks group with133cases, the pole of retina behind nasal side arteriovenous vascular branches were obvious in81cases (60.9%). In these cases, the blood vessels and the stripes were clear, the nasal side of retina started to show secondary branch blood vessels,. Thesurrounding retina was not completely vascularized. The retina of temporal side was completely vascularized in133cases (100%),. In the37-40weeks group with603cases of premature infants, premature retina at nasal lateral was completely vascularized in467cases (77.4%).;237(50.7%) cases of premature infants presented obviousarteriovenous branches after the pole of the temporal retina. The blood vessels and the stripes are clear, the temporal range with retinal vascularization reached its temporal retina II area. The temporal retinal blood vessels have serrated edge in187cases (40.4%), vascularization reached III area. In the41-46weeks group with388cases of premature infants, the retina at nasal side has completely retinal vascularization in388cases (100%). The secondary retinal blood vessels surrounding the nasal side stripe are still clearly visible. The peripheral blood vessels near serrated edge and distal retina did not present cloudy. The lateral temporal retina was vascularized from areaⅢ to the temporal side in357cases (92%). In the greater than46weeks group,93cases (100%) had completely vascularized premature nasal lateral temporal retina.(4)The types of retina pigment:Among the1217normal cases,901cases (71%) had retinal darker and pewter.278cases (21.8%) had mild leopard shaped fundus change. For the choroid type,91cases (7.2%) had lighter color sclera. The premature fundus can be seen in876cases (72%), after long ciliary nerve.2. The occurrence of dfundus disease:(1)ROP:In the study of1270cases,14cases of children had ROP. The lesions subsided in12cases during follow-up, The lesions subsided in2cases after laser treatment.(2) retinal hemorrhage:In the1217normal cases,32cases had varied degrees of retinal hemorrhage.20cases were monocular,12cases were binocular.22cases of retina had small bleeder,6cases of retina had large focal hemorrhage,4cases had a few small bleeder in the pole.32cases were natural birth child. The weight of1case of ROP children was greater than2450g.4cases had a history of forceps. The bleeding was completely absorbed in27cases after4weeks follow-up. The retina is still visible traces in5cases.(3) Vitreous lesions:In the1217normal cases,5cases had vitreous lesions.1case was confirmed as residual vitreous artery;1case was observed with a white eye glance, which was confirmed by color doppler ultrasound and CT examination for permanence original vitreous hyperplasia.2twins had vitreous hemorrhage. For very low birth weight, temperature box feeding, and doubt ROP, the infants were recommended to a higher level hospital to make a diagnosis and give treatment. Those infants due to poor general condition and family economic difficulties, their parents refused to transfer them to a better treatment and then missed follow-up.1case had large clumps gray haze in the vitreous, retinal structure is not clear, was suggested to turn to the next higher level hospitals for further examination, after the diagnosis of retinoblastoma.(4) Optic neuropathy:In1217normal infants, examination showed apparent papilla edema in2cases, neonatal hypoxic ischemic encephalopathy in1cases.1case was confirmed as intracranial pressure.3. Complications:Before and after the inspection process,35cases occurred with different degrees of ball subconjunctival hemorrhage. The incidence was2.76%, and natural faded after2weeks follow-up.2cases had massive haemorrhage under the scalp. The incidence is0.16%and was natural faded after1week follow-up.1case had acute conjunctivitis and was treated with tobramycin eyedrops and eye ointment for3days. The rate is0.08%, and was healed in1week.28cases underwent screening and often exclaimed. The incidence was2.2%, and the symptoms disappeared in around1week. Serious complications such as apneaand shock have not been found.4. ROP:According to the screening criteria of Guangzhou city,14cases had ROP. If according to the screening standard set by the ministry of health,13cases had ROP. Among them,7cases is in III area I period;3cases is in III area Ⅱ period,2cases is in III area III period,2casesis in II area III period. No cases were found in stage IV and V lesions.2cases with threshold lesions needed treatment. 5. Birth weight, gestational age, and their relationships with ROPIn the14cases of ROP,11cases birth weighed from1000to1500g, accounted for21.1%of the total52cases, accounting for78.6%of the total number of ROP (11/14).2cases weighed from1501to2000g, accounting for1.01%of the182cases total, accounting for14.3%of the total number of ROP (2/14).1case weighed among2001-2500g, accounting for0.1%of the688cases total, accounting for7.1%of the total number of ROP (1/14). No premature illness was found whenthe birth weight was greater than2500g (x2=201.431, P=0.000<0.05), suggesting that the smaller the birth weigh, a higher ROP rate. The difference is statistically significant.In the14cases with ROP,11cases were born in27to32weeks of gestational age, accounting for10%of110total cases.2cases was33-34weeks gestational age, accounting for0.96%of the207total cases.1case was35to37weeks gestational age at birth, accounting for0.1%of the793total cases. No birth gestational age greater than37weeks was noted with premature illness(x2=88.63, P=0.000<0.05), suggesting that smaller the gestational age, higher the ROP rateat birth. The difference is statistically significant.In the14cases of ROP,10cases were singleton, saccounting for0.82%of the total cases1225cases of premature infants. There are4twins, accounting for8.9%of the total of45twins (x2=28.486, P=0.001<0.05), suggesting that the incidence of ROP in twins is higher than singletons. The difference is statistically significant.6. Comparison of the incidence of ROP between different screening standardsAccording to Guangzhou screening criteria (<37weeks premature birth or birth weight2500g), the prevalence of ROP in low birth-weight infants was1.1%(14/1270). According to screening