Contact lenses: delicate means for correction of sight
modern people quite often have problems with sight. And short-sightedness, perhaps, the most widespread of them. There are various ways of fight against it, one of which - use of contact lenses. In certain cases they provide much the best, than points, quality of correction of sight, and the most important - do not cause any damage to image because are not visible to people around.
Convenience, but not panacea
Use of contact lenses for the purpose of correction of pathology of an organ of vision call contact correction of sight . Lenses are put on directly an eye cornea. From - for such direct contact the rays of light refracting only on a forward surface of a lens pass further in the optical environment, uniform in refraction. Therefore the image of objects is not distorted, decreases visual exhaustion and visual working capacity increases. Besides, contact lenses do not limit a field of vision (the maximum space examined by one eye) whereas lenses wearing spectacles, focusing the image on a retina, at far-sightedness at the same time increase, and at short-sightedness reduce it. As a result there is a visual distortion of objects, the distance to them changes. And in completion of all-point frames limit a field of vision.
Nevertheless contact lenses cannot force out points completely. On medical indications of a lens have to be used when correction of sight by means of points is inefficient. Also they are appointed according to professional and cosmetic indications. Incorrectly picked up contact lenses or the incorrect treatment of them can become the eye injury reason, besides procedure of their replacement demands accuracy and a certain skill.Classification of contact lenses
Contact lenses are made by
of various materials. Depending on it they are divided into rigid (ZhKL) and soft contact lenses (MKL). Rigid contact lenses, in turn, are subdivided into gas-tight and gas-permeable .
Rigid contact lenses
Rigid gas-tight lenses demand quite long adaptation, and through them oxygen does not get. Patients transfer rigid gas-permeable lenses much better.Should consider
that ZhKL demand more exact compliance of an internal surface of a lens of a surface of a cornea therefore they are made individually in special laboratories.
Soft contact lenses
As for soft contact lenses of standard series - they are made by the industry of various polymeric materials and differ in elasticity, gas permeability and hydrophily (property to connect water). Therefore - are more convenient for use. However MKL are effective only in the absence of considerable changes of a form of a cornea as, unlike ZhKL, from - for the elasticity do not correct its deformation. Besides, soft contact lenses - less strong, than ZhKL. At the inaccurate address they easily overstrain, sprout bacteria and fungi, fats and proteins, inorganic substances (calcium, an iron oxide) from plaintive liquid, cosmetics etc. are laid for their surfaces. It leads to discomfort, reduction of transparency of lenses and decrease in visual acuity. To avoid it, it is necessary to use the disinfecting (disinfecting) solutions and other means of cleaning.
soft lenses of so-called planned replacement appeared in recent years: they can be changed independently through a certain period, at the same time care of them significantly becomes simpler. Such lenses are issued in a set (several pieces in tight packing) and are divided into three groups:
- according to plan replaced lenses - the lenses replaced in the range from 1 till 6 months (need disinfection and cleaning);
- of a lens of frequent planned replacement - the lenses replaced at least 2 times a month (need disinfection and cleaning);
- of a lens of one day - replaced daily (do not need disinfection and cleaning).
After created soft lenses with very high oxygen permeability, they became possible to be carried without removing within several days.
On value undressed!contact lenses are divided
On the functions into optical , therapeutic , cosmetic and ottenochny .Optical contact lenses are intended to
for sight correction, at short-sightedness, an astigmatism 1 , a keratokonus 2 .
as therapeutic are applied by usually soft lenses which use as protection of a cornea at its defeats and also as the tank for medicinal substances (for example, antibiotics, etc.) at various diseases and damages of a cornea.Cosmetic lenses are applied by
to correction of congenital or post-traumatic defects of eyes (for example, turbidity of a cornea, lack of an iris of the eye, decolouration of a raduzhka - albinism).Recently the increasing value is given by
to protection of organs of vision against ultra-violet radiation. MKL providing such protection are especially recommended to patients after removal of a crystalline lens at a cataract 3 .
(tinted) MKL increasing natural color of eyes, and even considerably changing it were widely adopted ottenochny .to
When need lenses?
of Indications for contact correction of sight exists much:
- of Miopiya (short-sightedness) of high degree, and also the progressing miopiya. Carrying contact lenses at the progressing miopiya promotes its stabilization, due to improvement of accommodation 4 .
