Optic papillitis is a specific type of optic neuritis. Inflammation of the optic nerve head is called "papillitis" or "intraocular optic neuritis"; inflammation of the orbital portion of the nerve is called "retrobulbar optic neuritis" or "orbital optic neuritis". It is often associated with substantial losses in visual fields, pain on moving the globe, and sensitivity to light pressure on the globe. It is often an early sign of multiple sclerosis.

Papillitis may have the same appearance as papilledema. However, papillitis may be unilateral, whereas papilledema is almost always bilateral. Papillitis can be differentiated from papilledema by an afferent pupillary defect (Marcus Gunn pupil), by its greater effect in decreasing visual acuity and color vision, and by the presence of a central scotoma. Papilledema that is not yet chronic will not have as dramatic an effect on vision. Because increased intracranial pressure can cause both papilledema and a sixth (abducens) nerve palsy, papilledema can be differentiated from papillitis if esotropia and loss of abduction are also present. However, esotropia may also develop secondarily in an eye that has lost vision from papillitis. Retrobulbar neuritis, an inflamed optic nerve, but with a normal-appearing nerve head, is associated with pain and the other findings of papillitis. Pseudopapilledema is a normal variant of the optic disk, in which the disk appears elevated, with indistinct margins and a normal vascular pattern. Pseudopapilledema sometimes occurs in hyperopic individuals.

Workup of the patient with papillitis includes lumbar puncture and cerebrospinal fluid analysis. B henselae infection can be detected by serology. MRI is the preferred imaging study. An abnormal MRI is associated with a worse visual outcome.

The onset of ocular symptoms are usually preceded by episode of viral or flu-like symptoms such as fever, cough or sore throat (however this is not always the case). Patients can typically present erythema nodosum, livido reticularus, bilateral uveitis, and sudden onset of marked visual loss associated with the appearance of multiple lesions in the retina. These lesions may be colored from grey-white to cream-shaded yellow.

Other symptoms include scotomata and photopsia. In weeks to a month times the lesions begin to clear and disappear (with prednisone) leaving behind areas of retinal pigment epithelial atrophy and diffuse fine pigmentation (scarring). Rarely choroidal neovascularization occur as a late onset complication.

Major symptoms are sudden loss of vision (partial or complete), sudden blurred or "foggy" vision, and pain on movement of the affected eye. Early symptoms that require investigation include symptoms from multiple sclerosis (twitching, lack of coordination, slurred speech, frequent episodes of partial vision loss or blurred vision), episodes of "disturbed/blackened" rather than blurry indicate moderate stage and require immediate medical attention to prevent further loss of vision. Other early symptoms are reduced night vision, photophobia and red eyes. Many patients with optic neuritis may lose some of their color vision in the affected eye (especially red), with colors appearing subtly washed out compared to the other eye. Patients may also experience difficulties judging movement in depth which can be particular troublesome during driving or sport (Pulfrich effect). Likewise transient worsening of vision with increase of body temperature (Uhthoff's phenomenon) and glare disability are a frequent complaint. However, several case studies in children have demonstrated the absence of pain in more than half of cases (approximately 60%) in their pediatric study population, with the most common symptom reported simply as "blurriness." Other remarkable differences between the presentation of adult optic neuritis as compared to pediatric cases include more often unilateral optic neuritis in adults, while children much predominantly present with bilateral involvement.

On medical examination the head of the optic nerve can easily be visualized by a slit lamp with high plus or by using direct ophthalmoscopy; however, frequently there is no abnormal appearance of the nerve head in optic neuritis (in cases of retrobulbar optic neuritis), though it may be swollen in some patients (anterior papillitis or more extensive optic neuritis). In many cases, only one eye is affected and patients may not be aware of the loss of color vision until they are asked to close or cover the healthy eye.

Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is an acquired inflammatory uveitis that belongs to the heterogenous group of white dot syndromes in which light-coloured (yellowish-white) lesions begin to form in the macular area of the retina. Early in the course of the disease, the lesions cause acute and marked vision loss (if it interferes with the optic nerve) that ranges from mild to severe but is usually transient in nature. APMPPE is classified as an inflammatory disorder that is usually bilateral and acute in onset but self-limiting. The lesions leave behind some pigmentation, but visual acuity eventually improves even without any treatment (providing scarring doesn't interfere with the optic nerve).

