From the Guidelines
Optic nerve lesions can cause several distinct types of vision loss, including total blindness, central scotoma, altitudinal hemianopia, and arcuate scotoma, as well as color vision defects and reduced visual acuity. The specific pattern of vision loss helps localize the lesion within the visual pathway. According to the most recent study 1, optic nerve damage can be detected through examination of the optic nerve head and retinal nerve fiber layer, and may precede functional defects detected by standard automated perimetry. The study also highlights the importance of careful examination of the optic disc neural rim for small hemorrhages, as these may herald focal disc damage and visual field loss.
Some of the key types of vision loss associated with optic nerve lesions include:
- Total blindness, where complete vision loss occurs in the affected eye
- Central scotoma, characterized by a blind spot in the central visual field while peripheral vision remains intact
- Altitudinal hemianopia, where either the upper or lower half of the visual field is lost
- Arcuate scotoma, which appears as an arc-shaped blind spot
- Color vision defects and reduced visual acuity, even when total blindness doesn't occur
The location and extent of the damage to the optic nerve can affect the type and severity of vision loss, and early diagnosis through visual field testing, ophthalmoscopy, and neuroimaging is crucial, as some causes of optic nerve lesions (like optic neuritis or compressive lesions) may be treatable if identified promptly 1. Additionally, the study by 1 highlights the importance of considering underlying conditions such as systemic lupus erythematosus, which can cause optic neuropathy and result in vision loss.
In terms of diagnosis, a comprehensive clinical examination, including magnified stereoscopic visualization of the optic nerve head and retinal nerve fiber layer, is essential for detecting optic nerve damage 1. This examination can help identify signs of glaucomatous damage, such as vertical elongation of the optic nerve cup, enlargement of the optic nerve cup, and diffuse or focal narrowing of the neuroretinal rim.
Overall, the type and severity of vision loss associated with optic nerve lesions can vary widely, and early diagnosis and treatment are critical for preserving vision and preventing further damage.
From the Research
Types of Vision Loss
The types of vision loss associated with optic nerve lesions include:
- Blindness: as seen in a female patient diagnosed with a closed fracture in the right frontal lobe, irradiated to the optic canal, resulting in blindness in the right eye 2
- Visual impairments: immediate visual impairments can occur due to damage to the vessels of the optic nerve and break of the optical fibers 2
- Loss of visual acuity: optic neuritis, an inflammatory disease of the optic nerve, can result in an abrupt loss of vision, with recovery of vision almost never complete 3, 4, 5
- Loss of contrast sensitivity: optic neuritis can also result in a loss of contrast sensitivity, with no conclusive evidence of benefit in terms of recovery to normal contrast sensitivity with corticosteroid treatment 3, 4, 5
- Loss of visual field: optic neuritis can result in a loss of visual field, with no conclusive evidence of benefit in terms of recovery to normal visual field with corticosteroid treatment 3, 4, 5
Causes of Vision Loss
The causes of vision loss associated with optic nerve lesions include:
- Trauma: craniocerebral trauma can result in optic nerve injury, leading to vision loss 2
- Inflammation: optic neuritis, an inflammatory disease of the optic nerve, can result in vision loss 3, 4, 5
- Ischemia: damage to the vessels of the optic nerve can result in ischemia, leading to vision loss 2
- Compression: compression of the optic nerve can result in vision loss 6
- Infiltration: infiltration of the optic nerve can result in vision loss 6
- Toxic or hereditary metabolic dysfunction: toxic or hereditary metabolic dysfunction can result in vision loss 6