Pseudoduplication of the optic nerve head.

BACKGROUND: Pseudo-doubling of the optic nerve head is a spectacular clinical entity, in which a lesion resembling an optic disk appears adjacent to the true optic disk. CASE REPORT: A case of unilateral pseudo-doubling of the optic disk with bilateral optic nerve pits is presented. CONCLUSIONS: The lesion is congenital, and represents a chorioretinal coloboma with optic disk involvement. Pseudo-doubling can be differentiated from true doubling of the optic nerve by the imaging techniques of ultrasonography, computerized tomography, and magnetic resonance imaging.     

"Morning glory syndrome" and "Handmann's anomaly" in congenital macropapilla. Extreme variants of "confluent optic pits"?

Seventeen optic disks with morning glory syndrome were measured in absolute and relative size units (millimeters and parapapillary retinal vessel caliber) in 5 and 12 eyes, respectively. Their respective mean areas were 7.47 +/- 2.63 mm2 and 7.84 +/- 4.96 mm2. They were significantly (Mann-Whitney test) larger than 457 unselected normal optic nerve heads (2.69 +/- 0.70 mm2; p less than 0.0001) and 15 optic disks with pits (4.84 +/- 1.42 mm2; p less than 0.001). They are the largest optic nerve heads, probably with constant postnatal size, measured so far, and form part of a spectrum of optic disk anomalies and diseases whose frequency correlates with the size of the optic disk. This spectrum includes abnormally small optic nerve heads with increased prevalence of drusen, pseudopapilledema and nonarteritic anterior ischemic optic neuropathy, asymptomatic macrodisks with physiologic, "pseudoglaucomatous" macrocups, symptomatic macrodisks with pits and, finally, optic nerve heads with morning glory syndrome. The last-mentioned may be considered an extreme variation of optic disks with pits which have combined to form a single macropit covering the entire optic nerve head.     

Pits of the optic papilla in large optic nerve papillae. Papillometric characteristics in 15 eyes

Fifteen optic nerve heads with pits measured by optic disk planimetry according to Littmann and Jaeger's method were significantly larger than previously determined normal optic nerve heads. Their area measured 4.84 +/- 1.42 mm2 (2.77-8.02 mm2), their horizontal diameter 2.42 +/- 0.42 mm (1.76-3.38 mm) and their vertical diameter 2.53 +/- 0.30 mm (1.14-3.06 mm). The quotients of minimum to maximum diameter and the angle between the maximum diameter and the horizontal line were similar to those in normal optic disks. Because of their enlarged area but normal form this pathologic entity forms a subunit of macrodisks. The pits were located in 14 optic disks on the temporal side on average 100 degrees from the upper disk pole, and in two optic disks on the nasal side about 85 degrees from the upper pole. In two cases they were double and in one bilateral. Their area and number were significantly correlated (p less than 0.001 and p less than 0.05) to the area of the optic disk. With increasing optic nerve head size the optic cup was less excavated. The largest optic disk seen in this study did not have one at all. There might be a stepless continuation from normal-sized optic disks to macrodisks with physiologic macrocups and to optic nerve heads with pits. These represent a maximum extreme in the spectrum of optic disk anomalies and diseases associated with optic nerve head size.     

Optic disk and choroidal coloboma

Most of the optic nerve head abnormalities are clinically innocuous, but sometimes they can cause significant symptoms and lead to visual disturbance, or even to visual loss; optic pists can cause defects in the visual fields, not necessarily explicable by the serous maculopathy, that is the most important complication associated with optic pits. Our purpose is to present a case of an optic pit with sensory macular detachment associated with a choroidal coloboma located at a distance of two optic disc diameters from the optic nervehead. This finding to our knowledge has not been previously reported.     

Optic disc pit: primary diagnosis in a child

Congenital abnormalities of the optic nerve head are commonly detected by optometrists in practice. While some severe abnormalities can lead to poor visual acuity and are associated with other ocular and systemic disorders, others such as pits of the optic disc are predominantly benign with a latent risk of visual loss. This report details the primary diagnosis of unilateral optic disc pit in a seven‐year‐old patient.     

Author index

A 48-year-old diabetic woman was referred to us for retinopathy screening. Visual acuity was 20/20 with a refraction of –8.00 in each eye. Fundoscopy of the left eye revealed an inferotemporal optic pit and inferior typical retinochoroidal coloboma independent of the disc. The right optic disc was normal. There was a small choroidal coloboma just inferior to optic nerve head. Systemic and neurologic examinations were normal. Our case is a rare example of optic pit and independent coexistent choroidal coloboma. This observation supports the theory that optic disc pits may be the result of a faulty closure of the embryonic fissure.     

