Visual and cerebral sequelae of very low birth weight in adolescents

Brain MRI findings and their association with visual impairment in young adolescents born very preterm

PURPOSE

Very preterm birth increases risk for neonatal white matter injury, but there is limited data on to what extent this persists into adolescence and how this relates to ophthalmological outcomes. The aim of this study was to assess brain MRI findings in 12-year-old children born very preterm compared to controls and their association with concurrent ophthalmological outcomes.

METHODS

We included 47 children born very preterm and 22 full-term controls (gestational age <32 and >37 weeks, respectively). Brain MRI findings were studied in association with concurrent ophthalmological outcomes at 12-year follow-up.

RESULTS

Evans index (0.27 vs 0.25, p<0.001) and a proposed "posterior ventricle index" (0.47 vs 0.45, p=0.018) were increased in children born very preterm. Higher gestational age associated with larger corpus callosum area (β=10.7, 95%CI 0.59-20.8). Focal white matter lesions were observed in 15 (32%) of very preterm children and in 1 (5%) of full-term controls. Increased posterior ventricle index increased risk for visual acuity ≤1.0 (OR=1.07×1011, 95%CI=7.78-1.48×1021) and contrast sensitivity <0.5 (OR=2.6×1027, 95%CI=1.9×108-3.5×1046). Decreased peritrigonal white matter thickness associated with impaired visual acuity (β=0.04, 95%CI 0.002-0.07).

CONCLUSION

More white matter lesions and evidence of lower white matter volume were found in children born very preterm compared with full-term controls at 12-year follow-up. The association between larger posterior ventricle index and reduced visual acuity and contrast sensitivity suggests disturbances of the posterior visual pathway due to diffuse white matter lesions.

Visual Acuity and Contrast Sensitivity in Preterm and Full-Term Children Using a Novel Digital Test

Visual assessment in preverbal children mostly relies on the preferential looking paradigm. It requires an experienced observer to interpret the child's responses to a stimulus. DIVE (Device for an Integral Visual Examination) is a digital tool with an integrated eye tracker (ET) that lifts this requirement and automatizes this process. The aim of our study was to assess the development of two visual functions, visual acuity (VA) and contrast sensitivity (CS), with DIVE, in a large sample of children from 6 months to 14 years (y) of age, and to compare the results of preterm and full-term children. Participants were recruited in clinical settings from five countries. There were 2208 children tested, 609 of them were born preterm. Both VA and CS improved throughout childhood, with the maximum increase during the first 5 years of age. Gestational age, refractive error and age had an impact on VA results, while CS values were only influenced by age. With this study we report normative reference outcomes for VA and CS throughout childhood and validate the DIVE tests as a useful tool to measure basic visual functions in children.

Ophthalmological data on 4.5- to 7-year-old Danish children

PURPOSE

To report normative data on visual acuity (VA) for near and distance, refraction, ocular alignment, ocular motility and stereo acuity in a cohort of children aged 4.5-7 years.

METHODS

A total of 950 children with normal development from the municipality of Roskilde, Denmark, were invited to participate in an ophthalmic cross-sectional population-based survey, of which 445 children in the age of 54-87 months participated with a complete ocular examination including cycloplegia. Visual acuity (VA) was tested using Kay Picture charts and notified in logMAR units.

RESULTS

Mean distance VA was 0.010 logMAR [standard deviation (SD): 0.048] in right eye, and near VA in right eye was 0.012 logMAR (SD: 0.054), with a nonsignificant difference between right and left eye in both parameters (paired t-test, p = 0.15 and p = 0.08, respectively). Amblyopia was found in 12 children (2.7%), mainly related to refractive errors. The mean refractive error of right eye was +1.75 D, and significant hyperopia (greater than +3.0 D) was found in 7.9%. No myopia (greater than or equal to -0.5 D) was found, astigmatism (>1 D) was seen in 4.3%. Manifest strabismus was present in 1.6%, and heterophoria in 4.0%. Reduced or absent stereo acuity was present in 35 children (7.9%) and was related to a reduced VA, refractive error and strabismus.

CONCLUSION

Ophthalmic data of 445 normally developed children are presented, supplementing previous reported normative data in children. We found a relatively high prevalence of amblyopia and of hyperopia, while myopia was not found, confirming previous studies that myopia is not developing at early age in Danish children.

