**3. Optic neuritis**

Optic neuritis is a condition that produces abnormal vision loss without causing ocular abnormalities and we have to differentiate between typical and atypical optic neuritis.

Examination of a patient with acute optic neuritis reveals evidence of optic nerve dysfunction [24]. In addition, color vision (especially red color) is typically impaired in almost all cases

Visual Loss in Neuro-Ophthalmology http://dx.doi.org/10.5772/intechopen.80682 41

A relative afferent pupillary defect (RAPD) is demonstrable with the swinging flashlight test in all unilateral cases of optic neuritis. Patients with optic neuritis may also have a reduced

Visual field (VF) scotomas involve many forms of central or peripheral field disturbances such as ceco-central scotoma, inferior or superior altitudinal hemianopia, central scotoma, Bejerrum scotoma, hemianoptic defects, and more, almost any type of visual field defect (see

Presentation of optic disk in the acute phase is mostly normal with sharp disk margins and reddish color. Some of the patients with acute optic neuritis have minor degree of disk swelling with no correlation to visual acuity or visual field loss [25]. Over approximately 4–6 weeks, the optic disk in an eye with acute optic neuritis may become or remain normal or become pale, and most parameters of vision improve. In the chronic phase, the pallor of the optic disk may be diffuse or sectorial from my personal experience often the temporal part (42%) because the papillo-macular bundle is damaged in many patients with optic

and is helpful to differentiate from other optic neuropathies.

**Figure 4**).

neuritis [26].

**Figure 4.** Visual field possibilities in optic neuritis.

sensation of brightness and contrast sensitivity in the affected eye.


#### **3.1. Typical optic neuritis**

Optic neuritis is a term used to refer to inflammation of the optic nerve, and it appears in two forms: (1) when associated with a swollen optic disk, it is called papillitis or anterior optic neuritis. (2) When the optic disk appears normal, the term retro bulbar optic neuritis is used. Acute optic neuritis is the most common type of optic neuritis that occurs throughout the world and is the most frequent cause of optic nerve dysfunction in young adults mostly women. In this chapter, we will provide information about the clinical profile of optic neuritis, its natural history, its relationship to multiple sclerosis (MS), and the efficacy of corticosteroid treatment according the Optic Neuritis Treatment Trial (ONTT) [19–22].

#### **3.2. Demographics**

The annual incidence of acute optic neuritis is estimated in population-based studies to be between 1 and 5 per 100,000 people in the general population [23]. The majority of patients with acute optic neuritis are aged between 18 and 46 years, with a mean age of 30–35 years. However, optic neuritis can occur at any age, and females are affected more commonly than males by a ratio of 3:1 to 4:1.

#### **3.3. Clinical presentation**

Clinically, there are three major symptoms in patients with acute optic neuritis: (A) central visual loss in 90% of the patients. (B) Pain especially is exacerbated by eye movement around the affected eye in more than 90% of patients. (C) Relative afferent pupillary defect (RAPD) in all patients with unilateral optic neuritis [24].

Loss of central visual acuity occurs within few hours to several days, and the degree of visual loss varies from very minimal reduction to counting fingers (in rare cases, complete blindness can be observed). The majority of patients describe central vision loss predominately, and some of them complain of peripheral field defects. The visual loss is monocular in most cases, but particularly in children, both eyes are simultaneously affected.

The presence of pain is a very helpful, differentiating optic neuritis from other causes of optic neuropathies such as anterior ischemic optic neuropathy, which produces painless visual loss.

Examination of a patient with acute optic neuritis reveals evidence of optic nerve dysfunction [24]. In addition, color vision (especially red color) is typically impaired in almost all cases and is helpful to differentiate from other optic neuropathies.

A relative afferent pupillary defect (RAPD) is demonstrable with the swinging flashlight test in all unilateral cases of optic neuritis. Patients with optic neuritis may also have a reduced sensation of brightness and contrast sensitivity in the affected eye.

Visual field (VF) scotomas involve many forms of central or peripheral field disturbances such as ceco-central scotoma, inferior or superior altitudinal hemianopia, central scotoma, Bejerrum scotoma, hemianoptic defects, and more, almost any type of visual field defect (see **Figure 4**).

