CENTRAL MACULAR THICKNESS IN 6.5-YEAR-OLD CHILDREN BORN EXTREMELY PRETERM IS STRONGLY ASSOCIATED WITH GESTATIONAL AGE EVEN WHEN ADJUSTED FOR RISK FACTORS

Foveal thickness and its association with visual acuity in adults born preterm with very low birth weight: A two-country birth cohort study

PURPOSE

To explore foveal and parafoveal thickness in adults born preterm with very low birth weight (VLBW) and its association with best-corrected visual acuity (BCVA) and gestational age (GA) compared to adults born at term.

METHODS

In a joint study of the Helsinki Study of Very Low Birth Weight Adults (Finland) and the NTNU Low Birth Weight Life study (Norway), 106 VLBW and 143 term-born controls were examined with spectral-domain optical coherence tomography and BCVA at age 31-43 years. Thickness of retinal layers was segmented in the foveal and parafoveal areas of the macula.

RESULTS

The total retinal thickness in the foveal area was thicker in VLBW adults compared with controls; mean (SD): 292.5 μm (28.2) and 272.4 μm (20.2); p < 0.001, and thinner in the parafoveal areas of the macula. These findings could be explained by a thicker inner retinal layer in the foveal area found in VLBW adults compared with controls (mean difference 20.4 μm; CI: 15.0 to 25.9), where a thicker fovea was associated with lower GA, but not BCVA.

CONCLUSION

Adults born preterm with VLBW had a thicker retina in the foveal area than controls and this was associated with GA, but not with BCVA. These changes seem to be related to a thicker inner retinal layer in VLBW adults. The findings imply that signs of macular underdevelopment are still present in adulthood, but not necessarily related to reduced visual function.

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.

Macular thickness variation and interocular symmetry by gestational age in preterm school-age children

PURPOSE

To determine changes in macular thickness profile according to gestational age (GA) and to assess interocular symmetry in the macula of children born very preterm.

METHODS

In this cross-sectional study of preterm (n = 106) and term-born (n = 49) children 5-8 years of age at time of examination, optical coherence tomography was used to measure macula thickness as described in the ETDRS study. Statistical analyses included stratified and multivariable analyses.

RESULTS

Foveal minimum thickness increased with decreasing GA (P for trend, <0.001; 254.7 ± 32.8 μm for children born at 24-25 weeks and 193.2 ± 32.8 μm in term-born children). Inner and outer area thickness differed for term and preterm children, but did not vary with the degree of prematurity (inner area, 267.0 ± 11.0 μm for 24-25 weeks' GA and 305.4 ± 11.8 μm for term children [P < 0.01]; outer ring, 305.5 ± 10.4 μm in extreme preterm and 271.0 ± 10.4 μm in term children [P < 0.01]). Interocular asymmetry in preterm children was not significant for most areas; the largest interocular difference was found in the central zone (16.3 ±16.6 μm).

CONCLUSIONS

In our study cohort, children born very preterm examined at school age compared to term born children had greater central thickness with decreased foveal pit, decreased inner ring, and increased thickness of the outer ring. They did not show greater interocular asymmetry.

Structural impact of arrested foveal development in children born extremely preterm without ROP at 6.5 years of age

Objectives

To characterize changes of foveal topography and microstructure of persisting foveal immaturity at 6.5 years of age in children born extremely preterm without retinopathy of prematurity (EPT-NoROP).

Methods

Images from previous optical coherence tomography examinations of 37 EPT-NoROP and 92 control eyes were selected from a regional cohort of the EXPRESS (Extremely Preterm Infants in Sweden) study. Thickness of ganglion cell + inner plexiform layer (GCL+), outer nuclear layer (ONL), retinal thickness (RT) at the foveal centre (FC), foveal depth (FD) and RT at the foveal rim were evaluated.

Results

Layer thickness of GCL+, ONL and RT was increased at FC in the EPT-NoROP group. More than two-thirds had thickness values above the control limit (control mean +2 SD) at FC (GCL + 68%, ONL 76%, and RT 68%), and 50% had reduced FD compared to controls. All parameters showed a high correlation within the EPT-NoROP group, whereas no or weaker correlation was seen in control eyes. The EPT-NoROP sub-groups, divided based on the control limit, did not differ in terms of associated factors such as gestational age, birth weight, visual acuity, and refraction.

