Outcome of Laser Photocoagulation for Retinopathy of Prematurity

Abstract

BACKGROUND Retinopathy of prematurity (ROP) is a disease affecting the retina of premature infants due to retinal neovascularization and the spectrum of outcome findings in ROP ranges from the most minimal sequelae without affecting vision in the mild cases to bilateral, irreversible, and total blindness in more severe cases.In India children less than 1500 g have almost 38 percent chance of developing any stage of ROP and 7 – 16 % chance of developing threshold ROP or blinding ROP. (2)Laser photocoagulation has replaced cryotherapy as the established treatment for ROP in most centers and this study aims to evaluate the functional and structural outcome in preterm infants who received laser photocoagulation for retinopathy of prematurity. In this study we wanted to find out the structural outcome of retinopathy of prematurity infants who underwent laser photocoagulation. We also wanted to find out the functional outcome of ROP preterm infants who underwent laser photocoagulation and identify the factors affecting the structural outcome in retinopathy of prematurity. METHODS A hospital based descriptive study was conducted among 31 preterm infants with retinopathy of prematurity who received laser photocoagulation treatment after obtaining parental consent in the Retina clinic, Regional Institute of Ophthalmology, Trivandrum. Screening examination was done at 34 weeks or 4 weeks postnatal whichever was earlier. Those infants who were detected to have ROP and were given laser photocoagulation by the ophthalmologist were followed up till retina becomes stable / ROP regresses. Thereafter follow up examinations were performed at 3 months, 6 months and 10 months. Structural outcome was classified as favorable and unfavorable. Visual or functional outcome was assessed by noting the fixation pattern, ocular alignment for strabismus and by performing cycloplegic refraction (retinoscopy) to rule out refractive errors. Data was entered into excel sheet and statistical analysis was done using SPSS trial version. RESULTS The study was conducted in 31 preterm infants with Retinopathy of Prematurity who underwent laser photocoagulation in Regional Institute of Ophthalmology Trivandrum. The structural and functional outcome was assessed at 3months, 6 months and 10 months. Of the 62 eyes of 31 infants, stage2 and 3comprised 48.4%each.3.2% of eyes had stage1 disease affecting zone1.None had stage 4 or 5.Of the 62 eyes, majority had zone 2 disease (83.9%). Only 10 eyes had zone1 disease. Out of the 60 eyes, 54 eyes had a favorable structural outcome at 3months.The functional outcome was assessed in terms of visual behavior by assessing the fixation of light, whether child is following light and by preferential looking pattern. Out of the 30 babies only 1 had an unfavorable visual behavior. The baby was not fixing and following light. Out of the 30 infants, 2 had (6.6%) strabismus at 6months and 10 months. Myopia was the predominant refractive error in the studied group accounting for about 55%. Among the study group 16.7 % had hypermetropia. CONCLUSIONS The incidence of favorable structural outcome in our study was 90%.Low gestational age and low birth weight were associated with an unfavorable structural outcome. There is a high prevalence of refractive errors in our study group accounting for about 71.5 % at 6 months. The refractive errors increased at 10 month follow up to 77%. Among the refractive errors, myopia predominates accounting 55% at 6 months and 61 % at 10 months. KEY WORDS Laser Photocoagulation, Retinopathy of Prematurity