Presentation of optic disk in the acute phase is mostly normal with sharp disk margins and reddish color. Some of the patients with acute optic neuritis have minor degree of disk swelling with no correlation to visual acuity or visual field loss [25]. Over approximately 4–6 weeks, the optic disk in an eye with acute optic neuritis may become or remain normal or become pale, and most parameters of vision improve. In the chronic phase, the pallor of the optic disk may be diffuse or sectorial from my personal experience often the temporal part (42%) because the papillo-macular bundle is damaged in many patients with optic neuritis [26].

**Figure 4.** Visual field possibilities in optic neuritis.

**3. Optic neuritis**

sheath is the target of attack.

40 Causes and Coping with Visual Impairment and Blindness

**3.1. Typical optic neuritis**

**3.2. Demographics**

males by a ratio of 3:1 to 4:1.

all patients with unilateral optic neuritis [24].

but particularly in children, both eyes are simultaneously affected.

**3.3. Clinical presentation**

mation treatment can help to improve vision.

Optic neuritis is a condition that produces abnormal vision loss without causing ocular abnor-

**1. Typical optic neuritis:** Condition of visual loss caused by inflammatory demyelization of the optic nerve either idiopathic or associated with multiple sclerosis (MS). The myelin

**2. Atypical optic neuritis:** The nerve becomes inflamed as a part of uveitis or systemic inflam-

Optic neuritis is a term used to refer to inflammation of the optic nerve, and it appears in two forms: (1) when associated with a swollen optic disk, it is called papillitis or anterior optic neuritis. (2) When the optic disk appears normal, the term retro bulbar optic neuritis is used. Acute optic neuritis is the most common type of optic neuritis that occurs throughout the world and is the most frequent cause of optic nerve dysfunction in young adults mostly women. In this chapter, we will provide information about the clinical profile of optic neuritis, its natural history, its relationship to multiple sclerosis (MS), and the efficacy of corticosteroid

The annual incidence of acute optic neuritis is estimated in population-based studies to be between 1 and 5 per 100,000 people in the general population [23]. The majority of patients with acute optic neuritis are aged between 18 and 46 years, with a mean age of 30–35 years. However, optic neuritis can occur at any age, and females are affected more commonly than

Clinically, there are three major symptoms in patients with acute optic neuritis: (A) central visual loss in 90% of the patients. (B) Pain especially is exacerbated by eye movement around the affected eye in more than 90% of patients. (C) Relative afferent pupillary defect (RAPD) in

Loss of central visual acuity occurs within few hours to several days, and the degree of visual loss varies from very minimal reduction to counting fingers (in rare cases, complete blindness can be observed). The majority of patients describe central vision loss predominately, and some of them complain of peripheral field defects. The visual loss is monocular in most cases,

The presence of pain is a very helpful, differentiating optic neuritis from other causes of optic neuropathies such as anterior ischemic optic neuropathy, which produces painless visual loss.

malities and we have to differentiate between typical and atypical optic neuritis.

treatment according the Optic Neuritis Treatment Trial (ONTT) [19–22].

#### **3.4. Diagnostic studies**

Imaging studies in patients with presumed acute optic neuritis are usually performed for the following reasons: (A) to rule out particularly a compressive lesion; (B) to determine if a cause other than demyelization is responsible for inflammation of the optic nerve; or (C) to determine the visual and neurologic prognosis of optic neuritis.

more noncontrast enhancing lesions typical of multiple sclerosis on MRI is called a "clinically isolated syndrome" and is associated with a high risk of MS. Multiple sclerosis arises in only 25% of patients in whom MRI reveals no foci of demyelination in the brain. If one or two such

Visual Loss in Neuro-Ophthalmology http://dx.doi.org/10.5772/intechopen.80682 43

Many studies have shown that there are no data to support the efficacy in any treatment to alter the final visual outcome during a period of a year after optic neuritis. Treatment with corticosteroids is the main treatment option for patients with acute idiopathic optic neuritis. The prognosis for visual recovery after acute optic neuritis is very good also without treatment. According the ONTT (IV regimen of corticosteroids) [19–21, 32], steroid treatment should be delivered in acute optic neuritis if symptoms of 8 days duration or less. Begin with 3 days of intravenous Methylprednisolone in a dose of 1 g/day followed by 11 days course of oral prednisone at a dose of 1 mg/kg/day with a taper over 3 days. The ONTT was done in randomizing 457 patients with acute optic neuritis, comparing a group of patients following the IV steroid regimen versus a group of patients receiving placebo. The results of the trial showed that this regimen does not affect the final visual outcome of a patient, but it accelerates the recovery of vision compared with no treatment in the first 2 years. In addition, patients who experience an attack of acute optic neuritis should not be treated with low-dose oral prednisone alone because it provide no effect of visual outcome and may double the