Optic nerve cyst associated with optic disk pits

Purpose To report a case with two optic disk pits which were associated with an optic nerve cyst in the same eye.Methods Observational case report.Results A 47-year-old patient noted visual impairment in the right eye. On examination the best corrected visual acuity in the right eye was 20/80 and in the left eye was 20/20. Biomicroscopy revealed, in the right eye, a very pale optic disk with two optic disk pits without macular elevation. Magnetic resonance imaging (MRI) revealed a well circumscribed 6×6-mm² round cystic lesion within the right optic nerve sheath adjacent to the temporal aspect of the right optic nerve at its retrobulbar segment, which compressed and displaced the nerve.Conclusions In the case of an extremely pale optic disk with congenital pits and visual impairment without macular detachment, radiological examination is indicated in order to exclude the possibility of coexisting optic nerve anomalies.     

Congenital Pits of the Optic Nerve Head: II. Clinical Studies in Humans

The clinical characteristics of 75 eyes with congenital pits of the optic nerve head were reviewed, particularly in relation to associated serous retinal detachment. Retinal detachment was found in 52% of all eyes with pits and 63% of eyes with temporally located pits. Of 20 untreated eyes with a pit and coexistent macular retinal detachment followed for more than one year, 55% (11/20) had visual acuity 6130 and 75% (15/20) had subretinal fluid at the most recent visit. Visual fields and intravenous fluorescein angiographic characteristics of pits are discussed and clinical evidence is presented supporting the theory that the associated subretinal fluid is derived from liquified vitreous.     

Macular schisis and detachment associated with presumed acquired enlarged optic nerve head cups

PURPOSE: To describe a clinical syndrome of macular schisis and detachment in patients with acquired optic nerve head cupping resulting from glaucoma. DESIGN: Retrospective review of five patients. METHODS: Patients were included if they had optic nerve cupping and macular schisis with or without detachment with no other identifiable cause. The patients had to have no leakage on fluorescein angiography and no vitreous traction on examination or on optic coherence tomography (OCT). These patients were followed up and visual acuity, intraocular pressure, and the findings of serial fundus and OCT examinations were noted. RESULTS: Five patients had schisis with or without detachment of the macula with pronounced optic nerve head cupping. One patient had resolution of the macular fluid after filtering surgery for uncontrolled glaucoma. Two patients underwent a vitrectomy with intraocular gas and had almost total resolution of macular fluid and improved vision. CONCLUSIONS: Macular schisis and detachment can occur in patients with presumed enlarged optic nerve head cups in the absence of obvious congenital anomalies of the disk. The authors believe the cause is leakage of fluid from the vitreous through a tiny hole in the thin tissue of the cup. This is a similar mechanism to that seen in patients with optic pits. A vitrectomy or steps to reduce the intraocular pressure may result in resolution of the fluid and improved vision.     

Prevalence of congenital optic disc pits in adult Chinese: The Beijing Eye Study

PURPOSE: To determine the prevalence of optic disc pits in the elderly Chinese population. METHODS. The Beijing Eye Study, a population-based, cross-sectional cohort study, included 4439 subjects out of 5324 subjects invited to participate (response rate 83.4%) with an age of 40+ years. The present study included 4027 (90.7%) subjects for whom readable optic disc photographs were available. RESULTS: A pit of the optic nerve head was detected in one (0.02%) patient. Prevalence was 0.02 +/-1.58% (95% confidence interval: -0.02, 0.07). CONCLUSIONS: A congenital optic disc pit was found in one subject of the present population-based study in mainland China. In a mathematical sense, the calculated prevalence of optic disc pits in the whole population would be 0.02 +/- 1.58% (95% confidence interval: -0.02, 0.07) or about 1:4.000 subjects. From a statistical point of view, however, population-based studies with about 10,000 subjects are necessary to confirm this finding.     

Optic nerve head microvasculature of the rabbit eye.

Vascular luminal castings of rabbit eyes were microdissected and studied with scanning electron microscopy to elucidate the three-dimensional angioarchitecture of the optic nerve head. Using sequential microdissection, an incomplete arterial circle was identified as terminal branches of two to three short posterior ciliary arteries around the optic nerve head. Several recurrent branches from the arterial circle form a pial arterial network. This pial system supplies the optic nerve head microvasculature and receives numerous venules from them. The only large vessel to enter the optic nerve is a central retinal artery that has few branches within the optic nerve and provides several branches at the surface of the optic disc. Moderately numerous vessels connect the retinal and ciliary vascular layers within the optic nerve head. Few arterioles to the optic nerve head arise from the choroid; however, there are a small number of capillary and numerous venous connections between them. These results indicate that the principal blood supply of the rabbit optic nerve head is derived from the short posterior ciliary arteries by the arterial circle. The retinal arteries contribute to the surface vasculature of the optic nerve head. The pial system also plays a significant role in both supply and drainage of the rabbit optic nerve head.     

