Acuity In Infants Research Articles

Visual and refractive outcome after 12 years of treatment of type 1 prethreshold retinopathy of prematurity

Aim: In this study, the best corrected visual acuity (BCVA) and refraction in preterm-born infants in South-Eastern Bulgaria after 12 years of treatment for type 1 prethreshold retinopathy of prematurity were presented, and the outcomes of laser treatment and cryotherapy were compared. Materials and methods: Since 2010, we have treated 319 eyes of 164 prematurely born children for type 1 prethreshold retinopathy of prematurity and were prospectively followed up. The mean (range) gestational age was 28.6 weeks of gestation (23–33) and the mean (range) birth weight was 1143 g (570–1990). Cryotherapy was applied on 76 eyes (23.2%), laser was used in 215 eyes (65.5%), anti-VEGF – in 10 eyes (3%) and surgery – in 18 eyes (5.5%). Twelve children (24 eyes, 7.3%) were lost to the follow-up. BCVA was tested in 114 eyes and refraction in 190 eyes. Because of the small number of eyes treated surgically or with anti-VEGF (18 and 10, respectively), these children’s eyes were excluded from the statistical analysis. Results: Fifty eyes showed BCVA between 0.6 and 1.0; 25 eyes – between 0.2 and 0.5; 5 eyes – between 0.04 and 0.1; 5 eyes between light perception –0.03 and 4 eyes were totally blind. Laser-treated eyes showed statistically significantly higher BCVA compared to the cryotherapy treated eyes (Fisher’s exact test, p=0.012). Myopia (any myopic refraction) was found in 50 eyes; hyperopia (>+2 D) – in 20 eyes; astigmatism (difference between the two principal meridians >0.75 D) – in 70 eyes, and emmetropia – in 30 eyes. Although in the laser-treated group more eyes showed emmetropic and hyperopic refraction compared to cryo treated group (25 eyes vs. 7 eyes – emmetropia and 15 eyes vs. 5 eyes – hyperopia, respectively), the difference did not reach statistical significance (Fisher’s exact test, p=0.106). Conclusion: Timely treatment of type 1 prethreshold retinopathy of prematurity leads to very good anatomical and functional results. Laser treatment leads to significantly higher BCVA, compared to cryotherapy. Emmetropia and hyperopia are more commonly seen in laser-treated eyes.

Visual Acuity Thresholds in Preterm Newborns: An Experimental Study.

Purpose: Visual acuity plays a role in mediating neurological development in infants by enabling the differentiation of shapes and discriminating objects. Given the rapid structural development of the brain in the first days of life, this aspect is particularly significant for preterm infants, who typically experience this developmental phase while hospitalized in the neonatal intensive care unit (NICU). Therefore, this study aimed to assess visual acuity thresholds in preterm infants during hospitalization and to evaluate possible correlations between visual acuity and clinical parameters. Methods: A cross-sectional study was conducted in an NICU in Northeast Brazil. The visual acuity thresholds were tested using the Teller Acuity Cards II, comprised of 17 gray cards, with one 4 mm diameter peephole at the center and presented with about 35% reflectance. Preterm infants were positioned supine, at 30° elevation on the laps of their caregivers. The evaluator presented both sides of the cards and observed the eye fixation and reactions on both sides. Results: A total of 42 preterm infants with corrected gestational age between 30 to 36 weeks and 6 days were included. Visual acuity ranged from 0.23 to 0.64 cycle per degree. The mean visual acuity threshold was 0.32 cycles per degree for preterm infants at around 32 weeks of corrected gestational age. The visual acuity was not correlated with gestational age (p = 0.18), and neither were birth weight (p = 0.83) or duration of respiratory support (p = 0.98). However, days of phototherapy were inversely correlated with visual acuity (p = 0.04). Conclusions: Despite the challenges of hospitalization, it was possible to carry out a psychophysical test to assess visual acuity in preterm infants. The visual acuity showed no correlation with clinical parameters such as gestational age, birth weight, and duration of respiratory support. However, there was an inverse correlation between the number of days in phototherapy and visual acuity. Understanding the visual acuity levels in preterm infants during their NICU stay can contribute to tailoring interventions and care strategies that specifically address their visual developmental needs. This knowledge may guide healthcare professionals in optimizing the NICU environment to provide appropriate visual stimuli that support neurological development.