The ONTT [19] results had another important aspect of treatment for acute optic neuritis regarding the possibility of having impact on the development of MS. Patients who were treated with the intravenous followed by oral corticosteroid regimen had a reduced rate of developing clinically definite MS during the first 2 years following treatment. MS developed in only 8% of patients who were treated according the corticosteroid regimen versus 17% of patients in the placebo group. This benefit of treatment was seen only in patients who had abnormal brain MRI at the time of onset of the optic neuritis. The protective effect was short and by 3 years after optic neuritis groups treated with ONTT IV regimen versus placebo groups had equal incidence to develop MS. These findings suggest that a patient with acute optic neuritis who has an abnormal brain MRI may benefit in the short term (2 years) from

A number of agents other than or in addition to systemic corticosteroids have been found to reduce the risk of the development of MS following an attack of acute optic neuritis over a longer period of time than corticosteroids alone. The Controlled High-Risk Avonex MS [33] Prevention Study (CHAMPS), a randomized, double-blind, placebo-controlled trial that enrolled patients with a first demyelinating event, offer some help. Weekly intramuscular injection with 30 ug of beta interferon 1a (Avonex) to patients who had 2 or more white-matter lesions of at least 3 mm on a brain MRI together with a 14-day course of Methylprednisolone followed by prednisone lowered the probability for MS. The group of patients receiving interferon beta-1a had a 44% reduction in the 3-year risk of developing MS compared with those receiving placebo. In addition, patients in the interferon group had fewer new and enhancing

foci are initially present, the risk is 65%; if three or more are present, it is 78% [31].

**3.7. Treatment**

recurrence rate for optic neuritis.

treatment with the IV/oral steroid regimen.

brain MRI lesions.

The best imaging study can be done by magnetic resonance imaging (MRI), it can reveal demyelization lesions of the optic nerve, manifesting as foci of T2-bright signal, areas of enhancement, and even optic nerve enlargement. These lesions are nonspecific, and a similar appearance can be observed in patients with infectious and other inflammatory optic neuropathies. The most important application of MRI in patients with optic neuritis is the identification of signal abnormalities in the white matter of the brain, usually in the periventricular region, consistent with demyelization. MRI is the strongest predictor of the eventual development of MS in patients with acute isolated optic neuritis. It can show multiple white-matter lesions in both cerebral hemispheres, including the periventricular regions.

Cerebrospinal fluid (CSF) analysis in the evaluation of patients with acute optic neuritis is not any more a strong predictor for MS. The presence of oligoclonal banding in the CSF is associated with the development of MS, but it can show false positive results. The powerful predictive value of brain MRI for MS is increased also because the Lumbar puncture examination is invasive. Therefore, CSF examination in the evaluation of patients with optic neuritis has been reduced. CSF studies in patients with optic neuritis are mostly useful to detect another inflammatory or infectious disorder.

#### **3.5. Associated neurologic disorder**

#### *3.5.1. Risk factors for developing MS*

The presence of at least 1 lesion in the periventricular white matter of the brain MRI is highly predictive, family history of MS, white race, old neurologic complains, winter onset, and younger age of optic neuritis. Conversely, patients with acute optic neuritis who have a normal brain MRI, severe disk swelling, a macular star, or disk hemorrhages or older age of onset have a low risk of developing MS.

The risk of developing MS [27–29] in a patient who experiences an attack of acute optic neuritis is about 75% in women and 34% in men over the subsequent 15–20 years, with the risk being greatest in the first 5 years after the first attack.

#### **3.6. MRI diagnostic criteria for multiple sclerosis**

Multiple sclerosis can be diagnosed when the MRI [30–32] in a patient with optic neuritis reveals two or more typical lesions of multiple sclerosis, at least one of which is contrast enhancing. The demyelization foci in the brain commonly appear in the corpus callosum and periventricular white matter and are best seen on T2-flair images.

