Camera and the human eye. Human field of vision and its meaning Measuring visual fields

This article examines in detail the concept of “visual field”, methods for determining the indicators of this parameter in humans and its significance in ophthalmology.

Human field of vision size

All people are unique, each person has certain characteristics. The angle of view and the size of the field of view are different for everyone. U specific person they are determined by the following factors:

individual characteristics eyeball;
individual shape and size of eyelids;
individual characteristics of the bones near the orbits of the eyes.

In addition, the angle of view is determined by the size of the object being viewed and the distance from it to the eye (this distance and a person’s field of vision are inversely related).

The structure and structure of its skull are natural limits to its field of vision. In particular, the visual angle is limited to the brow ridges, the bridge of the nose and the eyelids. However, the limitation created by each of these factors is minor.

190 degrees is the value of the visual angle of both human eyes. One separate eye has the following normal indicators:

55 degrees for gradation upward from the fixation point;
60 degrees for gradation to the lower side and to the side going from the nose inward;
90 degrees for gradation from the side of the temple (outside).

When visual field testing shows a discrepancy normal level, the cause, often related to the eyes or nervous system, should be determined.

The visual angle improves a person’s spatial orientation and allows him to receive more data about the world around him, which enters the brain with the help of visual receptors. As a result scientific research visual analyzers it was found that human eye can clearly distinguish one point from another only if focusing at an angle for at least 60 seconds. Because the angle human vision directly determines the volume of perceived information; some people strive to expand it, since this allows them to read texts faster and remember the content well.

Ophthalmological significance of visual fields

Peripheral vision determines the visual fields for different colors, perceived by human eyes. In particular, the most developed angle is at white. In second place - Blue colour, and on the third - red. The narrowest angle occurs in visual perception Green colour. Examination of the patient's visual field allows the ophthalmologist to identify any visual abnormalities that are present.

Moreover, even a slight deviation in the fields sometimes indicates severe eye pathologies. Each person has his own individual norm, but certain general indicators to detect deviation.

Modern ophthalmologists can, upon detecting a discrepancy of this kind, identify eye diseases and some other ailments, primarily related to the central nervous system. In particular, by determining the angle and field of view, as well as the places where loss of visual fields occurs (disappearance of the image), the doctor is able to easily identify the place where hemorrhage occurred, a tumor or retinal detachment occurred, or inflammation occurred.

Field of view measurement

Computer perimetry of the eye - modern method diagnosing the narrowing of the field of human vision. Now this method has quite affordable price. This is a painless procedure that takes little time and allows you to detect deterioration peripheral vision to start treatment on time.

How the process works:

The first stage is a consultation with an ophthalmologist, during which he gives instructions. Before starting the procedure, the doctor must explain in detail all its nuances to the patient. No optical devices are used in this study. If the patient wears glasses or contacts, he will have to remove them. The left and right eyes are examined separately.
The patient directs his gaze to a fixed point located on a special device surrounded by a dark background. During the process of determining the patient's visual angle, points with different brightness levels appear in the periphery. These points must be seen by the patient in order to be recorded using a special remote control.
There are changes in the point placement scheme. Usually this pattern is repeated computer program and thanks to this, the moment of loss of vision can be determined with absolute precision. Since during perimetry there is a possibility that the patient will blink or press the remote control at the wrong time, the repetition method is more correct and leads to an accurate result.
The research takes place quite quickly; in a few minutes a special program will process all the information and produce the result.

In some clinics, such information is provided in printed form, in others it is recorded on disk. This is quite convenient when planning a consultation with a doctor of another specialization, and for assessing the dynamics during treatment of the disease.

Expanding the angle of human vision

Many studies have led to the conclusion that during the treatment of diseases that have caused the deterioration of this indicator, it is possible to increase the angle of human vision with special exercises. A completely healthy person can take advantage of this opportunity in order to improve individual visual perception.

A set of such exercises is called the representation technique and involves some special actions during normal reading. For example, you can change the distance from the text to the eyes. When this procedure is carried out regularly, the value of the individual angle of vision improves, which provides some advantages, since the quality of vision is largely determined by its angle.

