Infant Vision Research Articles

Postnatal Development of Onset Transient Responses in Macaque V1 and V2 Neurons

Vision of newborn infants is limited by immaturities in their visual brain. In adult primates, the transient onset discharges of visual cortical neurons are thought to be intimately involved with capturing the rapid succession of brief images in visual scenes. Here we sought to determine the responsiveness and quality of transient responses in individual neurons of the primary visual cortex (V1) and visual area 2 (V2) of infant monkeys. We show that the transient component of neuronal firing to 640-ms stationary gratings was as robust and as reliable as in adults only 2 wk after birth, whereas the sustained component was more sluggish in infants than in adults. Thus the cortical circuitry supporting onset transient responses is functionally mature near birth, and our findings predict that neonates, known for their "impoverished vision," are capable of initiating relatively mature fixating eye movements and of performing in detection of simple objects far better than traditionally thought.

Color vision in children and the Lanthony New Color Test

Much is known about color vision in infants, adolescents, and adults, but very few studies report the changes, which occur in color perception of children in their early schooling years. There is also a shortage of suitable color vision tests for children. This study investigated the changes in color vision of school students between 5-12 years old using the Lanthony New Color Test (NCT). Subjects of all ages were able to complete a shortened form of this test adequately. The Vingrys and King-Smith (1988) method of panel test analysis and Adams and Rodic (1982) color confusion score were adapted to analyze their performance of the test. This study confirmed that there are changes in color perception occurring in this age group. Color perception abilities increased as a function of age and there was also an improvement in the performance on the NCT with age. This can be attributed to both cognitive development and changes occurring to the color vision system.

Cortical vision, MRI and developmental outcome in preterm infants

Objectives:To test two measures of visual cortical function in the first year of life as early markers of functionally significant brain damage in infants born preterm: orientation-reversal visual event-related potentials...

Pay attention to specialization of pediatric penetrating keratoplasty

Pediatric corneal transplantation is one of most important means to avoid corneal blind and promote infant vision development, but low scleral rigidity increases the forward displacement of the lens-iris diaphragm and significant refractive errors after corneal transplantation. The underlying disease process will also influence the timing of surgery. For high risk of grafts failure in pediatric penetrating keratoplasty, it is potential for excellent long term outcome to determine operative opportunity cautiously and prevent and treat appropriately grafts rejection, glaucoma, infection and corneal erosions.

The development of vision

Disorders of visual function are common findings in children with neonatal brain lesions of antenatal and perinatal onset. In the last few years the development of age appropriate batteries for assessing visual function in the first years and the combined use of neuroimaging and neurophysiological techniques have allowed to achieve better understanding of the mechanisms underlying development of vision in low risk infants and in those with brain lesions. We will review the main models of visual development and the tests available to assess visual function in infancy, focusing on the recently described battery of tests for assessing early visual abilities in preterm and full term infants.

A computational approach for modeling the infant vision system in object and face recognition

Background Most research in vision systems has been focused on the fully developed visual system of adult humans. During early developmental stages, there are communication pathways between the visual and other sensory areas of the cortex, showing how the biological network is selforganizing. Within a few months of birth, the brain can differentiate faces from other faces or objects from other objects.

Visual development in infants with prenatal post-haemorrhagic ventricular dilatation

Objective: The aim of this study was to assess visual function in 13 infants with evidence of prenatal post haemorrhagic ventricular dilatation. Design: Infants were assessed at 5, 12 and...

Accuracy of the Contrast Sensitivity Card Test for Infants: Retest Variability and Prediction of Spatial Resolution

We assessed the retest variability of a new contrast sensitivity (CS) card procedure and its ability to predict spatial resolution. Twenty-four 3-month-olds were tested twice with the CS cards and once with the Teller acuity cards (TAC) within a single session. Coefficient of repeatability (COR) analysis revealed that retest variability of the new cards is superior to that of an earlier prototype at low to mid spatial frequencies. Furthermore, retest variability is comparable to that of infant visual evoked potential studies and the Vistech 6500, a chart commonly used to measure CS in adults. Finally, estimates of visual acuity based on the CS cards were consistent with those provided by the TAC (although CS-based estimates were generally lower overall). Given its reliability and accuracy, the new CS card procedure has good potential as a clinical tool for assessing spatial vision in infants and toddlers.