- Astigmatism. To choose glasses, especially, at an astigmatism of high degree, very difficult. Usually apply a combination of spherical and cylindrical eyeglass lenses, but it is possible to achieve the maximum visual acuity not always. Contact lenses allow to reach it. They automatically compensate deformation of a cornea, creating the accurate image on a retina. Anizometropiya`s
- - a state at which the refraction 5 the right and left eye is not identical from - for what the affected eye can deviate aside. As a result squint develops and visual acuity decreases.-Point correction at an anizometropiya is well transferred if the difference of a refraction makes no more than 2,0 of D. Contact correction is effective at any difference of a refraction of both eyes. Afakiya`s
- - lack of a crystalline lens. Most often it happens after surgical removal of a crystalline lens at the congenital or acquired cataract, and also owing to a trauma. At correction of an afakiya by means of points it is necessary to apply strong positive glasses (from +8,0 to +17,0 of D). In view of a big difference in the optical power of both eyes-point correction becomes intolerable. Therefore in a similar case an optimum method of optical correction are contact or intraocular lenses (that is implanted - implanted - an artificial crystalline lens).
- of the Disease of eyes. Thanks to emergence of MKL prospects of their application at treatment of various diseases of a cornea, for example its superficial or deep defects (erosion, ulcers), and also - consequences of chemical and thermal burns of eyes opened. MKL are as if an artificial bandage which allows to prolong the effect of drugs, entered into lenses at defeat of a cornea. At the same time process of restoration of corneal fabric accelerates. >
of the Rule of the choice
In order that it is correct to li to pick up contact lenses, it is necessary to address the ophthalmologist (better in the specialized center for contact correction of sight) that the expert conducted full examination and drew a conclusion on an opportunity or impossibility of application of this type of correction.
Ophthalmologic inspection includes special methods of definition of quantity and structure of a tear, and also - passability of plaintive ways. By means of optical devices eyelids look round to exclude their inflammation. Besides, the doctor of course defines visual acuity of each eye, a refraction, estimates an accommodation condition, investigates an eye bottom, a form, thickness and sensitivity of a cornea etc. Only after careful inspection of an organ of vision the doctor appoints this or that type of contact lenses, trains the patient in use and care of them.
At selection of lenses in an office of contact correction to the patient will be offered for fitting of a lens, being in tight packing which will be opened at his presence.
Correctly picked up lens has to settle down on the center of an eye, move freely a forefinger too much of a lower eyelid up and come back quickly to a starting position.by
That, picked how correctly up lenses, it is possible to determine by personal feelings. The patient has to test comfort and note improvement of quality of sight. The objective data obtained at the subsequent surveys of the ophthalmologist will help with it also: for example, existence or lack of reddening of eyes, mobility of a lens on a cornea when blinking etc.
How to use lenses
For a start - several general recommendations. Before putting on lenses, it is necessary to brush hair that they did not get into eyes, to remove cosmetics from eyes and the person (having got on a lens, especially on MKL, cosmetics can take root into it and injure a cornea), then carefully with soap to wash up hands. The last is especially actual for those who smoke to avoid adjournment on a lens of the remains of nicotine. Nails have to be short.
we Learn to handle ZhKL
can Put on rigid contact lenses in two ways.the Tip of a forefinger of the right hand (at putting on of a lens on the right eye) or special tweezers to take
- from the container with solution a lens so that it was a concave surface up. A middle finger of the right hand to delay a lower eyelid. A forefinger of the left hand to raise an upper eyelid of the right eye. The look at the same time has to be directed to a lens. After that it is necessary to bring closer a lens to the center of a cornea and to put on approximately. Then slowly to lower eyelids.
About the correct provision of a lens on a cornea can be judged by visual acuity: if objects have accurate contours - the lens is put on correctly if outlines are indistinct, the lens is displaced on a cornea. By the same principle put on ZhKL and the left eye, only the “main“ hand at the same time, left. However, if to work left it is inconvenient, it is possible to use right again.
- This way differs from the first only in use of a mirror. Looking at own reflection, it is easier to control actions and is more visible, how correctly the lens is located on a cornea. If the lens is displaced, it is possible to correct it through the closed eyelids by means of fingers or at open centuries. >
it is the best of all for li to Remove ZhKL over a table, previously having laid on it a pure napkin (not to lose and to damage a lens). And this process can be made in two ways too:
- to Incline the head over a napkin. Removing a lens from the right eye, a forefinger of the right hand to press ciliary edge of an upper eyelid in the center, and a forefinger of left - ciliary edge of a lower eyelid. At oncoming traffic of forefingers under a lens the vial of air comes, and it easily drops out. Similar reception it is possible to remove a lens from the left eye, having replaced position of hands as appropriate (left above, right below).
