Refraction and its development in young adults born prematurely and screened for retinopathy of prematurity

Early ophthalmic growth deficits in preterm-born children are not compensated for during later development

The renewed focus on eye growth in preterm-born children was primarily triggered by Danish cohort studies, including the Copenhagen Project, which focused on children born from 1959-1961. The retinotoxic effects of excessive oxygen on premature neonates had long been clarified and therapeutically adjusted for. Later, ultrasound oculometry and keratometry established that ocular size deficits, linked to development, also occurred in normally developing children, not just frail outliers. This indicated that general catch-up had not been achieved. This paper discusses whether one early segment of eye development does not occur in preterm, and here even in more robust neonates, without later compensation.

Blindness is decreasing among children born preterm during the last four decades in Denmark

PURPOSE

Children born preterm are believed to be at increased risk of visual impairment (VI). The increased survival rate of extremely preterm children may have changed the spectrum of diseases occurring postnatally. The aim of this study was to analyse the prevalence and causes of VI in an ex-preterm Danish population during the last 4 decades.

METHODS

The study was based on the National Register of Blind and Visually Impaired Children (NRVIC). Ex-preterms born at gestational age (GA) <32 weeks and enrolled in NRVIC at any time between 1988 and 2020 were included. The main cause of VI, the severity of VI and systemic comorbidities were analysed for temporal changes.

RESULTS

A total of 335 patients were included. The prevalence of VI decreased from 26/1000 preterm children in the 1980s to 15/1000 in 2000s. Blindness due to preterm birth is almost eliminated affecting 1/1000 today. Sequelae to retinopathy of prematurity (ROP) was the most common cause of VI (51% of cases) in the 1980s but decreased to 34% in 2010s, whereas non-ocular causes of VI increased from 1% to 36%, respectively. More than half of the children (64%) had combined comorbidities and 36% had isolated VI.

CONCLUSION

The improved monitoring in neonatal intensive care units and management of ROP has reduced the prevalence of severe VI due to ROP and almost eliminated blindness over the last decades in Denmark. However, preterm children are still at risk of non-ocular causes of VI and comorbidities following the premature delivery.

Temporal trends in paediatric hydrocephalus - Rising prematurity and persistent ophthalmological challenges

AIM

To study changes in aetiology, prematurity, comorbidity and ophthalmological outcomes in children with surgically treated hydrocephalus to provide information needed to maintain the best possible healthcare for a fragile and changing population.

METHODS

Two population-based cohorts, born two decades apart in Region Västra Götaland Sweden, surgically treated for hydrocephalus at Sahlgrenska University Hospital in Gothenburg were recruited at approximately 10 years of age. The participants were examined according to an ophthalmological protocol, including history taking regarding perceptual visual dysfunction (PVD). Gestational age, aetiology and comorbidities were registered.

RESULTS

The 1989-1993 group, comprised 52 children (48% girls; mean age 10, range 7.7-12.8 years), was compared with 24 children, born in 2007-2012 (29% girls; mean age 10, range 7.0-13.8 years). Extreme prematurity (gestational age ≤ 28 weeks) increased over time (p = 0.001). The vast majority of the children showed ophthalmological abnormalities, although motility defects and nystagmus decreased in the latter population. Subnormal visual acuity was associated with extreme prematurity (RR = 4.69; p = 0.030), and PVD with learning disability (RR = 2.44; p = 0.032).

CONCLUSION

Paediatric hydrocephalus populations may change with improved healthcare. Since a high percentage shows ophthalmological abnormalities and more children are born extremely preterm, the entirety needs consideration both neurologically and ophthalmologically.

Central macular morphology and optic nerve fibre layer thickness in young adults born premature and screened for retinopathy of prematurity

PURPOSE

To investigate central retinal morphology and optic retinal nerve fibre layer (RNFL) in prematurely born young adults and compare to term born controls.

MATERIALS AND METHODS

The participants were 59 prematurely born individuals, with a birthweight ≤1.500 g, and 44 term born controls, all 25-29 years of age. Visual acuity (VA) and contrast sensitivity (CS) were assessed. The retinal macular thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness and RNFL thickness were assessed with Cirrus optical coherence tomography (OCT).

