[Light pollution]. / Pollution lumineuse.

LIGHT POLLUTION Artificial light can be a polluting agent deleterious for the retina, in relation to the toxicity of the blue band (380-500 nm) of the visible spectrum (380-700nm) specifically used in light-emitting diodes (LEDs). Photo-toxicity results from photochemical damage to the pigmented epithelium and retinal photoreceptors responsible for the visual function of the retina. Their photosensitive pigments, opsins for the cones and rhodopsin for the sticks, are consumed during the day and regenerated at night. Exposure to light at night seriously disrupts their metabolism. Photo-toxicity, along with heredity, is a major factor in degenerative diseases of the retina with, in addition to, the impact of age and tobacco for the most common of them, age-related macular degeneration: ARMD.Exposure to artificial light at night (LAN) has a deleterious effect on the internal clock. Intrinsically photosensitive ganglion cells (ipRGSs) are responsible for the non-visual functions of the retina, and perceive the light signal that is transmitted to the internal clock to reach the pineal gland. Light inhibits the secretion of melatonin and is able to advance or delay the clock depending on the time of exposure, causing desynchronization. Shift and night workers, like teenagers, are exposed to LAN. The incidence of breast cancer, higher in nurses exposed to LAN, is related to melatonin inhibition, sleep deprivation and desynchronization. The exposure of adolescents to screens is also questionable because the LEDs of the devices emit a blue light, the impact of which on the clock is considerable. The chronic desynchronizations of both shiftworkers and adolescents should be considered a major public health concern.

POLLUTION LUMINEUSE La lumière artificielle peut être un agent polluant délétère pour la rétine, en rapport avec la toxicité de la bande bleue (380-500 nm) du spectre visible (380-700 nm), notamment utilisée dans les diodes électroluminescentes (LED). La phototoxicité résulte de lésions photochimiques au niveau de l'épithélium pigmenté et des photorécepteurs rétiniens responsables de la fonction visuelle de la rétine. Leurs pigments photosensibles, opsines pour les cônes et rhodopsines pour les bâtonnets, sont consommés le jour et régénérés la nuit. L'exposition à la lumière la nuit perturbe gravement leur métabolisme. La phototoxicité constitue, avec l'hérédité, un facteur majeur pour les maladies dégénératives de la rétine avec, en plus, l'impact de l'âge et du tabac pour la plus fréquente d'entre elles, la dégénérescence maculaire liée à l'âge (DMLA). L'exposition à la lumière artificielle la nuit (LAN) dérègle l'horloge interne. Les cellules ganglionnaires intrinsèquement photosensibles (ipRPC), responsables des fonctions non visuelles de la rétine, perçoivent le signal lumineux qui est transmis à cette l'horloge interne pour aboutir à la glande pinéale. La lumière inhibe la sécrétion de mélatonine et est capable d'avancer ou de retarder l'horloge selon l'heure d'exposition, dans le cadre d'une désynchronisation. Les travailleurs postés et de nuit, comme les adolescents, sont exposés à la LAN. L'incidence de cancer du sein, plus élevée chez les infirmières exposées à la LAN, est attribuée à l'inhibition de la mélatonine, la privation de sommeil et la désynchronisation. L'exposition des adolescents aux écrans pose aussi question, car les diodes électroluminescentes (LED) des appareils émettent une lumière bleue dont l'impact sur l'horloge interne est considérable. Les désynchronisations chroniques des travailleurs postés, comme celles des adolescents, doivent être considérées comme des préoccupations importantes de santé publique.

Recurrent lacrimal gland choristoma of the ciliary body in an infant mimicking a medulloepithelioma.

PURPOSE: Choristoma is a congenital tumor made up of ectopic normal tissue. Different histopathologic subtypes have been described. Among them, lacrimal gland choristoma is found mainly in infants and can affect the iris, the ciliary body, or the choroid and epibulbar region. Our aims were to report a case of lacrimal gland choristoma, review the published cases, and present the main differential diagnoses. METHODS: A local resection of a limited mass of the ciliary body was performed on a 12-month-old girl who had a 6-month history of visual loss, leukocoria, and pupillary deformation. RESULTS: Histopathologically, we observed a well-demarcated lesion involved under the epithelium of the ciliary body. It was composed of acini delineated by a well-differentiated epithelium without atypia and mitotic figures. Immunohistochemical analyses confirmed the lacrimal nature with the expression of epithelial markers (cytokeratin 7 positive and cytokeratin 20 negative) and neuron-specific enolase without immunoreactivity for other neuronal markers. Two years later, a local recurrence appeared and was resected. It showed nearly the same histopathologic features. CONCLUSIONS: Lacrimal gland choristoma is a very rare lesion of the infant. Diagnosis is based on a histopathologic analysis with immunohistochemical studies to exclude other differential diagnoses such as a more common malignant tumor in childhood, medulloepithelioma. This observation shows an atypical clinical presentation of this benign lesion characterized by local recurrences.

