Optic Nerve Hypoplasia

Optic nerve hypoplasia appears to be the result of excessive pruning of the optic nerve bundles during its development. The disc is pale and may be surrounded by a variably pigmented yellow–white ring. This appearance has been referred to as the “double ring” sign. While the nerve head is small, the retinal vessels are usually of normal caliber. It may occur in one or both eyes and be associated with mild to severe visual impairment, including limited visual acuity and visual field deficits.

This patient has a hypoplastic right optic disc. An incomplete “double ring” is present on the temporal aspect of the nerve. The retinal arteries and veins appear of normal caliber and exit and enter centrally. The crowded central cup places these nerves at risk for vascular occlusive disease, including large retinal venous and arterial occlusions, as well as ischemic papillopathy.

This patient exhibits the classic complete “double ring” sign of optic nerve hypoplasia.

Megalopapilla

Megalopapilla classically presents as an enlarged, but otherwise normal appearing optic disc. Patients often present with good visual acuity, but mild to moderate visual deficits may be seen.

This patient exhibits distinct asymmetry between the sizes of the optic discs compatible with megalopapilla. Visual function was normal.

Optic Nerve Aplasia

Optic nerve aplasia denotes total absence of the optic nerve, retinal blood vessels, and retinal ganglion cells. It is a rare condition, most commonly unilateral, and associated with microphthalmos, retinochoroidal colobomas, and cataracts. No light perception visual acuity and an afferent pupillary defect are common findings.

This patient has unilateral optic nerve aplasia. This photograph was taken in the region where the optic nerve should have been located. Note the complete absence of the optic nerve and associated blood vessels, and the extensive thinning of the retinal pigment epithelium (RPE).

Congenital Prepapillary Vascular Loops

Congenital vascular anomalies, or congenital prepapillary vascular loops, usually appear as tortuous loops of an arteriole or venule that extend above the plane of the optic nerve and into the vitreous cavity. It may have a corkscrew or spiral shape and is often encased in a white fibroglial sheath as it enters the vitreous cavity. They are usually found in eyes with good visual acuity, though may be associated with retinal arterial obstruction in the distribution of the retina supplied by the loop. Amaurosis fugax and vitreous hemorrhage have also rarely been reported.

A congenital vascular loop with a “hairpin” configuration is seen on the nasal aspect of the optic nerve extending into the vitreous cavity. The vast majority of congenital vascular loops are arteriolar malformations. Visual function was normal in this patient.

A corkscrew-shaped retinal arterial loop is seen overlying the center of the optic nerve in this asymptomatic patient.

A patient with a congenital prepapillary venous loop located along the superior border of the optic disc. Note the slow venous filling. There is no leakage or evidence of vascular compromise within the vascular arcades.

Persistent Fetal Vasculature (PFV)

Regression of the hyaloid artery usually begins in the third month of gestation and is complete by the eighth month of gestation. Failure of regression may result in variable findings, from only threadlike remnants protruding from the optic nerve to a grossly visible vessel attached to the posterior capsule of the lens, usually in an inferonasal location. If the hyaloid artery is encased by a glial sheath of neuroectodermal cells it is known as Bergmeister papilla.

Incomplete regression of the hyaloid artery, with an attachment to the posterior surface of the lens. This patient also had a localized posterior retinal detachment. This 5-month-old patient underwent lensectomy/vitrectomy surgery, with stabilization of the anatomic abnormalities. Dense amblyopia limited visual recovery in spite of ocular patching and utilization of a corrective contact lens.

Bergmeister Papilla

A fibrous encased vascular stalk coursing above the plane of the optic disc, though not reaching the posterior surface of the lens. This finding was of no visual consequence.

Congenital Retinal Macrovessel

A congenital retinal macrovessel is a rare vascular anomaly that appears as an enlarged vessel exiting the optic nerve and traversing the macula with several first-order tributaries extending superior and inferior to its horizontal course. The optic nerve itself is generally normal. Venous macrovessels are more common than arterial and are most commonly located in an inferotemporal location. Visual acuity is usually preserved despite the vessel crossing over or through the foveal avascular zone.