Оценка фовеальной гипоплазии у недоношенных детей как прогностический фактор формирования центрального зрения

Original article Assessment of foveal hypoplasia in premature infants as a prognostic factor in the formation of central vision R. Atamuradov, I.B. Astasheva, M.R. Guseva, V.V. Marenkov, Yu.A. Kyun, A.R. Baranova Pirogov Russian National Research Medical University, Moscow, Russian Federation Yudina City Clinical Hospital, Moscow, Russian Federation Morozov Children’s City Clinical Hospital, Moscow, Russian Federation Purpose. Assessment of foveal hypoplasia (FH) in premature infants as a prognostic factor in the formation of central vision. Material and methods. We’ve examined 61 patients (118 eyes) aged 8.83±3.5 years who were born prematurely (gestational age 24–34 weeks, birth weight 690–2,700 grams). Among the preterm infants, 22 (36%) had a history of spontaneous regression of retinopathy of prematurity (ROP), 31 (51%) had laser retinal photocoagulation for ROP and 8 (13%) preterm patients were without ROP. All children were assessed for the best corrected visual acuity (BCVA) according to the Sivtsev and Orlova tables, optical coherence tomography (OCT), and registration of visual evoked potentials (VEP). Results. We have noted 4 degrees of FH in preterm infants: 1st degree – no extrusion of plexiform layers, foveal depression is significant (BCVA on average 0.91±0.1); 2nd degree – mild foveal depression, no extrusion of plexiform layers (BCVA on average 0.83±0.2); 3rd degree – absence of foveal depression and extrusion of plexiform layers, elongation of photoreceptor outer segments and thickening of the outer nuclear layer were observed (BCVA on average 0.7±0.2); 4th degree – foveal depression, extrusion of plexiform layers and elongation of photoreceptor outer segments are absent, thickening of the inner nuclear layer is preserved (BCVA on average 0.4±0.2). A significant difference of BCVA from the norm was noted at 4th degree (p<0.05). Conclusion. Different degrees of FH have been identified, which can be used as a prognostic factor of visual acuity in premature infants. An uncorrectable decrease in visual acuity can be expected in children with 4th degree FH. Key words: foveal hypoplasia (FH), retinopathy of prematurity (ROP), optical coherence tomography (OCT), macula, visual evoked potentials (VEP)

Prenatal fluoride exposure, offspring visual acuity and autonomic nervous system function in 6-month-old infants

BackgroundPrenatal fluoride exposure can have adverse effects on children’s development; however, associations with visual and cardiac autonomic nervous system functioning are unknown. We examined associations between prenatal fluoride exposure and visual acuity and heart rate variability (HRV) in 6-month-old infants. MethodsWe used data from Canadian mother-infant pairs participating in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. We estimated prenatal fluoride exposure using: i) fluoride concentration in drinking water (mg/L), ii) maternal urinary fluoride adjusted for specific gravity (MUFSG; mg/L) and averaged across pregnancy, and iii) maternal fluoride intake (µg/kg/day) from consumption of water, tea, and coffee, adjusted for maternal body weight (kg). We used multivariable linear regression to examine associations between each measure of fluoride exposure and Teller Acuity Card visual acuity scores (n = 435) and assessed HRV (n = 400) using two measures: root mean square of successive differences (RMSSD) and the standard deviation of N-N intervals (SDNN) measured at 6-months of age. ResultsMedian (IQR) values for water fluoride, MUFSG, and daily fluoride intake were 0.20 (IQR: 0.13–0.56) mg/L; 0.44 (0.28–0.70) mg/L and 4.82 (2.58–10.83) µg/kg/day, respectively. After adjustment for confounding variables, water fluoride concentration was associated with poorer infant visual acuity (B = -1.51; 95 % CI: −2.14,-0.88) and HRV as indicated by lower RMSSD (B = -1.60; 95 % CI: −2.74,-0.46) but not SDNN. Maternal fluoride intake was also associated with poorer visual acuity (B = -0.82; 95 % CI: −1.35,-0.29) and lower RMSSD (B = -1.22; 95 % CI: −2.15,-0.30). No significant associations were observed between MUFSG and visual acuity or HRV. ConclusionFluoride in drinking water was associated with reduced visual acuity and alterations in cardiac autonomic function in infancy, adding to the growing body of evidence suggesting fluoride's developmental neurotoxicity.