Author of the article: Vladislav Solovyov

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Vision Options

The patient's visual complex is a complex structure with the help of which the object examines objects surrounding it, freely orients itself in areas regardless of lighting conditions and moves without problems in it.

Ophthalmic research has divided vision into two main types.

Central - playing central department The retina of the eye is responsible for analyzing the shapes of visible objects, fine detail and visual acuity. This view is inseparably interconnected with the angle of view - the value formed between two points located at the edges. The higher the angle, the lower the level of sharpness.
Peripheral - helps to evaluate things located near the focal point of the eyeball. This type is responsible for orientation in space under any lighting conditions. The visual acuity of this subtype is weaker than that of the central one. Secondary vision is directly related to the field - the space recorded without the need for additional eye movement.

Both types make up the overall picture when trying to consider surrounding things in relation to space.

Standard dimension

The body structure of any person is strictly individual, due to which the angle of view and field may differ in terms of indicators. The main influence on them (on the angle of view and field) is exerted by:

specific features of the personal structure of the eyeball;
the shape of the eyelids, their size;
individual characteristics in the structure of the eye orbits.

The angle of view is directly dependent on the object being considered - on its size, location at a distance from the eyes (in this case, the field of view expands if the object is at close range).

Natural limiters of the angle of view are anatomical features facial structures - eyelids, brow ridge, bridge of the nose. These factors give minor deviations; against the background of the collected data, a conditional norm of the visual angle for all studied patients was made - 190 degrees.

Features of the process and interesting facts

The organs of vision are a complex system through which we can collect visual information. The organ of vision is one of the most important sense organs, which directly affects the functioning of the brain and the development of intelligence and speech. This organ belongs to the peripheral part visual analyzer and it consists of the eyeball.

All these components of the eyeball are interconnected, and therefore if one of them is damaged, visual function will be impaired.

We wrote earlier what each of the shells is and what function it performs.

And here are some Interesting Facts about the human visual organs:

Techniques for expanding the angle of view

Designed to increase the field of view for better orientation in the surrounding space, extensive perception and analysis of the information received. The main example is reading books on any media - the patient remembers the information viewed faster and better.

An important factor in improving these features is pre-treatment. possible diseases which caused a narrowing of the node or field of vision. After correctly carried out therapeutic measures the patient can practice techniques to expand the visual field. They are also recommended to be taken into account by healthy people to improve overall visual perception.

The basis of these methodological actions– change in distance when reading literature. Viewing at different distances (near, far) will significantly expand the viewing angle.

Diagnostic tests

The process of the objects in question falling out of sight can occur either gradually or in an accelerated manner. In this regard, all citizens are recommended to undergo an annual planned medical checkup to identify initial stages deviations.

Modern medicine conducts studies necessary to determine deviations using computer perimetry. This technique is capable of identifying incipient deviations from general standards; its implementation is painless for the applicant.

Diagnosis is carried out according to the following scheme:

If additional consultation with a highly specialized doctor is necessary, the patient is given the test result on paper or in printed form.

The influence of a computer on human vision

The influence of a computer on human vision is not clear. Most people are convinced that a computer monitor, or rather its radiation, simply kills their eyesight. That the computer causes fatigue, dry eyes, and so on.

What's really going on? Does a computer affect the quality of vision?

According to numerous studies by American and European researchers, ultraviolet and x-ray radiation, which comes from a computer monitor, is very insignificant and cannot harm vision. A much larger portion of these rays comes from incandescent lamps.

human vision photoAt the same time, a modern computer monitor is covered with a special protective film that minimizes radiation even further. This film can be compared to sunglasses. This applies to modern monitors, the elements of which practically do not blink and do not contain mercury or other harmful substances.

At the same time, one cannot argue with the fact that since the computer has become a natural “inhabitant” in every home, the number of people with visual impairments has increased.

Negative influence Computer vision is affected for the following reasons:

Long and continuous work at the computer. If you work at a computer all day, and in the evening you watch movies on the computer, communicate on in social networks, then it is no wonder that the eyes become red, watery, the clarity of readable information is impaired, and so on. Children are especially susceptible to fatigue, so they especially need to control the time they spend in front of the computer.
Poor visual hygiene. That is, in most cases workplace and time is not organized correctly: the computer is too close to the eyes, it is not positioned correctly in relation to the window. In addition, users often sit hunched over, stretching their head forward. This disrupts the transmission of nerve impulses to the brain and thus the person sees poorly and gets tired quickly.
Poor quality lighting. If you work in front of a computer in a dark room or in a poorly lit room, your eyes quickly get tired due to strain.