The number of inactive typical white-matter lesions is the most important criterion for estimating the risk that the patient will develop multiple sclerosis [31]. Optic neuritis with two or more noncontrast enhancing lesions typical of multiple sclerosis on MRI is called a "clinically isolated syndrome" and is associated with a high risk of MS. Multiple sclerosis arises in only 25% of patients in whom MRI reveals no foci of demyelination in the brain. If one or two such foci are initially present, the risk is 65%; if three or more are present, it is 78% [31].

#### **3.7. Treatment**

**3.4. Diagnostic studies**

42 Causes and Coping with Visual Impairment and Blindness

inflammatory or infectious disorder.

**3.5. Associated neurologic disorder**

*3.5.1. Risk factors for developing MS*

have a low risk of developing MS.

being greatest in the first 5 years after the first attack.

periventricular white matter and are best seen on T2-flair images.

**3.6. MRI diagnostic criteria for multiple sclerosis**

Imaging studies in patients with presumed acute optic neuritis are usually performed for the following reasons: (A) to rule out particularly a compressive lesion; (B) to determine if a cause other than demyelization is responsible for inflammation of the optic nerve; or (C) to

The best imaging study can be done by magnetic resonance imaging (MRI), it can reveal demyelization lesions of the optic nerve, manifesting as foci of T2-bright signal, areas of enhancement, and even optic nerve enlargement. These lesions are nonspecific, and a similar appearance can be observed in patients with infectious and other inflammatory optic neuropathies. The most important application of MRI in patients with optic neuritis is the identification of signal abnormalities in the white matter of the brain, usually in the periventricular region, consistent with demyelization. MRI is the strongest predictor of the eventual development of MS in patients with acute isolated optic neuritis. It can show multiple white-matter

Cerebrospinal fluid (CSF) analysis in the evaluation of patients with acute optic neuritis is not any more a strong predictor for MS. The presence of oligoclonal banding in the CSF is associated with the development of MS, but it can show false positive results. The powerful predictive value of brain MRI for MS is increased also because the Lumbar puncture examination is invasive. Therefore, CSF examination in the evaluation of patients with optic neuritis has been reduced. CSF studies in patients with optic neuritis are mostly useful to detect another

The presence of at least 1 lesion in the periventricular white matter of the brain MRI is highly predictive, family history of MS, white race, old neurologic complains, winter onset, and younger age of optic neuritis. Conversely, patients with acute optic neuritis who have a normal brain MRI, severe disk swelling, a macular star, or disk hemorrhages or older age of onset

The risk of developing MS [27–29] in a patient who experiences an attack of acute optic neuritis is about 75% in women and 34% in men over the subsequent 15–20 years, with the risk

Multiple sclerosis can be diagnosed when the MRI [30–32] in a patient with optic neuritis reveals two or more typical lesions of multiple sclerosis, at least one of which is contrast enhancing. The demyelization foci in the brain commonly appear in the corpus callosum and

The number of inactive typical white-matter lesions is the most important criterion for estimating the risk that the patient will develop multiple sclerosis [31]. Optic neuritis with two or

determine the visual and neurologic prognosis of optic neuritis.

lesions in both cerebral hemispheres, including the periventricular regions.

Many studies have shown that there are no data to support the efficacy in any treatment to alter the final visual outcome during a period of a year after optic neuritis. Treatment with corticosteroids is the main treatment option for patients with acute idiopathic optic neuritis. The prognosis for visual recovery after acute optic neuritis is very good also without treatment. According the ONTT (IV regimen of corticosteroids) [19–21, 32], steroid treatment should be delivered in acute optic neuritis if symptoms of 8 days duration or less. Begin with 3 days of intravenous Methylprednisolone in a dose of 1 g/day followed by 11 days course of oral prednisone at a dose of 1 mg/kg/day with a taper over 3 days. The ONTT was done in randomizing 457 patients with acute optic neuritis, comparing a group of patients following the IV steroid regimen versus a group of patients receiving placebo. The results of the trial showed that this regimen does not affect the final visual outcome of a patient, but it accelerates the recovery of vision compared with no treatment in the first 2 years. In addition, patients who experience an attack of acute optic neuritis should not be treated with low-dose oral prednisone alone because it provide no effect of visual outcome and may double the recurrence rate for optic neuritis.