Chinese expert consensus on the visual acuity testing for infants and preverbal children (2023)

Abnormal visual experience in the first 3 years of life may lead to permanent visual impairment without early screening and timely intervention. It is of great clinical significance to evaluate the visual acuity of infants and preverbal children with suspected visual abnormality. However, the evaluation is difficult due to the inability of these children to express their complaints and the lack of unified standards. In order to promote the standardization of the visual acuity testing in infants and preverbal children, including the screening and follow-up examinations, a consensus has been reached by the Chinese Association for Pediatric Ophthalmology and Strabismus along with the Pediatric Ophthalmology and Strabismus Group of Chinese Ophthalmologist Association, based on the research results of evidence-based medicine.

A prospective cohort study on visual development in infants and young children

Objective: This study aimed to analyze the trends and characteristics of early visual development in infants and young children. Methods: A prospective cohort study was conducted, including full-term infants born between 2008 and 2013 at the Maternal and Child Health Hospital in Sanhe City, Hebei Province, China. Visual acuity was assessed at three time points 42 days after birth, 9 months of age, and 18 months of age, using the Teller Acuity Card Ⅱ (TAC Ⅱ) grating visual acuity test. At 3 years of age, visual acuity was assessed using the Lea Symbols chart and converted to grating visual acuity. Visual acuity of both eyes was measured at 42 days, 9 months, and 18 months. For children at 9 and 18 months, monocular visual acuity was also assessed, while at 3 years of age, monocular visual acuity was measured. Visual acuity measurements at different time points and changes in visual acuity within each period were recorded. The visual development of the participants was analyzed and compared with previous literature results. Results: A total of 1 496 children were included in the study, including 773 males (51.67%) and 723 females (48.33%). The binocular visual acuity at 42 days, 9 months, and 18 months was 0.9 (0.6, 1.1), 6.4 (6.4, 9.6), and 9.6 (9.6, 9.6) cycles per degree (cpd), respectively, with statistically significant differences (P<0.001). Visual acuity increased by a factor of 3.21±0.70 between 42 days and 9 months, and by a factor of 0.23±0.48 between 9 and 18 months. At 9 months of age, the monocular visual acuity in the right and left eyes was 6.4 (4.8, 6.4) cpd, which remained the same at 18 months, and the median visual acuity at 3 years of age for both eyes was 18.75 cpd, with a Snellen visual acuity of 20/32 (20/40, 20/32). The differences in binocular visual acuity at each time point were not statistically significant (all P>0.05). At 9 months of age, 68.7%(633/921) of children had visual acuity of ≥6.5 cpd, which increased to 92.7%(342/369) at 18 months. Monocular visual acuity increased by a factor of 0.26±0.46 between 9 and 18 months, and by a factor of 1.36±0.52 between 18 months and 3 years. At 9 months of age, 72.01% (921 out of 1 279) of children who completed binocular visual acuity testing also underwent monocular visual acuity testing, while this proportion decreased to 35.83% (369 out of 1 030) at 18 months. Visual acuity improved with increasing age (P<0.001). The visual acuity of children at each age group in this study was higher than that reported in the literature for children in Guangzhou (P<0.001). Conclusions: The visual acuity of healthy infants and young children below 3 years of age improves with age. Visual development progresses rapidly before 9 months of age, slows down afterward, and then resumes rapid growth at 18 months of age.

