Extreme prematurity linked to increased prevalence of visual and ocular deficits in young adulthood: JAMA

The purpose of the study by Saurabh Jain and team was to evaluate visual function and ocular morbidity in a large well characterized cohort of young adults who were born at 25 weeks' gestation or less and to contrast their outcomes with those of full-term controls. Extreme prematurity is associated with an increased prevalence of visual and ocular deficits in young adulthood; the study suggested that, for individuals born EP, visual and ocular deficits appear to be partially independent of ROP status in the neonatal period but reports similar overall visual function.

This prospective cohort study of a geographically based birth cohort in the UK and Ireland born from March 1 through December 31, 1995, included 128 participants aged 19 years (born at 22-25 weeks' gestation) and 65 age-matched controls born at full term. Statistical analysis was performed from March 1, 2020, to November 26, 2021. Participants underwent eye examinations as part of a comprehensive outcome evaluation.

The study comprised 128 participants (256 eyes; 68 female participants and 65 age-matched controls born at full term. Compared with control eyes, the mean (SD) best-corrected visual acuity among eyes in the EP group was significantly worse (monocular vision: P < .001; binocular vision: P < .001).

Participants in the EP group had a significantly higher prevalence of strabismus (P < .001), abnormal ocular motility (P < .001), and nystagmus (P < .001) than the control group.

No significant differences between participants in the EP group and controls were observed for refractive error, contrast sensitivity, color vision, or patient reported visual function.

Among the participants in the EP group, 48% of eyes (120 of 250) had no retinopathy of prematurity (ROP), 39% (98 of 250) had ROP not requiring neonatal treatment, and 13% (32 of 250) received cryotherapy or laser ablation for ROP.

Within the EP group, there was no significant difference in binocular visual function parameters, prevalence of ocular morbidity, and patient-reported visual function by neonatal ROP status.

Study findings demonstrate overall worse monocular and binocular BCVA and binocular contrast sensitivity in participants in the EP group compared with control participants who were born full term. This finding is unsurprising given the already strong body of evidence showing a higher prevalence of reduced visual acuity (VA) in children and adolescents born preterm with or without low birth weight.

Compared with previous studies reporting a positive correlation between the severity of neonatal ROP and degree of VA deficit, authors observed a significant difference in monocular but not binocular BCVA when participants were grouped by ROP status and in monocular but not binocular contrast sensitivity in the EP-ROP-NT group compared with the EP-ROP-T group. Some of the disparity may be explained by the inclusion of intereye correlation in analyses, which reduces the risk of falsely significant results. In addition, the data from individual eyes within the EP group show a large range of VA scores, suggesting that the previously reported positive correlation between ROP severity and VA deficit is not necessarily associated with a similar correlation in the eyes in the EP group.

Although the presence of neonatal ROP might account for the VA deficit in individuals born EP, the cause of reduced VA in eyes without ROP among those born EP remains unclear. These ROP-independent factors are likely to be complex and multifactorial. Several hypotheses have been proposed, including cone damage secondary to prolonged exposure to phototherapy for neonatal jaundice and alterations to the retina and optic nerve from prenatal endotoxin exposure through intrauterine infections associated with preterm delivery. Reduced VA may also be associated with neonatal neurologic insults, including ischemic brain lesions and intraventricular hemorrhage, in children born preterm.

Despite the higher rate of visual impairment associated with extreme prematurity, authors found no difference in perceived visual function among young adults born EP compared with that of controls born at full term; most participants reported good functional vision. This discrepancy between objective measurement of vision and perceived visual function indicates that the former is not necessarily associated with overall visual effect in a real-world setting. There is evidence that emotional and psychological factors may be associated with the level of perceived visual ability. These findings may also reflect a compensatory mechanism for visual deficit among individuals born EP through multisensory adaptation and integration in early life, which is associated with a more positive outcome for perceived visual function.

This study demonstrates the increased prevalence of visual and ocular deficits in a population of individuals born EP and suggests that children born EP may remain "preterm for life," with ophthalmic sequelae persisting into adulthood. Comparison, both directly with full-term controls and indirectly with less premature cohorts, indicates that individuals born EP have the greatest risk for visual and ocular morbidity, although their perceived visual health status remains good overall. Although ROP remains a risk factor, the mixed findings in our study emphasize that all individuals born EP are at risk of visual and ocular morbidity irrespective of ROP status. These findings provide important insight into the ophthalmic outcome of EP birth on a population level and have implications for the screening and management of such deficits as they evolve over a lifespan.

Source: Saurabh Jain; Peng Yong Sim; Joanne Beckmann et al; JAMA Network Open. 2022;5(1):e2145702.