National population-based cohort study found that visual-motor integration was commonly affected in extremely preterm born children at six-and-a-half years

AIM

This study aimed to explain the relationship between visual-motor integration (VMI) abilities and extremely preterm (EPT) birth, by exploring the influence of perinatal variables, cognition, manual dexterity and ophthalmological outcomes.

METHODS

This was part of the population-based national Extremely Preterm Infant Study in Sweden (EXPRESS) study. We studied 355 children, born at a gestational age of <27 weeks from April 2004 to March 2007, and 364 term-born controls. At six-and-a-half years of age, we assessed VMI, cognitive function, motor skills and vision. VMI impairment was classified as <-1 standard deviation (SD).

RESULTS

The mean (SD) VMI score was 87 (±12) in preterm children compared to 98 (±11) in controls (p < 0.001). VMI impairment was present in 55% of preterm infants and in 78% of children born at 22-23 weeks. Male sex and postnatal steroids showed a weak association with poorer visual-motor performance, whereas low manual dexterity and cognitive function showed a stronger association.

CONCLUSION

Poor VMI performance was common in this EXPRESS cohort of children born EPT. Its strong association to cognition and manual dexterity confirms that all of these factors need to be taken into account when evaluating risks in preterm born children.

Motion Perception and Form Discrimination in Extremely Preterm School-Aged Children

This population-based study evaluated motion and form perception in 71 children born extreme premature (EPT; < 27 gestational weeks), aged 6.5 years, as compared to a matched group of 79 control children born at term. Motion and form perception were evaluated by motion coherence and form coherence tests. The EPT group showed a poorer performance on both tasks as compared to the control group. However, after controlling for IQ and visual acuity, the EPT group showed only a significant deficit in motion perception. No association was found between motion perception accuracy and gestational age, previous retinopathy of prematurity, or previous intraventricular hemorrhage in the EPT group. The results highlight the long-term motion perception deficits in children born EPT.

Visual-motor and executive functions in children born preterm: the Bender Visual Motor Gestalt Test revisited

Visual-motor development and executive functions were investigated with the Bender Test at age 5½ years in 175 children born preterm and 125 full-term controls, within the longitudinal Stockholm Neonatal Project. Assessment also included WPPSI-R and NEPSY neuropsychological battery for ages 4-7 (Korkman, 1990). Bender protocols were scored according to Brannigan & Decker (2003), Koppitz (1963) and a complementary neuropsychological scoring system (ABC), aimed at executive functions and developed for this study. Bender results by all three scoring systems were strongly related to overall cognitive level (Performance IQ), in both groups. The preterm group displayed inferior visual-motor skills compared to controls also when controlling for IQ. The largest group differences were found on the ABC scoring, which shared unique variance with NEPSY tests of executive function. Multiple regression analyses showed that hyperactive behavior and inattention increased the risk for visual-motor deficits in children born preterm, whereas no added risk was seen among hyperactive term children. Gender differences favoring girls were strongest within the preterm group, presumably reflecting the specific vulnerability of preterm boys. The results indicate that preterm children develop a different neurobehavioral organization from children born at term, and that the Bender test with a neuropsychological scoring is a useful tool in developmental screening around school start.

Ophthalmologic Outcomes of Children Born Premature Without ROP: Correlations With Gestational Age and Psychomotor Development

PURPOSE

To study ophthalmological outcomes of premature children with no retinopathy of prematurity (ROP) and correlate with neurodevelopmental outcomes.

METHODS

A total of 69 former preterm infants were evaluated at 2 to 7 years of age. Detailed ophthalmologic examinations were performed. Neurodevelopment was assessed using the Peabody Developmental Motor Scale and Wechsler Preschool and Primary Scale of Intelligence. Another 69 healthy children served as controls.

RESULTS

The 69 preterm children (38 of 69 boys) and 69 controls (38 of 69 boys) had a mean age of 4.9 ± 1.5 and 4.9 ± 1.4 years, respectively. Compared to controls, preterm infants had vision impairment of 19% versus 1.4% (P = .001), hyperopia of 87% versus 98.5% (P = .21), myopia of 11% versus 1.4% (P = .017), and astigmatism of 39% versus 30.4% (P = .37). Children with any motor disability tended to have worse vision.

CONCLUSIONS

In the absence of ROP, hyperopia was more common in infants 32 weeks or older who weighed more than 1,500 g at birth; other vision problems were similar in subgroups. This may represent impending myopia in those younger than 32 weeks weighing less than 1,500 g. [J Pediatr Ophthalmol Strabismus. 2017;54(1):32-38.].