Association between prenatal exposure to trace elements mixture and visual acuity in infants: A prospective birth cohort study

BackgroundPrenatal environmental factors may affect the development of the offspring and can bring long lasting consequences to the offspring's health. To date, only few studies have reported inconclusive association between prenatal single trace element exposure and visual acuity, and no studies have investigated the association between prenatal exposure to trace elements mixture and visual acuity in infants. MethodsIn the prospective cohort study, grating acuity in infants (12 ± 1 months) was measured by Teller Acuity Cards II. Concentrations of 20 trace elements in maternal urine samples collected in early-trimester were measured by Inductively Coupled Plasma Mass Spectrometry. Elastic net regression (ENET) was applied to select important trace elements. Nonlinear associations of the trace elements levels with abnormal grating were explored using the restricted cubic spline (RCS) method. The associations between selected individual elements and abnormal grating acuity were further appraised using the logistic regression model. Then Bayesian Kernel Machine Regression (BKMR) was used to estimate the joint effects of mixture and interactions between trace elements combining with NLinteraction. ResultsOf 932 mother-infant pairs, 70 infants had abnormal grating acuity. The ENET model produced 8 trace elements with non-zero coefficients, including cadmium, manganese, molybdenum, nickel, rubidium, antimony, tin and titanium. RCS analyses identified no nonlinear associations of the 8 elements with abnormal grating acuity. The single-exposure analyses using logistic regression revealed that prenatal molybdenum exposure possessed a significantly positive association with abnormal grating acuity (odds ratio [OR]: 1.44 per IQR increase, 95% confidence interval [CI]: 1.05, 1.96; P = 0.023), while prenatal nickel exposure presented with a significantly inverse association with abnormal grating acuity (OR: 0.64 per IQR increase, 95% CI: 0.45, 0.89; P = 0.009). Similar effects were also observed in BKMR models. Moreover, the BKMR models and NLinteraction method identified potential interaction between molybdenum and nickel. ConclusionsWe established that prenatal exposure to high concentration of molybdenum and low concentration of nickel was associated with the increased risk of abnormal visual acuity. Potential interaction may exist between molybdenum and nickel on abnormal visual acuity.

An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System.

Visual acuity measurement is an important visual function test to perform in infancy and childhood. However, accurate visual acuity measurement in infants is difficult because of deficiencies in their communication ability. This paper presents a novel automated method to assess visual acuity in children (5-36 months old). This method, the automated acuity card procedure (AACP), uses a webcam for eye tracking and recognizes children's watching behaviors automatically. A two-choice preferential-looking test is performed when the tested child watches the visual stimuli shown on a high-resolution digital display screen. When the tested child watches the stimuli, their facial pictures are recorded by the webcam. These pictures are used by the set computer program to analyze their watching behavior. With this procedure, the child's eye movement responses to different stimuli are measured, and their visual acuity is assessed without communication. By comparing the results with grating acuity obtained by Teller Acuity Cards (TACs), AACP performance is deemed comparable to that of TACs.

Automated assessment of grating acuity in infants and toddlers using an eye-tracking system.

The purpose of this study was to assess the feasibility of testing binocular visual acuity using the automated acuity card procedure (AACP)-a new automated method that uses an eye-tracking system. We included participants aged 5 to 36 months old. Binocular grating acuity was tested using the AACP and Teller Acuity Cards (TACs) with a uniform testing distance (55 cm) in random order. Electronic stimuli in the AACP were similar in size and form to TACII and roughly equivalent to the printed TACII stimuli. The AACP tracked the participant's gaze from the recorded image sequences and automatically determined the grating acuity. Differentiation, correlation, and consistency were compared between the AACP and TACs. Ultimately, 77.11% (155/201) of participants completed both tests. Fewer participants failed the TAC test than the AACP (15 [7.46%] vs. 31 [15.42%]). The average duration of the AACP (median interquartile range [IQR] = 60 [IQR = 41] seconds) was significantly shorter than that of the TAC (median [IQR], 185 [IQR = 66] seconds, p < 0.001). AACP and TAC visual acuities were robustly correlated (r = 0.83, p < 0.001). Bland-Altman plots revealed a mean difference between AACP and TAC visual acuities of 0.10 cycles per degree (cpd; 95% limits of agreement = 7.70 cpd). Both the AACP and TACs indicated improved visual acuity with age progression (both, p < 0.001), with no significant differences between the tests. Electronic stimuli were presented using the AACP yielded clinically useful data on grating acuity in infants and toddlers. AACP performance was comparable to that of TACs, the current clinical gold standard for assessing infant vision regarding testability, reliability, and accuracy.