- to Put a finger to an external corner of an eye and to delay skin in the direction of an ear. As a result eyelids, being closed, will push out a lens from a cornea.
If ZhKL got to the area of the top arch of an eye, it is necessary to displace through eyelids a lens in the lower arch and to remove it from an eye with one of the specified ways.
Is put on and we remove MKL
Before use of MKL should be checked: they have to be pure, transparent, without anguishes. And put on them as follows: tip of a forefinger of the right hand (for the right eye) take from the container with solution a lens so that it was a concave surface up. Sometimes the lens is turned out outside therefore it is better to check it, having bent it and having compared edges of a lens: if they are slightly turned inside, the lens in the correct situation if are rejected outside, so a lens is turned out. Then a forefinger of the left hand it is necessary to delay a lower eyelid (it is necessary to look at the same time up) and to put a lens to a cornea. Then - slowly to release a lower eyelid and to blink. At the same time the lens has to rise on the center of a cornea. That it was placed in an eye better, it is possible to massage slightly an eyeball through an upper eyelid. Similarly put on a lens the left eye, but the right hand delay a lower eyelid, and put on a lens the left hand. After lenses are put on, it is recommended to cover eyes for 1 - 2 minutes. During this time under a lens the plaintive film is formed, and unpleasant feelings disappear. >
it is easier for p to Remove soft contact lenses, than rigid. It is enough to delay only one hand a lower eyelid, and another a pinch “to take“ a lens on an eye and to remove it. It is better not to use tweezers and suckers for removal of soft contact lenses as similar tools can damage them.
the Main condition of successful application of contact lenses - adaptation to them got used. Eyes have to get used to some hypoxia (decrease in amount of the oxygen coming to a cornea) arising when using this method of correction of sight.
One of the main criteria allowing to control process of adaptation of an eye to lenses is research of thickness of a cornea: at the beginning of carrying lenses it increases at the expense of hypostasis, and then gradually approaches norm. When carrying contact lenses sensitivity of a cornea decreases a little, and it facilitates accustoming process. Besides, contact lenses, irritating the nervous terminations of a cornea and conjunctiva, increase slezoproduktion volume that, in turn, I promotes adaptation, but it is possible only at normal functioning of the plaintive device.by
developed the optimum mode of accustoming of an eye to MKL and ZhKL. The recommended time of carrying contact lenses for adaptation: in the first three days - 2 hours. In the subsequent daily increase carrying time on 1 - 2 hour, gradually leading up it till 12 - 14 o`clock in day.
Care of contact lenses
Contact lenses demand special methods of leaving, storage and cleaning. It is necessary to clean them, strictly adhering to recommendations of the expert and according to the instruction of firm - the manufacturer. And it is necessary to store lenses in special containers which are regularly required to be disinfected. Besides each type of contact lenses has a certain service life no later than which they should be replaced with similar or to pick up others for doctor`s instructions.Rigid contact lenses
recommends to store
ZhKL in special containers with disinfecting solutions. Similar measures reduce a possibility of their deformation and allow to disinfect a lens surface. Soft contact lenses
Now the large companies release
universal multipurpose complex remedies for cleaning, disinfection and storage of MKL. Daily cleaning of soft contact lenses is carried out by
as follows: they are put on the opened palm and put several drops of universal solution from a bottle, then accurately wipe with a forefinger a surface of lenses and washed out the same universal solution.carry out by
by means of this means daily disinfection of MKL. For this purpose pour out old solution of the container, place each contact lens in the corresponding cell of the container and fill in a fresh portion of solution there so that it completely pokryvat lenses. The cover of the container is closed and leave in it lenses at least for 4 hours (usually for the night).
Procedure of disinfection is repeated daily.it is necessary to carry out by
When using MKL weekly or monthly their enzymatic (by means of enzymes) cleaning. For this purpose wash out both cells of the container for storage of contact lenses universal solution and fill them with a fresh portion of this substance. Then in each cell put one special tablet containing enzyme - a cleaner. Remove lenses, wash out them solution for daily cleaning then immerse lenses in fermental solution.
are Closed by both lids of the container and keep lenses in solution within 2 hours. Strongly polluted contact lenses demand longer time of keeping in solution, but this period should not exceed 4 hours.After procedure contact lenses take out from the container and wash out universal solution, as at usual daily cleaning. The used solution is poured out and carefully wash out the container in the new portion of this substance then in solution contact lenses are located.