The ONTT [19] results had another important aspect of treatment for acute optic neuritis regarding the possibility of having impact on the development of MS. Patients who were treated with the intravenous followed by oral corticosteroid regimen had a reduced rate of developing clinically definite MS during the first 2 years following treatment. MS developed in only 8% of patients who were treated according the corticosteroid regimen versus 17% of patients in the placebo group. This benefit of treatment was seen only in patients who had abnormal brain MRI at the time of onset of the optic neuritis. The protective effect was short and by 3 years after optic neuritis groups treated with ONTT IV regimen versus placebo groups had equal incidence to develop MS. These findings suggest that a patient with acute optic neuritis who has an abnormal brain MRI may benefit in the short term (2 years) from treatment with the IV/oral steroid regimen.

A number of agents other than or in addition to systemic corticosteroids have been found to reduce the risk of the development of MS following an attack of acute optic neuritis over a longer period of time than corticosteroids alone. The Controlled High-Risk Avonex MS [33] Prevention Study (CHAMPS), a randomized, double-blind, placebo-controlled trial that enrolled patients with a first demyelinating event, offer some help. Weekly intramuscular injection with 30 ug of beta interferon 1a (Avonex) to patients who had 2 or more white-matter lesions of at least 3 mm on a brain MRI together with a 14-day course of Methylprednisolone followed by prednisone lowered the probability for MS. The group of patients receiving interferon beta-1a had a 44% reduction in the 3-year risk of developing MS compared with those receiving placebo. In addition, patients in the interferon group had fewer new and enhancing brain MRI lesions.

To conclude, a clinician should discuss with a patient having acute optic neuritis the treatment benefits comparing to no treatment emphasizing that there is a good chance (more than 80%) that visual acuity will recover to 20/20 within a year without treatment. It is important to explain the patient the relation between optic neuritis and the chances of developing MS. No treatment affects the final outcome of visual acuity.

**3.11. Immune optic neuritis**

or immunosuppressive medications.

**3.12. Sarcoidosis**

common [39].

○ C-reactive protein

○ Serum chemistry

○ Rheumatoid factor

○ Antinuclear antibodies

○ Anti-ds-DNA antibodies

○ Lupus anticoagulant

○ *Borrelia* serology

○ Urinalysis

○ Anti-phospholipids antibodies

○ Serum angiotensin-converting enzyme test

○ Anti-neutrophilic cytoplasmic antibodies (ANCA)

○ Extractable nuclear antibody (ENA) profile

• Additional tests in case of "clinically possible differential diagnosis"

○ Blood sugar

○ Vitamin B<sup>12</sup>

○ Complete blood count

authors recommend high dose of corticosteroid treatment.

disease, Wegener's granulomatosis, and lupus erythematosus.

• Recommended laboratory tests mostly for atypical cases

Optic neuritis can appear within days or weeks after systemic influenza illness [34] or vaccination [38]; often binocular with good vision recovery [32]. Atypical optic neuritis is also associated with acute disseminated encephalomyelitis (ADEM), a condition in which multiple CNS manifestations occur at once; in most cases, patients recover and never recur. Some

Visual Loss in Neuro-Ophthalmology http://dx.doi.org/10.5772/intechopen.80682 45

In optic neuritis, if an underling cause is found, it should be treated with either corticosteroid

Optic neuritis is rare in Guillain-Barre syndrome, Crohn's disease, ulcerative colitis, behest's

When the optic nerve is involved, the vision declines and the optic disk might be swollen, with or without systemic signs. Vision recovers with corticosteroid therapy. Relapses are

#### **3.8. Visual prognosis**

The natural history of acute idiopathic optic neuritis is to worsen over several days to 2 weeks and then to improve mostly rapidly. Improvement can continue to occur up to 1 year after the onset of visual symptoms. I had some patients of which improvement started only after 2 months but it is uncommon. The mean visual acuity 1 year after an attack of otherwise uncomplicated optic neuritis is 20/20, and less than 10% of patients have permanent visual acuity less than 20/40. Most parameters of visual function, including contrast sensitivity, color perception, and visual field, improve in conjunction with improvement in visual acuity. According to some investigators, most patients retain excellent vision for at least 15 years after their first attack [24].

