What is implantation iol. Intraocular lenses to replace the lens of the eye. In which clinic - public or private - is it better to perform cataract surgery

31.10.2019

Used in the treatment of cataracts.
We can thank the English ophthalmologist-surgeon Ridley, who worked during the Second World War, for this breakthrough in medicine. He noticed that when plastic particles get into the tissues of the eye and even if they are present for some time, inflammation does not occur. This discovery was the impetus for the creation of materials for an artificial lens.

Lenses (IOL) are of different types and have, accordingly, different indications for the treatment of certain diseases.

Types of intraocular lenses

Conventional monofocal IOLs are made from a biocompatible material, thereby minimizing the risk of developing a secondary cataract.
There are also lenses with a yellow optical filter. With age, the lens of the human eye acquires a yellowish tint, which is the natural protection of retinal tissues from the dangerous effects of ultraviolet radiation. The use of this type of lens due to a similar protection mechanism reduces the likelihood of developing macular degeneration. This is one of the most widely used IOL models.
There are also multifocal intraocular lenses. Their peculiarity and advantage lies in the special structure that allows the lens to work similarly to a natural lens, i.e. focus and clearly distinguish objects at different distances. This technology allows not only to restore vision, but also to completely get rid of wearing glasses or contact lenses.
Aspherical intraocular lenses. Due to the special shape of the surface, the lens transmits images without any distortion (spherical aberrations). These IOLs allow you to achieve the best image quality, contrast, clarity even in poor lighting conditions. This lens is convenient because allows you to see clearly at any time of the day. These lenses are indicated for the treatment of hyperopia ( age), cataracts and other diseases.

IOLs are now very popular, because. this implantation of an artificial lens is a safe procedure that takes from 4 to 10 minutes of your time and allows you to recover very quickly after the operation.

Postponing cataract treatment is dangerous, as complications caused by cataracts can lead to complete and irreversible loss of vision. How to treat cataract, what method of treatment will be most effective in each specific case, you will be helped to determine by experienced specialists of our center.

The artificial lens of the eye is referred to as an intraocular lens (IOL). This is a special implant that replaces the human lens in case of loss of its functions. An intraocular lens (IOL) is an excellent alternative to glasses, as it is able to correct severe visual deviations and save a person from nearsightedness, farsightedness and astigmatism. Thanks to the placed IOL, it is possible to achieve all the functions of the natural lens. As a result, vision should be restored in full.

Artificial lens of the eye (IOL)

IOLs are:

Rigid - not flexible, stable shape. Implantation is carried out through a large incision. After the operation, sutures are applied, and the patient goes through a long rehabilitation period.
Soft - such lenses are now used often, implanted in a folded form. They are elastic, made of synthetic materials. Implantation is carried out through a self-sealing micro-incision (2.5 mm), no sutures are applied. After placing the element, the lens unfolds and locks itself.

Soft lenses are:

with yellow filter;
accommodating IOLs;
toric;
multifocal;
monofocal;
phakic IOLs.

Monofocal lenses often used during cataract removal. This element is able to give excellent visual function in the distance under different lighting conditions. But as far as near vision is concerned, additional correction with the use of glasses is necessary here. For example, if you need to read a book or watch TV, etc. The patient, before determining the type of lens, is informed about possible problems. If he agrees out of necessity, monofocal lenses are the best option.

Accommodating monofocal lens used to obtain 100% distance and near vision. At the same time, this element is able to independently and imperceptibly change its position in the eye, as a result of which the object is correctly and fully fixed on the retina, regardless of how far it is located. With the help of an accommodating lens, normal accommodation of the lens is ensured. The only negative is that today there is only 1 brand of CRISTALENS IOL lenses. It is released in the USA. All persons who have been implanted with just such a lens do not require additional correction and wearing glasses.

Multifocal lenses provide full vision at any distance without wearing glasses. Such lenses have all the necessary characteristics: super-precision, simultaneous projection of an image to different points.

Spherical lenses improve far vision. At the same time, they provide excellent vision of the central region. But, according to patients' reviews, such lenses bring discomfort after surgery and the picture is distorted at the first stages.

Aspherical lenses shown to improve vision that has been impaired by the natural aging process. Unfortunately, this type of lens has not yet been tested in Russia.

Aspheric lens

Toric lenses intended for patients with a high degree of astigmatism. At the same time, IOLs of this type are able to correct postoperative and corneal astigmatism.