Targeted resequencing identifies PTCH1 as a major contributor to ocular developmental anomalies and extends the SOX2 regulatory network.

Ocular developmental anomalies (ODA) such as anophthalmia/microphthalmia (AM) or anterior segment dysgenesis (ASD) have an estimated combined prevalence of 3.7 in 10,000 births. Mutations in SOX2 are the most frequent contributors to severe ODA, yet account for a minority of the genetic drivers. To identify novel ODA loci, we conducted targeted high-throughput sequencing of 407 candidate genes in an initial cohort of 22 sporadic ODA patients. Patched 1 (PTCH1), an inhibitor of sonic hedgehog (SHH) signaling, harbored an enrichment of rare heterozygous variants in comparison to either controls, or to the other candidate genes (four missense and one frameshift); targeted resequencing of PTCH1 in a second cohort of 48 ODA patients identified two additional rare nonsynonymous changes. Using multiple transient models and a CRISPR/Cas9-generated mutant, we show physiologically relevant phenotypes altering SHH signaling and eye development upon abrogation of ptch1 in zebrafish for which in vivo complementation assays using these models showed that all six patient missense mutations affect SHH signaling. Finally, through transcriptomic and ChIP analyses, we show that SOX2 binds to an intronic domain of the PTCH1 locus to regulate PTCH1 expression, findings that were validated both in vitro and in vivo. Together, these results demonstrate that PTCH1 mutations contribute to as much as 10% of ODA, identify the SHH signaling pathway as a novel effector of SOX2 activity during human ocular development, and indicate that ODA is likely the result of overactive SHH signaling in humans harboring mutations in either PTCH1 or SOX2.

High prevalence of PRPH2 in autosomal dominant retinitis pigmentosa in france and characterization of biochemical and clinical features.

PURPOSE: To assess the prevalence of PRPH2 in autosomal dominant retinitis pigmentosa (adRP), to report 6 novel mutations, to characterize the biochemical features of a recurrent novel mutation, and to study the clinical features of adRP patients. DESIGN: Retrospective clinical and molecular genetic study. METHODS: Clinical investigations included visual field testing, fundus examination, high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence imaging, and electroretinogram (ERG) recording. PRPH2 was screened by Sanger sequencing in a cohort of 310 French families with adRP. Peripherin-2 protein was produced in yeast and analyzed by Western blot. RESULTS: We identified 15 mutations, including 6 novel and 9 previously reported changes in 32 families, accounting for a prevalence of 10.3% in this adRP population. We showed that a new recurrent p.Leu254Gln mutation leads to protein aggregation, suggesting abnormal folding. The clinical severity of the disease in examined patients was moderate with 78% of the eyes having 1-0.5 of visual acuity and 52% of the eyes retaining more than 50% of the visual field. Some patients characteristically showed vitelliform deposits or macular involvement. In some families, pericentral RP or macular dystrophy were found in family members while widespread RP was present in other members of the same families. CONCLUSIONS: The mutations in PRPH2 account for 10.3% of adRP in the French population, which is higher than previously reported (0%-8%) This makes PRPH2 the second most frequent adRP gene after RHO in our series. PRPH2 mutations cause highly variable phenotypes and moderate forms of adRP, including mild cases, which could be underdiagnosed.

Visual Impairment in Pseudoxanthoma Elasticum: A Survey of 40 Patients.