of Means, improving shipping of lenses
If the discomfort, dryness, burning, feeling of “sand“ in eyes arises, special means are necessary for elimination of discomfort. Recently gained distribution uvlazhnyayushche - the greasing drops containing substances for moistening of eyes and wetting of lenses. Effect of these drops temporary therefore they are recommended to be dug in periodically.When contact lenses are contraindicated to
Unfortunately, it is possible to use contact lenses not everything and not always. For this method of correction of sight treat contraindications:
- of Inflammatory diseases of eyes : inflammation of a mucous membrane of an eye (conjunctivitis); the inflammation of a cornea (keratit); the inflammation skler (sklerit); the inflammation of a vascular cover of an eye (uveit); the inflammation (blefarit) a century etc. The mechanical irritation and shortage of oxygen caused by carrying lenses can aggravate these diseases.
At sharp inflammatory diseases carrying contact lenses stops before treatment. At chronic processes of contraindication to contact correction it is necessary to consider as relative, that is to stop carrying lenses at exacerbations of a disease for the period of treatment.
- of Impassability of plaintive ways, dakriotsistit (an inflammation of a plaintive bag) and small production of plaintive liquid . In these cases preliminary therapeutic or surgical treatment is recommended.
- Mental diseases.
Besides, bad shipping of lenses can be observed at patients with diabetes, at pregnancy, periods, a climax; safe adaptation is not promoted also by hot climate, the dusty atmosphere.Possible complications
usually are the Main reasons for adverse reaction of an organism to use of contact lenses
violation by the patient of the mode of their carrying, non-compliance with storage conditions and processing, rules of hygiene; damage of lenses; education of deposits on them; toxic effect of the disinfecting and clearing solutions, and also the wrong selection of lenses by the doctor which are not revealed by it initial pathological changes of a cornea.
can be carried To number of complications:Superficial keratit
- of , arising in the course of carrying lenses with defects (an anguish of edge, scratch and so forth) and also the cornea erosion which are formed at incorrectly picked up gas-permeable ZhKL (especially at their long carrying). The main symptoms of a superficial keratit and erosion is dacryagogue, a photophobia, sight “zatumanivaniye“. Usually these phenomena pass when the person stops carrying the spoiled contact lenses.
- Allergic conjunctivitis . This disease is usually connected with intolerance of chemical means of cleaning and disinfection of MKL, is more rare - with reaction to polymeric materials of which lenses are made. Also deposits on lenses can be allergens. As a result there is an itch, reddening, cornea hypostasis which is followed by decrease in visual acuity, a photophobia. At the similar phenomena it is necessary to stop carrying lenses and to see a doctor.
Even if process of adaptation of an eye to lenses takes place
normally, unpleasant symptoms which should not be confused to complications can be observed.
Decrease in sharpness sight sometimes arises at incorrectly picked up optical power of a lens, its shift, at deposits on lenses.
the Discomfort (burning in eyes, feeling of sand, pain, visual exhaustion, an itch) is usually noted at damage of a lens, deposits on a lens, hit of foreign particles under it, inflammatory process of eyes.Reddening of eyes, dacryagogue can be observed by
at incorrectly picked up lenses, allergic reaction, inflammatory process, dryness of eyes. Change of a form of edge of a lens, its pollution, conjunctivitis can also become the reason of similar reaction.
If there is pain in eyes, reddening, dacryagogue, decrease in visual acuity, it is necessary to remove lenses and to see immediately a doctor for the corresponding treatment or change of the disinfecting and clearing means.
the People using contact lenses have to pass regular inspection at the ophthalmologist. It will allow to avoid complications. A certain schedule of visit of the expert is provided: during adaptation which lasts about a month it is necessary to appear at the doctor of 1 times in 2 weeks or in process of emergence of inconveniences, and further - each half a year.
If it is about MKL of the prolonged carrying, patients need to be examined carefully after they for the first time spend the night, without removing lenses. The following inspection needs to be performed in a week, then - in a month, three months later, and further - each half a year.
On each reception the doctor investigates visual acuity without lens and with it. It checks the provision of a lens on an eye. Then the ophthalmologist studies a condition of eyes at the removed lenses, defines existence of reddening of a conjunctiva, conducts research of a cornea. Besides, the doctor makes an assessment of a condition of a contact lens - existence of defects, scratches, cracks, gaps, chips, deposits - and draws conclusions about need of its replacement.