The type of lens is determined by the ophthalmologist. This takes into account the age of the patient and the pathology of the eye.

Reasons for lens replacement

The main causes leading to pathology are:

advanced age of the patient;
diabetes;
radiation;
eye damage;
congenital pathologies of the eyes;
genetic predisposition.

The pathological process of visual impairment occurs gradually. At the beginning, a person sees a blurry image, then color perception is disturbed, photophobia develops. In such situations, doctors prescribe treatment. But, if there are no results, surgical intervention is indicated to eliminate the pathology.

Note!

It is impossible to wait for the onset of complete blindness. Otherwise, even the replacement of the lens will not be able to restore vision!

Indications for IOL implantation

The main indication in which an immediate replacement of the lens is required is it. As soon as the natural eye lens loses its transparency, visual acuity decreases and blindness occurs. In medicine, this process is called a cataract.

The operation is also shown:

at ;
at ;
at .

Lens replacement is indicated only in situations where conventional treatment has failed. However, even IOL implantation does not give a 100% guarantee of vision restoration and the absence of additional correction. Situations in which additional correction is required also depend on concomitant pathologies of the eye, which can simultaneously lead to a violation of human vision.

Can the IOL be replaced?

As a rule, repeated replacement of an already implanted lens is not carried out. In order to perform the next replacement, weighty reasons are required. But often patients have situations that make them think about the need for a second operation. Such situations include:

Vision after implantation was not restored.
The patient is diagnosed with astigmatism.
There was a loss of vision after the initial replacement of the lens.
A secondary was formed.

The above cases do NOT require secondary lens implant surgery.

If a cataract recurs, they resort to cleaning the surface of the lens using a laser. Such surgical interventions to replace the IOL are extremely rare.

Why does the eye see poorly after lens implantation?

If, after the implantation of the optical element, vision has not been restored or partially restored, this is usually due to several reasons:

infection during implantation;
subconjunctival hemorrhage;
sudden jump;
edema;
retinal detachment.

Usually, if vision is not restored within three days, an appeal to an ophthalmologist is indicated.

Life time

The main properties that distinguish almost all models of IOL manufacturers are their wear resistance and durability.

TOP 3 leading IOL manufacturers

Artificial lenses are made in Russia, England, USA, Israel and Germany.

But the TOP 3 are:

UK - Rumex. This is the first company in the world to start the production and production of artificial lenses.
United States - Alcon. Produce high quality lenses.
Germany - Carl Zeiss. They produce different lenses, but the most popular are the two-fraction elements.

Each of the companies has its own line of products, as a result of this, the cost of lenses is different.

Price

The cost of an intraocular lens directly depends on:

material;
manufacturer;
brands;
optical characteristics;
and clinics where lenses are installed.

The price may also depend on the intermediary selling the IOL to the healthcare facility.

Surgical treatment of cataracts and presbyopia is based on the removal of the natural lens that has lost its function and its replacement with an artificial intraocular lens (IOL). Today, there are many models of intraocular lenses that perform strictly defined functions. Lenses are not divided into bad and good: all this is high-quality optics. However, certain properties inherent in their design make some models more functional and preferable.

Types and types of intraocular lenses

Modern methods of implantation of intraocular lenses aim not only to get rid of the disease. Their task is to provide the patient with the best quality of visual functions after surgery. Guided by the same goal, the leading manufacturers of intraocular optics are constantly improving the design of artificial lenses. And today there are two types of intraocular lenses that can provide good vision - monofocal and multifocal.

Monofocal lenses have one optical focus and provide good vision only at one distance (near or far). Multifocal lenses have two (usually) or three optical foci and allow you to see well, both near and far.

Most patients who need surgical replacement of the lens of the eye after the operation want to be independent of the means of external optical correction - glasses or contact lenses, and to see equally well at all distances, under any light conditions. However, during cataract surgery and implantation of conventional monofocal IOLs, people with age-related farsightedness will definitely need reading glasses.

The ability to see clearly both near and far without additional wearing glasses is provided by multifocal lenses, the models of which are bifocal and trifocal.

Classical bifocal lenses, which are especially often used in cataract surgery, do not provide good vision at any distance. They are capable of good focus only at two distances - close and far. Focusing at an average distance leaves much to be desired. So, a person after cataract surgery is not allowed to have 100% full vision?

