Field of vision loss: what causes scotomas and what is the field of vision?

Visual field loss indicates a disorder of the eye, optic nerve or visual center in the brain. It occurs for head injuries, neurological diseases and other conditions. It can be temporary or permanent.

It can affect a child or an adult.

Most interested in:
What is visual field?
What are scotomas and what are the causes of narrowing/disorders of peripheral vision?
Can they be short-term or permanent?

A certain form is referred to as a scotoma. This refers to a condition of partial disturbance/change in the visual field that results in partial or complete loss of the ability to see. It can be a blurring (i.e. a reduction in visual acuity) or also a complete loss.

A scotoma is limited by an area of normal vision or relatively preserved vision.

+ Briefly: what is the field of vision?

The visual field is the portion of the visible space in front of the human eye.

The central (main) object that the eye focuses on (fixates on) is displayed on the retina at the point of sharpest vision (technically the fovea centralis). The other areas of vision do not achieve the same quality and sharpness.

However, quality and absolute visual acuity are not the issue in the case of peripheral vision.

In peripheral vision, it is not the acuity that is important, but the range.
Peripheral vision has a lower resolving power than central vision.
The fovea contains a higher number of light-sensitive cells, also for colour resolution.
In other parts of the retina, this power decreases.

Peripheral vision is used to orient us in space and to see during twilight and in reduced light conditions.

The range of vision is the same for almost every person under normal circumstances. What we see in front of us is the field of vision. More specifically, it refers to the area of vision when looking straight ahead with one eye.

The extent of the field of vision is affected by several factors, an example being:

• the anatomical proportion of the face
• the shape of the orbit, nose, forehead, eyelids
• distance
• lighting
• colour and colour saturation
• age

The range of the visual field is also affected by age, decreasing with age.

• The normal range of one eye is given as:
  • 90°-100° temporally - towards the temple, half
  • 60° nasal - towards the nose and upwards
  • 70° down

When looking with both eyes, the joint range partially overlaps, at approximately 120 degrees. This gives us the ability to see binocularly, i.e. to see with both eyes. This provides us with spatial perception and orientation in our surroundings.

The field of vision is further divided into central and peripheral.

1. Central - for sharp and colour vision
   • with the help of cones
   • gives us approximately 83% of all information
   • view of an object in the central part of the retina - the sharpest part - the fovea
2. peripheral - for orientation and motion recognition and twilight vision
   • the part where peripheral vision is mediated is mainly where the rods are located, which are able to capture black and white light

What are the causes of visual field loss?

The visual field narrows due to age and in old age. In such a case, of course, this condition is not labeled as a disorder/disease, but is a natural occurrence.

The opposite is the limitation of perception of one's surroundings, which affects orientation in space. Possibly vision in twilight.

The damage can affect one or both eyes. Monocular in one eye and binocular in both.

Scotoma as the number 1 disorder
Scotoma is a technical term used to refer to a loss of visual field. We know scotomas as complete (absolute) or also relative (partial).

Positive scotomas are those that a person perceives. However, there are also those that a person does not subjectively perceive. These are referred to as negative.

The perception of motion but not colors is referred to as a relative scotoma (especially in visual pathway disorders).

Causes of scotoma include:

• trauma to the eye
• retinal haemorrhage
• inflammation of the retina
• degenerative damage to the retina
• retinal detachment
• clouding of the optical structure of the eye (vitreous, lens) - cataract/glaucoma
• damage to the optic nerve

The human and mammalian eye also has what is called a natural (physiological) scotoma. This is a blind spot. A blind spot is a spot on the retina where there are no light-sensitive cells.

The optic/optic nerve enters the retina at this point.

Marriott's spot = blind spot = entrance of the papilla optic nerve (papilla nervi optici).

By examining it, increased intraocular pressure (pinpoint depression) or increased intracranial pressure (by its protrusion) can be determined.

In addition to the natural scotoma, we also know scotomas that indicate a visual disturbance. These scotomas can affect different areas of the field range and can also have different shapes.

Depending on the location, they are referred to as central, paracentral, arcuate or other.

2. Peripheral visual field defect

These defects are also differentiated into several forms. These include concentric narrowing of the visual field (tube/tunnel vision) or central area defect and also defect of half (hemianopsia) or quarter of the visual field (quadrianopsia).

Causes include:

• glaucoma
• retinal pigmentary degeneration and other retinal degenerations
• age-related macular degeneration
• damage to the visual pathway
• retinal damage, retinal detachment
• tumour in the eye
• cyst in the eye
• inflammation of the optic/optic nerve
• retinal blood flow disorders - when a blood vessel is blocked
• disorders of the cerebral cortex
• head trauma and brain damage
• atrophy of the visual target
• toxic optic neuropathy

Other causes

In the case of visual field disorders, various causes can be assumed. These involve the eye itself, the optic nerve (optic pathways) or the visual centre in the brain.

In addition, the disorder can arise after a head injury, brain injury or due to oppression due to a tumour, bleeding, such as in a stroke.

Possible causes of visual field loss:

• Head/brain injury
• stroke
• increased intracranial pressure - pressure inside the skull
• brain tumour/pituitary tumour
• Amaurosis fugax - transient impairment of blood supply to the eye or brain - loss of vision for a few minutes/loss of field
• Migraine and ophthalmic migraine - lasts about 15-30 minutes, transition of scotoma in visual field, with subsequent onset of headache
• multiple sclerosis - multiple sclerosis
• diabetic retinopathy
• retinopathy due to high blood pressure or in malignant hypertension and hypertensive crisis
• epilepsy
• exposure to toxic substances (methyl alcohol, quinine) and alcoholism
• malnutrition
• after surgery on the eye
• in pregnant women and as a manifestation of pre-eclampsia
• and others

Diagnosis and treatment in brief

Of course, the diagnosis of the cause is important. Otherwise, the right treatment cannot be chosen. As can be seen, the causes can be more numerous. Some are responsible for a short-term disorder, others for a permanent one. However, it is still true that the sooner the reason is found out, the better.

And this is especially true in the case of serious health and life-threatening conditions.

The history, i.e. information from the person, is important, as are imaging methods such as CT or MRI, X-rays in the case of injuries, and laboratory blood tests.

In the case of peripheral vision, several specialist examinations are carried out to determine the extent and damage.

Example:

• confrontation method examination - comparison of the extent in two persons
• perimetry - kinetic (moving object from the periphery to the centre) and static perimetry (light signs), there are several forms
  • manual perimetry
  • computerised perimetry
  • Maggiore-type projection perimeter
  • Föerster perimeter
  • Goldman perimeter

The peripheral vision check can also be done by yourself.

1. Without glasses, we can cover one eye
2. looking straight ahead
3. raise your free hand with your index finger up.
4. with your hand, slowly arc your eyes outwards.
5. stop the hand when it disappears from sight
6. on the other hand, with the same eye covered

The angle from the starting point to the vanishing point should be 90 degrees.
Towards the nose from the eye to the nose, approximately 60 degrees, as the nose overlaps the field of view on the inside.

Of course, this is an approximate result. Therefore, if in doubt, a professional examination is recommended.

Are you asking about treatment?

The choice is based on the diagnosis and so no specific or general treatment can be given.

More importantly...

+ when should I see a doctor?

When you feel a disturbance in the perception of the range of vision. Also, when the condition is recurrent and not just a one-off and short-term problem.