PC57 VISUAL EVOKED POTENTIALS IN INFANTS AFTER DIETARY SUPPLY OF DOCOSAHEXAENOIC ACID AND 5-METHYL-TETRAHYDROFOLATE DURING PREGNANCY

Introduction: The requirement of docosahexaenoic acid (DHA) is increased during pregnancy. DHA plays an important role in the visual development of infants and it is not proven if various European diets meet the DHA requirements. Supplementation of pregnant women with folic acid might enhance the placental transfer of DHA. Methods: Women recruited in Spain (S) and Germany (G) were randomized to nutritional code A (0,5 g DHA and 0,4 mg methyl-tetrahydrofolate (MTHF)/d), B (0,5 g DHA/d), C (0,4 mg MTHF/d) or D (placebo) from week 20 of gestation until child birth. Infants not fully breastfed were supplied with formulas with or without supplementary DHA according to the nutritional code assigned. Cortical visual evoked potentials (VEPC) were obtained at 8 weeks. Subjects were exposed to an alternating black-and-white checkerboard pattern and P1 latencies and N1-P1 amplitudes at different pattern sizes were measured. The Student t-test (paired test) was performed (p<0.05) using SPSS version 11.5. Results: 249 pregnant women (152 S, 97 G) were recruited and in 168 children (102 S, 35 G) VEPC were obtained. P1 latencies measured at diminishing visual angles were 151.7 ms + 27.8 ms at 2° (S), 162.8 ms + 28.2 ms at 1° (S+G), 172.2 ms + 31.3 ms at 30′ (S), 178.7 ms + 30.6 ms at 20′ (G), 184.6 ms + 29.7 ms at 15′ (S), and 204.5 ms + 49.2 ms at 7.5′ (S). The corresponding amplitudes were 25.0 μV + 11.8 μV at 2° (S), 28 μV + 12.3 μV at 1° (S+G), 23.8 μV + 12.0 μV at 30′ (S), 20.2 μV + 8.7μV at 20′ (G), 16.7μV + 10.2 μV at 15′ (S) and 10.0 μV + 7.2 μV at 7.5′ (S). Statistically significant differences could only be found between nutritional code 3 (158.9 ms + 24.8 ms) and 4 (168.5 ms + 34.0 ms) (S+G) concerning p1 latencies at 1°. Conclusion: There were no statistically significant differences between amplitudes and latencies for the nutritional codes for S and G separately in infants 8 weeks old. Statistically significant differences between two codes was only found for p1 at 1° for S and G together, but it has to be discussed if these are clinically significant. The results are relevant for providing dietary advice in pregnancy as well as for the development of formula meeting physiological needs and as prenatal development influences health in later life, new findings have the potential to improve health on a population-wide basis.

Multicenter trial of early treatment for retinopathy of prematurity: study design

The Early Treatment for Retinopathy of Prematurity (ETROP) study was a randomized, prospective multicenter trial comparing the safety and efficacy of earlier vs. conventionally timed ablation of the peripheral retina for the management of moderate to severe retinopathy of prematurity (ROP). Approximately 7000 infants with birth weights <1251 g were screened at 26 centers over a 2-year period to achieve the sample size of 401 consented infants for the randomized trial. In order to minimize treatment of eyes with ROP that were likely to undergo spontaneous regression of the disease, a risk analysis model, RM-ROP2, was used to select for inclusion in the randomized trial only prethreshold eyes that had a high risk of an adverse outcome. The primary outcome measure was grating visual acuity measured by Teller acuity card testing conducted by masked testers in eyes randomized to earlier treatment vs. eyes randomized to conventional management when infants were 9 months post-term. Results were categorized into favorable (≥1.85 cycles/degree) vs. unfavorable (<1.85 cycles/degree). The secondary outcome measure was retinal structure, assessed by ophthalmological examinations conducted at 6 and 9 months post-term. Here we describe a unique approach used in the ETROP study to select high-risk prethreshold ROP eyes for randomization and details about design of the study. Study results indicated that earlier intervention in selected high-risk prethreshold eyes results in improved vision in premature infants with ROP.

