The vast majority of people with visual impairment are older than 50 years, reports Postnauka.
See also: How to maintain sharp vision until old age
Refractive disorders are violations of the optical system of the eye, this includes hyperopia, myopia, astigmatism and "senile vision." Myopia (myopia) occurs when the refraction of light is excessive, the image is focused in front of the retina. Because of this, a person sees very well everything near and very poorly – far away. This visual impairment is one of the most common in the world – in 2015-2016, about 2 billion people with this disease were recorded on Earth. Hyperopia (hyperopia) occurs when the refractive power of the lens is not enough, which is why the image focuses behind the retina. A person sees close objects blurry, and distant clear ones. Astigmatism is when the power of the optical system of the eye in the mutually perpendicular axes is not the same. Light rays do not converge at one point on the retina, and the image is blurry. Such an anomaly as presbyopia is also common, as it is also called – "senile vision". With this disease, a person cannot see the small print or small objects at close range.
Farsightedness and myopia
Macular degeneration is when retinal pigment epithelial cells die, excess protein is not ejected, and photoreceptor cells die.
In the world, approximately 50-60% of the population suffers from this disease. Usually this phenomenon begins after 60 years and is called age-related macular degeneration.
Glaucoma is a group of eye diseases that are usually accompanied by high intraocular pressure.
During glaucoma, the optic nerve atrophies, which can lead not only to a decrease in vision, but also to blindness.
There are two main categories of glaucoma: open-angle and closed-angle. Open-angle glaucoma is a chronic disease that progresses slowly, and a person does not notice visual impairment up to the manifestation of serious consequences. This is the most common form of the disease. Angle-closure glaucoma occurs suddenly and progresses rapidly, however, tangible discomfort allows patients to seek help before their vision completely drops.
Cataracts are a clouding of the lens that causes visual disturbances and can lead to loss of lens.
This disease can be congenital or occur at any age. Fortunately, now there are methods that make it easy to replace the lens.
Strabismus (strabismus) is when the visual axes are deviated from the direction of the object.
There are many types of strabismus: horizontal, when the axes simply converge or diverge, or vertical, with a deviation up or down. There is also a monocular strabismus, when only one specific eye squintes, or alternating – when a person looks with his right or left eye in turn, using both.
The most common vision problems
Diabetic retinopathy is a serious retinal disease caused by diabetes. Vision worsens against the background of progressive diabetes.
About 50% of patients with diabetes have diabetic retinopathy.
Color blindness is the inability to distinguish colors. It can be either congenital or acquired.
During life, color blindness can occur due to eye injury, age-related changes, or clouding of the lens.
There are many forms of color blindness, but deuteranopia is the most common – when the green spectrum and shades of red are not perceived, and they are replaced by blue and yellow spectra. Less common are cases when a person sees the world in black and white.
Congenital color blindness cannot be cured, but there are special glasses that provide accents to specific colors and a person has the opportunity to see the world in a full palette.
For more news regarding treatment, medicine, nutrition, a healthy lifestyle, and more, read the Health section.