Until recently, this was true, but today a way out has been found. Good vision at any distance is designed to provide trifocal intraocular lenses.

Trifocal lenses AT LISA tri

ZEISS's latest development is the AT LISA tri, a high-tech trifocal lens with three foci. It provides high quality vision at three main distances - near, far and medium distances. With the AT LISA tri lens, a solution was found to the problem of soft focusing of vision without glasses at any distance. The nature of the optics of the lens is refractive-diffractive, with a monoblock design and aspherical properties. It is able to correct postoperative distortions (aberrations) and provide high contrast sensitivity. Thus, the implantation of a trifocal IOL makes it possible to achieve the highest possible visual characteristics.

The AT LISA tri trifocal lens provides the best depth of field at any distance and vision in its properties comparable to vision with a healthy human lens.

An innovative development of Zeiss company - trifocal intraocular lens of the new generation AT LISA tri is already available to the patients of our clinic.

Vision after AT LISA tri implantation

Trifocal lenses AT LISA tri from Carl Zeiss are produced using modern innovative high-precision technologies. Compared to conventional spherical IOLs, they have many advantages, especially in low light conditions such as driving at night or reading in the evening. After the implantation of a trifocal IOL, drivers will be able to clearly see road signs, navigation instruments and the entire environment even at night. In addition, with such an IOL it is much easier to read and write in dim light than with a conventional one.

Due to its aberration-neutral aspherical design, the AT LISA tri, unlike other IOL models, does not add additional distortion to the human eye. Thus, only the mild positive corneal aberrations that are present in good vision remain, providing additional depth to the field of view. In other words, the quality of vision can become even better than it was in youth.

Official studies and patient reviews

The trifocal lens AT LISA tri has passed all the necessary clinical trials in Europe, where it showed excellent refractive results and earned a lot of positive feedback from patients who were implanted. Due to the good contrast sensitivity it provides, 100% of patients are satisfied or very satisfied with the quality of vision. This also applies to watching TV and reading newspapers; when working with a computer, 92% of patients left positive feedback.

A month after AT LISA tri implantation, a high and very high level of satisfaction with the quality of vision at any distance was observed in almost 100% of operated patients.

The German company ZEISS, the world leader in the field of intraocular optics, offers the best solution for people who need to replace the lens of the eye, supplying the ophthalmic market with the most modern, high-precision optical systems. And the specialists of our clinic are always ready to help patients with the choice of an artificial eye lens that is suitable for all parameters and they need.

Do you want to restore excellent vision with cataracts? Just make an appointment!

Over the past 25 years of development of refractive surgery, ophthalmologists have achieved that today it is possible to correct almost any degree of myopia, hyperopia and astigmatism.

Phakic intraocular lenses are a salvation for patients with a high degree of myopia, hyperopia and astigmatism. They are the only surgical treatment for patients who are contraindicated in laser vision correction.

Advantages of phakic lens implantation:

being in the eye, they do not come into contact with the iris and cornea, which prevents the possibility of dystrophy;
unique biocompatibility with the human eye;
protection of the retina from ultraviolet rays;
vision is restored in 2-3 hours after the operation;
maintaining the integrity of the cornea structure

Phakic lens implantation is successfully used in cases where the natural accommodation of the lens has not yet been lost, and lenses can be implanted into the eye without removing the person's natural lens. At its core, the implantation of phakic lenses is similar to the correction with contact lenses. Only contact lenses are worn on the cornea, and phakic lenses are implanted inside the eye in the posterior or anterior chamber of the eye, while preserving the natural lens. Phakic lenses allow you to maintain the ability of the eye to see objects both near and far.

Phakic IOL implantation is a more advanced method of refractive surgery for refractive errors (nearsightedness, farsightedness, astigmatism) of high degrees, as it is a reversible, stable method and does not violate the shape and integrity of the cornea.

The implantation of phakic IOLs is more physiological than the clear lens extraction method and is thus suitable for younger patients.

With promising results and modern surgical and diagnostic equipment, PRL/MPL implantation is becoming one of the most interesting and promising areas of refractive surgery. 10 years of experience with PRL/MPL implantation gives encouraging results. The lenses are used in Europe, South America, China, and the 3rd phase of FDA testing in the USA has been completed.

PRL/MPL Phakic Lenses Video

The necessary conditions for the use of phakic lenses are high requirements for the accuracy of calculation and selection of a particular type of lens, and the quality of work of an ophthalmic surgeon.

