Neurogenesis in the ventricular layer and the development of cell topography in the ganglion cell layer have been studied in whole-mounts of human fetal retinae. At the end of the embryonic period mitotic figures were seen over the entire outer surface of the retina. By about 14 weeks gestation mitosis had ceased in central retina and differentiation of photoreceptor nuclei was evident within a well-defined area which constituted about 2% of total retina area. This area was approximately centered on the site of the putative fovea, identified by the exclusive development of cone nuclei at that location. The area of retina in which mitosis had ceased increased as gestation progressed. By mid-gestation mitosis in the ventricular layer occupied about 77% of the outer surface of the retina and by about 30 weeks gestation mitosis in the ventricular layer had ceased. Cell density distributions in the ganglion cell layer were nonuniform at all stages studied (14-40 weeks). Densities were highest at about 17 weeks gestation, and by mid-gestation the adult pattern of cell topography was present with maps showing elevated cell densities in posterior retina and along the horizontal meridian. Cell densities generally declined throughout the remainder of the gestation period, except in the posterior retina, where densities in the perifoveal ganglion cell layer remained high during the second half of gestation. There is a rapid decline in cell density in the foveal ganglion cell layer toward the end of gestation, and it is suggested that the persistence of high densities in the perifoveal region may be related to migration of cells away from the developing fovea. The total population of cells in the ganglion cell layer was highest (2.2-2.5 million cells) between about weeks 18 and 30 of gestation. After this the cell population declined rapidly to 1.5-1.7 million cells. It is suggested that naturally occurring neuronal death is largely responsible for this decline.

Congenital cataracts are a significant cause of lifelong visual loss. They may be isolated or associated with microcornea, microphthalmia, anterior segment dysgenesis (ASD) and glaucoma, and there can be syndromic associations. Genetic diagnosis is challenging due to marked genetic heterogeneity. In this study, next‐generation sequencing (NGS) of 32 cataract‐associated genes was undertaken in 46 apparently nonsyndromic congenital cataract probands, around half sporadic and half familial cases. We identified pathogenic variants in 70% of cases, and over 68% of these were novel. In almost two‐thirds (20/33) of these cases, this resulted in new information about the diagnosis and/or inheritance pattern. This included identification of: new syndromic diagnoses due to NHS or BCOR mutations; complex ocular phenotypes due to PAX6 mutations; de novo autosomal‐dominant or X‐linked mutations in sporadic cases; and mutations in two separate cataract genes in one family. Variants were found in the crystallin and gap junction genes, including the first report of severe microphthalmia and sclerocornea associated with a novel GJA8 mutation. Mutations were also found in rarely reported genes including MAF, VIM, MIP, and BFSP1. Targeted NGS in presumed nonsyndromic congenital cataract patients provided significant diagnostic information in both familial and sporadic cases.

Aims: To assess the aetiological factors associated with the occurrence of perforating ocular injuries in children in an urban setting and to assess the visual outcomes of such injuries. Methods: All cases of perforating ocular injury presenting to a single paediatric hospital (age less than 16 years) over a 17 year period were identified by a medical record search. All new cases of perforating ocular injury identified were included. All information was obtained retrospectively from the medical records. Results: There were 72 cases identified. The commonest causes of perforating ocular injury were sharp tools (knives/scissors) poked by the child into his/her own eye (17%), or objects thrown at the child (17%). Injuries were most likely to have occurred at home (58%). The age range for injuries was 8 months to 14 years 8 months. Perforating ocular injury was most frequent in the 3-6 year group (32%) followed by the 6-9 year group (25%). Males were more frequently involved than females (48-24). There was no correlation between the laterality of the eye, the time of day of the occurrence, or the day of the week of the occurrence. The final acuity achieved was better or equal to 6/12 in 36% and less than 6/60 in 31%. Injuries occurred more frequently on weekends than on weekdays. There were six enucleations (8%). Follow up was for an average period of 25 months. Conclusions: Penetrating ocular injury occurs most frequently in the home setting and mostly as the result of the use of sharp tools or by thrown objects. Prevention of penetrating ocular injury requires greater education of children and their carers especially on the potential dangers within the home. P erforating ocular injuries are a frequent cause of unilateral visual loss. Children account for between 20% and 50% of all ocular injuries.1-3 It has been estimated that 90% of all ocular injury are preventable. 4 Strategies for prevention require a knowledge of the cause of injury and may hence enable more appropriate targeting of resources towards prevention of such injuries. The aetiology of paediatric ocular injuries is likely to differ from that of adults, and is hence worthy of further investigation.The principles of management of penetrating ocular injury are the same for children and adults. However, the management of the child is made more difficult by variable cooperation with both assessment and continuing therapy. The possibility of amblyopia in young children further complicates treatment.This study addresses the epidemiology of penetrating ocular injury in children presenting to a single institution in a metropolitan centre. It also reviews the outcomes of these injuries. METHODSAll cases of full thickness perforating ocular injury presenting initially to the Royal Alexandria Hospital for Children in Sydney, Australia, between 1 January 1983 and 31 December 1999 were identified by a medical record search for the ICD code 871. Royal Alexandria Hospital for Children is a paediatric hospital (age 0-16 years) and is a tertiary referral centre. Pati...