A congenital retinal macrovessel emanates from the superior aspect of the optic nerve and courses along the superior vascular arcade. The vessels then cross the macular region and extend inferiorly. While visual function was normal, there appears to be slight enlargement of the macular capillary free zone. The optic nerve was normal.

Cilioretinal Artery Occlusion

A cilioretinal artery is seen in approximately 5 to 10% of patients and is generally temporal in location. It emerges from the optic nerve separately from the vessels derived from the central retinal artery. It often has a hook-like appearance and exits from the nerve substance and/or the edge of the nerve with approximate equal frequency. A cilioretinal artery becomes significant when an occlusion occurs. This may occur by itself or in conjunction with a central retinal vein occlusion. If the artery supplies blood to the papillomacular bundle and the macular region, significant visual loss may occur. The converse scenario may also be seen, in that in the setting of a central retinal artery occlusion, a cilioretinal artery may be protective in the preservation of central visual function.

A cilioretinal artery occlusion is seen in this patient, with ischemia along the superior portion of the papillomacular bundle. While the patient was aware of a pericentral visual field deficit, the central vision remained 20/25.

Optic Nerve, Retinochoroidal, and Iris Colobomas

Congenital coloboma of the optic nerve is characterized by absent tissue and may show enlargement of the papillary area, partial or total excavation with a white surface, and retinal vessels that enter and exit from the borders of the defect. The affected nerve is commonly larger than normal in diameter. The coloboma may be unilateral or bilateral, and it is thought to be secondary to a failure of fusion of the posterior part of the embryonic fissure. Coloboma of the optic nerve may be caused by a mutation in the PAX6 gene.

These two patients have a coloboma of the optic nerve in conjunction with a contiguous coloboma of the choroid. In the lower photo, there is a fistulous tract that extends posteriorly, simulating a second optic nerve in appearance.

Excavation of the optic nerve, essentially a coloboma of the optic nerve secondary to cupping from glaucoma (top and middle rows) . In some patients, the colobomatous nature with fibrous proliferation and additional retinal vascular anomalous changes serve to differentiate this group of patients from other congenital anomalies and acquired disorders, such as glaucoma, trauma, or acquired ischemia.

A coloboma may involve the retinochoroid with or without concurrent optic nerve involvement. In this patient, there is a ridge of fibrous tissue bordering the superior aspect of the coloboma (middle left, arrows) . There is pre- and subretinal fibrosis (upper right, arrows) and a fissure through the sclera (arrowhead) . Colobomas may be associated with non-rhegmatogenous serous retinal detachments of the macula. Pigment epithelial hyperplasia is often seen at the margins of such a coloboma, sometimes in conjunction with a zonal area of atrophy from a resolved antecedent detachment.

A patient with a very large inferonasal retinochoroidal coloboma and an associated iris coloboma. The fluorescein angiogram documents almost complete hypofluorescence due to lack of RPE and choriocapillaris within the confines of the coloboma.

Morning Glory Disc Anomaly

The morning glory disc anomaly is a variant of an optic nerve coloboma. It is classically an enlarged, unilateral, funnel-shaped excavation of the optic nerve head with a central core of pale glial tissue. The margins are raised and chorioretinal pigmentary changes are commonly present at its border. Retinal vessels course near the margins, but are obscured centrally by glial tissue. It is more common in females and affects right eyes to a slightly greater degree than left eyes. There may be persistent hyaloidal remnants in the base of the excavation.

All of these patients have morning glory disc anomalies. Centrally, pale glial tissue is present, while more peripherally at the margin of the optic nerve there are numerous radially distributed retinal vessels. Variable degrees of chorioretinal pigmentary changes are present near or adjacent to the optic nerve head and its surrounding annulus.

A patient with a morning glory disc anomaly showing a glial cap over the optic nerve. The retinal vessels appear to exit the nerve in a more peripheral location, and this is seen quite readily on the accompanying fluorescein angiograms.