Ophthalmological findings in 10-year-old full-term children--a population-based study

PURPOSE

To determine different ophthalmological parameters in 10-year-old, healthy, full-term children in Stockholm County, Sweden.

METHODS

Two hundred and seventeen children were included in the study. Best-corrected distance and near visual acuities (VA) were measured using logMAR charts. Cycloplegic retinoscopy was performed, and spherical equivalent and astigmatism were determined. Examination of ocular movement and cover test for distance and near were performed. Stereopsis was assessed with the TNO test, and contrast sensitivity with the Vistech test. The Royal Air Force rule was used for assessing accommodation, and near point of convergence was measured with the Lang fixation stick. Ophthalmoscopy was performed through dilated pupils.

RESULTS

Eighty-two per cent of the children had a distance VA of -0.1 logMAR (1.3 Snellen acuity) or better. None of the children were visually impaired [VA>0.6 logMAR (<0.3 Snellen acuity)]. Ninety-three per cent had a near VA of -0.1 logMAR (1.25 Snellen acuity) or better. Mean spherical equivalent was 0.6 D. Eight (3.6%) children had hypermetropia (≥+2 D), and 17 (7.8%) were myopic (≤-0.5 D). Nine (4.1%) children had an astigmatism≥1 D, and two (0.9%) had anisometropia of ≥1 D. Manifest strabismus was found in seven (3.2%) children, five of whom had exotropia. Heterophoria for distance and/or near was found in 80.2% of the children. In children without manifest strabismus, stereopsis>60 seconds of arc was found in five (2.4%). Three (1.4%) of 215 children had contrast sensitivity below normal limits. Binocular median near point of accommodation was 14 D, and median near point of convergence 6 cm.

CONCLUSION

Knowledge of various visual functions in normally developing children is crucial to be able to draw conclusions from ophthalmological examinations in children with eye diseases. This population-based study describes different ophthalmological parameters in full-term ten-year-old children. The material can be used as a control when examining children of similar ages with various ophthalmological conditions, such as groups of children with specific neurological or retinal diseases, and syndromes.

Visual-motor deficits relate to altered gray and white matter in young adults born preterm with very low birth weight

Individuals born preterm and at very low birth weight (birth weight ≤ 1500 g) are at an increased risk of perinatal brain injury and neurodevelopmental deficits over the long term. This study examined whether this clinical group has more problems with visual-motor integration, motor coordination, and visual perception compared to term-born controls, and related these findings to cortical surface area and thickness and white matter fractional anisotropy. Forty-seven preterm-born very low birth weight individuals and 56 term-born controls were examined at 18-22 years of age with a combined cognitive, morphometric MRI, and diffusion tensor imaging evaluation in Trondheim, Norway. Visual-motor skills were evaluated with the Beery-Buktenica Developmental Test of Visual-Motor Integration-V (VMI) copying test and its supplemental tests of motor coordination and visual perception. 3D T1-weighted MPRAGE images and diffusion tensor imaging were done at 1.5 T. Cortical reconstruction generated in FreeSurfer and voxelwise maps of fractional anisotropy calculated with Tract-Based Spatial Statistics were used to explore the relationship between MRI findings and cognitive results. Very low birth weight individuals had significantly lower scores on the copying and motor coordination tests compared with controls. In the very low birth weight group, VMI scores showed significant positive relationships with cortical surface area in widespread regions, with reductions of the superior temporal gyrus, insula, and medial occipital lobe in conjunction with the posterior ventral temporal lobe. Visual perception scores also showed positive relationships with cortical thickness in the very low birth weight group, primarily in the lateral occipito-temporo-parietal junction, the superior temporal gyrus, insula, and superior parietal regions. In the very low birth weight group, visual-motor performance correlated positively with fractional anisotropy especially in the corpus callosum, inferior fronto-occipital fasciculus bilaterally, and anterior thalamic radiation bilaterally, driven primarily by an increase in radial diffusivity. VMI scores did not demonstrate a significant relationship to cortical surface area, cortical thickness, or diffusion measures in the control group. Our results indicate that visual-motor integration problems persist into adulthood for very low birth weight individuals, which may be due to structural alterations in several specific gray-white matter networks. Visual-motor deficits appear related to reduced surface area of motor and visual cortices and disturbed connectivity in long association tracts containing visual and motor information. We conjecture that these outcomes may be due to perinatal brain injury or aberrant cortical development secondary to injury or due to very preterm birth.