When choosing the type of phakic lenses, ophthalmologists of the International Ophthalmological Center take into account various features: the individual state of eye optics, the age of the patient, his lifestyle, occupation. Our specialists have the appropriate certificates of phakic intraocular lens manufacturing companies, which gives them the right to implant phakic lenses and guarantees the highest quality of eye surgery.

Implantation of a phakic refractive lens PRL/MPL (phakic refractive lens)

Since 2001, the use of PRL/MPL silicone posterior chamber phakic lenses (CIBA Vision, Switzerland, now owned by Carl Zeiss, Germany) has been allowed in all European countries. In the United States, the 3rd stage of clinical trials under the passage of the Food and Drug Administration, which gives promising clinical results.

The PRL posterior chamber phakic refractive lens is made from purified biocompatible silicone with a high refractive index (1.46) and features an ultra-thin design, only 30 microns thick. The optical part has a diameter of 4.5 to 5 mm and is located on the front surface of the lens. The non-optical part is not completely transparent, has a unique matte color, which reduces glare and gall effects after surgery. The radius of curvature of the lens is identical to the radius of curvature of the natural lens, as a result of which the phakic lens gently rests its edges on the lens ligaments, "floating" in the posterior chamber of the eye without touching the lens due to the direct current of the intraocular fluid, resulting in a constant distance between the phakic lens and the lens.

Video of implantation of modern intraocular lenses PRL/MPL

The first such lens was implanted in 1986. Today's PRL is a 4th generation phakic posterior chamber lens. It has been clinically approved in the West and received the so-called CEE mark in 2000. To date, over 20,000 PRL implants have been performed worldwide with very promising results.

During the implantation of phakic lenses, the ophthalmic surgeon performs all manipulations through a self-sealing micro-incision up to 2.5 mm in size. not requiring sutures. This type of surgery is performed within 10-15 minutes, on an outpatient basis, without hospitalization. Drip anesthesia is used, which is easily tolerated by patients of different ages and does not put a strain on the cardiovascular system. After the procedure, the patient quickly returns to his usual rhythm of life. Restrictions are minimal and they mainly relate to hygiene procedures in the first time after the operation.

Doctor Dementiev is the world's leading specialist in the implantation of this lens. He participated in its development, developed and improved the modern surgical technique of implantation. The entire set of microsurgical instruments for the operation bears his name. All doctors who use the PRL / MPL phakic lens implantation technique (there are only 900 of them worldwide) have completed master classes Dr. Dementiev, which are regularly held by Carl Zeiss, with the receipt of the appropriate certificate.

Standard lens implantation surgery is performed on an outpatient Day Hospital basis, under local drip anesthesia (no need for an anesthetic injection), lasts approximately 15-20 minutes in both eyes, does not require suturing and dressing.

A new model of the PRL phakic lens is MPL, manufactured by Medennium, USA. The new model of the phakic lens has an enlarged optical zone and the haptic is made thinner, elastic and soft, which facilitates implantation and reduces the possibility of the presence of a "halo" in the postoperative period. This lens can correct myopia. up to -30 diopters

Eye after PRL/MPL phakic lens implantation

As a result of implantation of a phakic lens, the optical structures of the eye (cornea and lens) do not undergo anatomical and optical changes. PRL does not touch the anterior lens capsule because the lens is made of hydrophobic material and its curvature follows the curvature of the lens, the edges of the lens are located on the zonular fibers and it floats in the posterior chamber, keeping away from the anterior capsule. The "floating" state allows the fluid to pass under the PRL without changing the metabolism in the lens itself, which does not disturb its transparency. Removal of PRL is easily feasible if necessary, but as world practice shows, it is extremely rare.

Selection of patients for PRL phakic lens implantation

patients with a high degree of myopia (up to -30.0 D);
patients with a high degree of hyperopia (up to +15.0 D);
patients with a high degree of astigmatism (up to 6.0 D);
patients with thin corneas.

Contraindications for implantation are:

dystrophy and clouding of the cornea;
cataract;
subluxation of the lens;
glaucoma or increased intraocular pressure;
shallow anterior chamber (less than 2.5 mm);
retinal or vitreous problems that prevent good vision or require posterior segment surgery
previous eye surgeries such as retinal, vitreous or antiglaucoma surgery.
chronic inflammation of the choroid of the eye.