We have estimated the number of axons in the optic nerves of human fetuses ranging in gestational age from approximately 10 to 33 weeks. At 10-12 weeks of gestation there were an estimated 1.9 million axons in the optic nerve. A peak count of 3.7 million axons was obtained from a specimen of 16-17 weeks gestation. The estimated number of axons then declined, stabilizing at an estimated 1.1 million axons by about week 29 of gestation. This figure is in close agreement with an estimate of 1.1-1.3 million optic axons in the human adult optic nerve. The results indicate that at least 70% of optic axons generated during development of the primary visual pathway are lost during fetal life. Part of this loss probably occurs as a result of the refinement of the terminal distribution of ganglion cell projections within their target nuclei. The significance of the relatively prolonged period of axonal loss is discussed.

Anophthalmia and pituitary gland hypoplasia are both debilitating conditions where the underlying genetic defect is unknown in the majority of cases. We identified a patient with bilateral anophthalmia and absence of the optic nerves, chiasm and tracts, as well as pituitary gland hypoplasia and ear anomalies with a de novo apparently balanced chromosomal translocation, 46,XY,t(3;14)(q28;q23.2). Translocation breakpoint analysis using FISH and high-resolution microarray comparative genomic hybridization (CGH) has identified a 9.66 Mb deleted region on the long arm of chromosome 14 which includes the genes BMP4, OTX2, RTN1, SIX6, SIX1, and SIX4. Three other patients with interstitial deletions involving 14q22-23 have been described, all with bilateral anophthalmia, pituitary abnormalities, ear anomalies, and a facial phenotype similar to our patient. OTX2 is involved in ocular developmental defects, and the severity of the ocular phenotype in our patient and the other 14q22-23 deletion patients, suggests this genomic region harbors other gene/s involved in ocular development. BMP4 haploinsufficiency is predicted to contribute to the ocular phenotype on the basis of its expression pattern and observed murine mutant phenotypes. In addition, deletion of BMP4 and SIX6 is likely to contribute to the abnormal pituitary development, and SIX1 deletion may contribute to the ear and other craniofacial features. This indicates that contiguous gene deletion may contribute to the phenotypic features in the 14q22-23 deletion patients.

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Four cases of an apparently benign ocular motor syndrome of childhood are reported. The features of the disorder are: (1) onset in early life; (2) periods of constant or variably sustained tonic conjugate upward deviation of the eyes; (3) down-beating saccades in attempted downgaze, which are difficult to sustain below the neutral positions; (4) apparently normal horizontal eye movements; (5) frequent relief by sleep; (6) otherwise normal neurological findings apart from mild ataxia, chronic in one boy and at times of illness in one of the other patients; (7) absence of deterioration during observation spanning up to 15 years; (8) eventual improvement but with some residual ocular movement problems in two cases; (9) normal metabolic, electroencephalographic, and neuroradiologic investigations; (10) normal brain examination findings in one patient who died accidentally; and (11) an apparently good response to levodopa therapy in one patient. To the authors' knowledge, this condition has not been described previously. It may be a new levodopa-responsive condition, secondary to a localized neurotransmitter deficiency.