BACKGROUND: Pseudoxanthoma elasticum is an inherited disorder of connective tissue characterized, among other symptoms, by impaired vision. OBJECTIVE: To evaluate the nature and age of onset of ophthalmologic manifestations in pseudoxanthoma elasticum. PATIENTS AND METHODS: Forty consecutive patients affected with pseudoxanthoma elasticum underwent measurements of their refractive error and visual acuity, together with slit-lamp examination. RESULTS: The mean age of the patients (8 M, 32 F) was 43.35 years. Fifty-seven eyes (33 patients, mean age: 40.75 years) had a BCVA >20/50 whereas 23 eyes in 16 patients (mean age: 53.31 years) had ≤20/50. Seven patients (17.50%), all but one over 52 years old, were visually disabled. BCVA ≤20/50 in at least one eye was observed in 73.33% of patients of 52 years old or older and in 20.00% of patients younger than 52, respectively. Angioid streaks were observed in 75 eyes (93.75%) and extended toward the macula in 51 eyes from 29 patients. Macular involvement was observed for the first time at a mean age of 44.28 years. Neovascularization was observed in 28 eyes (17 patients; mean age: 51.70 years), all with poor BCVA. CONCLUSION: Macular choroidal neovascularization is frequent in pseudoxanthoma elasticum, and accounts for the poor ophthalmologic natural history of the disease. Patients should be advised to self-monitor their visual acuity using the Amsler grid. The frequency of choroidal neovascularization appears age-dependent, suggesting that bi-yearly fundus examination is appropriate in young patients whereas patients older than 40 should be examined twice a year.

Genetic characterization of congenital tufting enteropathy: epcam associated phenotype and involvement of SPINT2 in the syndromic form.

Congenital tufting enteropathy (CTE) is a rare and severe enteropathy recently ascribed to mutations in the epcam gene. Here we establish SPINT2, previously ascribed to congenital sodium diarrhea, as a second gene associated with CTE and report molecular and immunohistochemistry data in 57 CTE patients. Inclusion criteria were early onset diarrhea and intestinal insufficiency with the typical histological CTE abnormalities. The clinical phenotype was registered, the entire coding regions of epcam and SPINT2 sequenced, and immunostaining of EpCAM and SPINT2 performed on intestinal biopsies. An epcam mutation was involved in 41 patients (73 %) who mainly displayed isolated digestive symptoms. Mutations severely affected gene expression since the EpCAM signal on intestinal tissues was either undetectable or low and irregular. Twelve other patients (21 %) carried mutations in SPINT2, and were phenotypically characterized by systematic association with keratitis (p < 10(-4)) and, for half of them, with choanal atresia (p < 10(-4)). Dependency on parenteral nutrition (PN) was comparable in patients with epcam or SPINT2 mutations, but the frequent epcam mutation c.556-14A>G (abnormal splicing) was significantly associated with a better outcome (p = 0.032) with milder PN dependency to weaning in some cases. Finally, four patients (7 %) with isolated digestive symptoms had no detectable epcam or SPINT2 mutation. Two candidate genes, Elf3 and Claudin7, were excluded from this population. Our study allows us to separate CTE patients into at least three genetic classes, each with specific phenotypes. The genetics approach raises the question of the distinction between two congenital enteropathies. Our findings should help improve the diagnosis of CTE, guide toward strategies of long-term PN management, and limit indications for intestinal transplantation to life-threatening PN complications.

Acro-osteolysis, keloid like-lesions, distinctive facial features, and overgrowth: two newly recognized patients with premature aging syndrome, Penttinen type.

We report on two unrelated patients with a rare progeroid syndrome first described by Penttinen. Patients presented with prematurely aged appearance, delayed dental development, acro-osteolysis, diffuse keloid-like lesions, and ocular pterygia. Facial features are progressive but recognizable at birth. Premaxillary and maxillary retraction with pseudo-prognathism and palpebral malocclusion are characteristic. Thumbs and halluces are broad and spatulated. Linear growth is increased and intellectual functions are preserved. Skin retractions and joint contractures progressively developed during adolescence. Death occurred in the second decade in one of the patient due to restrictive respiratory insufficiency and cachexia. LMNA and ZMPSTE24 sequencing were normal. The molecular basis of the disorder remains unknown.

Benefit of bi-ocular visual stimulation for postural control in children with strabismus.