In addition, PRL implantation is most effective and safe in patients younger than 50 years of age. In cases of progressive myopia, operations are indicated that strengthen the sclera.

Results of PRL/MPL phakic lens implantation

PRL/MPL implantation is relatively safe, has predictable results, and is reversible. The lens allows you to achieve an immediate and stable refractive effect.

The most common complications associated with these lenses are:

inaccuracy in the calculation of the power of the lens,
decentering of the optical zone.

Implantation of toric phakic intraocular lenses ICL

In cases of high astigmatism and its combination with high degrees of hyperopia or myopia, the correction is carried out with the posterior chamber phakic IOL model ICL. The implantation technique, indications and contraindications remain the same as in cases of PRL implantation.

Friends and partners

Kenneth Hoffer (Professor, UCLA University, Los Angeles, USA) Kenneth Hoffer (Professor, UCLA University, Los Angeles, USA) — Founding President of the American Society for Refractive and Cataract Surgery, Pioneer in the application and development of phacoemulsification surgery cataracts and intraocular elastic artificial lenses

Participants-Organizers of the Congress in Jerusalem 2007, Israeli ophthalmologists with D. Dementiev From left to right: Dr. I.Barequet Dr.D.Israeli Dr.D.Dementiev Dr.A.Hirsh Dr.S.Levinger — Chairman of the Congress

international vision research team: after the first pressbiopia correction, Sicily 2005 John Beilock, Canada Paolo Fazio, Italy Dmitry Dementiev, Italy-Russia Claudio Luchinni, Italy Anmari Hipsley, USA

Intraocular lenses (IOLs) have been used in the West since the early 1980s. These medical devices are implanted inside the eye to treat and correct vision for diseases such as myopia and astigmatism. Before the invention of intraocular lenses, people had to wear very thick glasses or special contact lenses in order to see after cataract surgery. Then there was nothing else to replace the focusing power of a natural lens. Today, there are many different IOLs to choose from, which depends on many factors, including lifestyle and individual visual needs.

Intraocular lenses and their applications

An intraocular, or intraocular, lens (IOL) is an artificial lens implanted in the eye in place of or over its own natural lens as part of the treatment of cataracts or myopia (nearsightedness). The design of an artificial lens consists of an optical body and sliding supports - fixing elements that hold the lens in place inside the capsular bag in the eye. The implant is made from a material that has a high biological compatibility with the human eye (does not cause allergies and is not rejected by the tissues of the eye). Initially, it was an inflexible polymethyl methacrylate (PMMA), but over time it began to be replaced by more high-tech elastic materials. Advances in technology have led to the use of silicone and acrylic, both of which are soft foldable inert materials. This allows you to bend the lens and insert it into the eye through a minimal incision, significantly reducing trauma and possible complications.

The lens consists of a capsule, an epithelium, and the lens itself.

Implantation of an artificial lens is indicated in the following cases:

cataracts (clouding of the natural lens);
myopia (myopia);
farsightedness;
astigmatism.

In the presence of these ophthalmic pathologies, existing separately or in various combinations, often due to contraindications for laser correction due to thin cornea, the only way out is to replace the non-functioning lens with an artificial one. The intraocular lens, being inside the eye, provides a person with the necessary functions of the native lens and successful vision correction, based on individual pathologies. All modern artificial lenses have an ultraviolet filter that provides 100% protection of the eye from sunlight.

Intraocular lenses have different designs: three-piece (left) and monoblock (right)

It is known that the lens becomes yellow with age. According to medical research, the implantation of a yellow lens protects the retina from the negative effects of strong light, which causes retinal diseases such as macular degeneration. Other scientists disagree with this statement. In their opinion, the yellow filter cuts off the blue spectrum, due to which the eye loses the necessary sensitivity.

The yellow filter IOL is designed to provide additional protection to the retina, similar to the natural lens.

To date, European and American companies are considered the best manufacturers of IOLs. Their products have the highest rating of workmanship. Lenses from the USA and European countries meet the highest standards that apply to the material and production conditions.

There are no absolute contraindications to implantation. But in the presence of certain diseases, the doctor will suggest the appropriate type of lenses and other individual solutions. Such diseases include:

eye:, keratitis, severe pathologies of the retina or optic nerve;
metabolic diseases: diabetes mellitus.