Conclusions

Extreme prematurity without impact of ROP is associated with increased GCL + , ONL, and RT thickness at FC as well as reduced FD compared to full-term controls at age 6.5. This indicates that prematurity per se may have a profound effect on foveal anatomical maturation during the first months after birth. Our results suggest RT at FC to be a simple and useful measure of foveal anatomical immaturity.

RETINAL THICKNESS AND FOVEAL HYPOPLASIA IN ADULTS BORN PRETERM WITH AND WITHOUT RETINOPATHY OF PREMATURITY: The Gutenberg Prematurity Eye Study

PURPOSE

This study analyses whether prematurity, retinopathy of prematurity (ROP), and associated factors lead to altered foveal shape in adulthood and whether these alterations are associated with visual acuity.

METHODS

The Gutenberg Prematurity Eye Study is a German cohort study with a prospective ophthalmologic examination (participants aged 18-52 years) of individuals born preterm and full-term that were examined with spectral domain optical coherence tomography. Participants were grouped according to gestational age (GA) and postnatal ROP status. Multivariable linear regression analyses for foveolar retinal thickness, foveal hypoplasia, and posterior vitreous status were performed.

RESULTS

A total of 755 eyes of 414 preterm and full-term individuals were included (aged 28.6 ± 8.6 years, 233 female individuals). Central foveal retinal thickness increased as GA decreased. The prevalence of foveal hypoplasia was 2% (control group), 9% (GA 33-36), 18% (GA 29-32), 48% (GA ≤28), 50% (ROP without treatment), and 82% of eyes (with ROP requiring treatment). In multivariable analyses, central foveal thickness was independently associated with GA and advanced stages of ROP requiring treatment while foveal hypoplasia was only associated with GA. Posterior vitreous was more frequently visible as partially detached in full-term than in preterm individuals. Lower distant-corrected visual acuity correlated with increased foveolar thickness (rho = 0.08; P = 0.03) and with foveal hypoplasia (rho = 0.15, P < 0.001).

CONCLUSION

Our findings indicate that there are fetal origins affecting foveal shape, resulting in foveal hypoplasia potentially affecting the visual acuity in adulthood.

Altered retinal nerve fiber layer thickness in children with allergic conjunctivitis: the Nanjing eye study

Background

So far, few data are available on the relationship between allergic conjunctivitis (AC) and ocular fundus. Whether retinal parameters change in patients with AC remains unknown. In this study, we investigated the influence of AC on retinal thickness and vessel density among 7-years-old school-age children.

Methods

This large population-based study is part of the Nanjing Eye Study (NES). Comprehensive examinations including anthropometric parameters, refraction, ocular biometric parameters, intraocular pressure and retinal parameters were conducted on each child. Retinal thickness and vessel density were assessed using the optical coherence tomography angiography. Information on AC was obtained from a comprehensive questionnaire.

Results

A total of 739 children (mean age ± SD: 7.40 ± 0.29 years) had complete eye examination and questionnaire data we needed. Ninety-four children (12.7%) had AC, among which, 5 children had the history of corticosteroid use and were excluded from the final analysis. Spherical equivalent, axial length, body mass index and birth weight were correlated with retinal parameters. After adjusting for sex, age, spherical equivalent, axial length, body mass index, birth weight and premature history, children with AC had thinner retinal nerve fiber layer thickness for average (117.39 versus 120.97 μm, p = 0.007), temporal (80.73 versus 84.34 μm, p = 0.001), nasal (98.82 versus 102.18 μm, p = 0.049) and inferior (152.68 versus 157.06 μm, p = 0.034) quadrants than the control group.

Conclusions

Children with AC tended to have thinner retinal nerve fiber layer thickness. More attention is needed to fundus condition of children with AC.

Supplementary information

The online version contains supplementary material available at 10.1186/s12886-022-02399-7.

Association of Birth Weight With Foveolar Thickness in Adulthood: Results From a Population-Based Study

Purpose

Low birth weight (BW) is associated with alterations of foveal shape development in childhood-leading to an increased retinal thickness of the fovea. The aim of the present study was to assess whether BW has a long-term effect on foveal retinal thickness (RT) and is still present in adulthood.

Methods

In the German population-based Gutenberg Health Study (GHS), participants were examined with spectral-domain optical coherence tomography. The association between self-reported BW and RT in the foveolar and perifoveal locations was assessed. Multivariable linear regression analyses with adjustment for potential confounders and grading of foveal hypoplasia were performed.