Non-cycloplegic refractive screening can identify infants whose visual outcome at 4 years is improved by spectacle correction

The Second Cambridge Population Infant Vision Screening Programme using the VPR-1 videorefractor without cycloplegia was undertaken in order to identify those infants with refractive errors who were potentially amblyogenic or strabismogenic. Infants identified at eight months were entered into a control trial of treatment with partial spectacle correction and underwent a long-term follow-up that monitored a wide range of visual, visuoperceptual, visuocognitive, visuomotor, linguistic and social development. In the present paper, the authors report on the outcome measures of visual acuity and strabismus. Poor acuity was defined as a best-corrected acuity of 6/12 or worse on crowded letters or 6/9 or worse on single letters, at age 4 years. Acuity was measured in 79 infants who were significantly hyperopic and/or anisometropic at 11-12 months of age, 23 who showed hyperopia of +3D but less than +3.5D, 196 control subjects, 14 controls with refractive errors, and 126 others who showed an accommodative lag on screening but were not significantly hyperopic on first retinoscopy. There was a poorer acuity outcome in the untreated group of hyperopes compared to controls (p < 0.0001) and to the children who were compliant in spectacle wear (p < 0.001) or who were prescribed spectacles (p < 0.05). Children who were significantly hyperopic at eight months were also more likely to be strabismic by 5.5 years compared to the emmetropic control group (p < 0.001). However, the present study did not find a significant difference in the incidence of strabismus between corrected and uncorrected hyperopic infants. Children who were not refractively corrected for significant hyperopia were four times more likely to have poor acuity at 5.5 years than infants who wore their hyperopic correction, supporting the findings of the First Cambridge Population Infant Vision Screening Programme.

Standard full-field electroretinography in healthy preterm infants.

The purpose of this study was to determine electroretinographic parameters according to the standard protocol from the International Society for Clinical Electrophysiology of Vision (ISCEV) in healthy preterm infants with normal fundus. Seventeen healthy preterm infants with normal fundus were recruited and divided in two age groups: 3-week group, nine infants with mean adjusted age at test = 2.67 +/- 0.92 weeks and 8-week group, eight infants with mean adjusted age at test = 7.92 +/- 1.72 weeks. Full-field ERGs were obtained with a Burian-Allen bipolar contact lens electrode from the anesthetized cornea in one eye, through a fully dilated pupil after 30 min of dark adaptation. The standard ISCEV protocol was used and the following responses were recorded: rod, maximal, oscillatory potentials, cone and 30 Hz flicker. Median values and 1st, 5th, 95th and 99th percentiles for amplitude and implicit time are described for both age groups. There was statistically larger amplitude for 30 Hz flicker (t = 2.191; p = 0.046) and for cone response (t = 2.307; p = 0.044) in the 8-week-old group. Statistically shorter implicit times were found in 8-week group for rod response (t = 3.219; p = 0.015), cone response (t = 2.839; p = 0.016) and flicker response (t = 3.326; p = 0.005). Shortening of implicit time was evident in the older group of preterms and this finding is consistent with other maturational studies confirming the anatomical and functional development of the photoreceptors. Medians and ranges between the 1st and 99th and the 5th and 95th percentiles can be used as a baseline for future comparisons with infants with ROP.