Prognostic value of transient pattern visual evoked potentials in children with cerebral visual impairment.

To investigate whether pattern reversal visual evoked potentials (PRVEPs) could predict future visual acuity in infants with cerebral visual impairment (CVI). Fifty-five children (27 males, 28 females) with severe CVI seen in the ophthalmology department of a specialist children's hospital were identified retrospectively. Behavioural visual acuity and visual evoked potentials (VEPs) at presentation (time 1, T1) were compared with final visual acuity at late preschool/early school age (time 2, T2). Predictors of visual acuity at T2 were identified using univariate and multivariate logistic and linear regression analysis. Median age was 14 months at T1 (range: 6-44mo) and 63 months at T2 (range: 29-150mo). The presence of a PRVEP produced by a check width of 50' (minutes of arc) or smaller (T1) predicted (p=0.05) the presence of measurable preferential looking acuity at T2. The presence of PRVEP to check widths of 25' or smaller (T1) predicted (p=0.02) better preferential looking acuity (logMAR-equivalent) scores at T2. The latter association was independent of presenting acuity at T1. The presence of PRVEPs to check widths of 50' and 25' in infancy provided useful information. VEPs in young children with CVI may have prognostic value regarding future acuity.

Is initial training with blurry images beneficial for the development of object recognition systems?

A recent study claimed that the initially poor visual acuity of infants might be critical for the visual system to learn to integrate information over larger spatial scales. Specifically, when convolutional neural networks (CNNs) were initially trained on blurry face images, followed by progressively clearer images, the CNN acquired robustness to variations in spatial resolution (Vogelsang et al., 2018). Here, we asked whether initial training with blurry images would confer a similar benefit to general object recognition, possibly offering a clue to the robust nature of human vision. To evaluate this question, we trained AlexNet with 1,000 ImageNet object categories in which the resolution of inputs was gradually increased over training epochs. Although training with blurry objects initially led to good performance on blurry test images, such robustness to blur soon disappeared after training with clear images. These findings deviated from the robustness to blur that occurred for a CNN trained with face images. Curiously however, we found that a CNN trained concurrently on faces and objects, progressing from blurry to clear, lost the ability to recognize both blurry faces or objects. This problem of catastrophic forgetting can be attributed to the fact that proportionally greater discriminating information resides in the higher spatial frequencies of objects as compared to faces. As the CNN learns to leverage this finer scale information, it tends to lose the ability to leverage information at coarser spatial scales for both objects and faces. While our findings do not rule out the possibility that poor initial acuity might lead to important developmental benefits in face recognition ability, they do bring into question whether people’s ability to recognize blurry faces and objects in adulthood can be explained by these early experiences alone.

Chronic nutritional restriction of omega-3 fatty acids induces a pro-inflammatory profile during the development of the rat visual system