Diseases identified by determining the visual angle

Small deviations from generally accepted normative data indicate the presence pathological processes in organism. After determining the angle, field and designation of the loss of individual areas, medical personnel determine the specific ailment leading to the development of further processes. The doctor determines:

exact location of hemorrhages;
presence of tumors;
retinal detachment;
inflammatory processes;
retinitis;
glaucoma;
exudates;
hemorrhagic changes.

To confirm changes in the fundus, the ophthalmoscopy method is additionally used. In cases where the patient’s visual angle is measured, the visual analyzer produces part of the image (up to half of the overall picture), and suspicions of tumor-like processes and extensive hemorrhages in the brain arise.

Further treatment of such deviations is carried out according to symptomatic phenomena, general therapy pathological conditions does not exist. Refusal necessary treatment will complicate the situation further development tumors and deterioration general condition after local hemorrhages.

Field of view is a set of points that human eyes can distinguish when stationary. Determining the boundaries of vision plays an important role in diagnosing peripheral vision. The latter is responsible for vision in the dark. If lateral vision is weakened, perimetry or other research methods are performed, based on the interpretation of which the diagnosis and appropriate treatment are established.

1. What is being examined?
2. Normal indicators human visual angle

What is being examined?

Lateral vision captures changes in objects in space, namely movements with an indirect gaze. First of all, peripheral gaze is necessary for coordination and vision in twilight. Visual angle is the size of the space that covers the eye without changing gaze fixation.

Fields of view

Using these diagnostic methods, it is possible to detect hemianopsia - pathologies of the retina. They are:

homonymous (impaired vision in one eye in the temple area, in the other in the nose area),
heteronymous (identical violations on both sides),
complete (disappearance of half the visual field),
binasal (loss of medial or internal fields),
bitemporal (loss of temporal areas of reference),
quadrant (pathology is located in any of the quadrants of the picture).

Uniform narrowing on all sides indicates a pathology of the optic nerves, and narrowing in the nasal area indicates glaucoma.

Normal visual angle in humans

Visual angle indicators are measured in degrees. Normally, the data should be as follows:

along the outer border - 90 degrees,
top – 50-55,
bottom – 65,
internal – 55-60.

The meaning will be different for each person, as several factors influence this. This:

skull shape,
anatomical features of the orbit,
drooping eyebrows,
eye planting,
shape, size of eyelids,
structure of the eyeball.

On average, the horizontal field of view is 190 degrees, and vertically – 60-70.

The normal line of sight corresponds to a comfortable position of the level of the eyes and head when viewing objects and is located 15 degrees below the horizontal line.

To start.

Visible light is electromagnetic waves, to which our vision is tuned. You can compare the human eye to a radio antenna, only it will be sensitive not to radio waves, but to a different frequency band. As light, humans perceive electromagnetic waves with a wavelength of approximately 380 nm to 700 nm. (A nanometer is equal to one billionth of a meter). Waves in this particular range are called the visible spectrum; on one side it is adjacent to ultraviolet radiation(so dear to the hearts of tanning enthusiasts), on the other hand, the infrared spectrum (which we ourselves are able to generate in the form of heat generated by the body). The human eye and brain (the fastest processor in existence) visually reconstruct the visible in real time the world(often not only visible, but also imaginary, but more on this in the article about Gestalt).

For photographers and amateur photographers, a comparison with a radio receiver seems meaningless: if we draw analogies, then with photographic equipment there is a certain similarity: the eye and the lens, the brain and the processor, the mental picture and the image saved in a file. Vision and photography are often compared on forums, and very different opinions are expressed. I decided to compile some information and draw analogies.