Photoreceptor Function in School-Aged Children is Affected by Preterm Birth

PURPOSE

Prematurely born children have affected visual functions at school age. Optical coherent tomography (OCT) has shown morphological changes in the retina, suggesting a disturbance in normal retinal development in these children. The aim of this study was to examine retinal function with fullfield electroretinogram (ffERG) in school-aged children born prematurely and compare with children born at term. A second aim was to correlate retinal function with visual acuity (VA), gestational age (GA), birth weight, and retinopathy of prematurity (ROP).

METHODS

The study group consisted of 35 former preterm children born before GA of 32 weeks. A group of 42 children born at term acted as controls. All children were between 5- and 18-years old. FfERG was performed in both eyes. Best-corrected VA and refraction in cycloplegia was determined.

RESULTS

The a-wave of the combined rod/cone responses was significantly reduced in the prematurely-born children compared with children born at term. There was a correlation between reduced a-wave amplitude in the combined rod/cone response and ROP and GA at birth.

CONCLUSION

Function of photoreceptors was affected in prematurely born children, possibly also in children without previous ROP. Whether immaturity per se affects the retinal function remains to be elucidated.

TRANSLATIONAL RELEVANCE

The present study illustrates that electrophysiological studies of the retinal function can help us understand visual dysfunctions in prematurely born children.

Social attribution skills of children born preterm at very low birth weight

Children born prematurely at very low birth weight (<1500 g) are at increased risk for impairments affecting social functioning, including autism spectrum disorders (e.g., Johnson et al., 2010). In the current study, we used the Happé-Frith animated triangles task (Abell, Happé, & Frith, 2000) to study social attribution skills in this population. In this task, typical viewers attribute intentionality and mental states to shapes, based on characteristics of their movements. Participants included 34 preterm children and 36 full-term controls, aged 8-11 years. Groups were comparable in terms of age at test, gender, handedness, and socioeconomic status; they also performed similarly on tests of selective attention/processing speed and verbal intelligence. Relative to full-term peers, preterm children's descriptions of the animations were less appropriate overall; they also overattributed intentionality/mental states to randomly moving shapes and underattributed intentionality/mental states to shapes that seemed to be interacting socially. Impairments in the ability to infer the putative mental states of triangles from movement cues alone were most evident in children displaying more "autistic-like" traits, and this may reflect atypical development of and/or functioning in, or atypical connections between, parts of the social brain.

Compromised approximate number system acuity in extremely preterm school-aged children

AIM

The aim of this study was to compare the approximate number system acuity in children born extremely preterm aged 6 years 6 months and typically developing, age-matched peers.

METHOD

This population-based follow-up study included 65 children born before 27 gestational weeks (35 males, 30 females; mean gestational age 25.4 wks [SD 1.1 wk]; mean birthweight 789 g [SD 158 g]) and 47 typically developing children (24 females, 23 males) at the age of 6 years 6 months. A battery of cognitive tests was administered, including a computerized test for measuring approximate number system acuity and tests for general cognition, working memory, processing speed, and visual attention. Approximate number system outcome measures were means of Weber fraction (w) values and response time in milliseconds.

RESULTS

The 43 extremely preterm children in whom usable data were obtained performed significantly worse than the typically developing children on the approximate number system task (w=0.30 [SD 0.23] vs. 0.17 [SD 0.13]; p=0.003) and were significantly slower (response time=2934 ms [SD 1102 ms] vs 2376 ms [SD 310 ms]; p=0.002). The differences remained when adjusting for differences in other cognitive functions (p=0.03).

INTERPRETATION

Preterm birth has a negative impact on an individual's ability to rapidly approximate and compare numbers of visually presented items. This deficiency is thought to be a consequence of dorsal stream dysfunction. Future studies will investigate whether this deficiency is correlated with lower mathematical proficiency in this group of children.

Ophthalmological outcome and visuospatial ability in very preterm children measured at 2.5 years corrected age

AIM

To investigate the ophthalmological outcome of very preterm children at 2.5 years corrected age (CA) and perform a test of visuospatial and cognitive abilities.

METHODS

A population-based, prospective study (LOVIS study) in Uppsala County, Sweden, comprised 111 very preterm children (<32 w gestational age [GA]) born between 1 January 2004 and 31 December 2007. Ophthalmic evaluations were undertaken in 98/109 children (89.9%) alive at 2.5 years. Spatial cognition was investigated with a test of five alternative blocks in 48 preterm and 25 term-born children.