standard issued by Chinese ministry of health, the incidence was5.56%(13/234). If according to this standard screening,2cases with III area III ROP were missed. Children will have less screening,1036cases were tested5times. According to the screening criteria (<2000g birth weight or gestational age<28weeks premature babies), incidence of ROP is21.1%(11/52).According to this standard by the ministry of health,1case with II period III area ROP was missed., The amount of infant with ROP will reduce182cases, equivalent to21.1%of examined children.7. Comparion with other domestic tertiary hospitals on the incidence and screening objectIn recent years, the incidence of premature infants reported by the tertiary hospitals variable in our country. The incidence of premature infants in Shanghai is6.6%, the rest is from10%to-20%. Screening tool in Xi’an city was the RetCam. The rest used the binocular indirect ophthalmoscope. RetCam as a complementary and binocular indirect ophthalmoscope at the same time was used Hubei and shenzhen. The object of screening was different:Beijing and Shanghai is a children’s hospital, maternal and child health care or comprehensive hospital inpatient children with neonatal unit. In xi’an and Hubei general hospital, the object is pediatric inpatient and ophthalmic outpatient children.The object is a children’s hospital inpatient and ophthalmic outpatient children in Hunan and Guangzhou. It is the maternity and child care hospital and an eye clinic in Guangdong. Children in shenzhen were from comprehensive hospitals, health care of women and children, the inpatients of ophthalmology and eye hospital outpatient service. The birth weight for screening object ranged from500-3500g. The difference of birth weight is large. The birth weight at Guangzhou children’s hospital was1256.2+/-268.1g;1487.3+/-276.15g a Shangha;1771.5+/-362.7g at Beijing, and1722.2+/-363.8g at Xi ’an,1650g atGuangdong Shenzhen,1972.2+478.3g at Hubei. Birth gestational age ranged from24to38.86weeks. The average gestational age at birth was32weeks. Conclusion1. Premature fundus, have different characteristics according to the growth of the age due to its amature development of anatomical structure. Most retinas of ROP retard development than normal preterm infants. Most OPTIC CUPfundus are not round with mild color and unclear cup rims. The retinal veins of the posterior retina showed stripe type and visible branch. The macular halo is obvious with intense reflection, its range is big. Most macular foveas are not obvious.2. Preterm infants usually had some special lesions in the fundus due to abnormal embryonic development, the production process and the maternal disease.. Premature retinopathy, retinal hemorrhage, vitreous artery residual, persistent primary vitreous hyperplasia, papillary edema are very commonly appeared. Retinopathy of prematurity (ROP) is a kind of retinal vascular proliferative lesions happens in premature and low birth weight babie. It is based on immature retinal disease. Its pathogenesis is unclear. There are many theoriesexplain the formation of ROP as free oxygen radicals theory,cytokine and spindle cells theories. The etiology of ROP was unknown. Premature birth and low birth weight have been recognized as the cause of ROP. Low birth weight is the major cause of ROP. Lower the birth weight, higher the incidence of ROP. Lesser the birth gestational age, higher the incidence of ROP. If give late operation for ROP, visual function has not significant improvement in children. The pharmaceutical prevention and its early intervention for premature retinopathy have been in investigation for years. There is no currently effective drug for controlling ROP occurrence and development. Therefore, early screening is the only effective way to prevent blindness due to ROP.3. Our results showed that the digital binocular indirect ophthalmoscope system can reliably and directly provide clear digital images and videos of the peripheral retina. This system has several advantages. It provides accurate high-quality images. It is affordable, and it remains the advantages of the "gold standard" binocular indirect ophthalmoscope. Because of its low price, it is suitable for screening ROP in all small hospitals, especially primary hospitals in China.4. The compound tropicamide eye drops did not show obvious complications for mydriatic inspection in premature babies. The on-table examination with binocular indirect ophthalmoscope is safe for premature retina in infanst. But for reducing the fear of parents and children and the testing time, we suggest a skilled, special trained and gentle doctor.5. The screening standard set by the ministry of health in China works well for ROP screening in the Panyu district at present. It still needs further research of large sample to decide whether the minimal weight of infant for enrollment should reduce to1500g. The study period is short, the sample size is relatively small. In the later work, we will continue to increase the sample size in accordance with the standards set by the ministry of health screening, in order to investigate the best suitable threshold of screening criteria in for different regional hospital in China.6. Due to different objective of ROP screening in various areas and various medical institutions, the incidence is also variable. It is difficult to assess the epidemiological characteristics of ROP. A uniform screening object and screening tool has to be needs or unified training and analysis of all data in all levels of hospital for epidemiological studies. Because of far distance and high cost, it’s easy to miss the follow-up in tertiary hospital. Therefore, we should focus ROP screening work on the secondary and even lower hospitals. As far as we know, this is the first study on ROP screening in the basic-level hospitals (second class hospital). The screening model for other secondary hospitals in our country to carry out the ROP screening work will have a very good model function. The results of retina screening, its prevention and epidemiology research for premature infants in China has great significance. |
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