Let's try to find analogies in the design:

The cornea acts as the front element of the lens, refracting incoming light and at the same time as a “UV filter” that protects the surface of the “lens”,

The iris acts as a diaphragm - expanding or contracting depending on the required exposure. In fact, the iris, which gives the eyes the color that inspires poetic comparisons and attempts to “drown in the eyes,” is just a muscle that expands or contracts and thus determines the size of the pupil.

The pupil is a lens, and in it is a lens - a focusing group of objective lenses that can change the angle of refraction of light.

The retina, located on the back inner wall of the eyeball, works de facto as a matrix/film.

The brain is a processor that processes data/information.

And the six muscles responsible for the mobility of the eyeball and attached to it from the outside - with a stretch - but are comparable to both the autofocus tracking system and the image stabilization system, and even to the photographer pointing the camera lens at the scene of interest to him.

The image actually formed in the eye is inverted (as in a pinhole camera); Its correction is carried out by a special part of the brain that turns the picture “from head to toe.” Newborns see the world without this correction, so they sometimes shift their gaze or reach in the opposite direction of the movement they are following. Experiments with adults wearing glasses that reversed the image to an “uncorrected” view showed that they easily adapted to reverse perspective. Subjects who removed their glasses required a similar amount of time to “adjust” again.

What a person “sees” can actually be compared to a constantly updated stream of information that is assembled into a picture by the brain. The eyes are in constant motion, collecting information - they scan the field of view and update changed details, storing static information.

The area of the image that a person can focus on at any given time is only about half a degree of the field of view. It corresponds to the “yellow spot”, and the rest of the image remains out of focus, becoming increasingly blurred towards the edges of the field of view.

The image is formed from data collected by the eye's light-sensitive receptors: rods and cones, located on the back inner surface of the eye - the retina. There are 14 times more rods - about 110-125 million rods versus 6-7 million cones.

Cones are 100 times less sensitive to light than rods, but they perceive colors and react to movement much better than rods. Rod cells - the first type of cell - are sensitive to the intensity of light and to the way we perceive shapes and contours. Therefore, cones are more responsible for daytime vision, and rods are more responsible for night vision. There are three subtypes of cones, differing in their sensitivity to the different wavelengths or primary colors to which they are tuned: S-type cones for short wavelengths - blue, M-type for medium wavelengths - green and L-type cones for long wavelengths - red. The sensitivity of the corresponding cones to colors is not the same. That is, the amount of light required to produce (the same intensity of exposure) the same sensation of intensity is different for the S, M and L cones. Here is the matrix of a digital camera - even there are twice as many green photodiodes in each cell as there are photodiodes of other colors, as a result, the resolution of such a structure is maximum in the green region of the spectrum, which corresponds to the characteristics of human vision.

We see color primarily in the central part of the visual field - this is where almost all the cones that are sensitive to colors are located. In conditions of insufficient lighting, the cones lose their relevance and information begins to come from the rods, which perceive everything in monochrome. This is why much of what we see at night appears in black and white.

But even in bright light, the edges of the field of view remain monochrome. When you are looking straight ahead and a car appears at the edge of your field of vision, you will not be able to determine its color until your eye glances in its direction for a moment.

The rods are extremely photosensitive - they are able to register the light of just one photon. Under standard illumination, the eye registers about 3000 photons per second. And because the central part of the visual field is populated by daylight-oriented cones, the eye begins to see more off-center image detail as the sun dips below the horizon.

This can be easily verified by watching the stars on a clear night. As your eye adapts to the lack of light (full adaptation takes about 30 minutes), if you look at one point, you begin to see groups of faint stars away from the point where you are looking. If you move your gaze towards them, they will disappear, and new groups will appear in the area where your gaze was focused before moving.

Many animals (and birds - almost all) have much larger number cones compared to the average human, allowing them to detect small animals and other prey with high altitude and distances. Conversely, nocturnal animals and creatures that hunt at night have more rods, which improves night vision.

And now the analogies.

What are the focal lengths of the human eye?

Vision is a much more dynamic and capacious process to compare it with a zoom lens without additional information.

