Retinopathy of prematurity in a tertiary center in south of Brazil

    作者：Joao Borges Fortes Filho1, Cristiano Koch Barros1, Gabriela Unchalo Eckert1, Leticia Procianoy1 , Renato S. Procianoy2   

    作者单位：1Departments of Ophthalmology, 2Neonatology，Hospital de Clinicas de Porto Alegre，Federal University of Rio Grande do Sul, Brazil

    【摘要】 To investigate the incidence of retinopathy of prematurity in the southern Brazil, the rate of treatment and outcomes in all premature infants born at Hospital de Clinicas de Porto Alegre, Brazil, from October 2002 to October 2006. METHODS: A prospective cohort study was conducted on 323 premature children born at Hospital de Clinicas de Porto Alegre, Brazil, from October 2002 to October 2006 with birth weight equal to or less than 1 500g or a gestational age at birth of 32 weeks or less. All of the newborns were examined by indirect binocular ophthalmoscopy with the 28 diopters lens after pupil's dilation and a lid speculum after the sixth week of life with examinations repeated depending on the disease classification. The main clinical outcome was the occurrence of ROP at any stage. RESULTS: Retinopathy of prematurity occurred in 82 infants with an incidence rate of 25.7%. Threshold disease occurred in only 17 of the patients (5.3%), all of them had the disease affecting posterior Zone II needing laser treatment. None of the treated children had Zone I or aggressive posterior disease despite that three of the treated children needed a second laser session. One patient of the re-treated group needed scleral buckling with an equatorial silicon band after progression to stage 4 of ROP. CONCLUSION: The incidence of retinopathy and the threshold disease in this study was similar to the international results reported. This study showed a high survival rate (70.1%), high incidence of retinopathy, and high laser treatment necessity among newborns under 28 weeks of gestational age or under 1 000g of birth weight. This study drove attention about the no identification of any Zone I posterior disease in this cohort of patients.

    【关键词】  prematurity; blindness prevention; retinopathy of prematurity;ROP epidemiology;ROP incidence; ROP treatment

    INTRODUCTION

    Retinopathy of prematurity (ROP) is a leading cause of childhood blindness in all of the developed countries nowadays and also in many of the middle-income countries, like Brazil. ROP is a multifactorial disease affecting the development of the retinal vessels, occurring most frequently in the smallest and sickest infants. ROP is under constant study around the world due to the increasing survival of newborns of preterm delivery specially within the groups of greater risk for the appearance of this disease: very low birth weight (VLBW), comprised neonates born under 1 500g or under 32 weeks of gestational age (GA) at birth and extremely low birth weight（ELBW） including prematures born under 1 000g or under 28 weeks of GA at birth. In recent years, the survival rate in the ELBW patients increased from 8% to 35% in many of the middle-income countries [1-5].

    The Brazilian recommendations for the ROP screening were established only after 2002 in a national meeting occurred in Rio de Janeiro. [6] At that time some decisions were taken in order to achieve a better understanding of the incidence of ROP and to reduce the incidence of blindness by adequate prevention and early treatment whenever necessary. The Hospital de Clinicas de Porto Alegre (HCPA), a universitary and tertiary care center hospital implemented after 2002 a screening program according to the standards defined for Brazil which recommended binocular indirect ophthalmoscopy examination under dilation of pupils in all infants with a birth mass equal to or less than 1 500g or with a GA equal to or less than 32 weeks at birth[6].

    The objectives of this study are to evaluate the incidence of ROP among VLBW and also among ELBW infants, the survival rate in these groups of patients, the rate of treatment and the main outcomes at HCPA between October 2002 and October 2006.

    MATERIALS AND METHODS

    Subjects The study was approved by the ethics committee of the HCPA and a prospective cohort study of all VLBW (defined as born under 1 500g or under 32 weeks of GA) infants born at the HCPA from October 2002 to October 2006 was done. All neonates that met the recommended criteria for the Brazilian screening for ROP were included, except for those infants that died during hospitalization before the 6th week of life, moment of the initial ophthalmological examination, that were excluded from this study.

    Methods The incidence of ROP was evaluated among the ELBW infants (defined as group 1 and including all of newborns with BW under 1 000g at birth or GA less than 28 weeks at birth). Was also evaluated the incidence of ROP among VLBW infants (group 2, defined over de extreme premature group but excluding in the group 2 all of the infants in the group 1). The main clinical outcome was the occurrence of ROP at any stage in both groups. The treatment was performed always in ROP 3 stage, threshold disease (defined as stage of ROP in which the chances of progression to retinal detachment are 50%, if left untreated)[7]. Main outcomes were described by mean and standard deviation with a confidence level of 95%. All data were processed in the software SPSS 13.0 (Statistical Package for Social Sciences).