Vision is important for postural control as is shown by the Romberg quotient (RQ): with eyes closed, postural instability increases relative to eyes open (RQ = 2). Yet while fixating at far distance, postural stability is similar with eyes open and eyes closed (RQ = 1). Postural stability can be better with both eyes viewing than one eye, but such effect is not consistent among healthy subjects. The first goal of the study is to test the RQ as a function of distance for children with convergent versus divergent strabismus. The second goal is to test whether vision from two eyes relative to vision from one eye provides better postural stability. Thirteen children with divergent strabismus and eleven with convergent strabismus participated in this study. Posturtography was done with the Techno concept device. Experiment 1, four conditions: fixation at 40 cm and at 200 cm both with eyes open and eyes covered (evaluation of RQ). Experiment 2, six conditions: fixation at 40 cm and at 200 cm, with both eyes viewing or under monocular vision (dominant and non-dominant eye). For convergent strabismus, the groups mean value of RQ was 1.3 at near and 0.94 at far distance; for divergent, it was 1.06 at near and 1.68 at far. For all children, the surface of body sway was significantly smaller under both eyes viewing than monocular viewing (either eye). Increased RQ value at near for convergent and at far for divergent strabismus is attributed to the influence of the default strabismus angle and to better use of ocular motor signals. Vision with the two eyes improves postural control for both viewing distances and for both types of strabismus. Such benefit can be due to complementary mechanisms: larger visual field, better quality of fixation and vergence angle due to the use of visual inputs from both eyes.

Postural control in nonamblyopic children with early-onset strabismus.

PURPOSE: In healthy subjects, the postural stability in orthostatic position is better when fixating at near than at far. Increase in the convergence angle contributes to this effect. Children with strabismus present a deficit in vergence. We evaluated postural control in children with respect to the vergence angle as they fixated at different depths, thereby engaging in active vergence movements. METHODS: A TechnoConcept platform was used to record the postural stability of 11 subjects (mean age 11.18 ± 4.02 years) with convergent strabismus and 13 (mean age 11.31 ± 3.54 years) with divergent strabismus in 3 conditions: fixation at 40 cm, at 2 m, and active vergence movements between 20 and 50 cm. RESULTS: The mediolateral body sway decreased significantly with proximity for convergent strabismus (from 3.78-2.70 mm) but increased significantly for divergent strabismus (from 3.27-3.97). Relative to fixation, vergence eye movements resulted in a statistically significant increase in mediolateral body sway for convergent strabismus (3.55 vs. 2.70) and a decrease for divergent strabismus (3.11 vs. 3.97, P = 0.047). Vergence eye movements were associated with the least variance of speed (99 mm(2)/s(2) for convergent and 117 mm(2)/s(2) for divergent strabismus), so less energy was required to control body sway. CONCLUSIONS: The fixation depth at which postural stability is best is proximal for convergent strabismus and distal for divergent strabismus. Optimal postural stability might be mediated by preponderant eye movement signals related to the angle of strabismus. Reduction of variance of speed in the active vergence condition corroborates our hypothesis.

[From congenital glaucoma to chronic open angle glaucoma in adulthood: a clinical and genetic continuum]. / Du glaucome congénital au glaucome chronique de l'adulte: un continuum clinique et génétique.

Congenital glaucoma, a true hydrocephalus of the eye, is defined by ocular hypertension resulting in buphthalmos in children up to three years old, the elasticity of the eye wall allowing its expansion. Juvenile glaucoma in teenagers and chronic glaucoma in adults do not alter the external aspect of the eye, as the eyeball has lost its elasticity. However, chronic ocular hypertension always causes ischemic excavation of the optic nerve head, leading to insidious amputation of the visual field and, potentially, blindness. Like most ophthalmological disorders, the different types of glaucoma have been shown to be genetically determined, and alterations in several genes have been identified. These altered genes can be expressed more or less early in life, suggesting a role of modifier genes. The role of CYP1B1 alterations in classic primary congenital glaucoma is well known, as is the role of PITX2, FOXC1, PAX6 and LOXC1 alterations in secondary congenital glaucoma due to iridogoniodysgenesis, and of MYOC alterations in the genesis of chronic glaucoma in adulthood. An outbred family carrying CYP1B1 mutations in the compound heterozygous state includes two sibs with primary congenital glaucoma and two others who developed chronic glaucoma in adulthood.

Ocular manifestations of cobalamin C type methylmalonic aciduria with homocystinuria.