Results

Overall, RT measurements and self-reported BW were available for 2,539 participants (1300 female, mean age 54.5 ± 9.7 years). The absolute foveolar RT was 239.6 ± 25.8 µm, 232.2 ± 20.1 µm and 234.8 ± 21.0 µm, respectively, in the low (<2500 g), normal (2500-4000 g) and high (>4000 g) BW groups (P < 0.001). After adjustment for confounders, an association was observed between lower BW and increased foveolar thickness (B = -0.35 [95% confidence interval {CI}: -0.49; -0.20] µm/100 g; P < 0.001), whereas only a weak association with RT was observed with the nasal (P = 0.010), temporal (P = 0.011), and inferior (P = 0.021) quadrants in the 1 mm distance, with no association in the 2 mm distance to the fovea. Foveal hypoplasia grade 1 was more frequent in the low BW group (6.8%) compared to the normal (0.9%) and high BW group (1.2%).

Conclusions

This study provides evidence of an association between lower BW and increased foveolar thickness and foveal hypoplasia, indicating that prenatal growth may affect macular morphology, which in turn may persist until adulthood and predispose to retinal disease later in life.

Retinal choroidal and retinal nerve fiber layer thickness in former preterm and full-term infants aged 4 to 8 years

PURPOSE

To compare the retinal thickness at the fovea center, peripapillary retinal nerve fiber layer (RNFL) thickness and choroidal thickness (CT) in former preterm and full-term infants.

METHODS

A total of 121 healthy children aged 4-8 years were divided 4 groups: group 1; children born on time, group 2; preterm children without a history of retinopathy of prematurity (ROP), group 3; preterm children with a history of spontaneously regressed ROP and group 4; preterm children who underwent diode laser photocoagulation for ROP. The retinal thickness at the fovea, peripapillary RNFL thickness at global, superior, inferior, nasal and temporal quadrants and submacular CT at 7 different points were measured by using spectral-domain optical coherence tomography.

RESULTS

The mean retinal thickness at the fovea center was statistically higher, whereas the mean RNFL thickness values in global, nasal, superior and inferior quadrants were statistically lower in group 4. No difference was found in the mean submacular CT value of any point between the groups.

CONCLUSION

Transpupillary diode laser photocoagulation treatment for ROP seems to cause an increase in macular thickness and a decrease in RNFL thickness.

Decreased retinal thickness in preschool offspring of maternal gestational hypertension: the Nanjing Eye Study

PURPOSE

To evaluate the influence of maternal gestational hypertension (GH) on retinal thickness of 5-6-year-old children, including macular thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness and peripapillary retinal nerve fibre layer (RNFL) thickness.

METHODS

As part of Nanjing Eye Study, comprehensive ocular examinations were conducted in children aged 61-72 months, including noncycloplegic refraction, ocular biometric parameters and retinal parameters. Retinal thickness was measured by Spectral Domain-Optical Coherence Tomography. Data on pregnancy and birth history were obtained from a detailed questionnaire completed by parents.

RESULTS

Among 1062 children [mean age (standard deviation): 66.9 (3.4) months] with complete from eye examination and questionnaire, 30 (2.8%) children were born with maternal GH. In generalized linear models (adjusted for sex, age, spherical equivalent, axial length, body mass index, birth weight and premature history), children born with maternal GH had thinner average RNFL thickness (100.5 versus 104.4 μm, p = 0.035), superior RNFL thickness (123.7 versus 132.0 μm, p = 0.007), superior GC-IPL thickness (83.7 versus 86.4 μm, p = 0.005), superior-nasal GC-IPL thickness (86.3 versus 88.4 μm, p = 0.029) and superior outer macular thickness (278.0 versus 283.0 μm, p = 0.034) than children born with normal pregnancy.

CONCLUSION

Children exposed to maternal GH tended to have thinner macular, RNFL and GC-IPL thickness. These findings suggest that maternal GH may affect the development of retina in children thus hinders the development of the offspring's nervous system.

POTENTIAL UTILITY OF FOVEAL MORPHOLOGY IN PRETERM INFANTS MEASURED USING HAND-HELD OPTICAL COHERENCE TOMOGRAPHY IN RETINOPATHY OF PREMATURITY SCREENING

PURPOSE

To investigate dynamic foveal morphology with postmenstrual age, in preterm infants with and without retinopathy of prematurity using hand-held optical coherence tomography, adjusting for gestational age (GA) and birthweight (BW).

