When a person loses his side (or peripheral) vision, he is said to suffer from tunnel vision. Glaucoma and damage to the retina are some of the most common causes of tunnel vision. This HealthHearty article informs you about the causes, symptoms, diagnosis, and treatment measures for tunnel vision.
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Looking through a microscope, telescope, binoculars, or wearing underwater diving masks or protective helmets (welding helmets) creates the sensation of a severely constricted visual field, a common feature of tunnel vision.
A person affected with tunnel vision cannot see objects that are outside the field of central vision. This happens because the peripheral area of vision is damaged, while central vision is not.
- Loss of clarity or blur in side vision is one of the most common symptoms of tunnel vision. A person affected with tunnel vision can only see objects that lie exactly in front of him.
- The person has to turn his head completely to see objects that are not within the field of central vision. In simple words, objects that lie straight ahead are visible, but others aren’t.
- Tunnel vision is more of viewing through a letterbox. It gives a feeling of looking through a narrow tube where the visual field is restricted.
- Also, due to the narrowed field of vision, it is not possible to view things from the corners of the eye.
Deterioration of side vision has been associated with glaucoma, a condition that is marked by damage to the optic nerve, which is mostly caused by increased intraocular pressure. The optic nerve that is located at the rear of the eye carries visual signals from the retina to the brain. In glaucoma, there is gradual loss of peripheral vision but it may eventually cause blindness if the proper treatment is not administered.
Taking alcoholic drinks in moderate amounts will not cause peripheral vision loss, although it may temporarily affect your eyesight and cause blurred vision. However, if you are a heavy drinker, vision problems are eminent. To be more specific, excess alcohol can have a negative impact on side vision. Alcohol abuse can damage the optic nerve, which is vital for peripheral vision.
The retina is a transparent tissue that lies at the back of the eye and is involved in converting light into electrical signals, which are transmitted through the optic nerve to the brain where they are identified as images. However, an injury or damage to the peripheral portion of the retina may eventually lead to tunnel vision. A medical condition like retinitis pigmentosa that is marked by decline in the functioning of rod photoreceptor cells of the retina, may also cause loss of peripheral vision.
When the body does not get adequate oxygen, a condition commonly referred to as hypoxia, it can cause vision problems. Insufficient supply of oxygen can also affect the working of retinal cells, which may lead to a wide range of eye problems including tunnel vision. No wonder, staying or traveling at high altitudes where oxygen levels are scarce does increase the risk of loss of side vision.
Getting addicted to hallucinogenic drugs such as LSD, peyote, PCP, and psilocybin can also cause vision difficulties that may manifest in the form of tunnel vision. These drugs produce hallucinations and tend to give a false notion of reality. They alter the perception of sight, sound, and images. These drugs can particularly distort the peripheral field of vision, which may lead to tunnel vision.
A rigorous physical activity such as running can also cause eyesight problems that include double or peripheral vision. During an intense workout, the oxygen needs of our body increase dramatically. However, while exercising if your brain does not get an adequate supply of oxygen, the processing of visual signals is disrupted, which can cause vision problems that may manifest in the form of tunnel vision. These vision problems may not resolve immediately after exercise until the oxygen balance of the body is restored.
When blood circulation to a specific part of the brain gets blocked, the medical condition is known as a stroke. In case, blood supply to the part of the brain that interprets visual images, is cut off, it may cause poor eyesight that may manifest in the form of peripheral vision loss. Formation of tumors in the pituitary gland (located below the base of the brain) can also cause vision difficulties in which the side vision may deteriorate.
Anger, anxiety, or panic attacks often cause adrenaline levels to rise. Adrenaline is a hormone secreted by the adrenal glands, as a reaction to something that is perceived as a stressful situation. However, this increased adrenaline production elevates pressure within the eyes, which can lead to eyesight problems such as peripheral loss of vision. In most cases, these vision problems are temporary and resolve after adrenaline levels return to normal. Even a roller coaster ride or sitting in a speedboat gives you an adrenaline rush, which may temporarily interfere with your normal eyesight.
The venom of a snake is neurotoxic, which can affect the peripheral nerves of the eye if the treatment is delayed. Blurred peripheral vision has been one of the ocular complications associated with snakebites. When bitten by highly venomous snakes such as the Black Mamba, the victim may suffer from peripheral vision loss.
Other causes of tunnel vision include:
- Severe cataracts
- Hypovolemia (severe blood loss)
- Migraine (during the aura phase, one may experience reduced peripheral vision or its loss)
- Prolonged exposure to air contaminated with heated hydraulic fluids and oils
The amount of peripheral vision loss can be ascertained through 3 major diagnostic tests. These tests that are done at an eye clinic can correctly diagnose if there is any decline in peripheral vision: They are given below:
Automated Perimetry: The patient is advised to view the screen of a bowl-shaped instrument. The instrument flashes light that may appear anywhere in his visual field. Whenever the patient detects the flash, it is recorded by pressing a button. The machine helps to identify the different areas of vision that cannot notice the flash of light.
Tangent Screen: In this test, a computer screen will be placed 1 m away from the patient. The patient will be advised to maintain his focus at an object that is located in the center of the screen. Different images appear on the peripheral areas of the screen. Now, without moving the eyes, you need to identify the images using your peripheral vision.
Confrontation Testing: In this test, you will be asked to close one eye and look at the doctor who is sitting in front of you. The doctor will move his hand sideways and ask whether the patient can see the hand. This is the basic test to measure the clarity of visual field.
Treatment will depend on the underlying cause. Tunnel vision related to stress, exercise, and even alcohol consumption usually resolves without any medical intervention. However, if this eye problem persists, consultation with an ophthalmologist is a must to diagnose the underlying cause. Medical conditions like glaucoma may be treated with prescription drugs or laser therapy to prevent further deterioration of vision. One may also consult a sports therapist to know some eye exercises that may help in enhancing peripheral vision.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.