RESULTS

Central macular thickness was increased (mean 26.7 μm) in prematurely born individuals compared to controls. The macular GC-IPL was thinner (mean 3.84 μm), also when excluding those with previous retinopathy of prematurity (ROP) and those with neurological complications. Gestational age at birth and previous treatment of ROP were risk factors for a thicker macula, however, not for reduced GC-IPL. The average peripapillary RNFL was thinner (mean 4.61 μm) in the prematurely born individuals, also when excluding those with previous ROP and/or neurological complications. Within the prematurely born group, treated ROP was correlated with increased average RNFL. Further, both better VA and CS were associated with thinner optic nerve RNFL and thicker average GC-IPL.

CONCLUSION

Macular and optic nerve morphology were influenced by premature birth as assessed with OCT in adult individuals. Gestational age at birth and treatment for ROP seemed to affect central macular thickness, and treated ROP affected the peripapillary RNFL. Thus, retinal sequelae remained in adulthood.

Strabismus, stereoacuity, accommodation and convergence in young adults born premature and screened for retinopathy of prematurity

PURPOSE

The aim of the study was to evaluate strabismus, stereoacuity, accommodation and convergence in prematurely born young adults; screened for retinopathy of prematurity in the neonatal period and compare with term-born individuals of the same age.

MATERIALS AND METHODS

The study participants included 59 prematurely born individuals with a birthweight of ≤1,500 grams and 44 term-born controls, all born during 1988-1990 in Stockholm County, Sweden. Ocular alignment was assessed with a cover test, stereoacuity with the TNO stereo test and the amplitude of accommodation and the near point of convergence with the Royal Air Force Rule.

RESULTS

Seven of 59 (12%) preterms had manifest strabismus, 4/59 (7%) had esotropia and 3/59 (5%) exotropia. One of 44 (2%) controls had esotropia; no other controls had manifest strabismus. Stereoacuity was within normal limits in 38/59 (64%) preterms and 43/44 (98%) controls, p < 0.01; the difference remained after excluding those with strabismus. A neurological complication at 2.5 years of age was the strongest risk factor for subnormal stereoacuity within the preterm group after excluding those with strabismus. The mean amplitude of accommodation was poorer in the preterms than the controls in better (p < 0.05) and worse eyes (p < 0.05). The preterms were more likely to have an amplitude of accommodation below the minimum, according to Hofstetter's equation. There were no differences between the groups regarding the near point of convergence.

CONCLUSION

Prematurely born young adults had a higher prevalence of strabismus, reduced stereoacuity and worse amplitude of accommodation than term-born controls.

Refractive status and optical components in premature infants with and without retinopathy of prematurity: A 4- to 5-year cohort study

This study was aimed to investigate the characteristics of refractive parameters in premature infants and children aged 3-8 years with mild retinopathy of prematurity (ROP) and to explore the effects of premature delivery and mild ROP on the development of refractive status and ocular optical components. Premature infants who underwent ocular fundus oculi screening in our hospital between January 2009 and February 2011 were included and divided into the ROP group and the non-ROP group. Full-term infants were the controls. The results of the annual ocular examination conducted between 2014 and 2018 were analysed, and the refractive status, optical components, and developmental trends were compared among the three groups. The total follow-up time was 4-5 years. The prevalence of myopia and astigmatism was high in the ROP group (P < 0.05). In the non-ROP group, the prevalence of myopia was also higher than that in the control group. The prevalence of myopia increased with age in the ROP and non-ROP groups, while the prevalence of astigmatism remained unchanged. In the ROP group, the corneal refractive power was the largest, the lens was the thickest and the ocular axis was the shortest; in the control group, the corneal refractive power was the smallest, the lens was the thinnest, and the ocular axis was the longest. These parameters in the non-ROP group were between those in the two groups mentioned above (P < 0.05). The corneal refractive power was relatively stable at 3-8 years old in the three groups. The change in lens thickness was small in both the ROP group and the non-ROP group (P = 0.75, P = 0.06), and the lens became thinner in the control group (P < 0.001). The length of the ocular axis increased in the three groups. Preterm infants are more likely to develop myopia than full-term infants, and children with ROP are more likely to develop both myopia and astigmatism. Thicker lenses were the main cause of the high prevalence of myopia in premature infants with or without ROP.