METHODS

Prospective mixed cross-sectional/longitudinal observational study of 87 participants (23-36 weeks GA; n = 30 with, n = 57 without retinopathy of prematurity) using hand-held optical coherence tomography images (n = 278) acquired between 31 weeks and 44 weeks postmenstrual age excluding treated retinopathy of prematurity. Measurements included foveal width, area, depth, central foveal thickness, maximum slope, and parafoveal retinal thickness at 1,000 µm nasal and temporal to the central fovea.

RESULTS

Retinopathy of prematurity was significantly correlated with only foveal width in either GA or BW adjusted statistical models. In contrast, severity of prematurity (GA, BW) correlated with foveal area (P < 0.005), depth (P ≤ 0.001), and slope (P < 0.01), although central foveal thickness (P = 0.007) and parafoveal retinal thickness (P < 0.001) correlated with GA, but not with BW.

CONCLUSION

Foveal width is independent of GA and BW with potential in retinopathy of prematurity screening assessment using hand-held optical coherence tomography. Foveal morphology could be graded in prematurity during development, with possible implications for future management of preterm infants.

Macular thickness in children aged 3-6 years born preterm

PURPOSE

To determine macular thickness in 3- to 6-year-old children who were born preterm compared with age-matched controls born at term.

METHODS

Children 36-72 months of age born ≤34 weeks and age-matched control children born at term were included in this prospective case-control study. Macular thickness measurements obtained using spectral domain optical coherence tomography were compared between groups and correlations of macular thickness were investigated in the preterm group.

RESULTS

A total of 45 preterm children (median age, 57.7 months) and 44 controls (median, 56.1 months) were included. Central macula thickness (CMT) was significantly higher (P = 0.010) and perifoveal thickness was significantly lower (P = 0.029) in the preterm group compared with the control group. Moderate negative correlations of CMT with gestational age and birth weight were found in the preterm group. Best-corrected visual acuity was similar between groups and was not correlated with CMT in the preterm group. No significant difference in macular thickness was found between subjects who had retinopathy of prematurity and those who did not.

CONCLUSIONS

Compared with controls, children in the preterm group had thicker retinas at the central macula and thinner perifoveal retinas. These subtle alterations were not correlated with visual acuity and may be considered a reflection of prematurity.

Retinopathy of prematurity, visual and neurodevelopmental outcome, and imaging of the central nervous system

Recent findings indicate that retinopathy of prematurity (ROP), presently classified by clinical examinations of retinal vascular tissue, is associated with structural alterations of the central nervous system. Such alterations may be the correlate of the association between ROP and impaired long-term neurocognitive and visual development. The advent of imaging techniques such as structural and diffusion tensor magnetic resonance imaging of the brain, and optical coherence tomography of the retina, will allow the complete visual system to be characterized in greater detail. It has been suggested that ROP may be not only a vascular, but a neurovascular disease, being part of a spectrum that includes pathological development in both the retinal and cerebral neurovascular interphase. We review the present knowledge in the field and point to future directions for research to tackle these questions.

Visual function is reduced in young adults formerly born prematurely: a population-based study

Aims

To assess visual function in young adults born preterm and compare with full-term individuals of the same age.

Methods

Young adults, born preterm (birth weight ≤1500 g) in 1988–1990, previously included in a population-based study on the incidence of retinopathy of prematurity (ROP) in Stockholm County, Sweden were included. A control group of participants born at term, in the same area during the same time period, was used for comparison. Best-corrected visual acuities were assessed at distance and near with logMAR charts. Distance visual acuity was also measured with single symbols to calculate crowding. Visual fields were measured with Humphrey 24-2 and the mean deviation was noted. Contrast sensitivity was assessed with Vistech contrast sensitivity test and the area under the curve was calculated.

Results

Fifty-nine preterm (females 37) and 44 full-term (females 18) individuals were included. All individuals were between 25 and 29 years of age. Preterm individuals had significantly lower distance visual acuity (mean −0.08 (SD 0.11) vs −0.14 (SD 0.07) logMAR, p=0.009), near visual acuity (mean −0.08 (SD 0.11) vs −0.13 (SD 0.06) logMAR, p=0.049), mean deviation (mean −1.09 (SD 1.13) vs −0.80 (SD 1.03) dB, p=0.05) and contrast sensitivity (mean 2.02 (SD 0.19) vs 2.16 (SD 0.14), p<0.001) in the better eye compared with full-term individuals. The differences in distance visual acuity and contrast sensitivity were also evident after excluding persons with previous ROP and neurological complications. In multivariable analyses, treated ROP was a risk factor for reduced near visual acuity and visual fields.