It occurs more commonly in females and is more likely to affect persons between 20 and 30 years of age, but has been seen in people aged 16 to 40. It is known to occur after or concurrently with a systemic infection (but not always), showing that it is related generally to an altered immune system. Recurrent episodes can happen, but are extremely rare.

The sequence of clinical events in VKH is divided into four phases: prodromal, acute uveitic, convalescent, and chronic recurrent.

The prodromal phase may have no symptoms, or may mimic a non-specific viral infection, marked by flu-like symptoms that typically last for a few days. There may be fever, headache, nausea, meningismus, dysacusia (discomfort caused by loud noises or a distortion in the quality of the sounds being heard), tinnitus, and/or vertigo. Eye symptoms can include orbital pain, photophobia and tearing. The skin and hair may be sensitive to touch. Cranial nerve palsies and optic neuritis are uncommon.

The acute uveitic phase occurs a few days later and typically lasts for several weeks. This phase is heralded by bilateral panuveitis causing blurring of vision. In 70% of VKH, the onset of visual blurring is bilaterally contemporaneous; if initially unilateral, the other eye is involved within several days. The process can include bilateral granulomatous anterior uveitis, variable degree of vitritis, thickening of the posterior choroid with elevation of the peripapillary retinal choroidal layer, optic nerve hyperemia and papillitis, and multiple exudative bullous serous retinal detachments.

The convalescent phase is characterized by gradual tissue depigmentation of skin with vitiligo and poliosis, sometimes with nummular depigmented scars, as well as alopecia and diffuse fundus depigmentation resulting in a classic orange-red discoloration ("sunset glow fundus") and retinal pigment epithelium clumping and/or migration.

The chronic recurrent phase may be marked by repeated bouts of uveitis, but is more commonly a chronic, low-grade, often subclinical, uveitis that may lead to granulomatous anterior inflammation, cataracts, glaucoma and ocular hypertension. Full-blown recurrences are, however, rare after the acute stage is over. Dysacusia may occur in this phase.

Optic neuritis is a demyelinating inflammation of the optic nerve. It is also known as optic papillitis (when the head of the optic nerve is involved) and retrobulbar neuritis (when the posterior part of the nerve is involved). It is most often associated with multiple sclerosis, and it may lead to complete or partial loss of vision in one or both eyes.

Partial, transient vision loss (lasting less than one hour) can be an indication of early onset multiple sclerosis. Other possible diagnoses include: diabetes mellitus, low phosphorus levels, or hyperkalaemia.

In the early stages, papilledema may be asymptomatic or present with a headache. It can progress to enlargement of the blind spot, blurring of vision, visual obscurations (inability to see in a particular part of the visual field for a period of time). Ultimately, total loss of vision can occur.

The signs of papilledema that are seen using an ophthalmoscope include:

- venous engorgement (usually the first signs)

- loss of venous pulsation

- hemorrhages over and/or adjacent to the optic disc

- blurring of optic margins

- elevation of the optic disc

- Paton's lines (radial retinal lines cascading from the optic disc)

On visual field examination, the physician may elicit an enlarged blind spot; the visual acuity may remain relatively intact until papilledema is severe or prolonged.

Many times, an optic pit is asymptomatic and is just an incidental finding on examination of the eye by a physician. However, some patients may present with the symptoms of a posterior vitreous detachment or serous retinal detachment. This is because optic pits are associated with these disorders and are even speculated to be the actual cause of these disorders when they arise in patients with optic pits (see "Associated Retinal Changes" below for a more in-depth discussion on this theory). The most common visual field defects include an enlarged blind spot and a scotoma. Visual acuity is typically not affected by the pit but may get worse if serous detachment of the macula occurs. Metamorphopsia (distorted vision) may then result.

Optic pits were first described in 1882 as dark gray depressions in the optic disc. They may, however, appear white or yellowish instead. They can also range greatly in size (e.g. some can be minuscule while others may be large enough as to occupy most of optic disc surface). Optic pits are associated with other abnormalities of the optic nerve including large optic nerve size, large inferior colobomas of the optic disc, and colobomas of the retina. The optic disc originates from the optic cup when the optic vesicle invaginates and forms an embryonic fissure (or groove). Optic pits may develop due to failure of the superior end of the embryonic fissure to close completely.