RESULTS

Visual impairment, strabismus or refractive errors, were found in 12% of the children. None of the children were blind in both eyes. Logistic regression analyses revealed significant associations between strabismus and periventricular leucomalacia/intraventricular haemorrhage (OR 9.6, p = 0.025) and between refractive errors and severe retinopathy of prematurity (OR 9.8, p = 0.011) and GA (OR 0.763, p = 0.034). Oval and rectangular blocks were significantly more difficult to insert into a box for preterm than full-term children (p = 0.048 and 0.013, respectively). There was a significant correlation between total scores for the five blocks and GA at birth (p = 0.035).

CONCLUSION

Eye and visual problems were found in 12% of the preterm children at 30 months CA. Preterm children had difficulties with blocks of complex shapes.

Long-term neurobiological consequences of early postnatal hCMV-infection in former preterms: a functional MRI study

Early postnatal infection with human cytomegalovirus (hCMV) may contribute to an adverse cognitive outcome in early preterm-born children (PT). We here set out to explore whether long-term neurobiological consequences of such an infection are detectable using fMRI in children and adolescents who were born very preterm and who either did (PThCMV+ ) or did not (PT(hCMV-)) suffer from an early postnatal hCMV-infection, when compared with typically developing healthy control (HC) subjects. Overall, data from 71 children and adolescents could be included, 34 PT (of which 15 were PT(hCMV+) and 19 were PT(hCMV-)) and 37 HC. Using a recently established "dual use" fMRI task, we investigated language and visuospatial functions. There were significant activation differences in the left hippocampus (PT > HC and PT(hCMV+) > HC), and in the right anterior cingulate cortex (PT(hCMV-) > PT(hCMV+)) when performing the language task. Surprisingly, only a small region in the occipital cortex showed a significant activation difference (HC > PT(HCMV-)) when performing the visuospatial task. Targeted analyses revealed differences in gray matter volume, but not density, in several brain regions. Our results suggest that long-term neurobiological consequences of an early postnatal hCMV infection are detectable even in older children and adolescents formerly born very preterm, compatible with a higher effort when performing a cognitive task. This suggests that measures to prevent such an infection are warranted. Furthermore, an interrelation of brain structure and function was detected that may constitute a severe confound when using fMRI to compare structurally differing groups.

Outcome of retinopathy of prematurity

In prematurely born children, various visual and ophthalmologic sequelae occur because of both retinopathy of prematurity (ROP) and preterm birth per se. Several long-term follow-up studies have described the outcome of ROP. Visual impairment and blindness are well-known consequences, but the prevalence varies globally because of differing neonatal and ophthalmologic care. Improving treatment options and criteria for the treatment of ROP are continuously changing the ophthalmologic outcome. The anatomic outcome has improved with treatment, but good anatomic outcome in treated severe ROP does not always reflect the functional outcome. There is no consensus regarding long-term follow-up of prematurely born children.

Visual function in 6 to 7 year-old children born extremely preterm: a population-based study

PURPOSE

Progress in neonatal care has caused an increased survival of children born extremely preterm. The aims of this study were to examine the long-term visual function and ocular development in an unselected cohort of extremely preterm infants and relate the results to neonatal morbidity and long-term neurodevelopmental outcome.

METHODS

All children with gestational age of 22-27 completed weeks or birth weight of 500-999 g born in the years 1999-2000 in two counties of Western Norway (n = 52) were invited to an eye examination that included visual acuity, refractive error, binocular function, accommodative amplitude and fundus examination. Cognitive function was assessed with the WPSSI-R test and motor abilities with the ABC movement test.

RESULTS

Neonatal morbidities and neurodevelopmental outcome were known for all, while 37 of the 52 children underwent the eye examination. None were blind or visually impaired, but 46% had subnormal visual acuity (logMAR ≥0.1). Ninety per cent were emmetropic or slightly hypermetropic (0 to +3D), while 10% had manifest and 51% latent strabismus. Performance IQ on the WPSSI-R test and ABC total score were associated with best visual acuity (p = 0.03 and p < 0.01, respectively). In a multiple linear regression model, visual acuity in the best eye was significantly associated with performance IQ (p = 0.03) and ABC total score (p = 0.02).

CONCLUSION

This study suggests a more favourable long-term prognosis on important ocular and visual parameters in survivors of extreme prematurity than expected from similar reports on children born less prematurely and that performance IQ and motor function are related to visual acuity.