Although the overall prognosis for visual acuity after an attack of acute optic neuritis is extremely good, some patients have persistent severe visual loss after a single episode. Furthermore, even patients with improvement in visual function to "normal" may complain of movement-induced photopias or transient loss of vision with overheating or exercise (Uhthoff symptom). The ONTT since 1992 has made it clear that the risk of a recurrence or a new attack is substantially higher in patients treated with low-dose oral prednisone as opposed to patients who receive no treatment or who are treated according the ONTT [19]. About 25% of patients who experience an attack of acute optic neuritis will experience a second attack in that eye or a new attack in the previously unaffected eye.

#### **3.9. Atypical optic neuritis**

Optic neuritis that develops before the age of 15 years or after the age of 50 years may be atypical. Many of these cases have no periocular pain, and visual decline is over few weeks. Atypical optic neuritis should be divided to three categories: infectious, immune, and Sarcoid. Most of them appear with disk edema.

#### **3.10. Infectious optic neuritis**

This may occur in meningitis/encephalitis [34] and is treatable. The pathogens could be bacteria (Homophiles, Streptococcus, Staphylococcus, spirochetes, or mycobacteria), protozoa as Toxoplasmosis, fungi as Cryptococcus or Aspergillus, or herpes viruses [35, 36]. Syphilitic optic neuritis can develop very rapidly from every stage of the disease. Tuberculosis causes meningitis. Lyme optic neuritis is rare and mostly associated with those who visited near New Haven, Conn, USA.

Another type of optic neuritis is called Leber's stellate neuro retinitis caused by *Bartonella henselae* responsible for cat-scratch disease. States with disk edema and within weeks, we can find star shape collection of hard micro-exudates (star-shape) at the macula called neuroretinitis [37].

#### **3.11. Immune optic neuritis**

To conclude, a clinician should discuss with a patient having acute optic neuritis the treatment benefits comparing to no treatment emphasizing that there is a good chance (more than 80%) that visual acuity will recover to 20/20 within a year without treatment. It is important to explain the patient the relation between optic neuritis and the chances of developing MS. No

The natural history of acute idiopathic optic neuritis is to worsen over several days to 2 weeks and then to improve mostly rapidly. Improvement can continue to occur up to 1 year after the onset of visual symptoms. I had some patients of which improvement started only after 2 months but it is uncommon. The mean visual acuity 1 year after an attack of otherwise uncomplicated optic neuritis is 20/20, and less than 10% of patients have permanent visual acuity less than 20/40. Most parameters of visual function, including contrast sensitivity, color perception, and visual field, improve in conjunction with improvement in visual acuity. According to some investigators, most patients retain excellent vision for at least 15 years after their first attack [24]. Although the overall prognosis for visual acuity after an attack of acute optic neuritis is extremely good, some patients have persistent severe visual loss after a single episode. Furthermore, even patients with improvement in visual function to "normal" may complain of movement-induced photopias or transient loss of vision with overheating or exercise (Uhthoff symptom). The ONTT since 1992 has made it clear that the risk of a recurrence or a new attack is substantially higher in patients treated with low-dose oral prednisone as opposed to patients who receive no treatment or who are treated according the ONTT [19]. About 25% of patients who experience an attack of acute optic neuritis will experience a sec-

Optic neuritis that develops before the age of 15 years or after the age of 50 years may be atypical. Many of these cases have no periocular pain, and visual decline is over few weeks. Atypical optic neuritis should be divided to three categories: infectious, immune, and Sarcoid.

This may occur in meningitis/encephalitis [34] and is treatable. The pathogens could be bacteria (Homophiles, Streptococcus, Staphylococcus, spirochetes, or mycobacteria), protozoa as Toxoplasmosis, fungi as Cryptococcus or Aspergillus, or herpes viruses [35, 36]. Syphilitic optic neuritis can develop very rapidly from every stage of the disease. Tuberculosis causes meningitis. Lyme optic neuritis is rare and mostly associated with those who visited near

Another type of optic neuritis is called Leber's stellate neuro retinitis caused by *Bartonella henselae* responsible for cat-scratch disease. States with disk edema and within weeks, we can find star shape collection of hard micro-exudates (star-shape) at the macula called neuroretinitis [37].

ond attack in that eye or a new attack in the previously unaffected eye.

treatment affects the final outcome of visual acuity.

44 Causes and Coping with Visual Impairment and Blindness

**3.8. Visual prognosis**

**3.9. Atypical optic neuritis**

Most of them appear with disk edema.

**3.10. Infectious optic neuritis**

New Haven, Conn, USA.

