Blindness in humans

Damage to the visual apparatus and complete loss of vision significantly worsen the quality of life. Unfortunately, today blindness is not so rare. According to WHO statistics, about 2,2 billion people in the world have serious vision problems. Let’s figure out what can cause blindness, and in which cases the treatment will be effective.

What is blindness

For various reasons, a person’s vision may deteriorate, up to its complete loss, which is called blindness.

Blindness can be:

1. Absolute (congenital or acquired), when visual acuity is zero, and a person does not even see the outlines of objects, does not distinguish between light and darkness.
2. Partial – when a person retains light perception, but his field of vision is no more than 10%.
3. Color – in this case, color perception is impaired (most often the ability to perceive red).

There is another classification according to which blindness happens:

• reversible – that is, there is a treatment that can restore vision;
• irreversible – lost vision cannot be restored.

What you need to know about blindness

Causes of blindness in humans

Various factors can provoke loss of vision during life: infections, injuries, cataracts, glaucoma and many others.¹.

Congenital blindness in humans occurs due to pathologies in the structure of the eye, which developed during the period of intrauterine fetal formation. For example, when irreversible changes have touched the retina.

In other cases, the causes of blindness in humans lie in a whole list of diseases. The most common cause of acquired blindness is glaucoma. Due to the violation of the outflow of fluid, intraocular pressure increases, hence damage to the optic nerve occurs. In second place among the causes of blindness are eye injuries and trachoma (a chronic infectious eye disease caused by chlamydia).

Cataracts, a disease that causes clouding of the lens of the eye, can also lead to blindness. Cataracts are treatable and in most cases the patient’s vision can be restored.².

Another pathology dangerous for vision is retinal detachment from the underlying membranes of the eyeball. The situation is reversible, but only with the help of emergency surgery. The sooner the operation to repair the retinal tear is performed, the higher the chances of preserving vision.

Blindness in a person can be caused by clouding of the cornea and lack of blood supply against the background of diabetes mellitus and other diseases. Tumors of the visual structures and the brain can lead to loss of vision.

Signs of blindness in humans

The most characteristic symptom of blindness is the narrowing of the field of vision or its complete absence in one or both eyes. Acquired blindness can be sudden, for example, as a result of trauma, hemorrhage in the brain or retina. But more often the process of vision loss develops gradually. Blindness may be preceded by the following symptoms:

• with retinal detachment – periodic flashes of light before the eyes, loss of peripheral vision;
• with a stroke – a sharp deterioration in vision, which is often accompanied by nausea, headache, loss of sensation on one side of the body;
• with angle-closure glaucoma, a person is worried about severe pain and redness in the eye, headache;
• with cataracts, a veil appears before the eyes, it becomes difficult to distinguish letters when reading;
• with a corneal ulcer, a grayish spot appears on the mucous membrane, lacrimation occurs, a sensation of a foreign body in the eye.

Any discomfort in the eye area requires consultation with an ophthalmologist. Many diseases of the visual structures respond well to treatment at an early stage, which will allow a person to avoid complete loss of vision.

Diagnosis of blindness in humans

The primary diagnosis is to check the visual acuity of each eye. The procedure is called visometry and takes only a few minutes. During the study, the doctor will need special tables with letters, numbers and pictures. The patient, who is at a certain distance from the tablet, needs to read the lines indicated by the doctor. Each eye is examined in turn, closing the second eye at the time of examination.

The tables are different: Snellen (letters of the Latin alphabet), Sivtsev-Golovin (letters of the Russian alphabet), Orlova (with drawings) and Landolt (figures from half rings).

Other diagnostic methods include checking vision with a refractometer. This allows you to determine how clearly a person sees distant objects.

The next method of examining the eye, which is suitable for diagnosing glaucoma and cataracts, is the slit lamp. This ophthalmic device is used for the purpose of a detailed examination of the structure of the eyes, helps to identify the slightest pathology of the cornea³.

Computerized perimetry also helps to detect vision problems. This method of ophthalmological diagnostics allows the doctor to assess the boundaries of the patient’s field of view, to identify ophthalmic and neurological diseases such as glaucoma, retinal detachment, damage to the optic nerve.

Treatment of blindness in humans

Depending on the diagnosis, the treatment of blindness in a person can be conservative or surgical.

If the disease is detected at an early stage, then in patients with cataracts, the chances of restoring vision are high. In this case, it is necessary to carry out an operation to replace the lens in a timely manner.

In the case of retinal detachment, urgent fixation of the retina to the choroid is effective.

Patients with glaucoma are helped by drugs that lower intraocular pressure. In difficult cases, surgery is indicated.

If the optic nerve is damaged, it will not be possible to restore vision, and the patient needs to be helped to adapt to a blind lifestyle.

Of course, the treatment in each case is individual and is carried out under the strict supervision of a specialist.

Prevention of blindness in humans at home

The main rule of prevention is to protect your eyesight. Avoid working in poor lighting and overexertion, regularly rest your eyes and do special exercises. A set of simple exercises with blinking, focus on near and far objects can be done by children and adults. This is a simple method of preventing blindness in humans, accessible to everyone.

For those who work with chemicals, or there is a risk of foreign objects getting into the eyes, it is important to follow the rules of safe work and use safety glasses.

Elderly patients need regular preventive examinations by an ophthalmologist in order to detect glaucoma and cataracts at an early stage and start treatment. However, at any age, it is better to undergo an annual examination in a specialized eye clinic using several diagnostic methods.

Popular questions and answers

Popular questions about blindness and its treatment are answered by Candidate of Medical Sciences, ophthalmologist with more than 20 years of experience Svetlana Chistyakova.

Sources:

1. Blindness, the main causes. Belikova E.I. 2022. https://belikova.ru/encyclopedia/simptomy_bolezney/slepota/
2. Blindness from cataracts is removable. Akulov S.N. Chief physician of the South of Russia. 2008 https://cyberleninka.ru/article/n/slepota-ot-katarakty-ustranima
3. Methods for early diagnosis and prevention of disabling complications of diabetic retinopathy in the combined course of type 2 diabetes mellitus and hypertension. Moshetova L.K., Vorobieva I.V., Gigineishvili D.N., Neshkova E.A. Medico-social expertise and rehabilitation. 2015. https://cyberleninka.ru/article/n/metody-ranney-diagnostiki-i-profilaktiki-invalidiziruyuschih-oslozhneniy-diabetichskoy-retinopatii-pri-sochetannom-techenii