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Defects in choroid fissure (CF) formation and closure lead to coloboma, a major cause of childhood blindness. Despite genetic advances, the cellular defects underlying coloboma remain poorly elucidated due to our limited understanding of normal CF morphogenesis. We address this deficit by conducting high-resolution spatio-temporal analyses of CF formation and closure in the chick, mouse and fish. We show that a small ventral midline invagination initiates CF formation in the medial-proximal optic cup, subsequently extending it dorsally toward the lens, and proximally into the optic stalk. Unlike previously supposed, the optic disc does not form solely as a result of this invagination. Morphogenetic events that alter the shape of the proximal optic cup also direct clusters of outer layer and optic stalk cells to form dorsal optic disc. A cross-species comparison suggests that CF closure can be accomplished by breaking down basement membranes (BM) along the CF margins, and by establishing BM continuity along the dorsal and ventral surfaces of the CF. CF closure is subsequently accomplished via two distinct mechanisms: tissue fusion or the intercalation of various tissues into the inter-CF space. We identify several novel cell behaviors that underlie CF fusion, many of which involve remodeling of the retinal epithelium. In addition to BM disruption, these include NCAD downregulation along the SOX2 + retinal CF margin, and the protrusion or movement of partially polarized retinal cells into the inter-CF space to mediate fusion. Proximally, the inter-CF space does not fuse or narrow and is instead loosely packed with migrating SOX2 + /PAX2 + /Vimentin + astrocytes until it is closed by the outgoing optic nerve. Taken together, our results highlight distinct proximal-distal differences in CF morphogenesis and closure and establish detailed cellular models that can be utilized for understanding the genetic bases of coloboma., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: To quantify the improvements in visual performance for both distance and near tasks attained by children with bilateral chorioretinal coloboma (CRC) with use of low-vision aids (LVAs)., Methods: This was a hospital-based, cross-sectional, interventional case series of children with bilateral CRC. Demographic data were collected through a structured questionnaire and review of medical records. Distance and near best-corrected visual acuity, contrast sensitivity, and reading speed were evaluated with refractive correction alone and with the use of LVAs (Keplerian telescopes for distance; handheld magnifiers and a tinted lens [400 nm filter] for near). Effects are presented as medians of differences with 95% binomial-exact confidence intervals., Results: Six children were included (median age, 11.5 years; range, 7-17 years), of whom 5 were already using LVAs on a daily basis. The use of a Keplerian telescope achieved a significant median improvement in distance best-corrected visual acuity of 0.75 logMAR (95% CI, 0.20-1.20). Contrast sensitivity was also improved across all tested spatial frequencies. Use of near LVAs resulted in a significant median improvement in near reading acuity of 0.47 logRAD (95% CI, 0.28-0.90). Critical print size and reading speed at N10 were also improved., Conclusions: LVAs enable meaningful improvements in the visual performance of children with bilateral CRC, allowing noteworthy increases in distance and near visual acuities as well as good reading speeds at small print sizes., (Copyright © 2018 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: We reported the clinical and echographic features of colobomas, prevalence of retinal detachment, and associated visual acuity in these patients., Methods: The study is a nonrandomized consecutive case series of 140 colobomatous eyes in 98 patients (age range, 0-83 years). Coloboma depth, width, volume, and relative coloboma excavation (coloboma depth/axial length) were measured using standardized echographic images. The presence of structural and other ocular abnormalities was noted. The clinical and echographic findings present were correlated with visual acuity of the patient. In addition, these features were correlated with the presence or absence of retinal detachment., Results: Increased relative coloboma excavation was significantly associated with an increased risk of retinal detachment. A relative coloboma excavation (ratio of coloboma depth to axial length) greater than 0.15 was associated with an increased risk of retinal detachment (52%), compared to those with a relative coloboma excavation less than 0.15 (23%, P = 0.014). The presence of any structural abnormality and the presence of a retrobulbar cyst were associated with increased risk of retinal detachment and severe visual impairment (worse than 20/200). Increased coloboma depth, width, volume, and relative coloboma excavation were not associated with increased risk of severe visual impairment., Conclusions: Clinical and echographic features of colobomas may be used in predicting the risk of retinal detachment. Measuring relative coloboma excavation upon presentation may alter follow-up and assist in the diagnosis of retinal detachment.

Objective: To describe the features at the margin of the choroidal colobomas as evaluated clinically and by optical coherence tomography (OCT)., Design: Prospective observational case series., Participants: Seventeen patients (30 eyes) that presented to the outpatient department of a tertiary care center., Testing: Clinical examination and OCT testing of the 30 eyes., Main Outcome Measures: Description of OCT features of the margin of the choroidal colobomas., Results: Histologically, there is no normal choroid, retinal pigment epithelium, or retina overlying choroidal colobomas; rather, the overlying tissue is an extension of the retina called the intercalary membrane (ICM). In these patients, OCT showed that transition from normal retina to the ICM could be categorized as abrupt or gradual and also showed that the inner neurosensory retinal layers continued as the ICM, whereas the outer layers could not be traced beyond a point. In some cases with apparently attached retina, subclinical retinal detachments were identified along the margin of the coloboma. In cases with retinal detachment, OCT allowed for identification of the precise site of communication between the sub-ICM space and subretinal space at the locus minoris resistentiae. The margin of the choroidal coloboma, in some cases, showed the appearance of a hump owing to inward turning of the retinochoroidal layers with thickening of the layers at the margin. In small colobomas, OCT revealed the ICM thickness comparable to normal retina but showed structural alterations. Fundus lesions that were clinically labeled forme fruste of choroidal coloboma seemed to have normal retinal thickness and layering on OCT. In 1 patient, a temporal optic pit was associated with the forme fruste choroidal coloboma in 1 eye; the fellow eye had a typical choroidal coloboma., Conclusions: Optical coherence tomographic evaluation of the margins of choroidal colobomas helps in understanding the transition from retina to ICM, detects subclinical retinal detachments, and aids in identifying the site of communication between the sub-ICM space and the subretinal space in eyes with retinal detachment.