Optic Nerve Pit

(Also see Chapter 11 , Peripheral Retinal Degenerations and Rheg­matogenous Retinal Detachment)

An optic nerve head pit is an uncommon congenital anomaly that may result from imperfect closure of the superior edge of the embryonic fissure. It appears as a grey-white round or oval-shaped depression on the inferotemporal aspect of the optic nerve, often with adjacent peripapillary chorioretinal atrophy or retinal pigment epithelial pigment changes. Associated non-rhegmatogenous serous retinal detachments of the macula and schisis cavities are common. The origin of the subretinal fluid is controversial, but may arise from the vitreous cavity, leakage from retinal vessels within the pit or adjacent choroid, or may be cerebrospinal fluid leaking into the subretinal space via the subarachnoid space. In the presence of a long-standing serous macular detachment, pars plana vitrectomy surgery is often offered as treatment.

Several patients with optic nerve pits are shown. The pits are round, pale depressions most commonly found in a temporal location with adjacent chorioretinal pigmentary changes. Visual acuity is typically excellent except in cases of non-rhegmatogenous serous detachments. There is an association between optic nerve pits and glaucoma.

Third image courtesy of Dr. Eric Shrier

Two patients have an optic nerve head pit with a macular detachment, consisting of schisis and neurosensory elevation. Thinning of the inner limiting membrane is present in the fovea in the patient on the right, which gives the appearance of a macular hole (arrow) . Chronic serous detachments may result in localized formation of subretinal precipitates and mimic the appearance of central serous chorioretinopathy.

This patient has an optic nerve head pit in association with a dual macular detachment composed of intraretinal schisis and a neurosensory elevation. The middle image shows a serous detachment inferior to the nerve (arrows) . The detachment resolved following photocoagulation to the temporal edge of the disc. The fluorescein angiogram shows no leakage from the pit.

A color fundus photo and associated fluorescein angiogram in a patient with an optic nerve pit and serous macular detachment demonstrates no leakage near the pit or beneath the detachment. The optic pit is hypofluorescent on fluorescein angiography.

Courtesy of Dr. Jonathan G. Williams

A patient with an optic pit developed a serous neurosensory detachment and a lamellar hole. An external lamellar or full-thickness macular hole may develop within the detached retina of patients with optic pits.

Chronic serous detachments may result in localized formation of subretinal precipitates and chorioretinal pigmentary changes. The optic pit leaves degenerated photoreceptors in the subretinal space that contain chromophores detectable with fundus autofluorescence (FAF) (middle) . The optical coherence tomography (OCT) shows the pit of the retina combined with a schisis cavity.

A patient with an optic nerve pit and an associated serous schisis macular detachment. The detachment did not improve spontaneously, so therefore the patient underwent eventual pars plana vitrectomy surgery, which led to successful resolution of the serous macular detachment and improvement in visual function.

A patient with an optic disc pit in the inferotemporal location. The OCT shows a deep excavation of the optic nerve pit in this patient.

This patient presented with bilateral optic nerve pits and combined detachments. A schisis cavity and full-thickness retinal separation in contiguity with an excavation on the nerve head is readily apparent on the OCT image.

Bottom left image courtesy of Dr. Hideki Koizumi

Histopathologic light microscopy of an optic nerve head pit in the temporal aspect of the optic nerve head. Neuronal tissue can be seen entering the pit from the adjacent retina and extends far below the lamina cribrosa. Only a thin diaphanous tissue separates the optic pit from the subarachnoid space.

Situs Inversus

The retinal vessels exiting from the optic nerve generally progress directly temporally. However, on occasion they take a nasal bend, prior to heading temporally. The temporal half of the nerve generally appears full, and the optic cup is generally absent. Optic nerve hypoplasia may also be seen. This finding is also referred to as tilted disc syndrome (see below), nasal fundus ectasia, and Fuchs coloboma. Patients are generally asymptomatic.

The retinal vessels in this patient exit this optic nerve in a nasal direction prior to turning temporally. The patient was visually asymptomatic. Note the absence of a central optic nerve cup.

