OCTA Evaluation of Retinal Vascularization in Preterm Infants With or Without Bronchopulmonary Dysplasia

Overview

Retinal vascularization in humans develops between the 16th and 36th weeks of amenorrhea, in a centrifugal pattern starting from the optic disc. In the case of premature birth, the immature peripheral retina is at risk of ischemia due to incomplete vascular development. Prematurity is often associated with respiratory fragility. It frequently requires ventilatory support in the form of oxygen therapy, either invasive (orotracheal intubation) or non-invasive, which induces reflex arteriolar vasoconstriction, thereby worsening the existing ischemia. This raises the question of whether subclinical retinal vascular changes, detectable by OCT angiography, may explain the increased risk of amblyopia and the need for optical correction observed in these patients. OCT angiography is rapidly expanding in the field of retinal vascular diseases: it is a simple, fast, reliable, and non-invasive examination, requiring no injection, that enables high-resolution visualization of retinal vascularization, with separate analysis of the retinal plexuses and the choriocapillaris.

Retinal vascularization in humans develops between the 16th and 36th weeks of gestational age, progressing centrifugally from the optic disc. In the case of premature birth, the immature peripheral retina is at risk of ischemia due to incomplete vascular development. This lack of perfusion in the retinal periphery leads to abnormal secretion of pro-angiogenic factors, promoting the formation of abnormal neovessels, which may be complicated by vitreous hemorrhage and tractional retinal detachment, resulting in permanent visual impairment. Conversely, it is known that premature infants have a smaller central avascular zone compared with full-term infants. This region of the retina, where 90% of cones are concentrated, must remain free of vascular structures to allow optimal vision. Prematurity is often associated with respiratory fragility. It frequently requires ventilatory support in the form of oxygen therapy, either invasive (orotracheal intubation) or non-invasive, which induces reflex arteriolar vasoconstriction and worsens the ischemia already present in the periphery. Clinically, after birth, ocular disorders are more frequently observed in premature children, including amblyopia, impaired contrast sensitivity, refractive errors, strabismus, and optic nerve abnormalities. It is therefore reasonable to question whether subclinical retinal vascular changes exist, detectable by OCT angiography, and associated with these clinical differences. Indeed, OCT-A makes it possible to detect changes in foveal and peripapillary retinal microvascularization more sensitively than dilated fundus examination (allowing detection of subclinical microvascular abnormalities), as has been demonstrated in numerous retinal diseases. It thus contributes to diagnosis, follow-up, assessment of therapeutic response, and prognosis in many retinal pathologies. OCT angiography is rapidly expanding in the field of retinal vascular diseases: it is a simple, quick, reliable, non-invasive, dye-free examination that enables high-resolution study of retinal vasculature, with separate analysis of the retinal plexuses and the choriocapillaris. It would also be of interest to investigate whether there is a correlation between neonatal parameters, retinal vascular changes observed on OCT-A, and clinical findings (vision and refraction). If such a correlation is demonstrated, it could enable targeted and personalized visual screening of individuals identified as being at highest risk, with stratification of ocular risk based on neonatal history and OCT-A measurements. Finally, such a study would improve our understanding of retinal development during the neonatal period, the factors that may influence it, and the mechanisms potentially responsible for the observed disorders.