Treatment for retinopathy of prematurity in Sweden 2008-2021: Reduced gestational age of treated infants and remaining differences in treatment type and recurrence rates between hospitals.

PURPOSE: This study aimed to investigate various aspects of treatment for retinopathy of prematurity (ROP) in Sweden over the past 14 years, nationally and at a hospital level. METHODS: Data on screening and treatment for ROP in infants born in Sweden from 2008 to 2021 were extracted from the national ROP register, SWEDROP. During this period, Swedish screening guidelines were reduced from gestational age (GA) < 32 weeks to <31 weeks in 2012 and to <30 weeks in 2020. RESULTS: Altogether, 10 959 infants were screened and 600 infants treated for ROP during the study period. Parallel to changed guidelines, the number of screened infants decreased (p < 0.000) and the incidence of ROP and frequency of treatment increased (p < 0.001), while both remained similar in infants with a GA below 30 weeks. Among treated infants, GA and BW were reduced over the years (p < 0.001). Laser treatment (85.2% of primary treatments) became less common and anti-VEGF injections (13.6%) became more common over time (p < 0.001). Altogether 16 eyes were treated with the encircling band and 13 with vitrectomy. The total frequency of retreatment (32.7% of treated eyes) remained similar over time but was more common after primary anti-VEGF injection (67.7%) than laser treatment (27.2%). There were differences between the seven university hospitals regarding type of treatment and number of retreatments (p < 0.001). CONCLUSION: The frequency of treatment and retreatment for ROP remained similar over time, but the type of treatment changed and anti-VEGF injections became more common. Differences between treating hospitals emphasize the importance of centralizing the most severe cases.

Ophthalmological outcome of 6.5 years children treated for retinopathy of prematurity: a Swedish register study.

AIMS: To determine the ophthalmological outcome at 6.5 years of age in children treated for retinopathy of prematurity (ROP), and registered in the national Swedish National Register for ROP register. METHODS: Data on ROP, treatment and ophthalmological outcome were retrieved from the register. Visual acuity (VA), refractive errors and strabismus, together with visual impairment (VI) and any significant eye problem, defined as VA >0.5 logarithm of the minimal angle of resolution (logMAR) and/or strabismus and/or any refractive error were analysed. Risk factors such as sex, gestational age (GA), birth weight SD score, number of treatments and retreatments, postnatal age and postmenstrual age at first treatment were analysed. RESULTS: Follow-up data were available in 232 of 270 children born between 2007 and 2014 who had been treated for ROP. VI (VA >0.5 logMAR) was found in 32 (14%), strabismus in 82 (38%), refractive errors in 114 (52%) and significant eye problem in 143 (65%) children. Retreatment was a risk factor for VI and refractive errors. Male sex and neonatal brain lesion were risk factors for strabismus. An additional week of GA at birth reduced the risk for refractive errors, strabismus and significant eye problems. CONCLUSION: The results of the present study revealed a high number of eye problems in children treated for ROP, emphasising the need for long-term follow-up. Retreatment of ROP was a risk factor for VI, and emphasises the importance of an accurate first treatment for the long-term ophthalmological outcome.

Gene expression profile of extraocular muscles following resection strabismus surgery.

This paper aims to identify key biological processes triggered by resection surgery in the extraocular muscles (EOMs) of a rabbit model of strabismus surgery by studying changes in gene expression. Resection surgery was performed in the superior rectus of 16 rabbits and a group of non-operated rabbits served as control. Muscle samples were collected from groups of four animals 1, 2, 4 and 6 weeks after surgery and processed for RNA-sequencing and immunohistochemistry. We identified a total of 164; 136; 64 and 12 differentially expressed genes 1, 2, 4 and 6 weeks after surgery. Gene Ontology enrichment analysis revealed that differentially expressed genes were involved in biological pathways related to metabolism, response to stimulus mainly related with regulation of immune response, cell cycle and extracellular matrix. A complementary pathway analysis and network analysis performed with Ingenuity Pathway Analysis tool corroborated and completed these findings. Collagen I, fibronectin and versican, evaluated by immunofluorescence, showed that changes at the gene expression level resulted in variation at the protein level. Tenascin-C staining in resected muscles demonstrated the formation of new tendon and myotendinous junctions. These data provide new insights about the biological response of the EOMs to resection surgery and may form the basis for future strategies to improve the outcome of strabismus surgery.