Modern western diets have been associated with a reduced proportion of dietary omega-3 fatty acids leading to decreased levels of DHA (docosahexaenoic acid) in the brain. Low DHA content has been associated with altered development of visual acuity in infants and also with an altered time course of synapse elimination and plasticity in subcortical visual nuclei in rodents. Microglia has an active role in normal developmental processes such as circuitry refinement and plasticity, and its activation status can be modulated by omega-3 (ω3) and omega-6 (ω6) essential fatty acids. In the present study, we investigated the impact of dietary restriction of DHA (ω3−), through the chronic administration of a coconut-based diet as the only fat source. This dietary protocol resulted in a reduction in DHA content in the retina and superior colliculus (SC) and in a neuroinflammatory outcome during the development of the rodent visual system. The ω3− group showed changes in microglial morphology in the retina and SC and a corresponding altered pattern of pro-inflammatory cytokine expression. Early and late fish oil protocols supplementation were able to restore DHA levels. The early supplementation also decreased neuroinflammatory markers in the visual system. The present study indicates that a chronic dietary restriction of omega-3 fatty acids and the resulting deficits in DHA content, commonly observed in Western diets, interferes with the microglial profile leading to an inflamed microenvironment which may underlie a disruption of synapse elimination, altered topographical organization, abnormal plasticity, and duration of critical periods during brain development.

Imaging the pediatric retina: An overview.

Recent decade has seen a shift in the causes of childhood blinding diseases from anterior segment to retinal disease in both developed and developing countries. The common retinal disorders are retinopathy of prematurity and vitreoretinal infections in neonates, congenital anomalies in infants, and vascular retinopathies including type 1 diabetes, tumors, and inherited retinal diseases in children (up to 12 years). Retinal imaging helps in diagnosis, management, follow up and prognostication in all these disorders. These imaging modalities include fundus photography, fluorescein angiography, ultrasonography, retinal vascular and structural studies, and electrodiagnosis. Over the decades there has been tremendous advances both in design (compact, multifunctional, tele-consult capable) and technology (wide- and ultra-wide field and noninvasive retinal angiography). These new advances have application in most of the pediatric retinal diseases though at most times the designs of new devices have remained confined to use in adults. Poor patient cooperation and insufficient attention span in children demand careful crafting of the devices. The newer attempts of hand-held retinal diagnostic devices are welcome additions in this direction. While much has been done, there is still much to do in the coming years. One of the compelling and immediate needs is the pediatric version of optical coherence tomography angiography. These needs and demands would increase many folds in future. A sound policy could be the simultaneous development of adult and pediatric version of all ophthalmic diagnostic devices, coupled with capacity building of trained medical personnel.

Presentation acuity, induction mortality, and resource utilization in infants with acute leukemia.

Treatment of infants with acute leukemia remains challenging, especially for acute lymphocytic leukemia (ALL). Infants have shown markedly higher rates of induction mortality compared with noninfants. There are limited data on presentation acuity and supportive care utilization in this age group. In retrospective analyses of patients treated for new onset ALL or acute myeloid leukemia (AML) at pediatric hospitals contributing to the Pediatric Health Information System, we compared presentation acuity, induction mortality, and resource utilization in infants relative to noninfants less than 10years at diagnosis. Analyses included 10359 children with ALL (405 infants, 9954 noninfants) and 871 AML (189 infants, 682 noninfants). Infants were more likely to present with multisystem organ failure compared to noninfants for both ALL (12% and 1%, PR=10.8, 95% CI: 7.4, 15.7) and AML (6% vs. 3%; PR=2.0, 95% CI: 1.0, 3.7). Infants with ALL had higher induction mortality compared to noninfants, even after accounting for differences in anthracycline exposure and presentation acuity (2.7% vs. 0.5%, HR=2.1, 95% CI: 1.0, 4.8). Conversely, infants and noninfants with AML had similar rates of induction mortality (3.2% vs. 2.1%, HR=1.2, 95% CI: 0.3, 3.9), which were comparable to rates among infants with ALL. Infants with ALL and AML had greater requirements for blood products, diuretics, supplemental oxygen, and ventilation during induction relative to noninfants. Infants with leukemia present with higher acuity compared with noninfants. Induction mortality and supportive care requirements for infants with ALL were similar to all children with AML, and significantly higher than those for noninfants with ALL.