PURPOSE: To report the ocular complications of cobalamin-C type methylmalonic aciduria with homocystinuria (cblC) in a large consecutive series of patients. METHODS: Medical records of patients with genetically diagnosed cblC disease from Mount Sinai Medical Center, New York, and Hôpital Necker, Paris, France, were reviewed. All patients with the diagnosis of cblC seen after January 2008 at Mount Sinai and January 1998 at Hôpital Necker were included. RESULTS: A total of 9 cases are reported. Age at initial ocular examination ranged from 3.5 months to 10 years of age. All 9 patients had early-onset disease, with manifestation of disease presenting prior to 1 year of age. Two patients had definitive optic nerve pallor. All patients had retinal findings ranging from peripheral pigmentary retinal changes to central macular atrophy with Bull's eye lesions. Optical coherence tomography was performed on one child and showed retinal thinning in the area of the bull's eye lesions. Electroretinography was performed in 6 of the 9 patients, three of whom showed decreased scotopic and photopic responses. The other three patients had normal responses on electroretinography. CONCLUSIONS: Ocular findings in patients with cblC are variable. All patients in the study exhibited early-onset disease and had noteworthy ophthalmic findings. To the best of our knowledge, this is the first study in the literature correlating optical coherence tomography findings with fundus findings in cblC.

Asymptomatic atrophy of the temporal median raphe of the retina associated with cerebral vasculopathy in homozygous sickle cell disease.

A 13-year-old girl with homozygous sickle cell disease was referred for vision loss in her left eye of 1 year's duration. Clinical findings were consistent with a past retinal arterial occlusion. In the asymptomatic right eye, spectral domain optical coherence tomography showed a severe atrophy of the inner retinal layers of the temporal median raphe; a significant internal carotid stenosis was also present. We hypothesize that specific atrophy of the retinal temporal median raphe resulted from chronic ischemia. The inner layers of the retina are vascularized by terminal vessels and the median raphe can therefore be regarded as a junction territory; its atrophy may represent an ocular equivalent of a silent border zone cerebral infarct.

Subtypes of developmental coordination disorder: research on their nature and etiology.

Children with Developmental Coordination Disorder (DCD) are a group embracing clumsiness and developmental dyspraxia. Our study provides a better understanding of the nature of DCD and its etiology, and identifies subtypes of dyspraxia. Forty-three children with DCD (5-15 years) were enrolled on the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV-TR]; American Psychiatric Association, 2000) criteria. Extensive standardized evaluations were conducted. We distinguished from two patterns of "pure" developmental dyspraxia: ideomotor and visual-spatial/visual-constructional, and mix dyspraxia with more co-morbidities. Our study provides a better understanding of the nature of DCD, and sheds light on its etiology and brain dysfunction, so as to identify subtypes of developmental DCD/dyspraxia with specific clinical criteria.

Truncation of PITX2 differentially affects its activity on physiological targets.

The bicoid-like transcription factor PITX2 has been previously described to interact with the pituitary-specific POU homeodomain factor POU1F1 (human ortholog of PIT-1) to achieve cell-specific expression of prolactin (PRL) and GH in pituitary somatolactotroph cells. In this work, we have investigated the functional properties of three PITX2 mutants reported in Axenfeld-Rieger syndrome patients relative to the regulation of these genes, using reporter genes under the control of human PRL (hPRL), hGH, or POU1F1 promoters transfected in nonpituitary and pituitary cell lines. Among the three mutations studied, Y167X and E101X introduce a premature stop codon, and F104L leads to an amino acid substitution. While PITX2(E101X) is not expressed in the cells following transfection, and PITX2(F104L) is functionally inactive, the PITX2(Y167X) mutant keeps its DNA-binding capacity and displays a markedly enhanced activation of the hPRL and POU1F1 promoters, but not of the hGH promoter. Y167X is the first mutation of PITX2 described to result in a differential effect on the activation of its different physiological targets, hPRL and POU1F1 on one hand and hGH on the other hand. The differential effect of the Y167X mutation might be linked to an interaction of PITX2 with different transcription factors or cofactors when bound to the hPRL and POU1F1 or the hGH promoters. These results might form the basis for the identification of the PITX2 protein complex necessary for the differential GH or PRL expression.

[Under cover penetrating keratoplasty: a safer technique, especially for children]. / La kératoplastie transfixiante à ciel fermé, technique de sécurité dans certaines greffes de cornée, en particulier chez l'enfant.

Penetrating keratoplasty is usually performed when the cornea has lost all transparency Irrespective of the instruments used, the most awkward step occurs when the cornea is removed. In aphakic and infant eyes there is a high risk of lens expulsion, vitreous loss, or choroidal effusion. Under-cover penetrating keratoplasty never leaves the anterior segment exposed, and is therefore safer for infant and aphakic eyes and when large-diameter trepanation is necessary.