Vision and the achievement gap among urban minority youth

OBJECTIVES

To outline the prevalence and disparities of vision problems among school-aged urban minority youth, causal pathways through which vision problems adversely affects academic achievement, and proven or promising approaches for schools to address these problems.

METHODS

Literature review.

RESULTS

More than 20% of school-aged youth have some kind of vision problem. In a nationally representative sample of more than 48,000 youth under age 18, those from lower income families were less likely to have diagnosed eye conditions than White children and children living in higher income families. When diagnosed with eye care problems, Black youth living in poverty received fewer and less intensive services. Causal pathways through which vision problems adversely affect academic achievement include sensory perceptions, cognition, and school connectedness. Vision screening is widespread in the nation's schools, but the educational (and public health) benefits from these efforts are jeopardized by lack of follow-up and coordination of efforts.

CONCLUSIONS

Vision problems are highly and disproportionately prevalent among school-aged urban minority youth, have a negative impact on academic achievement through their effects on sensory perceptions, cognition, and school connectedness, and effective practices are available for schools to address these problems. School-based vision screening programs are a logical approach for the early detection and treatment of vision problems affecting youth and are widely implemented in the nation's schools. To more fully realize the educational (and public health) benefits of current investments in screening, programs will require improved follow-up and coordination between and among agencies conducting screening, school nurses, teachers and parents, and in some cases community resources.

Visual function and white matter microstructure in very-low-birth-weight (VLBW) adolescents--a DTI study

Premature birth is associated with visual impairments, due to both cerebral and ocular pathology. This study examined the relationship between cerebral white matter microstructure, evaluated by diffusion tensor imaging (DTI), and visual function, in 30 preterm born adolescents with very low birth weight (VLBW=birth weight⩽1500g) and an age-matched group of 45 term born controls. Visual acuity correlated positively with fractional anisotropy (FA) in corpus callosum and in frontal white matter areas in the VLBW participants, but not in the control participants. Callosal visual connections may play a more important role in the development of good visual acuity than previously acknowledged in preterm born children.

Follow-up studies of very low birthweight children in Sweden

Follow-up studies are essential to our knowledge of outcome in very low birthweight (VLBW) or extremely preterm (EPT) infants because those children have a greater risk for developing neurosensory disabilities and behavioural and educational problems and have decreased probability for an optimal transition into adulthood compared to term controls. Outcome data are of interest not only to healthcare professionals but also to parents, schoolteachers and society. The aim of this review is to describe the follow-up studies of seven populations of VLBW or EPT infants performed in Sweden and published between 1995 and 2009.

CONCLUSION

 The time has come to implement evident data from these Swedish follow-up studies into clinical practice and to perform regular and specific follow-up examinations during childhood for all VLBW and EPT children. These assessments, specially designed for high-risk infants, should consider the potential outcomes for neurological, visual, auditory function and cognitive function as well as behaviour and growth, from birth to school-start.

Development of smooth pursuit eye movements in very preterm infants: 1. General aspects

AIM

To investigate early oculo-motor development in a population-based cohort of very preterm infants.

METHODS

Early oculo-motor development was prospectively studied by measuring smooth pursuit eye movements at 2 and 4 months corrected age in a population of very preterm infants born in Uppsala County 2004-2007. Eighty-one preterm infants were studied, and 32 healthy term infants constituted the control group.

RESULTS

The study group consisted of infants with a mean gestational age of 28 + 5 weeks. At 2 and 4 months corrected age, infants born very preterm showed lower gain (p < 0.001) and proportion of smooth pursuit eye movements (p < 0.001) compared to the control group. The boys showed higher gain of smooth pursuit eye movements at both 2 and 4 months corrected age, compared to girls.

CONCLUSIONS

 Oculo-motor development measured by smooth pursuit eye movements is delayed in very preterm infants at 2 and 4 months corrected age. This might be a risk factor or early indicator of later perceptual and behavioural impairment.