Study to establish visual acuity norms with Teller Acuity Cards II for infants from southern China

ObjectivesTo establish the norms of binocular and monocular acuity and interocular acuity differences for southern Chinese infants and compare these norms with the results for northern Chinese infants.MethodsA prospective, comparative, and noninterventional study was conducted from January to August 2018. Teller Acuity Cards II were used to determine the binocular and monocular acuity of infants. The tolerance intervals and limits with a stated proportion and probability were used to evaluate the norms of binocular and monocular acuity and interocular acuity differences. An unpaired t-test was used to compare the obtained norms with the reported northern Chinese norms.ResultsThe tolerance intervals of binocular acuity (mean acuity of 3.73, 7.35, and 12.01 cpd, respectively, at 12, 24, and 36 months), monocular acuity (mean acuity of 2.88, 6.91, and 10.75 cpd, respectively, at 12, 24, and 36 months), and interocular acuity differences (mean difference of 0.92, 2.89, and 3.99 cpd, respectively, at 12, 24, and 36 months) were obtained, exhibiting an increasing trend with age. The binocular visual acuity norms of southern Chinese infants were significantly lower than those in northern China (4.37 vs. 6.9 cpd at 8 months and 7.35 vs. 26 cpd at 24 months) (P = 0.011).ConclusionsNorthern and southern Chinese infants exhibited distinct acuity norms and visual development patterns. The establishment of population-specific visual acuity norms is necessary for current populations of infants from different regions.

Alterations in visual acuity and visual development in infants 1-24 months old either exposed to or infected by Zika virus during gestation, with and without microcephaly

To evaluate visual acuity and visual acuity development in children from the state of São Paulo, Brazil, who were exposed to the Zika virus (ZIKV) gestationally. Children who had been exposed to ZIKV during gestation and age-matched control subjects received visual acuity and funduscopic examination. ZIKV exposure was confirmed by maternal quantitative polymerase chain reaction testing or serology assay. The ZIKV group was divided into two subgroups: exposed (ZE), with only the mother having confirmed ZIKV infection, and infected (ZI), with confirmed infection. Visual acuity development was compared with prior norms and quantified by measuring visual acuity correlation with age. A total of 110 children were included: 47 who had been exposed to ZIKV (ZE, 23; ZI, 24) and 63 controls. Abnormal visual acuity was found in 5 of 24 ZI children. Of the 4 children with microcephaly, only 2 had visual acuity loss (only 1 also had abnormal funduscopic findings). There was significant correlation between age and visual acuity in both the control group (R2=0.8; P<0.0000) and the ZE subgroup (R2=0.6; P<0.0000). However, visual acuity did not correlate with age in the ZI subgroup (R2=0.04; P=0.38). Furthermore, the increment in octaves/month was much lower in the ZI subgroup. Our data indicate that visual acuity losses only occur in infants who suffered gestational-infection, not simply exposure. Lack of correlation between age and visual acuity in the ZI subgroup suggests a slowing of visual development even in the absence of microcephaly. This result may have broad implications for the deleterious effects of ZIKV on the central nervous system.

Visual Maturation at Term Equivalent Age in Very Premature Infants According to Factors Influencing Its Development.

Introduction: Visual impairment is a concern in premature infants as perinatal factors may alter maturation during visual development. This observational study aimed at evaluating visual maturation at term equivalent age and factors associated with impaired visual maturation.Methods: Infants born before 32 weeks’ gestation were evaluated with routine brain MRI, visual acuity, refraction, fundus, and clinical eye examination. Environmental factors were collected from infant’s files.Results: Fifty-four infants (29.5 ± 1.7 weeks’ gestation, birth weight 1194 ± 288 g) were studied at term equivalent age. Visual acuity was higher in premature infants at term equivalent age than in a reference publication with the same method in term newborns at birth (1.54 ± 0.67 vs. 0.99 ± 0.40 cycles/degree, p = 0.008). In multivariate analysis, abnormal brain MRI was the only factor associated with visual acuity (r2= 0.203; p = 0.026). Incomplete retinal vascularization was observed in 29/53 of infants at term equivalent age and associated with MRI abnormalities of the posterior fossa (p = 0.027) and larger refractive sphere difference between both eyes (1.2 ± 0.8 vs. 0.6 ± 0.4 diopters; p = 0.0005). Retinopathy of prematurity was associated with indices of smaller cerebral volume (p = 0.035).Conclusion: Higher visual acuity in premature infants at term equivalent age than in term newborns at birth may be related to longer visual experience from birth. Lower visual acuity was correlated with abnormal MRI in preterm infants at term equivalent age.