Early binocular vision in human infants: limitations on the generality of the Superposition Hypothesis

The Superposition Hypothesis states that the binocular vision of newborn infants blends together the monocular visual responses of the two eyes, even when the visual stimulus evokes binocular rivalry in adults. According to the Superposition Hypothesis, this blending is replaced by binocular rivalry after the emergence of stereopsis [Neonate Cognition: Beyond the Blooming, Buzzing Confusion, Erlbaum, Hillsdale, NJ, 1985, p. 37; Early Visual Development Normal and Abnormal, Oxford University Press, New York, 1993, p. 201]. The main evidence for the Superposition Hypothesis is a preferential looking experiment [Vision Res., 26 (3) (1986) 501], in which 8–12-week-old infants fixated a rivalrous (for adults) dichoptic plaid, in preference over a fusible grating of parallel lines. This report describes our attempt to repeat that important experiment. Infant stereopsis emerged at 8.6 weeks under our conditions, but infants did not preferentially fixate the dichoptic plaid at any age between age 5 and 16 weeks. Control experiments showed that our result was not due to technical differences between their experiment and ours (red/green vs. polarizing glasses, the use of a fixation point, or the infant observation apparatus). Therefore, blending of the visual responses to rivalrous (for adults) stimuli is not a general feature of the pre-stereoptic infant visual system.

A computational model for the biological underpinnings of infant vision and face recognition

A scientists’ challenge is to understand how an infant's brain learns to efficiently process visual information. An infant's range of focus is short for several months, and faces enter into this range more often than any other scene. Within a few months of birth, the brain can differentiate faces from other objects and an infant can recognize a known face from a stranger's. The repetition of face stimulus in conjunction with the relatively short time it takes for recognition to occur suggests there may be more regularity among facial stimuli, or perhaps a more sensitive information processing mechanism biased towards facial stimuli.

Identification of infants with significant refractive error and strabismus in a population screening program using noncycloplegic videorefraction and orthoptic examination.

The second Cambridge Infant Vision Screening Program examined whether screening for accommodative errors by using videorefraction without cycloplegia could effectively serve as a first stage of screening for refractive errors, measured by standard cycloplegic retinoscopy. The screening also included an orthoptic examination for detection of strabismus. All infants born in the Cambridge (UK) Health District, over a 2-year period, were invited for screening. Of those 5142 (76%) with mean age 8.1 +/- 0.8 months (SD) attended and received noncycloplegic videorefraction and an orthoptic examination. All those with a focusing error or orthoptic problem, as well as a randomly selected sample of visually normal control subjects, were invited to follow-up a month later for cycloplegic retinoscopy, repeat noncycloplegic videorefraction and orthoptic examination. Of the 5142 screened, 514 had a focusing error or orthoptic problem (positives). Four hundred thirty-nine of these and 284 visually normal control subjects (negatives) attended follow-up. A refractive or orthoptic condition was confirmed in 59.0% of the positive cases, whereas infants in 96.8% of the negative cases were confirmed normal. Adjusting for the proportions of the population represented by those infants seen at follow-up, sensitivity for the screening procedure was calculated at 0.67 and specificity at 0.96. Detailed results are presented in terms of the different conditions detected at screening (far, near, and anisometropic focus and orthoptic error), distribution of greatest axes at screening, and a comparison of initial videorefraction with repeat videorefraction and cycloplegic retinoscopy. A noncycloplegic screening procedure, simpler to perform than cycloplegic screening, succeeded in detecting a large proportion of infants with significant ametropia, particularly those with significant hyperopia, which is considered to be a strabismogenic and amblyogenic risk factor.

Development of Vision and Visual Notions in Infants

The development of basic visual functions in children of the first year of life—the process of preparation of infants for visual perception has been considered. For children at the age until 2 years there were described stages and age standards of formation of visual notions about shape, size, color of stimuli and about their location and translocation in space. The effect of defects of basic visual functions on formation of visual notions is discussed.