The image received by the brain from both eyes has a visual field angle of 120-140 degrees, sometimes a little less, rarely more. (vertically up to 125 degrees and horizontally - 150 degrees, a sharp image is provided only by the macula area within 60-80 degrees). Therefore, in absolute terms, the eyes are similar to a wide-angle lens, but the overall perspective and spatial relationships between objects in the field of view are similar to the picture obtained from a “normal” lens. Unlike the traditionally accepted opinion that the focal length of a “normal” lens lies in the range of 50 – 55 mm, the actual focal length of a normal lens is 43 mm.

Bringing the total angle of the field of view to a system of 24 * 36 mm, we obtain - taking into account many factors, such as lighting conditions, distance to the subject, age and health of the person - a focal length from 22 to 24 mm (focal length 22.3 mm received greatest number voices as closest to the picture of human vision).

Sometimes there are figures of 17 mm focal length (or more precisely, 16.7 mm). This focal length is obtained by repulsion from the image formed inside the eye. The incoming angle gives an equivalent focal length of 22-24 mm, the outgoing angle is 17 mm. It's like looking through binoculars with reverse side– the object will not be closer, but further away. Hence the discrepancy in numbers.

The main thing is how many megapixels?

The question is somewhat incorrect, because the picture collected by the brain contains pieces of information that are not collected simultaneously, this is stream processing. And there is still no clarity on the issue of processing methods and algorithms. And you also need to take into account age-related changes and health status.

A commonly cited figure is 324 megapixels, a figure based on the field of view of a 24mm lens on a 35mm camera (90 degrees) and the resolution of the eye. If we try to find some absolute figure, taking each rod and cone as a full-fledged pixel, we will get about 130 megapixels. The numbers seem incorrect: photography strives for detail “from edge to edge,” and the human eye at a particular moment in time “sharply and in detail” sees only a small fraction of the scene. And the amount of information (color, contrast, detail) varies significantly depending on lighting conditions. I prefer the 20 megapixel rating: after all, “ yellow spot"is estimated at about 4 - 5 megapixels, the rest of the area is blurred and undetailed (on the periphery of the retina there are mainly rods, grouped into groups of up to several thousand around ganglion cells - a kind of signal amplifiers).

Where is the resolution limit then?

By one estimate, a 74-megapixel file, printed as a full-color photograph at 530 ppi resolution and measuring 35 by 50 cm (13 x 20 inches), when viewed from a distance of 50 cm, corresponds to the maximum detail of which the human eye is capable.

Eye and ISO

Another question that is almost impossible to answer unambiguously. The fact is that, unlike film and digital camera matrices, the eye has no natural (or basic) sensitivity, and its ability to adapt to lighting conditions is simply amazing - we see both on a sunlit beach and in a shady alley at dusk.

Anyway, it is mentioned that in bright sunlight The ISO of the human eye is equal to one, and in low light it is about ISO 800.

Dynamic range

Let’s immediately answer the question about contrast/dynamic range: in bright light, the contrast of the human eye exceeds 10,000 to 1 - a value unattainable for either film or matrices. Night dynamic range (calculated from visible to the eye- at full moon in the field of view - stars) reaches a million to one.

Aperture and shutter speed

Based on a fully dilated pupil, the maximum aperture of the human eye is about f/2.4; other estimates range from f/2.1 to f/3.8. Much depends on the person’s age and health status. The minimum aperture - how far our eye is able to “stop down” when looking at a bright snowy picture or watching beach volleyball players under the sun - ranges from f/8.3 to f/11. (The maximum changes in pupil size for a healthy person are from 1.8 mm to 7.5 mm).

In terms of shutter speed, the human eye can easily detect flashes of light lasting 1/100th of a second, and in experimental conditions up to 1/200th of a second or shorter depending on the ambient light.

Broken and hot pixels

There is a blind spot in each eye. The point at which information from the cones and rods converges before being sent to the brain for batch processing is called the apex of the optic nerve. At this “top” there are no rods and cones - you get a rather large blind spot - a group of dead pixels.

If you're interested, try a little experiment: close your left eye and look straight at the “+” icon in the picture below with your right eye, gradually moving closer to the monitor. At a certain distance - about 30-40 centimeters from the image - you will stop seeing the “*” icon. You can also make the “plus” disappear by looking at the “star” left eye, closing the right one. These blind spots do not particularly affect vision - the brain fills in the gaps with data - very similar to the process of getting rid of dead and hot pixels on the matrix in real time.