    All the exams were initially held at the Neonatal Intensive Care Unity (NICU) and the follow-up examinations were conducted in the section of Ophthalmology. The ophthalmological examination consisted of the external inspection of the eyeballs and binocular indirect ophthalmoscopy with a 28 diopters Nikon lens (Melville, NY, USA) and the lid speculum for newborns developed by Storz (Alfonso Eye Speculum, Bausch & Lomb Inc., San Dimas, CA, USA), after the dilation of the pupils with association of the eye drops tropicamide 5g/L and phenylephrine 25g/L. Infants were first examined after the 6th week of life with retinal mapping and staging of the retinopathy according to the International Classification of Retinopathy of Prematurity from 1984/1987 [8-10], and followed up depending on the severity of the disease until retinal vascularization was completed.

    For the treatment the diode laser FTC 2500 Diode Laser, 810 nm (Opto, S?觔o Carlos SP, Brazil) was used in all patients reaching threshold disease. Treatment was done with transpupillary photocoagulation with binocular indirect ophthalmoscopy under general anesthesia in surgical room or sedation in the NICU. Both eyes were treated in the same time..

    A six-month follow up study was performed, including the 91 prematures presented for the follow up appointment. All the patients were examined for presumed visual acuity, exam of the eye motility and alignment, cycloplegic refraction, indirect ophthalmoscopy and retinal mapping. Cycloplegic streak retinoscopy and the fundus examination were carried out 30 minutes after the instillation of cyclopentolate 1g/L, phenilephrine 25g/L and tropicamide 5g/L, two drops each. Refraction was performed using handheld lenses in front of the awaken infants.

    RESULTS

    Three hundred and twenty three patients were screened for ROP during the period and met the inclusion criteria for the study. Among of them 113 were in the group 1. The survival rate among ELBW infants (group 1) reached 33.7% and 70.1% in the VLBW infants (group 2). ROP at any stage affected 42.5% of the ELBW infants and only 16.2% of the VLBW (OR 3.82; CI 2.19-6.68; P <0.000 1). The ROP at any stage including the both groups in this institutional single-unit based approach occurred in 82 infants with an incidence rate of 25.7%. Mean BW in the group 1 was 910±199g and in the group 2 was 1 349±193g. Mean GA in the group 1 was 28.1±2.0 weeks while in the group 2 was 31.4±1.6 weeks (Table 1).

    The stages of ROP among all the cohort is showed in Table 2 and the number of patients affected in different stages of ROP according to the BW is showed in Table 3.

    Threshold disease occurred in only 17 of the 323 infants screened for ROP (5.0%). Among of them, 14 were in the ELBW group. The clinical characteristic of all treated patients was shown in the table 4. All threshold diseases were in posterior Zone II, none in Zone I. Mean BW of the treated group was 931±266g and mean GA was 28.4±2.4 weeks.

    Transpupillary diode laser was used in all of the patients with confluent spots, around 800 in each eye, without any complications of the treatment. Three patients needed a second laser treatment in both eyes, four weeks after the initial treatment. One patient of the re-treated group needed scleral buckling with an equatorial silicon band after progression for stage 4 of ROP. The anatomical outcome was good in all of the 17 neonates.

    Ninety one patients (182 eyes) were studied for main outcomes. From this group, 31(34.0%) developed ROP at any stage and nine needed laser treatment for threshold disease. Mean GA for the non-ROP group was 29.4 weeks (range 25-36 weeks), compared to 30.8 weeks (range 27-37 weeks) for the ROP group. At six months of corrected age, patients who developed ROP were significantly more myopic (10 patients, 31.0%) than those who didn't (2 patients, 3.3%). Otherwise, non-ROP patients were significantly more hyperopic (51 patients, 85.0%) than the ROP group (21 patients, 67.7%). Astigmatism presented in 23 (74.1%) of the ROP patients and in 29 (48.3%) of the non-ROP infants. Among the patients who underwent laser therapy, 55.5% developed myopia. On the other hand, only 31.0% of the patients on ROP group without laser therapy developed myopia. Strabismus was detected in 4 patients on ROP group and in 3 patients on non-ROP group and also in 2 babies treated by laser. (Table 4)

[1] [2] [3] 下一页