The most common eye defects are hyperopia, myopia and astigmatism. They can be treated with corrective glasses (mineral or organic) or with orthocorrection. If we do not want to wear glasses, we can replace them with hard and soft contact lenses.
He althy eyes - do not require any special treatments. However, they get tired quickly when you read a lot, watch TV, work at the computer, sew, and spend a lot of time in smoky or air-conditioned rooms. What can be done to prevent them from getting tired? Todayglassesare very light, durable and aesthetic. If you don't want to wear anything on your nose, we havecontact lenses . And when these do not meet our expectations, we can use the laser to correct our eyesight.
The most common eye defects requiring correction
In order for us to see clearly, the light rays entering the eye should focus precisely on the retina - the layer that lines the back of the eyeball. Its many nerve fibers pick up light signals and transmit them through the optic nerve to the brain. It is he who interprets the signals reaching him and "tells" us what we see. Unfortunately, the light rays are not always focused on the retina and then we talk aboutvisual impairment . The most common are:
Hyperopia
The light rays focus behind the retina. Farsight sees objects better at a distance than at close range. Focusing lenses correct this disadvantage. Their power is specified in diopters with a + (plus) sign. A type of hyperopia is presbyopia - a defect that develops with age, when the eye loses the ability to see clearly at close range.
Nearsightedness
The light rays focus in front of the retina, so myopia can see objects close to it more clearly. Myopia is corrected with distracting lenses. Their power is specified in diopters with the sign - (minus)
Astigmatism
Companions usually short or hyperopia. It is caused by an abnormal curvature of the cornea. The light rays that fall on it are refracted in such a way that they do not focus on a point, but as if in two planes. An astigmatist, looking at a cross, for example, can clearly see its vertical or horizontal arm. This defect is corrected by cylindrical lenses.
Types of glasses
U opticianwe can choose between mineral (glass) lenses and organic lenses made of plastics, commonly referred to as "plastics". Opticians can offer us lenses:
with a higher refractive index. They refract light rays more strongly, so they can be 25-50 percent thinner than traditional ones. Those with a power of e.g. minus 5 diopters look as if they had a power of only minus 1.5 diopters.
aspherical. They are flatter than "thinned" ones of the same strength. Thanks to this, the nearsighted eyes do not appear smaller, and the farsighted ones do not appear larger than they really are. Unfortunately, the flattening of the curvature of the lens causes the zone of worse visual acuity to expand on its periphery. We only see very well in the center. The farther to the side, the lower the sharpness.
progressive. For people with presbyopia who wear glasses for reading and walking on the street, or who wear bifocals with a clear border ("dash") in the center. This lens changes smoothly: over the so-called through a progression channel, ie a "bar", it can have, for example, minus 5 diopters, and at the bottom, for example, plus 2 diopters. When we want to see clearly something far away - we look through the upper part of the glass, and close - through the lower part.
photochromic. When exposed to light, they darken and protect the eyes from electrocution.
ImportantOpticians apply protective coatings to the lenses. The order in which they are applied is important, so when ordering glasses, we have to specify what we expect from them.
-anti UV . This coating stops ultraviolet rays that are harmful to the eyes.
-anti-reflection . Thanks to it, the light does not reflect on the surface of the lens. It is recommended for people who work a lot at the computer.
-polarizing . It organizes the light beam before it enters the eye. We avoid dazzling with reflected light, e.g. from the surface of water, snow.
-blueblocker . It prevents UV rays from entering the eyes. Improves the contrast of vision, e.g. at dusk.
-hydrophobic . It repels water droplets from the surface of the lenses. They fog up less when we enter a warm room from frost.
-antistatic . It prevents dust and dust from settling on the glasses.
Pros and cons of contact lenses
Contact lenses have many advantages. They ensure freedom of movement and good visibility even in bad weather conditions, do not limit the field of view and do not change the size of the image.
They can correct long-sightedness and myopia from minus to plus 25 diopters, astigmatism (toric lenses are needed) and presbyopia (progressive lenses are worn). Ophthalmologists recommend contact lenses to those who have more severe vision defectsthan 6 diopters or when the power difference between one eye and the other is 3-4 diopters.
Unfortunately, not everyone can wear contact lenses. For example, a tendency to conjunctivitis or an allergy may preclude their use. A serious contraindication is the so-called dry eye syndrome and only one eye is functional. Some diseases, such as diabetes or hyperthyroidism, also make it difficult to wear "contacts". They cause a change in the chemical composition of tears (increase in the amount of protein), which in turn causes the formation of a deposit on the lenses.
The ophthalmologist decides whether and what type of contact lenses we can wear. He conducts an interview about our he alth, also asks about the type of work performed, checks visual acuity, examines the so-called eye refraction (reading the letters on the test chart after atropine instillation into the eyes), checks the condition of the corneas and conjunctiva in a special slit lamp. If he finds no contraindications, he selects lenses for us.
Hard contact lenses
They are made of oxygen-permeable polymers. As it is not a very flexible material, the eye takes 2-3 weeks to adjust to the lenses. They are quite durable - with proper care and if the vision defect does not worsen, we can use them for up to three years. Hard lenses are only worn during the day. Every day before going to bed, you need to take them off, wash and store in special liquids, and deproteinize them once a week, that is, remove the accumulated protein by putting them into a previously prepared solution. Hard "contacts" are recommended for astigmatism and severe vision defects, as they allow to correct the incorrect shape of the cornea.
Soft contact lenses
They are made of hydrogel materials. Thanks to high flexibility, they easily adjust to the shape of the eyeball. In addition, they let air through, so the eyes tolerate them well. Among soft lenses, we can choose those that are worn in the following mode:
- daily. It is removed at bedtime and stored in a container with saline. They have to be replaced with new ones after the useful life, i.e. every two weeks, every month or every year.
- around the clock. We wear it for a day, a week, two weeks or a month. Then we take them off and throw them away. According to ophthalmologists, the safest for the eye are daily lenses - put on in the morning and discarded at bedtime
Night contact lenses
There are also contact lenses that you put on at night so you don't wear them or your glasses during the day. They are selected individually. This method of correcting blurred vision is called ortho-correction. Works best with sight defects up tominus 4.5 diopters and astigmatism up to 1.5 diopters.
Wearing ortho-corrective lenses systematically - initially every night, then every other, and finally only twice a week - we can forget about glasses.
- drops with blueberry extract (e.g. vitavision, klaritine) or visine or oral strix or bilberin tablets.