Amsler grid

I don’t want to talk about illnesses, but the need to include at least one test target in the article forces me to. And maybe it will help someone to recognize incipient vision problems in time. So, age-related macular degeneration (AMD) affects the macula, which is responsible for the acuity of central vision - a blind spot appears in the middle of the field. It is easy to carry out a vision test yourself using an “Amsler grid” - a sheet of checkered paper, 10*10 cm in size with a black dot in the middle. Look at the point in the center of the Amsler grid. The figure on the right shows an example of what an Amsler grid should look like in healthy vision. If the lines next to the dot look fuzzy, there is a possibility of AMD and you should consult an ophthalmologist.

Let’s not say anything about glaucoma and scotoma – enough of the horror stories.

Amsler grid with possible problems

If darkening or distortion of lines appears on the Amsler grid, check with an ophthalmologist.

Focus sensors or yellow spot.

The place of best visual acuity in the retina - called the “yellow spot” due to the yellow pigment present in the cells - is located opposite the pupil and has an oval shape with a diameter of about 5 mm. We will assume that the “yellow spot” is an analogue of a cross-shaped autofocus sensor, which is more accurate than conventional sensors.

Myopia

Adjustment – myopia and farsightedness

Or in more “photographic” terms: front focus and back focus – the image is formed before or after the retina. For adjustment, either go to a service center (to ophthalmologists) or use micro-adjustment: using glasses with concave lenses for front focus (myopia, aka myopia) and glasses with convex lenses for back focus (farsightedness, aka hyperopia).

Farsightedness

Finally

Which eye do we look through the viewfinder with? Among amateur photographers, they rarely mention the leading and trailing eyes. It can be checked very simply: take an opaque screen with a small hole (a sheet of paper with a hole the size of a coin) and look at a distant object through the hole from a distance of 20-30 centimeters. After this, without moving your head, look alternately with your right and left eyes, closing the second. For the dominant eye, the image will not shift. When working with a camera and looking into it with your dominant eye, you don’t have to squint your other eye.

And a few more interesting independent tests from A. R. Luria:

Cross your arms over your chest in the Napoleon pose. The leading hand will be on top.

Interlace your fingers several times in a row. Thumb Whichever hand is on top is the leading one when performing small movements.

Take a pencil. “Take aim” by selecting a target and looking at it with both eyes through the tip of a pencil. Close one eye, then the other. If the target moves strongly when the left eye is closed, then the left eye is the leading one, and vice versa.

Your lead leg is the one you use to push off when jumping.

A person’s angle of vision is one of the most important components of functioning today. visual system person. By this concept, many experts mean the sum of the projections of all spatial points that can fall into the field of vision of a person in a state of fixation of the eye on a certain point.

Determining the angle of view

Everything that the patient sees will be projected onto the retina in the area corpus luteum. Visual field is the ability to quickly perceive one's position in space. This ability is measured in degrees.

Central and peripheral vision

The human visual system is quite complex. Therefore, it allows you to look at objects, the world around you, navigate in space under different lighting conditions and move around in it. In ophthalmology today there are two types of vision:

Central. It is an important component of the human visual system. It is provided by the central part of the retina. It is with the help of this vision that you will have a wonderful opportunity to analyze the shapes of the visible and small details. A person's central visual perception will be directly related to the visual angle that is formed between two points located at the edges. The greater the angle reading, the lower the sharpness.
Peripheral. This type of vision provides a wonderful opportunity to analyze objects that were located around the focal point of the eyeball. It is this that later allows you to navigate in space and darkness. Peripheral vision is much lower in acuity than central vision.

It is important to know! If central vision a person is directly proportional to the angle of vision, then the peripheral will directly depend on the field of view.

What is the optimal field of view indicator?

Each person today has his own characteristics. Therefore, angles and field of view are individual and may differ from each other. The following factors usually influence a person's field of vision in degrees:

specific signs of the structure of the human eyeball;
eyelid shape and size;
features of the composition of the bones of the eye orbits.