Types of lenses and their purpose

In medical practice, there are 2 main types of intraocular lenses. The most common type is the aphakic IOL. It is implanted during cataract surgery in place of the patient's clouded lens, as well as after an injury or as a result of previous surgery with the removal of the natural lens. The aphakic IOL provides the same light focusing function as the natural lens of the eye.

The second type of IOL, better known as a phakic intraocular lens, is placed over the existing intrinsic lens and is used in refractive (light refraction) surgery to change the power of the eye as a treatment for nearsightedness, or myopia, age-related farsightedness, and astigmatism.

Phakic intraocular lenses came into widespread use in the early 2000s. These lenses are implanted in the anterior or posterior chamber of the eye without removing the native lens. Hence their name - anterior chamber and posterior chamber.

Most IOLs fitted today are distance-of-view fixed monofocal lenses. They require the additional wearing of distance or near glasses. But there are also other types of artificial lenses. These are multifocal IOLs that provide the patient with multifocal vision at both distance and reading distance. There are also adaptive accommodating IOLs that provide a certain accommodation (adaptation to clear vision of objects at different distances from the eye) of vision due to a special design. It allows this type of lens to move with the work of the ciliary muscle (the inner pair muscle of the eye, which provides accommodation for the organ of vision), changing the focus.

Monofocal IOL

Monofocal IOLs are the most common lens type today. This lens is the best option in terms of price and quality, providing a good effect and high-quality vision at a certain distance - near or far - depending on the needs of the person. If the patient's work is related to documentation, a computer, etc., then he needs a lens that will allow him to see perfectly at a reading distance. For a full-fledged life and work, such a lens is ideal. The focal length, or distance with maximum clarity, can be set to a predetermined distance, optimal for driving or watching TV, for reading, hobbies, etc. - at the choice and at the request of the patient. It is popularly believed that monofocal lenses guarantee a higher quality of vision without visual side effects. Sometimes the eye can become so accustomed to the implanted lens that pseudo-accommodation occurs. Then you can do without glasses at all.

Monofocal lenses, depending on the shape of their surface, are:

The disadvantage of a spherical lens is the unequal refraction of light rays in the center and at the edge of the lens. As a result, a beam of parallel rays does not converge strictly at one point, as it should ideally. This phenomenon is called optical aberrations, that is, distortions.

Aberrations cause such negative phenomena:

insufficient visual acuity;
reduced image clarity;
distorted perception in twilight conditions;
optical halo effect (halos around the light source).

The intensity of the negative effect is more pronounced at high lens diopters.

An aspherical lens is designed to improve contrast sensitivity and visual clarity in certain circumstances. Its optical design makes it possible to achieve refraction of parallel rays at a single point, which eliminates visual distortion of images. Aspherical lenses are high-tech, therefore they have a higher cost, which can be attributed to disadvantages. But at the same time they provide a correspondingly high visual acuity. Their benefits include:

perfect focus and visual acuity;
high contrast and clarity;
color rendering depth in dim (twilight) lighting.

Monovision (Monovision) - a method of implantation, when monofocal lenses of different power are placed in different eyes, which makes it possible not to use glasses for most everyday tasks. The dominant eye is usually set for distance vision and the other eye for near vision. Many people successfully combine monovision with contact lenses.

Accommodating intraocular lens

A variation of a monofocal lens is an option that is an intermediate solution between mono- and multifocal - accommodating. It has only one optical zone, unlike the multifocal one, but due to its design it can move inside the eye, controlled by the visual muscle. Glare and fuzziness of the image are much less pronounced due to the simplicity of the optical structure. Among the shortcomings, a modest focus range can be noted when compared with a multifocal lens. Therefore, the need for additional use of glasses is not excluded.

The accommodating IOL mimics the natural lens of the eye thanks to its unique design.

Multifocal IOL

The most advanced type of lens is the premium multifocal lens. Its design provides for the presence of several optical zones for focusing light at different distances. This is a modern type of lens that allows the patient to do without glasses and see well both near and far. We can say that this lens works on a principle similar to modern contact lenses or lenses for glasses. But due to the small size of the optical zones, problems such as a violation of the clarity and sharpness of the image are not ruled out.