Vitreal pathogenic role in optic pit foveolar retinoschisis and central serous chorioretinopathy

Purpose: To expand on current theories concerning the vitreal‐induced mechanism underlying the development of foveolar retinoschisis and macular sensory detachments associated with optic nerve head pits. To propose the notion that vitreal traction may contribute to the pathogenesis of serous detachments in central serous chorioretinopathy (CSC). Reports: We describe two patients, one with macular retinoschisis and the other with central serous detachment. The first patient, a 45‐year‐old Hispanic female, presented with a temporally located optic nerve head pit, foveolar retinoschisis and schisis retinal spaces extending to the surrounding macula and to the disc. The second patient, a 43‐year‐old Haitian male, developed a central serous retinal detachment OS with decreased visual acuity one day following in‐office administration of Apraclonidine (0.5 per cent Iopidine, Alcon) and Dorzolamide‐Timolol Maleate (Cosopt, Merck) to lower elevated intraocular pressure (IOP). Macular retinal pigment mottling and epiretinal membrane sheen OU had been observed on his initial visit. Visual acuity improved within a three day period with resolution of the serous detachment. Conclusion: We suggest that the persistence of Cloquet's canal may permit fluid leakage into the proximal vitreous in cases of congenital optic nerve head pits. Tangential vitreal traction may promote the opening of a fistula at the optic pit and additionally thrust vitreal fluid into the pit and retinal space inducing the formation of schisis spaces, foveolar‐schisis and underlying sensory serous detachment. We question whether a reduction in vitreous volume, induced by initial administration of anti‐glaucoma medications, may contribute to the development and/or recurrence of central serous choroidopathy in predisposed individuals.     

Optic nerve head drusen

Optic disc drusen are congenital and developmental anomalies of the optic nerve head seen commonly in clinical practice, often as an incidental ophthalmologic finding during routine exams. Optic disc drusen are a form of calcific degeneration in some of the axons of the optic nerve. Visual acuity is often not affected but the visual fields of these patients can be abnormal and deteriorate over time. Optic disc drusen are familial and are not uncommon. They are thought to be the result of pathology at the level of the optic nerve head itself. The diagnosis can be made with clinical findings combined with B scan ultrasound and computed tomography. In addition, newer modalities using optic nerve head tomography are proving to be very useful. Since children as well as adults are affected, it is important to consider optic nerve head drusen in the differential diagnosis of papilledema or optic nerve swelling.     

Optic nerve head drusen

Optic disc drusen are congenital and developmental anomalies of the optic nerve head seen commonly in clinical practice, often as an incidental ophthalmologic finding during routine exams. Optic disc drusen are a form of calcific degeneration in some of the axons of the optic nerve. Visual acuity is often not affected but the visual fields of these patients can be abnormal and deteriorate over time. Optic disc drusen are familial and are not uncommon. They are thought to be the result of pathology at the level of the optic nerve head itself. The diagnosis can be made with clinical findings combined with B scan ultrasound and computed tomography. In addition, newer modalities using optic nerve head tomography are proving to be very useful. Since children as well as adults are affected, it is important to consider optic nerve head drusen in the differential diagnosis of papilledema or optic nerve swelling.     

Measurement of normal optic nerve head parameters

All optic nerve pathologies, including the glaucomas and disorders such as non-arteritic ischemic optic neuropathy, affect the appearance of the optic nerve head. Morphological examination of the optic nerve head in a qualitative and quantitative manner is therefore clinically mandatory. With the advent of modern imaging modalities such as confocal scanning laser tomography and optical coherence tomography, new diagnostic avenues have opened up to further refine the examination. The new imaging devices are now becoming a major adjunct to the diagnosis and long-term management of optic nerve head pathology; before it is possible to identify an abnormal optic disk, however, it is essential to understand the morphology and measurement of the normal disk. We summarize recent data on the normal morphology and measurement of optic nerve head parameters as assessed by the major imaging modalities now available.     