Also, a person’s viewing angle will depend on the size of the object in question and its distance from the eyes. The structure of the human visual system, as well as the structural features of the skull, are natural limiters of the angle of vision inherent in nature. However, the angle of limitation of all these factors is insignificant.

It is important to know! Experts have conducted numerous studies and have found that the visual angle of both human eyes is 190 degrees.

The normal field of view for each individual human analyzer will be as follows:

50-55 degrees for gradation upwards from the fixation point;
60 degrees for downward and sideward measurements inside from the nose;
from the side of the temporal region, the angle can increase to 90 degrees.

If a person's vision examination shows a discrepancy with the norm, then it is necessary to identify the cause, which is most often associated with vision problems. The visual angle allows a person to navigate space much better and receive more information that comes through the visual analyzer.

Perimetry norm

A study of the visual analyzer showed that the human eye clearly distinguishes two points when it is focused at an angle of at least 60 seconds. According to many experts, the angle of view will directly affect the amount of information received.

Field of vision measurement

IN Lately Determining visual fields is a really important task. The human visual analyzer is complex optical system, which has been formed over a long period of time. Different color rays are associated with a variety of information components, so the human eye perceives them differently. Peripheral visual analysis ability affects the different color rays that are perceived by our eyes.

The most developed corner has a white tint. Then comes blue and red. The viewing angle decreases the most when analyzing green shades. In most cases, even a slight deviation can indicate serious pathologies in the visual system. Each person has his own norm, but there are indicators by which deviation is determined.

Modern medicine makes it possible to perform qualitative research visual fields and quickly identify diseases of the visual system. By determining the angle and identifying image loss, the doctor can quickly determine the location of hemorrhage and the appearance of tumor processes. A good ophthalmologist, as a result of the examination, can identify the following disorders:

Exudates.
Retinitis.
Hemorrhages.

In the presence of such conditions, measuring the visual angle paints a general picture of the condition of the fundus, which is further confirmed using ophthalmoscopy. The study of this indicator and deviation from the norm also gives a picture of the state of the visual analyzer when diagnosing glaucoma. Even on early stages This disease you will be able to notice certain changes.

If during the process of diagnosing the problem a significant part is missing, then this is a serious suspicion of a tumor lesion or extensive hemorrhage in certain parts of the brain.

How to measure

At sharp decline angle of view, a person will definitely be able to notice it. If the decrease in visual angle occurs gradually, then this process may go unnoticed. That is why many experts recommend undergoing an annual examination, which will allow you to quickly detect various impairments. Diagnosis and determination of narrowing of the visual field in modern ophthalmology is carried out using an innovative method called computer perimetry. The cost of such a procedure is quite low, and the duration is only a few minutes. However, thanks to computer perimetry, it is possible to quickly determine a decrease in peripheral vision, even with small deviations, and quickly begin treatment.

The diagnostic procedure consists of the following steps:

Conducting a study to determine the angle of the visual field begins with consultation with a specialist. Before the procedure, the doctor must tell you all the features and rules of the procedure. The patient is examined without optical instruments. Each patient's eye is examined separately.
The patient must focus his gaze on a static point, which is located on the dark background of the device. During the procedure for measuring the angle of the visual field, bright dots will appear in the peripheral field with different intensities. These are exactly what the patient's eye should see.
The location of the points is constantly changing, and this allows you to determine with 100% accuracy the moment the site falls out.
The speed of this examination is quite fast and within a few minutes the program will process the information received and display the result.

Most modern clinics today provide information in printed form. Others provide the opportunity to record the received data on storage media.

How to expand your perspective

A wide field of view allows a person to better navigate space and perceive information more widely. When reading a book, a person with a greater perspective will do it much faster.

Numerous studies have shown that the angle of the visual field can be further expanded with the help of special exercises. It is possible to develop the capabilities of the visual analyzer absolutely healthy person. This will significantly improve your perception of the world around you. The scheme of such activities has a name – representation. Speaking in simple words such exercises will be associated with certain actions during a process such as reading. By doing this regularly you can broaden your perspective.

Many experts today recommend monitoring your health. Therefore, try to visit your ophthalmologist more often. Any disease is much easier to treat in the early stages, and diagnosing the fields and angle of view is an indicative way early diagnosis many ailments.