Context: Vitreous surgery has been advocated as an alternative treatment of selected retinal detachments with choroidal colobomas., Aim: To study the long term anatomical and visual outcome of choroidal coloboma with retinal detachment managed by pars plana vitrectomy with silicone oil tamponade., Setting and Design: Retrospective study conducted in a tertiary eye care hospital., Materials and Methods: Fourty two eyes of 40 patients with retinal detachments related to coloboma of the choroid without any peripheral breaks were analyzed. All eyes underwent pars plana vitrectomy with internal tamponade using silicone oil. Endolaser was performed along the coloboma border. Silicone oil was removed in 50% of patients. The main outcome measures were retinal reattachment and visual recovery. SPSS (Statistical Package for the Social Science), version 10.0 was used for analysis., Results: The retina in all cases (100%) undergoing vitrectomy were completely reattached intra-operatively. After a mean follow-up of 14 months, 37 (88.1%) eyes had attached retina. The best corrected visual acuity was 10/200 or better in 33 (78.4%) eyes. The best corrected visual acuity improved from a preoperative median of counting fingers (range 20/40 to perception of light) to median best corrected visual acuity of 20/200 (range 20/40 to perception of light) at the end of 6 months. Of the 50% (21) cases that underwent silicone oil removal, two eyes had re-detachment of retina., Conclusion: Pars plana vitrectomy along with silicone oil tamponade for retinal detachment related to choroidal coloboma improves the long-term anatomical and visual outcome.

Described in the paper are the results of ophthalmologic, ultrasound and radiological examinations of 3 girls with the Aicardi syndrome. It was for the first time, that an expansion of the optic-nerve disk excavation was described in patients with the above syndrome; such expansion was conditioned by trans-synaptic neuron degeneration induced by lesions to optic radiation in view of prenatal of encephaloplastic processes. The changing brain white substance as projected by optic radiation was detected in all children by computer and magnetic resonance tomography. Besides, other anomalies of the optic nerve (bindweed syndrome, coloboma) and of the retina are elucidated. Finally, the pathogenesis and differential diagnostics of the Aicardi syndrome are under discussion.

Background: We investigated whether Stiles-Crawford (SCE) functions, a measure of photoreceptor orientation and alignment, are disturbed in patients with nasal fundus ectasia (tilted disc; Fuch's coloboma without apparent pupillary involvement)., Methods: SCE functions were obtained in three observers with nasal fundus ectasia, using psychophysical methods., Results: In all cases, disruption of photoreceptor alignment can be inferred. Results include location of the SCE peaks outside the pupil in the direction of the lesion, differential alignment, and reduction of the magnitude of SCE at various retinal loci (reduced curvature or p factor). Additional results obtained with the selective adaptation technique imply that receptor disarray (splaying) may be responsible for loss of retinal directional sensitivity., Conclusions: From these results, it may be surmised that mechanical tractional forces can play a major role in defining photoreceptor orientation in the retina. Inferred anomalous photoreceptor alignment has heretofore not been specifically linked with Fuch's coloboma/tilted disc syndrome.

We report a rare case of morning glory syndrome with choroidal neovascular membrane and contractile movement of the optic disc. A 12-year-old healthy boy was first seen in April 1992 with a chief complaint of transient visual loss in his left eye for 3 months. The diagnosis of morning glory syndrome was made by the characteristic optic nerve head. His visual acuity was 1.2 in both eyes. In August 1994, retinal hemorrhage associated with choroidal neovascular membrane was observed in the macula of his left eye, resulting in a decrease of visual acuity to 0.4. In October 1994, we observed contractile movement in the morning glory optic disc. Using a scanning laser ophthalmoscope (SLO), we could observe the disc contracting for approximately 2 seconds and then dilating again over a 20-second period. The contractile movement was not evoked by exposure to a strong light or by the Valsalva maneuver. However, it seemed to be induced by digital massage of the eyeball.

A case is reported in which large colobomas of the retina and choroid are found bilaterally in a young female who also has a pituitary tumor and mental retardation. Visual field data are presented and correlated with the retinal appearances. Relevant embryology is reviewed, and a table of systemic abnormalities associated with retinal/choroidal colobomas is presented.

Purpose/methods: In a patient with a coloboma of the optic nerve, inferior retina and choroid, and deep portions of the sclera, a retrobulbar vessel moved irregularly relative to the retinal vessels, which moved contiguously with the posterior globe., Results/conclusion: Fluorescein angiography showed the retrobulbar vessel filling slightly later than overlying retinal vessels. We conclude that the retrobulbar vessel was a vein situated inferiorly to the optic nerve.