Conclusion

Visual function seems to be reduced in prematurely born individuals even in adulthood. The reason may be prematurity per se since individuals without previous ROP or neurological complications are also affected.

Synopsis

Visual function, assessed as visual acuity, visual fields and contrast sensitivity, was reduced in young adults born preterm and previously included in a population-based study on the incidence of retinopathy of prematurity, as compared with controls.

INCREASED FOVEAL GANGLION CELL AND INNER PLEXIFORM LAYER THICKNESS IN CHILDREN AGED 6.5 YEARS BORN EXTREMELY PRETERM

PURPOSE

To analyze the ganglion cell layer and inner plexiform layer (GCL+) thickness in children born extremely preterm and control children.

METHODS

A study of 6.5-year-old children born before the gestational age of 27 weeks and age-matched controls. The GCL+ thickness and foveal depth (FD) were analyzed in a single optical coherence tomography B-scan. Association with neonatal risk factors and sex was investigated. Extremely preterm was divided into no, mild, and severe retinopathy of prematurity, retinopathy of prematurity treatment, and no, mild, and severe intraventricular hemorrhage.

RESULTS

Adequate measurements were obtained from 89 children born extremely preterm and 92 controls. Extremely preterm children had increased total (5 µm, P < 0.001) and central (21 µm, P < 0.001) GCL+ thickness and reduced FD (-53 µm, P < 0.001) compared with controls. Extremely preterm children receiving retinopathy of prematurity treatment had increased GCL+ thickness and reduced FD compared with other subgroups. Sex and gestational age were associated with increased central GCL+ thickness and reduced FD. Reduced total GCL+ thickness was associated with severe intraventricular hemorrhage.

CONCLUSION

Extremely preterm birth can cause incomplete extrusion of the GCL+ and reduced FD. Retinopathy of prematurity treatment, gestational age, and male sex were associated to increased central GCL+ thickness and reduced FD, while severe intraventricular hemorrhage was associated with reduced total GCL+ thickness.

Correlation of morphological parameters and visual acuity with neurological development in former preterm children aged 4-10 years

PURPOSE

The objective of this study was to investigate the relationship between visual acuity, peripapillary retinal nerve fibre layer (pRNFL), retinal thickness at the fovea and other factors with the neurologic status of former preterm children.

METHODS

In this cross-sectional hospital based study in a maximum care tertiary centre, detailed anthropometric and ophthalmological data of former preterm children ranging from 4 to 10 years of age with a gestational age (GA) ≤32 weeks were assessed. Analyses of the correlation between pRNFL and foveal thickness, as well as visual acuity (VA) parameters at 4-10 years of age, with neurological development were evaluated at 2 years of age by Bayley Scales II of Infant Development, including Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI).

RESULTS

Data were available for 106 former preterm children. Univariate analysis revealed a correlation between PDI with pRNFL thickness (B = 0.43; p = 0.013), VA (B = -29.2; p < 0.001), GA (B = 2.7; p = 0.002), retinopathy of prematurity (ROP; B = -16.3; p < 0.001) and intraventricular haemorrhages (IVH; B = -22.9; p < 0.001) but not with strabismus or foveal thickness. In the multivariable analysis, the association remained for visual acuity and IVH, but not for pRNFL thickness or ROP. Mental Developmental Index (MDI) was associated with visual acuity (B = -34.3; p = 0.001), GA (B = 2.53; p = 0.02) and IVH (B = -15.4; p = 0.02), the latter also in the multivariable analysis.

CONCLUSION

This study revealed an association between PDI at 2 years of age and lower visual acuity later in childhood. However, there was no correlation between retinal morphology and neurologic outcome in former preterm children after adjusting for several potential confounders.

Objective evaluation of size and shape of superficial foveal avascular zone in normal subjects by optical coherence tomography angiography

This study was conducted to investigate the size and shape of the foveal avascular zone (FAZ) determined by optical coherence tomography angiography (OCTA) and the relationship of the size and shape to the clinical findings in normal subjects. This was a cross-sectional study with seventy eyes of 70 volunteers. The size of the superficial FAZs were assessed by its area, length of perimeter, and Feret’s diameter, and the shape by the circularity, axial ratio, roundness, and solidity. The correlations between each parameter and the clinical findings were statistically determined. The coefficients of variation (CV) of the parameters of FAZ size were higher than that of the parameters of FAZ shape. The refractive error and axial length were significantly correlated with area-related factors. The central macular thickness (CMT) was significantly correlated with all parameters. Although the CMT was a critical factor that was significantly correlated with the size and shape characteristics of the FAZ, the shape might be a better factor for characterizing the FAZ than the size because of the low CV of shape-related factors and the characteristics are less affected by the other ocular factors.