Optic disc drusen (ODD) or optic nerve head drusen (ONHD) are globules of mucoproteins and mucopolysaccharides that progressively calcify in the optic disc. They are thought to be the remnants of the axonal transport system of degenerated retinal ganglion cells.

ODD have also been referred to as congenitally elevated or anomalous discs, pseudopapilledema, pseudoneuritis, buried disc drusen, and disc hyaline bodies. They may be associated with vision loss of varying degree occasionally resulting in blindness.

Raised intracranial pressure as a result of one or more of the following:

Optic nerve damage is progressive and insidious. Eventually 75% of patients will develop some peripheral field defects. These can include nasal step defects, enlarged blind spots, arcuate scotomas, sectoral field loss and altitudinal defects. Clinical symptoms correlate to visibility of the drusen. Central vision loss is a rare complication of bleeding from peripapillar choroidal neovascular membranes. Anterior ischemic optic neuropathy (AION) is a potential complication.

Optic pit, optic nerve pit, or optic disc pit is a congenital excavation (or regional depression) of the optic disc (also optic nerve head), resulting from a malformation during development of the eye. Optic pits are important because they are associated with posterior vitreous detachments (PVD) and even serous retinal detachments.

NAION typically presents suddenly and upon awakening. The patient notes seeing poorly in one eye. Vision in that eye is obscured by a dark shadow, often involving just the upper or lower half of vision, usually the area towards the nose. There is no pain. In approximately 6 months following the infarct visual acuity improves by 3 or more lines of vision on the Snellen Chart (the chart with smaller letters on each lower line) in 42.7% of patients. In addition, vision had worsened by 3 lines or more in 12.4% of patients. Second eye involvement occurs in approximately 15% to 20% of patients with NAION within 5 years. Fortunately, it may not be terribly devastating as the visual acuity may remain only moderately impaired. Furthermore, most cases of NAION involve the loss of a hemifield (either the upper or lower half of the visual field, but not both). A few cases of NAION involve almost total loss of vision.

Since arteritic AION is similar in presentation to non-arteritic AION, patients over the age of 50 diagnosed with NAION must be evaluated to exclude AAION (symptoms: painful jaw muscle spasms, scalp tenderness, unintentional weight loss, fatigue, myalgias and loss of appetite). Furthermore, NAION patients over the age of 75 should often be blood tested regardless.

The disease is characterised by bilateral diffuse uveitis, with pain, redness and blurring of vision. The eye symptoms may be accompanied by a varying constellation of systemic symptoms, such as auditory (tinnitus, vertigo, and hypoacusis), neurological (meningismus, with malaise, fever, headache, nausea, abdominal pain, stiffness of the neck and back, or a combination of these factors; meningitis, CSF pleocytosis, cranial nerve palsies, hemiparesis, transverse myelitis and ciliary ganglionitis), and cutaneous manifestations, including poliosis, vitiligo, and alopecia. The vitiligo often is found at the sacral region.

The diagnosis of POHS is based on the clinical triad of multiple white, atrophic choroidal

scars, peripapillary pigment changes (dark spots around optic disc of the eye), and a maculopathy caused by choroidal neovascularization.

Completely distinct from POHS, acute ocular histoplasmosis may rarely occur in immunodeficiency.

Anterior ischemic optic neuropathy (AION) is a medical condition involving loss of vision caused by damage to the optic nerve as a result of insufficient blood supply (ischemia). This form of ischemic optic neuropathy is generally divided into two types: arteritic AION (or AAION), where the loss of vision is an effect of an inflammatory disease of arteries in the head called temporal arteritis, and non-arteritic AION (abbreviated as NAION, or sometimes simply as AION) due to non-inflammatory disease of small blood vessels.

Arteritic anterior ischemic optic neuropathy (AAION or arteritic AION) is the cause of vision loss that occurs in temporal arteritis (aka giant cell arteritis). Temporal arteritis is an inflammatory disease of medium-sized blood vessels that happens especially with advancing age. AAION occurs in about 15-20 percent of patients with temporal arteritis. Damage to the blood vessels supplying the optic nerves leads to insufficient blood supply (ischemia) to the nerve and subsequent optic nerve fiber death. Most cases of AAION result in nearly complete vision loss first to one eye. If the temporal arteritis is left untreated, the fellow eye will likely suffer vision loss as well within 1–2 weeks. Arteritic AION falls under the general category of anterior ischemic optic neuropathy, which also includes non-arteritic AION. AION is considered an eye emergency, immediate treatment is essential to rescue remaining vision.