Inter-individual variation in blood supply of the optic nerve head

There is no one standard pattern of the blood supply of the optic nerve head in all human eyes. There is a marked inter-individual variation in the blood supply of the optic nerve head, and the various factors which produce this include variations in (I) the anatomical pattern of blood supply, (II) the pattern of posterior ciliary artery (PCA) circulation (the main source of blood supply to the optic nerve head), and (III) the blood flow. The variations in the pattern of PCA circulation include the variations in (a) number of PCAs supplying an eye, (b) area of supply to the optic nerve head by each PCA, (c) location of the watershed zones between the various PCAs in relation to the optic nerve head, and (d) blood pressure in various PCAs as well as short PCAs. The variations in the blood flow in the optic nerve head can be produced by changes in (i) the intraocular pressure, (ii) mean blood pressure in the capillaries of the optic nerve head and (iii) peripheral vascular resistance. These variations are discussed in detail. A lack of appreciation of these complexities of the blood supply of the optic nerve head in health and disease is responsible for many of the current problems in the understanding of the role of vascular disturbances in anterior ischemic optic neuropathy, glaucoma, low-tension glaucoma and various ischemic disorders of the optic nerve head.     

The normal optic nerve head.

BACKGROUND: The normal optic nerve head varies from one person to another, and there is often intraindividual variation as well. Factors such as race and age play an important role in distinguishing what may be considered normal variations in optic nerve head appearance. METHODS: A literature search and review of the latest studies on the optic nerve head was conducted. RESULTS: Results of recent studies showed that variations in the average cup-to-disc ratio exist for different races, and with age there is a gradual loss of nerve fibers leading to an overall increase in the cup-to-disc ratio. There is also evidence that congenitally larger optic nerves have larger cup-to-disc ratios and more nerve fibers. Smaller optic nerves, in contrast, have smaller cup-to-disc ratios and fewer nerve fibers. These findings are presented along with sample photographs depicting the normal variations in optic nerve head appearance. CONCLUSION: Over the past 30 years, technology has allowed for changing views about what may be considered normal in reference to the optic nerve head. This information is valuable to the eye care practitioner in helping to make appropriate patient care management decisions.     

The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series

Ophthalmic practitioners have to make a critical differential diagnosis in cases of an elevated optic nerve head. They have to discriminate between pseudopapilloedema (benign elevation of the optic nerve head) and true swelling of the optic nerve head. This decision has significant implications for appropriate patient management. Assessment of the optic disc prior to the advanced imaging techniques that are available today (particularly spectral domain optical coherence tomography and fundus autofluorescence), has mainly used diagnostic tools, such as funduscopy and retinal photography. As these traditional methods rely on the subjective assessment by the clinician, evaluation of the elevated optic nerve head to differentiate pseudopapilloedema from true swelling of the optic nerve head can be a challenge in clinical practice with patients typically referred for further neuroimaging investigation when the diagnosis is uncertain. The use of multimodal ocular imaging tools such as spectral domain optical coherence tomography, short wavelength fundus autofluorescence and ultrasonography, can potentially aid in the differentiation of pseudopapilloedema from true swelling of the optic nerve head, in conjunction with other clinical findings. By doing so, unnecessary patient costs and anxiety in the case of pseudopapilloedema can be reduced, and appropriate urgent referral and management in the case of true swelling of the optic nerve head can be initiated.     

The distribution of intravenously administered peroxidase in the optic nerve head of rabbit and monkey.

Peroxidase was used as an histologic tracer to study the permeability properties of the tissues in the optic nerve head of rabbit and monkey. The distribution of the tracer was observed by light microscopy. Within a short time after intravenous injection peroxidase was located extravascularly in the optic nerve head. The present study confirms earlier reports of a defect in the blood-optic nerve barrier in the region of the optic nerve head. The tracer was found to have reached the connective tissue of the optic nerve head, and to a lesser degree the optic nerve tissue proper. The observations made it probable that peroxidase had reached the connective tissue of the optic nerve head by diffusion from the perineural chorid and sclera.     

Abnormalities of the optic papilla in (peri)orbital encephaloceles--a contribution to the common pathogenesis of these abnormalities

Eleven patients (6 female, 5 male) with unilateral (6) or bilateral (5) (peri)orbital encephaloceles (nasofrontal in 4 cases, naso-orbital in 3, spheno-orbital in 4), were ophthalmologically examined. All had normal anterior segments, but ipsilateral or bilateral anomalies of the optic nerve head such as coloboma, pits, morning glory syndrome, dysplasia, tilted disk syndrome, hypoplasia, or a persistent hyaloid artery. In regard to the pathogenesis of (peri)orbital encephaloceles associated with optic disk malformations a common clefting defect in the neuroectodermal and neurocristal midline structures of the head is postulated, taking place in the fourth to sixth week of development.