Multifocal lens - a high-tech development with several optical zones for focusing light at various distances

Some patients occasionally notice various visual effects associated with the implant. Technology that allows you to read without glasses can cause mild side effects such as glare, ghosting, or reduced contrast sensitivity in certain conditions, such as night driving or lighting in a dark restaurant. Visual needs must be taken into account when choosing a multifocal lens. If the patient knows in advance that they will not be able to adapt to such visual manifestations, then a standard monofocal lens is probably ideal for such a person.

The cost of a multifocal lens is quite high, in addition, it is not shown to everyone. Contraindications to its implantation include eye diseases such as:

glaucoma;
diabetic retinopathy;
diabetic macular edema;
macular degeneration.

These diseases, even in their early stages, can cause problems with premium lenses and adversely affect eye health and quality of vision.

The multifocal lens is the choice of patients who, for various reasons, are motivated not to wear glasses. For example, it may be a teacher who often has to look from notes to the audience. Some people are used to wearing glasses and don't mind using them after surgery. The additional cost of a multifocal lens would not be a smart investment for these patients.

Trifocal intraocular lens

Unlike standard multifocal lenses, which, as a rule, have two foci - for reading and the ability to see into the distance, the trifocal IOL has three optical zones, which makes it possible to obtain high visual acuity at almost any distance accessible to a healthy eye. The benefits of this high-tech type of lens include:

soft focus at different distances;
aspherical properties - distortion correction.

The implantation of a trifocal intraocular lens allows you to gain complete independence from glasses.

Toric intraocular lens

This is a type of artificial eye lens, the main feature of which is the possibility of correcting corneal astigmatism as part of cataract or refractive surgery. Corneal astigmatism is a pathology in which the cornea refracts light differently in different meridians (conditional lines on the surface of the eyeball connecting its anterior and posterior poles). As a result, the light is focused not into one, but into many points at a certain distance. A patient with astigmatism may notice distortions, decreased visual acuity, and double vision. Since astigmatism is often a congenital pathology, its correction as part of cataract surgery makes it possible to achieve vision characteristics that were not even in youth, which significantly improves the quality of life. Toric intraocular lenses are indicated for patients with astigmatism greater than 1 diopter. Non-critical disadvantages of this type of lenses include the relatively higher cost of the lens, which increases the cost of the operation, as well as the need to wait for delivery, since they are ordered individually for each patient.

Astigmatism - uneven refraction of light by the cornea in different meridians

Cataract surgery with a toric IOL is essentially the same as cataract surgery with a conventional IOL. Toric IOLs have different refractive power in different meridians of the lens, therefore, they require preliminary adjustment along the meridians of astigmatism. Mismatch of the toric IOL with the corresponding astigmatic meridians or its displacement in the eye will lead to residual or even greater astigmatism. The problem will cause the need for repeated surgical intervention.

The most inexpensive lens in one product line is the spherical monofocal IOL without additional filters. It is optimally suited for those who cannot achieve ideal visual acuity due to pathology of the retina or optic nerve. In all other cases, the ideal option for a simple lens is an aspherical monofocal lens with protective filters, which prevents retinal pathology and, in comparison with spherical lenses, provides a higher quality of vision. All other options are intermediate. There are a lot of them. Which one is suitable for a particular patient - he decides together with the surgeon after a detailed examination.

IOL implantation

The operation uses a modern method called phacoemulsification - microsurgical removal of the lens nucleus after crushing it with a special needle operating at a high oscillation frequency (about 20 thousand times per second). The phaco-tip works on the principle of a "jackhammer". The advantages of phacoemulsification, when compared with the previous method of extracapsular extraction, include:

seamlessness;
the possibility of vacuum sampling of the lens body through a minimum incision of 2.2 mm;
accelerated postoperative rehabilitation;
reducing the risk of post-surgical astigmatism and other complications.

The phacoemulsifier is used for cataract surgery, as well as for other ophthalmic interventions in the posterior segment of the eye.

Manipulations are performed with the help of microsurgical instruments and apparatus - phacoemulsifier.

The phacoemulsification method was invented by the American ophthalmologist Charles Kelman in the 60s of the last century. However, for a number of reasons, at that time it was not introduced into wide clinical practice.

Preparation for surgery includes measuring the curve of the cornea and the shape of the eye, since some types of lenses are made to order and require careful preliminary measurements. The patient will also be asked to provide a list of medications they may be taking at the moment. The ophthalmologist will point out those that need to be temporarily stopped drinking due to the increased risk of bleeding during surgery.