Pathophysiology, screening and treatment of ROP: A multi-disciplinary perspective

The population of infants at risk for retinopathy of prematurity (ROP) varies by world region; in countries with well developed neonatal intensive care services, the highest risk infants are those born at less than 28 weeks gestational age (GA) and less than 1 kg at birth, while, in regions where many aspects of neonatal intensive and ophthalmological care are not routinely available, more mature infants up to 2000 g at birth and 37 weeks GA are also at risk for severe ROP. Treatment options for both groups of patients include standard retinal laser photocoagulation or, more recently, intravitreal anti-VEGF drugs. In addition to detection and treatment of ROP, this review highlights new opportunities created by telemedicine, where screening and diagnosis of ROP in remote locations can be undertaken by non-ophthalmologists using digital fundus cameras. The ophthalmological care of the ROP infant is undertaken in the wider context of neonatal care and general wellbeing of the infant. Because of this context, this review takes a multi-disciplinary perspective with contributions from retinal vascular biologists, pediatric ophthalmologists, an epidemiologist and a neonatologist. This review highlights the latest insights regarding cellular and molecular mechanisms in the formation of the retinal vasculature in the human infant, pathogenesis of ROP, detection and treatment of severe ROP, the risks and benefits of anti-VEGF therapy, the identification of new therapies over the horizon, and the optimal neonatal care regimen for best ROP outcomes, and the benefits and pitfalls of telemedicine in the remote screening and diagnosis of ROP, all of which have the potential to improve ROP outcomes.

Reduction of Rod and Cone Function in 6.5-Year-Old Children Born Extremely Preterm

Importance

The function of rods and cones in children born extremely preterm has not yet been fully investigated.

Objective

To compare retinal function via full-field electroretinographic (ffERG) recordings in 6.5-year-old children born extremely preterm with children born at term.

Design, Setting, and Participants

A subcohort study was conducted from July 1, 2010, to January 15, 2014, of the national Extremely Preterm Infants in Sweden Study, including preterm children (<27 weeks' gestational age) and children born at term, at 6.5 years of age and living in the Uppsala health care region in Sweden. Full-field electroretinography was performed binocularly, using DTL electrodes and electroretinographic (ERG) protocols with flash strengths of 0.009, 0.17, 3.0, and 12.0 candelas (cd)/s/m2, together with 30-Hz flicker and 3.0 cd/s/m2 single-cone flash.

Main Outcomes and Measures

The ffERG recordings were analyzed, and their associations with gestational age and retinopathy of prematurity were examined.

Results

Adequate ffERG recordings were obtained from 52 preterm children (19 girls and 33 boys; mean [SD] age at examination, 6.6 [0.1] years) and 45 children born at term (22 girls and 23 boys; mean [SD] age at examination, 6.6 [0.1] years). Lower amplitudes of the combined rod and cone responses (the a-wave of the dark-adapted ERG protocol of 3.0 cd/s/m2: mean difference, -48.9 μV [95% CI, -80.0 to -17.9 μV]; P=.003; the a-wave of the dark-adapted ERG protocol of 12.0 cd/s/m2: mean difference, -55.7 μV [95% CI, -92.5 to -18.8 μV]; P = .004), as well as of the isolated cone response (30-Hz flicker ERG: mean difference, -12.1 μV [95% CI, -22.5 to -1.6 μV]; P = .03), were found in the preterm group in comparison with the group born at term. The implicit time of the combined rod and cone responses (the a-wave of the dark-adapted ERG protocol of 12.0 cd/s/m2) was longer (mean difference, 1.2 milliseconds [95% CI, 0.3-2.0 milliseconds]; P = .01) in the preterm group, as were the isolated cone responses (30-Hz flicker ERG: mean difference, 1.2 milliseconds [95% CI, 0.5-1.8 milliseconds]; P < .001), than in the group born at term. No association was found between the ffERG recordings and gestational age or retinopathy of prematurity in the preterm group.

Conclusions and Relevance

Both rod function and cone function were reduced in children born extremely preterm when compared with children born at term. There was no association with retinopathy of prematurity in the preterm group, which suggests that being born extremely preterm may be one of the main reasons for a general retinal dysfunction.