An exhaustive review article published in March 2009 described the latest information on arteritic and non-arteritic ischemic optic neuropathy, both anterior (A-AION and NA-AION) and posterior (A-PION, NA-PION, and surgical).

Open-angle glaucoma is painless and does not have acute attacks, thus the lack of clear symptoms make screening via regular eye check-ups important. The only signs are gradually progressive visual field loss, and optic nerve changes (increased cup-to-disc ratio on fundoscopic examination).

About 10% of people with closed angles present with acute angle closure characterized by sudden ocular pain, seeing halos around lights, red eye, very high intraocular pressure (>30 mmHg), nausea and vomiting, suddenly decreased vision, and a fixed, mid-dilated pupil. It is also associated with an oval pupil in some cases. Acute angle closure is an emergency.

Opaque specks may occur in the lens in glaucoma, known as glaukomflecken.

There are several constitutional symptoms of temporal arteritis that may aid in diagnosis of AAION such as jaw claudication (spasms of the jaw muscle), scalp tenderness, unintentional weight loss, fatigue, myalgias and loss of appetite. However, many cases are asymptomatic. There are also elevations in three blood tests that help identify AAION: erythrocyte sedimentation rate (ESR), C reactive protein (CRP) and platelet count (thrombocytosis). A related rheumatic disease called polymyalgia rheumatica has a 15 percent incidence of giant cell arteritis.

The most common symptom of ONSM is a gradual loss of vision in one eye. In a minority of patients this may be intermittent, at least to begin with. Less common symptoms include pain in the affected eye, protrusion of the eye, or double vision.

Ocular causes include:

- Iritis

- Keratitis

- Blepharitis

- Optic disc drusen

- Posterior vitreous detachment

- Closed-angle glaucoma

- Transient elevation of intraocular pressure

- Intraocular hemorrhage

- Coloboma

- Myopia

- Orbital hemangioma

- Orbital osteoma

- Keratoconjunctivitis sicca

Presumed ocular histoplasmosis syndrome (POHS) is a syndrome affecting the eye, which is characterized by peripheral atrophic chorioretinal scars, atrophy or scarring adjacent to the optic disc and maculopathy.

The loss of vision in POHS is caused by choroidal neovascularization.

Tumors, infections, and inflammatory processes can cause lesions within the orbit and, less commonly, the optic canal. These lesions may compress the optic nerve, resulting optic disc swelling and progressive visual loss. Implicated orbital disorders include optic gliomas, meningiomas, hemangiomas, lymphangiomas, dermoid cysts, carcinoma, lymphoma, multiple myeloma, inflammatory orbital pseudotumor, and thyroid ophthalmopathy. Patients often have bulging out of the eye (proptosis) with mild color deficits and almost normal vision with disc swelling.

Neurological causes include:

- Optic neuritis

- Compressive optic neuropathies

- Papilledema: "The underlying mechanism for visual obscurations in all of these patients appear to be transient ischemia of the optic nerve head consequent to increased tissue pressure. Axonal swelling, intraneural masses, and increased influx of interstitial fluid may all contribute to increases in tissue pressure in the optic nerve head. The consequent reduction in perfusion pressure renders the small, low-pressure vessels that supply the optic nerve head vulnerable to compromise. Brief fluctuations in intracranial or systemic blood pressure may then result in transient loss of function in the eyes." Generally, this transient visual loss is also associated with a headache and optic disk swelling.

- Multiple Sclerosis can cause amaurosis fugax due to a unilateral conduction block, which is a result of demyelination and inflammation of the optic nerve, and "...possibly by defects in synaptic transmission and putative circulating blocking factors."

- Migraine

- Pseudotumor cerebri

- Intracranial tumor

- Psychogenic

Symptoms, if any, can be mild even in the presence of significant swelling or masses.

Lacrimal gland involvement may cause swelling of the upper eyelid, or proptosis if there is severe swelling. Other orbital masses or inflammation can result in visual disturbance (blurred vision, double vision, visual field impairment), restricted eye movements, pain or discomfort, numbness in the distribution of the supraorbital and/or infraorbital nerves, or proptosis.

IgG4-related ophthalmic disease has been estimated to account for approximately 25% of all cases of proptosis, eyelid swelling and other features of orbital swelling.