Development of human visual function

By 1985 newly devised behavioral and electrophysiological techniques had been used to track development of infants' acuity, contrast sensitivity and binocularity, and for clinical evaluation of developing visual function. This review focus on advances in the development and assessment of infant vision in the following 25 years. Infants' visual cortical function has been studied through selectivity for orientation, directional motion and binocular disparity, and the control of subcortical oculomotor mechanisms in fixation shifts and optokinetic nystagmus, leading to a model of increasing cortical dominance over subcortical pathways. Neonatal face processing remains a challenge for this model. Recent research has focused on development of integrative processing (hyperacuity, texture segmentation, and sensitivity to global form and motion coherence) in extra-striate visual areas, including signatures of dorsal and ventral stream processing. Asynchronies in development of these two streams may be related to their differential vulnerability in both acquired and genetic disorders. New methods and approaches to clinical disorders are reviewed, in particular the increasing focus on paediatric neurology as well as ophthalmology. Visual measures in early infancy in high-risk children are allowing measures not only of existing deficits in infancy but prediction of later visual and cognitive outcome. Work with early cataract and later recovery from blinding disorders has thrown new light on the plasticity of the visual system and its limitations. The review concludes with a forward look to future opportunities provided by studies of development post infancy, new imaging and eye tracking methods, and sampling infants' visual ecology.

The impact of pediatric vision disorders in adulthood

In addition to refractive errors such as myopia and astigmatism, ocular disorders that occur in infants, toddlers, and children may present lifelong problems for the child. Conditions such as strabismus, amblyopia, and retinopathy of prematurity may require adaptations in adulthood. In addition, vision disorders that occur in childhood may manifest as problems well into adulthood. When visual impairment is present, there may be further effects on overall health, self-perception, educational attainment, job choices, and a number of other social factors.

Visual function in congenital and childhood myotonic dystrophy type 1

OBJECTIVE

To investigate visual function in a group of individuals with congenital and childhood myotonic dystrophy type 1 (DM1), to correlate the results to the size of the cytosine-thymine-guanine (CTG) repeat expansion and the onset form, and to compare the results with those of a control group.

DESIGN

Cross-sectional study with age- and gender-matched control groups.

PARTICIPANTS AND CONTROLS

Forty-nine individuals with severe and mild congenital and childhood DM1 and controls matched for age and gender.

METHODS

The ophthalmologic examination included best-corrected visual acuity (BCVA), refraction, slit-lamp biomicroscopy, indirect ophthalmoscopy, and flash visual evoked potentials (VEPs).

MAIN OUTCOME MEASURES

Visual acuity, refractive error, pathology of lens, fundus, and VEP pathologic features.

RESULTS

The study shows a higher prevalence of low visual acuity, hyperopia, and astigmatism in the study population compared with the controls. The size of the CTG repeat expansion had an impact on BCVA in all subgroups with lower values in individuals with larger expansion size. In childhood DM1, individuals with high hyperopia and astigmatism had greater CTG repeat expansion size than those without. No true cataract was found. Subtle nonspecific fundus changes were present in addition to VEP pathology.

CONCLUSIONS

Children and adolescents with DM1 have a variety of visual function pathologies, and DM1 has an impact on the developing visual system, necessitating early ophthalmologic assessment and follow-up.

Visual fields and optic disc morphology in very low birthweight adolescents examined with magnetic resonance imaging of the brain

PURPOSE

We aimed to evaluate visual fields (VFs) and optic disc morphology in very low birthweight (VLBW) adolescents compared with age- and gender-matched controls, and to relate the findings to magnetic resonance imaging (MRI) results.

METHODS

Fifty-nine VLBW adolescents and 55 age- and gender-matched controls with normal birthweight were examined. Visual fields were tested using computerized rarebit perimetry (RB). Optic nerve and retinal vessel morphology were evaluated by digital image analysis of fundus photographs. Brain MRI was conducted in the VLBW subjects.

RESULTS

Ten of the 57 VLBW subjects (p = 0.022) had subnormal VF results defined as a mean hit rate below the fifth percentile of the controls (i.e. < 89%). All of these also had significantly lower mean hit rates (p = 0.039) in the inferior hemifield. Sixteen of 57 (28%) VLBW subjects had white matter damage of immaturity (WMDI) on MRI. Six of 15 subjects with WMDI (who underwent VF testing) also had subnormal RB results, compared with four of 39 with normal MRI findings (p = 0.02). The mean neural retinal rim area was 9% smaller (p = 0.018) in the VLBW group than in the control group. The VLBW adolescents had a significantly higher index for tortuosity of arterioles than the controls (p < 0.001).

CONCLUSIONS

In the present study, 18% of all VLBW adolescents and 40% of those with WMDI had subnormal RB VF findings. The VLBW group had increased arterial tortuosity and a somewhat smaller (9%) mean neural retinal rim area than the control group. Thus sequels to VLBW appear to persist in adolescence.