Superficial punctate keratitis and conjunctival erosions associated with congenital tufting enteropathy.

PURPOSE: To study the value of conjunctival biopsy in congenital tufting enteropathy diagnosis. DESIGN: Case-comparative study. METHODS: Between January 2000 and June 2007, all children seeking treatment with an early onset of intractable diarrhea were examined in the ophthalmology department of Necker-Enfants Malades Hospital, Assistance Publique-Hôpitaux de Paris, France. Children underwent complete ophthalmologic examination with concurrent conjunctival and intestinal biopsies. Main outcome measures were age at diagnosis, associated disorders, parenteral nutrition, and ophthalmologic symptoms. Conjunctival biopsies support diagnosis in the presence of specific alteration. RESULTS: Twenty patients were included. The mean age of the population was 30.2 months. Congenital tufting enteropathy was diagnosed in 15 cases. In the congenital tufting enteropathy group, 10 children exhibited ophthalmic functional disorders since the first months of life, with superficial punctate keratitis and conjunctivitis and in addition alacrima and cataract in 1 case, respectively, whereas 5 children had asymptomatic conjunctival hyperemia at presentation. Conjunctival biopsies showed epithelial parakeratosis, hyperplasia, basal cells hyperplasia, and tufts. In some cases, the lamina propria contained inflammatory cells or fibrosis, and the density of goblet cells then was abnormal. In the comparison group of 5 children with early-onset intractable diarrhea but without congenital tufting enteropathy diagnosis, no tuft occurrence was observed. CONCLUSIONS: In cases of intractable diarrhea in infancy, even without ocular symptoms, a systematic ophthalmologic examination should be performed. It also should be associated with the pathologic examination of both the conjunctival and the intestine mucosae, which helps to diagnose congenital tufting enteropathy (adhesion molecules disease). Specific conjunctival findings allow affirmation of congenital tufting enteropathy before the genetic confirmation of an EpCAM gene mutation.

Carotid artery dissection revealed by an oculosympathetic spasm.

Internal carotid dissection can be responsible for stroke and lead to severe neurological and functional complications. Thus, it must be diagnosed and treated with heparin as soon as possible. Horner syndrome is one of the most usual manifestations of internal carotid dissection. We report the case of a patient who presented with a unilateral non-reactive enlargement of the right pupil that did not last longer than 30 s. As a carotid dissection was not recognized from this atypical symptomatology, magnetic resonance angiography was performed only a few days later when Horner syndrome occurred. It disclosed a dissection of the internal carotid artery ipsilateral from its origin. The evolution and the duration of the pupil involvement suggest that the initial episode of mydriasis was caused by an oculosympathetic spasm, a rare form of sympathetic dysfunction that can be observed when the sympathetic nerve or the pericarotid plexus is irritated. It is important to recognize this oculosympathetic spasm because it has equal value as Horner syndrome for the diagnosis of internal carotid dissection.

TMEM126A, encoding a mitochondrial protein, is mutated in autosomal-recessive nonsyndromic optic atrophy.

Nonsyndromic autosomal-recessive optic neuropathies are rare conditions of unknown genetic and molecular origin. Using an approach of whole-genome homozygosity mapping and positional cloning, we have identified the first gene, to our knowledge, responsible for this condition, TMEM126A, in a large multiplex inbred Algerian family and subsequently in three other families originating from the Maghreb. TMEM126A is conserved in higher eukaryotes and encodes a transmembrane mitochondrial protein of unknown function, supporting the view that mitochondrial dysfunction may be a hallmark of inherited optic neuropathies including isolated autosomal-recessive forms.

Vertical and horizontal smooth pursuit eye movements in children: a neuro-developmental study.

An evaluation of eye movements is very useful in neurological disorders but is complicated by issues such as maturation and lack of normative data in children. In order to address these issues we studied smooth pursuit eye movements of 65 normal children aged 7-11 years old. The gain of horizontal smooth pursuit (HSP) was higher than the gain of the vertical smooth pursuit (SP) and this difference had a statistical tendency to disappear with aging from 7 to 11 years. These data suggest that, in the cerebral regions involved in the control of SP, i.e. posterior parietal and superior temporal lobe regions, the networks for VSP mature latter than those for HSP.