Cataract - clouding of the lens of the eye, causing varying degrees of visual impairment, up to its complete loss

Sir Harold Ridley was the first to successfully implant an intraocular lens on 29 November 1949 at St Thomas' Hospital in London. The material of the world's first lens is acrylic plastic. It is said that the idea of implanting an intraocular lens came to him after an intern asked him why he did not replace the lens he had removed during cataract surgery. Despite this, the intraocular lens did not find wide acceptance in cataract surgery until the 1970s.

In a few hours, the patient is given mild sedatives as a premedication (preliminary drug preparation of the patient for general anesthesia and surgery). The operation takes place under intravenous anesthesia, additionally "freeze" the cornea, locally using an anesthetic. However, the patient is conscious, albeit in a sleepy state. The nurses and technicians then clean the area around the eye and instill medicine inside to dilate the pupil.

After the anesthesia has taken effect, the doctor makes a tiny incision in the cornea (the clear outer covering of the eye) with a special scalpel so that surgical instruments can be inserted. Then a probe is inserted into the incision and the core of the clouded lens is crushed into small fragments using high-frequency sound waves. Simultaneously with the crushing of the nucleus, the probe sucks off the lens masses, leaving the lens capsule in place.

Through the same tiny incision, a microsurgical injection instrument is inserted into the eye. With its help, the surgeon places the folded IOL inside the eye capsule, replacing the removed lens. The new lens is unfolded in place and secured. The surgeon may make small adjustments to align the IOL based on measurements taken before surgery. No sutures are required as the incision is designed to seal itself. The service life of an implantable intraocular lens is not limited (about 200–300 years), so there is no need to change them in the future.

The essence of cataract surgery is the removal of the clouded lens and its replacement with an artificial one.

Phakic lenses are implanted by analogy with aphakic lenses, only without removing the patient's own lens. Such a lens is most often installed between the iris and the lens (posterior chamber arrangement). This operation belongs to reversible surgical interventions in ophthalmology, because if desired, the phakic lens can be removed without compromising the integrity and health of the eye.

In the early 2000s, more than 1 million IOLs were implanted annually in the United States. The World Health Organization estimates that by 2010 this figure had risen to 20 million annually worldwide (for cataract surgery). The WHO forecast indicates an increase in the number of operations to 32 million worldwide by 2020.

The tolerability of this operation is overwhelmingly very good, and vision is successfully restored. However, it should be understood that the final outcome of the operation largely depends on the initial state of eye health and concomitant diseases, such as pathology of the optic nerve or retina, opacities in the cornea, etc. It is worth saying that before the operation, the patient undergoes a preliminary thorough examination of the eye structures. In the case of possible postoperative problems, the doctor, as a rule, informs the person about this in advance, as well as gives an approximate forecast of what kind of improvement and quality of vision the patient can expect after surgery and rehabilitation.

Phacoemulsification with IOL implantation for cataracts: video

Risks and possible complications

IOL implantation is currently a widely practiced operation with a proven technique and minimal risk of complications. Based on the results of a three-year study, the following figures were identified, reflecting the annual risks:

loss of corneal endothelial cells - 1.8%;
retinal detachment - 0.6%;
cataract - 0.5–1.0%;
corneal edema - 0.4%;
the risk of eye infection, which in the worst case can lead to blindness, is 0.03 - 0.05%. This risk exists in all eye surgery procedures and is not unique to IOLs.

Other risks include:

glaucoma,
postoperative astigmatism,
residual myopia or farsightedness,
moving the lens inside the eye for one or two days after surgery.

One of the reasons for the above risks, namely lens displacement inside the eye, may be the wrong size of the lens (too short), as well as incorrect measurement of the eye. Toric IOLs should be positioned along the astigmatism meridians so as to correct for the patient's existing astigmatism. Again, these lenses can move inside the eye after surgery or be incorrectly placed by the eye surgeon. Revision surgery will be required.

Artificial lens implantation - video

Replacing the lens of the eye with an artificial one - video

Even 20 years ago, cataract surgery was performed with the same type of lens. Over the past 10 years, manufacturing companies have developed new technologies that allow the patient to gain additional benefits by improving the quality and comfort of life with maximum visual acuity. IOL implantation is a safe and effective way to restore normal visual function, with serious complications occurring in less than 1,000 cases. This outpatient surgery takes only a few hours, allowing you to quickly return to your daily life.