Optic neuritis can appear within days or weeks after systemic influenza illness [34] or vaccination [38]; often binocular with good vision recovery [32]. Atypical optic neuritis is also associated with acute disseminated encephalomyelitis (ADEM), a condition in which multiple CNS manifestations occur at once; in most cases, patients recover and never recur. Some authors recommend high dose of corticosteroid treatment.

In optic neuritis, if an underling cause is found, it should be treated with either corticosteroid or immunosuppressive medications.

Optic neuritis is rare in Guillain-Barre syndrome, Crohn's disease, ulcerative colitis, behest's disease, Wegener's granulomatosis, and lupus erythematosus.

#### **3.12. Sarcoidosis**

When the optic nerve is involved, the vision declines and the optic disk might be swollen, with or without systemic signs. Vision recovers with corticosteroid therapy. Relapses are common [39].

	- C-reactive protein
	- Complete blood count
	- Serum chemistry
	- Blood sugar
	- Vitamin B<sup>12</sup>
	- Rheumatoid factor
	- Antinuclear antibodies
	- Anti-phospholipids antibodies
	- Anti-ds-DNA antibodies
	- Lupus anticoagulant
	- Serum angiotensin-converting enzyme test
	- *Borrelia* serology
	- Urinalysis
	- Anti-neutrophilic cytoplasmic antibodies (ANCA)
	- Extractable nuclear antibody (ENA) profile

for this presumably is that a major element in these injuries is transection injury to retinal ganglion cell axons, which causes instantaneous loss of axonal conduction and an inability to

Visual Loss in Neuro-Ophthalmology http://dx.doi.org/10.5772/intechopen.80682 47

This is diagnosed when traumatic optic neuropathy occurs without a history of foreign body. It occurs in anterior indirect injuries, which associated with sudden rotation of the globe from blunt trauma. Examples include a digit trauma to the globe or falling and hitting the eye on the corner of a table. Anterior indirect traumatic optic neuropathy can cause partial or total

Posterior indirect injury is the most common cause of traumatic optic neuropathy. It results from blunt head trauma that transmits a concussive force to the optic nerve, resulting in contusion at the optic canal. There may be little or no evidence of significant head trauma; a fall from a bicycle may suffice. In other cases, there is multisystem trauma or significant brain injury. Loss of consciousness occurs in 40–72% of patients with traumatic optic neuropathy. Motor vehicle and bicycle accidents are the most frequent causes of traumatic optic neuropathy, accounting for 17–63% of cases. Traumatic optic neuropathy may be iatrogenic, especially after maxillofacial or endoscopic surgery as a result of inadvertent direct injury to the optic nerve or transmitted force fracturing the optic canal. The common site of posterior indirect optic nerve injury is at the optic canal; the intracranial optic nerve is the next most common site of injury. There may or may not be bone fractures. Despite being most common, posterior indirect traumatic optic neuropathies fortunately occasionally have the most favorable prognosis, its spontaneous visual recovery sometimes occurring at variable times after injury. Presumably, the injury causes concussion and focal blockade of axonal conduction without loss of its structural integrity. Once there is healing of the edema or other molecular events blocking conduction, axonal function can return. The severity of initial visual loss in patients with traumatic optic neuropathy varies from no light perception to 20/20, with sometimes only a visual field defect as functional evidence of disease. An afferent pupillary defect is always present and is the major clue for the diagnosis in the presence of otherwise normal eye. Patients with very poor vision (e.g., light perception only or no light perception) are less likely to improve, regardless of therapy, than patients with vision better than light perception. The reason is likely that severe injury causes axonal transection, membrane disruption, or cytoskeletal disorganization, any of which can lead to axonal dissolution and irreversible loss of conduction of visual information. In some cases, the visual loss only begins several hours to days after the injury. If this happens, the possibility of an intrasheath hemorrhage should

The diagnosis is radiological. It is essential in the evaluation of a patient with traumatic optic neuropathy not only for demonstrating correlative signs of injury but also detection of pre-existing

regenerate axons later.

**4.2. Indirect anterior traumatic optic neuropathy**

**4.3. Posterior indirect traumatic optic neuropathy**

be entertained, and neuroimaging should be repeated.

**4.4. Neuroimaging**

avulsion of the optic nerve, with associated peripapillary hemorrhage.