Tilted Disc Syndrome

Features of tilted disc syndrome include inferonasal tilting, an inferior or inferonasal crescent, situs inversus of the retinal vessels, fundus ectasia, myopia, and astigmatism. About 75% of cases are bilateral. Choroidal neovascularization may occur due to weakness in Bruch membrane, usually near the crescent of a staphyloma in myopic eyes.

In this patient with tilted disc syndrome, there is an absence of drusenoid change within a staphylomatous area (arrows) of the right eye. The nerve in the fellow eye (left) is only mildly tilted.

Left and second from right image, courtesy of Dr. Salomen Cohen

This patient has an inferonasal tilted disc with a crescent bordering on a staphyloma. There is a myopic conus on the inferior nasal margin of the disc. These patients are susceptible to exudative retinal detachments simulating central serous chorioretinopathy without serous pigment epithelial detachment. They may also experience choroidal neovascularization, usually at or near the crest of the staphyloma. The OCT shows a serous elevation of the retina in this patient.

A patient with a tilted disc and a classic myopic conus temporally.

Peripapillary Staphyloma

Peripapillary staphylomas are rare congenital anomalies characterized by a normal appearing optic nerve surrounded by a zone of staphylomatous excavation. Chorioretinal degeneration is a universal finding within the walls of the staphyloma. It is differentiated from myopic conus and staphyloma by a relatively normal refraction, normal appearing optic disc, absence of a progressive chorio­retinal degeneration, and lack of a temporal predilection of the peripapillary pigmentary alterations.

A typical posterior staphyloma in a highly myopic patient (−20 diopter myope).

Optic Nerve Head Drusen with Juxtapapillary Choroidal Neovascularization (CNV)

A young patient with optic nerve head drusen developed juxtapapillary subretinal hemorrhage, secondary to CNV. The optic nerve head drusen were confirmed echographically. The subretinal hemorrhage spontaneously cleared and visual function improved.

Optic nerve head drusen may provide a route for capillary proliferation and choroidal neovascularization to penetrate the subretinal space. This may result in type 2 CNV with associated serosanguineous fluid accumulation. Eventually, fibrous infiltration and disciform scar formation evolved in the macular region (arrow) .

This patient with optic nerve head drusen has a pigmentary scar in the macula (arrowhead, left) that is the result of abnormal choroidal neovascularization extending from the edge of the disc, around Bruch membrane, and into the subretinal space (arrow, middle) . There is late staining on fluorescein angiography from pooling into the subneurosensory detachment. Peripapillary hemorrhage is also present (arrowhead, right) .

This patient experienced an acute serosanguineous detachment of the macula in the right eye (upper left) from CNV associated with hemorrhage surrounding the optic nerve head drusen and in the subretinal space (arrow) . Regression of the neovascularization left a fibrous, atrophic hyperpigmented disciform scar (as seen in the middle upper photograph). The left eye also experienced choroidal neovascularization resulting in a fibrotic scar involving the fovea (upper right) . Follow-up on this patient 26 years later showed stabilization of the scar and visual function, though with an increase in the fibrous and pigmentary degenerative lesions in each eye.

Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION)

Non-arteritic anterior ischemic optic neuropathy (NAION) is a common optic neuropathy affecting primarily adults over the age of 50 years. Classically, the condition affects hyperopic, small discs, with a crowded central cup (“disc-at-risk”). It may result in altitudinal or arcuate visual field defects, disc hemorrhage, or edema of the optic nerve. These eyes must be differentiated from a vasculitis or temporal arteritis, which has a more threatening prognosis and generally necessitates intervention with systemic corticosteroid and/or other immunosuppressive agents.

This patient has a small, crowded optic nerve, which placed the patient at risk for development of NAION. At presentation, the nerve is hyperemic with a prominent microvascular papillopathy and flame-shaped hemorrhages (arrows) . The image on the right shows optic nerve edema in an eye with a similar process.