Neonatal Contrast Sensitivity and Visual Acuity: Basic Psychophysics.

PurposeThis research was prospectively designed to determine whether a 0.083 cycles per degree (cy/deg) (20/7200) square-wave stimulus is a good choice for clinical measurement of newborn infants' contrast sensitivity and whether the contrast sensitivity function (CSF) of the newborn infant is band-pass. The results were retrospectively analyzed to determine whether the method of constant stimuli (MCS) and the descending method of limits (dLIM) yielded similar results.MethodsIn across-subjects experimental designs, a pilot experiment used MCS (N = 47 visual acuity; N = 38 contrast sensitivity at 0.083 cy/deg), and a main experiment used dLIM (N = 22 visual acuity; N = 22 contrast sensitivity at 0.083 cy/deg; N = 21 at 0.301 cy/deg) to measure visual function in healthy newborn infants. Three candidate CSFs estimated maximum neonatal contrast sensitivity. MCS and dLIM psychometric functions were compared while taking the stimulus presentation protocols into account.ResultsThe band-pass CSF fit the data best, with a peak sensitivity near 0.31 at 0.22 cy/deg. However, the 0.083 cy/deg square-wave stimulus underestimated the best performance of newborn infants by less than 0.15 log10 units. MCS and dLIM data agreed well when the stimulus presentation contingencies were taken into account.ConclusionsNewborn contrast sensitivity is well measured using a 0.083 cy/deg square-wave target, regardless of which CSF shape is correct. MCS and dLIM yield wholly comparable results, with no evidence to suggest effects of other factors such as infant inattention or examiner impatience.Translational RelevanceThese measurements open the way for clinical behavioral measurement of infant visual acuity and contrast sensitivity in the neonatal period.

Changes in the central nervous system of prematurely born children.

Preterm birth adversely affects the maturation of the central nervous system, including the process of white matter myelination, still incomplete at this stage. Prematurity is also a risk factor for the future visual impairment. Decreased visual acuity in premature infants observed during their development, may be caused by both retinopathy of prematurity and the damage to the central nervous system. Owing to the development of new magnetic resonance imaging techniques such as diffusion imaging and diffusion tensor imaging, a detailed evaluation of changes to the cerebral white matter microstructure is now possible. As postulated in the newly published literature, ocular pathologies in premature infants may be related to abnormalities within the corpus callosum. Modern imaging techniques prove to be of the essencewhen facing diagnostic challenges in premature infants presenting with visual disturbances.

Maturation of Binocular, Monocular Grating Acuity and of the Visual Interocular Difference in the First 2 Years of Life.

The sweep visual evoked potential method (sVEP) is a powerful tool for measurement of visual acuity in infants. Despite the applicability and reliability of the technique in measuring visual functions the understanding of sVEP acuity maturation and how interocular difference of acuity develops in early infancy, as well as the availability of normality ranges, are rare in the literature. We measured binocular and monocular sVEPS acuities in 481 healthy infants aged from birth to 24 months without ophthalmological diseases. Binocular sVEP acuity was significantly higher than monocular visual acuities for almost all ages. Maturation of monocular sVEP acuity showed 2 longer critical periods while binocular acuity showed three maturation periods in the same age range. We found a systematic variation of the mean interocular acuity difference (IAD) range according to age from 1.45 cpd at birth to 0.31 cpd at 24 months. An additional contribution was the determination of sVEP acuity norms for the entire age range. We conclude that binocular and monocular sVEP acuities have distinct growth curves reflecting different maturation profiles for each function. Differences in IAD range shorten according to age and they should be considered in using the sVEP acuity measurements for clinical diagnosis as amblyopia.