Infant vision screening predicts failures on motor and cognitive tests up to school age

In a population-based infant vision screening programme, 5295 infants were screened and those with significant refractive errors were followed up. To assess the relationship between the development of vision and other domains, we report a longitudinal study comparing infants with significant hyperopia, identified at age 9 months (‘hyperopes’) with infants with normal refractions (‘controls’). Children are included who completed at each age a broad set of visual, cognitive, motor and language measures taken over a series of follow-up visits up to age 5.5 years. Hyperopes performed significantly worse than controls on the Atkinson Battery of Child Development for Examining Functional Vision at 14 months and 3.5 years and the Henderson Movement Assessment Battery for Children at 3.5 and 5.5 years. The Griffiths Child Development Scales, MacArthur Communicative Development Inventory and British Picture Vocabulary Scales showed no significant differences. Exclusion of those infants who became amblyopic and strabismic did not substantially alter these results, suggesting that the differences between groups were not a consequence of these disorders. These results indicate that early hyperopia is associated with a range of developmental deficits that persist at least to age 5.5 years. These effects are concentrated in visuocognitive and visuomotor domains rather than the linguistic domain.

Long-chain polyunsaturated fatty acids in infant nutrition: effects on infant development.

In the past year, two groups of investigators reported the effects of feeding n-3 and n-6 long chain polyunsaturated fatty acids on term-infant development. In general, these small randomised studies, along with two recent large randomised clinical trials, one with preterm and one with term infants, confirm and extend data on efficacy from smaller clinical studies reported in the past ten years. In addition, two independent systematic reviews published this year evaluated all but the most recent studies. Both systematic reviews concluded that there were benefits of feeding long chain polyunsaturated fatty acids to preterm infants in the short-term and acknowledged the absence of studies to address their effects on long-term visual development in infants. The continuing controversy as to the need for long chain polyunsaturated fatty acids by term infants is highlighted by the different conclusions reached in the systematic reviews. A middle view can also be supported by the data; that is, that fewer term infants than preterm infants can benefit from these fatty acids because of greater long chain polyunsaturated fatty acid accumulation in utero. Differences in intrauterine accumulation of these fatty acids may also play a role in inconsistent results among term studies.

Infant vision and retinal function in studies of dietary long-chain polyunsaturated fatty acids: methods, results, and implications

Animal and human studies have documented several effects of different dietary and tissue concentrations of long-chain polyunsaturated fatty acids (LCPUFAs) on retinal function and vision. The enhanced visual development associated with increased intakes of LCPUFAs, particularly docosahexaenoic acid (DHA), provides the strongest evidence for the importance of these fatty acids in infant nutrition. The 2 primary visual measures used to assess the efficacy of infant formula LCPUFA supplementation are the electroretinogram and visual acuity. This review briefly describes the methodology, neural basis, and interpretation of these measures, as well as other measures of visual development that may be used to extend the functional evaluation of infants fed formulas with different fatty acid compositions.

Fatty Acid Composition of Breast Milk from Low Income Lactating Mothers in Lubbock, Texas

Fatty acids in the n - 3 series are important in neurological and visual development in infants. The objective of this study was to evaluate fatty acid composition in the milk of lactating women from an inland area of Texas where fish consumption is rare.Methods; Twenty two breast feeding women had breast milk samples taken in a uniform manner 8 to 11 days after the birth of healthy infants. Gas chromatography was used to measure the fatty acid composition of the milk. Subjects completed a food frequency questionnaire and a 24 hour food record.Results; Nineteen of the women reported that they never eat fatty fish while the remaining women reported consumption at 1 time per year. Other characteristics of the diets of these women were low fruit and vegetable consumption (mean of 2 servings per day) and low milk consumption (mean of 1.25 servings per day). The percent of decosahexanoic acid (DHA) in the milk of these women was 0.08 ± 0.01% as compared to 0.2 to 0.4% reported in other studies. Linoleic, alpha linolenic and other fatty acids measured had values similar to those reported in the literature.Conclusions; Diets of low income women in Lubbock, Texas do not meet recommended number of servings of fruits, vegetables and milk and contain little fish. The low fish consumption appear to be reflected in the below expected levels of DHA in the breast milk.