These two patients have non-arteritic anterior ischemic optic neuropathy. Fluorescein angiography in anterior ischemic optic neuropathy may demonstrate a “watershed abnormality,” or a zone of delayed vertical hypoperfusion of the choriocapillaris (arrow) . These capillaries eventually perfuse and are homogeneously fluorescent compared to the other surrounding small vessels of the choroid (right) . In the acute stages, the optic nerve head will have late leakage (lower right image) .

This patient had a history of non-arteritic anterior ischemic optic neuropathy in the right eye followed by acute manifestations in the left eye. The right eye shows a pale, ischemic nerve with central crowding of the small cup from retinal blood vessels. The left eye demonstrates an acute presentation, with swelling of the optic nerve, blurring of the disc margins, and juxtapapillary hemorrhage (arrow) .

Bilateral non-arteritic anterior ischemic optic neuropathy may occur. This patient has a history of segmental atrophy from an antecedent acute episode of non-arteritic anterior ischemic optic neuropathy (arrows) . The left eye (right) now has acute manifestations of the disease with edema of the lower half of the nerve and a corresponding superior altitudinal field defect.

Optic Nerve Papillitis

Papillitis describes swelling of the optic disc caused by local inflammation of the optic nerve head. It is most commonly secondary to demyelinating disease in younger patients and ischemic optic neuropathy in patients older than 50 years of age. Infectious, inflammatory, autoimmune, and neoplastic entities must also be considered.

Acute Neuroretinitis (Bartonella henselae)

Bartonella henselae is a gram negative rod and a common cause of acute neuroretinitis characterized by inflammation of the optic disc vasculature with exudation of fluid into the peripapillary retina. In this patient, optic nerve edema is present with flame hemorrhages and deposition of exudate. OCT confirms the acute swelling.

Leber Idiopathic Stellate Neuroretinitis

Leber idiopathic stellate neuroretinitis is characterized by a papillitis, prominent optic nerve vessels and a maculopathy with macular star formation from deposition of intraretinal lipid exudates. Serous retinal detachment may occur in some cases. The majority of patients previously classified with acute macular neuroretinitis most likely had a Bartonella henselae infection.

Chronic Papillitis

These patients have chronic papillitis with different associated manifestations. There is pure edema and erythematous prominence to the papillary circulation (left), peripapillary neurosensory detachment (middle), as well as scattered hemorrhages and prominent retinal vessels from obstructive venous disease (right).

Chronic papillitis may be severe and result in a persistently swollen disc with blurred margins, peripapillary hemorrhage, occlusive vasculopathy, and obliteration of the normal physiologic cup, as seen in the accompanying image.

Chronic papillitis can result in optic atrophy with residual swelling and pallor of the optic nerve. Residual arterial attenuation may be present. The pallor is not usually associated with significant cupping, though it can be confused in certain cases with a glaucomatous optic neuropathy. The visual fields will be irreversibly constricted with poor visual acuity.

Ocular Syphilis

Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum that may involve almost any intraocular structure. It may present as an acute papillitis with associated serous retinal detachment. Syphilitic papillitis may resolve to leave optic disc pallor and adjacent retinal pigment epithelial atrophy.

Idiopathic Intracranial Hypertension (IIH)

Papilledema, or idiopathic intracranial hypertension (IIH), implies optic disc swelling due to raised intracranial pressure. This patient has papilledema, which has led to swelling of the optic nerve, peripapillary detachment, lipid deposition extending toward the fovea, and pre-retinal hemorrhage bilaterally.

Courtesy of Dr. Blake Cooper

Optic Nerve Glioma

Optic nerve gliomas are most commonly seen in children or young adults and present with unilateral proptosis and decreased visual acuity. They are strongly associated with neurofibromatosis.

These two patients have an optic nerve glioma, which has led to atrophy of the nerve head and dilated venous–venous collateralization to compensate for posterior retrobulbar venous obstructive disease. The pale disc with collateralization can be compared to ciliary retinal collaterals following central retinal vein thrombosis where the nerve head is pink from prominence of the lamellar circulation of the nerve head.

Right image courtesy of Dr. James Bollings

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