Most very low birth weight subjects do well as adults

AIM

To study health, quality of life, educational level and occupation in very low birth weight (VLBW) children in early adulthood and the relationship of the findings to neonatal risk factors and later handicap.

METHODS

This is a prospective long-term follow-up study of a regional cohort of 20-year-old VLBW subjects (n = 77) of all surviving VLBW children (n = 86) and 69/86 term controls born in 1987-1988 in the south-east of Sweden. Postal questionnaires were used: 1. A study-specific form, 2. Medical Outcomes Study, Short Form (SF-36), 3. Sense of Coherence.

RESULTS

VLBW subjects did not differ significantly from their controls in self-perceived health, use of tobacco, education, occupation and way of living, or scoring on SF-36 and Sense of Coherence. Sixteen had cerebral palsy, attention deficit hyperactivity disorder or isolated mental retardation, and these subjects differed significantly from controls on SF-36 in physical functioning and physical health score, but not on Sense of Coherence. VLBW subjects were significantly lighter and shorter than their controls. Extremely low birth weight (ELBW), bronchopulmonary dysplasia and intraventricular haemorrhage were significantly associated with poorer scores on physical function.

CONCLUSION

The 20-year old VLBW subjects reported perceived health and managed transition to adulthood similar to controls. Handicapped subjects had poorer self-perceived physical function. ELBW and severe neonatal complications were associated with poorer self-perceived physical health.

Visuospatial skills, ocular alignment, and magnetic resonance imaging findings in very low birth weight adolescents

PURPOSE

To describe ocular alignment and stereoacuity in adolescents with very low birth weight (VLBW) in comparison with a matched control group and to investigate associations with white matter damage of immaturity (WMDI) and visuospatial skills in the VLBW group.

METHODS

Fifty-nine 15-year-old VLBW subjects and 55 age- and sex-matched controls with normal birth weight underwent examination, including measurement of ocular alignment using cover test and Maddox rod and cycloplegic refraction. Stereoacuity was assessed with the TNO test, best-corrected visual acuity with a Konstantin Moutakis letter chart, and visuospatial skills with the performance tests, defined as performance intelligence quotient (IQ), in the Wechsler Intelligence Scale for Children (WISC-III). All VLBW subjects underwent magnetic resonance imaging of the brain.

RESULTS

Ocular misalignment was significantly more common in the VLBW group than in the control group (22% compared with 4%; p = 0.004). Exophoria, subnormal stereoacuity, and subnormal performance IQ were significantly more common in the VLBW group than in the control group (p = 0.006, p = 0.011, and p = 0.015, respectively). Ocular misalignment was associated with WMDI (p = 0.035) and subnormal performance IQ (p = 0.020). Of the VLBW subjects with ocular misalignment, 69% had WMDI and/or subnormal performance IQ.

CONCLUSIONS

The VLBW adolescents had more visuospatial problems, lower stereoacuity, and more ocular misalignment than the control subjects. Ocular misalignment was associated with visuospatial deficiencies and/or WMDI in the VLBW group and was a better predictor for visuospatial deficits than WMDI.

Academic achievement, behavioural outcomes and MRI findings at 15 years of age in very low birthweight children

AIM

To assess cognitive, academic and behavioural functions in 15-year-old very low birthweight (VLBW) children and relate results to gender, neonatal risk factors, growth and magnetic resonance imaging (MRI) findings.

METHODS

Sixty-one out of 86 VLBW children and 57/86 term controls born in the south-east region of Sweden were assessed regarding cognition (WISC III), school outcome, behaviour and growth. VLBW children were examined using cerebral MRI.

RESULTS

VLBW children performed significantly lower than their term controls on WISC III and 49% had IQ lower than 85. Ten VLBW children with IQ < 70 had not been clinically identified earlier and a majority of these children attended mainstream school. VLBW girls had significantly lower total problems scores. Using MRI, white matter damage (WMD) was detected in 16 (27%) children. VLBW boys with WMD had significantly lower IQ than those without. Small occipito-frontal circumference (OFC) correlated with low IQ. Mechanical ventilation and intraventricular haemorrhage (IVH) showed significant correlations with lower IQ and reading skills.

CONCLUSION

VLBW children achieved poorer results compared with their controls in cognitive tests. Mechanical ventilation and IVH were related to poorer academic outcome. Many of the children with low IQ had not been identified earlier. Therefore, we recommend that VLBW children undergo an IQ test before beginning school in order to receive adequate support.