Optic nerve hypoplasia and astigmatism: a new association.

Zeki, Sabah M.

doi:10.1136/bjo.74.5.297

Cited by 29 publications

(13 citation statements)

References 8 publications

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“…This has been reported in detail elsewhere. 17 Six patients (4, 6, 7, 10, 12, 13) had bilateral asymmetrical ONH with a significant refractive error in the eye which had the smaller D-M/DD ratio. The visual acuities both with and without correction were the same in the eye with the better visual acuity for two of these patients (12 and 13).…”

Section: Resultsmentioning

confidence: 99%

Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

Zeki

Dudgeon

Dutton

1991

British Journal of Ophthalmology

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The ratio of disc to macula/disc diameter is characteristically increased in eyes with optic nerve hypoplasia. We present the largest reported series of patients with a definitive diagnosis of optic nerve hypoplasia for whom this ratio has been determined. Ali measurements were made by an independent masked observer. Our Underdevelopment of one or both optic nerves is a common anomaly.' The aetiology is unknown. Optic nerve hypoplasia (ONH) is a diagnosis which should be considered in any person with poor vision for which there is no immediately apparent explanation. Although the small optic disc of ONH is easily detected in severe cases, more subtle forms of the disorder may present more difficulty. The differential diagnosis includes the apparently small optic nerve head of hypermetropia. Subtle forms of the disorder may be difficult to distinguish from normal appearances. Red-free fundus photography can aid in this differentiation by detecting evidence of nerve fibre layer defects which correspond with that of the pattern of visual field loss.2 However, many cases of ONH do not show such focal defects and are manifest solely as a uniformly thin nerve fibre layer within affected areas, which makes the condition more difficult to define than focal defects.3Franceschetti and Bock4 measured the optic disc diameter by means of focal illumination of the fundus, using contact lens biomicroscopy and a micrometer scale. Estimation of the size of the optic disc by comparing the slit beam width on the Hagg-Streit 900 slit-lamp with the optic disc diameter on contact lens biomicroscopy has also been advocated.5 These relative measurements are useful in comparing the diameter of the optic disc relative to the slit-lamp beam or the scale, because their magnification when projected on the optic disc is assumed to be the same as the magnification of the optic disc, as the slit beam and microscope optics are parfocal and both pass through the optical system of the eye.Other methods which have been described include comparison of the size of the optic disc with the size of the whole area of the fundus as seen in the standard fundus photograph,' measurement with a scale over the frontal lens during indirect ophthalmoscopy,7 direct measurements of the orbital part of the optic nerve by CT scanning,8 A-scan ultrasonography,8 and B-scan ultrasonography.9Variations in the size of the eye with concomitant differences in dioptric power even in emmetropic eyes render absolute measurement of intraocular structures difficult.'0" Interference fringes provide a means of accurate measurement' but necessitate sophisticated equipment and a co-operative patient. The alternative is to make relative measurements from fundus photographs. The apparent size of the optic disc in fundus photographs is influenced by several factors, including the axial length, corneal curvature, and the shape of the fundus,"3 and by refractive errors and optical aberrations, but because all photographed structures are equally influenced by anatomical and re...

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Section: Resultsmentioning

confidence: 99%

Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

Zeki

Dudgeon

Dutton

1991

British Journal of Ophthalmology

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“…Careful refraction and prescription of spectacles is indicated in selected cases to prevent an additional amblyopic component from astigmatism, which has been found to be commoner in children with ONH. 99 Prognosis Some children with bilateral ONH, who present as blind in early infancy, may show a degree of delayed visual maturation and go on to develop mobility vision or better during the ensuing 2 years. 100 Optic disc cupping in PVL F a variant of ONH?…”

Section: Treatmentmentioning

confidence: 99%

Congenital disorders of the optic nerve: excavations and hypoplasia

Dutton

2004

Eye

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“…Refractive error in patients with ONH has been variably reported, and previous analyses have relied on retrospective, uncontrolled comparisons . Thus, to strengthen information available on this topic, we recruited suspected ONH subjects, determined their classification based on optic nerve photographic analysis, and performed concurrent examination that included refractive assessment so that a more definitive analysis could be obtained.…”

Section: Introductionmentioning

confidence: 99%

Association of refractive error with optic nerve hypoplasia

Pang

Frantz

Roberts

2015

Ophthalmic Physiologic Optic

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Optic nerve hypoplasia subjects were more likely than control subjects to exhibit significant refractive errors, particularly hyperopia. Anisometropia tended to be more likely to occur in subjects with unilateral ONH than in bilateral ONH. Based on our findings, we recommend that clinicians perform a comprehensive eye examination on all patients with ONH and prescribe for existing refractive error when visual acuity or general visual function can realistically be improved.

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Optic nerve hypoplasia and astigmatism: a new association.

Cited by 29 publications

References 8 publications

Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

Congenital disorders of the optic nerve: excavations and hypoplasia

Association of refractive error with optic nerve hypoplasia

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