Reinforcement
On the issue of additional correction of refractive errors after implantation of premium-class intraocular lenses. What does an artificial eye lens look like? Reasons for implantation, indications, cost of surgery Adaptation period for implantation of special iols

On the issue of additional correction of refractive errors after implantation of premium-class intraocular lenses. What does an artificial eye lens look like? Reasons for implantation, indications, cost of surgery Adaptation period for implantation of special iols

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 can correct severe visual deviations and relieve a person from myopia, 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 eye lens (IOL)

IOLs are:

Rigid - not flexible, stable in shape. Implantation is performed through a large incision. After the operation, stitches are applied, and the patient undergoes a long rehabilitation period.
Soft – such lenses are now often used and are implanted folded. They are elastic and 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 independently unfolds and locks.

Soft lenses are:

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

Monofocal lenses often used during cataract removal. This element is capable of providing excellent distance vision in different lighting conditions. But as for near vision, additional correction using glasses is necessary. 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 as necessary, monofocal lenses are the best option.

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

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

Spherical lenses improve distant vision. At the same time, they provide excellent vision in the central region. But, according to patient reviews, such lenses bring discomfort after surgery and the picture, in the first stages, is distorted.

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

Aspheric lens

Toric lenses intended for patients with high degree astigmatism. Moreover, IOLs of this type are capable of correcting postoperative and corneal astigmatism.

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

Reasons for lens replacement

The main reasons leading to pathology are:

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

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

Note!

You cannot wait for complete blindness to occur. Otherwise, even replacing the lens will not be able to restore vision!

Indications for IOL implantation

The main indication for which immediate replacement of the lens is required is its. Once the natural lens of the eye loses its transparency, visual acuity decreases and blindness occurs. In medicine, this process is called cataract.

The operation is also indicated:

at ;
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Lens replacement is indicated only in situations where treatment with traditional methods is unsuccessful. However, even IOL implantation does not provide a 100% guarantee of vision restoration and the absence of additional correction. Situations in which additional correction is required also depend on concomitant eye pathologies, which can simultaneously lead to impaired vision of a person.

Can the IOL be re-exchanged?

As a rule, a lens that has already been implanted cannot be replaced again. In order to carry out the next replacement, compelling reasons are required. But often patients experience situations that make them think about the need for repeat surgery. Such situations include:

Vision was not restored after implantation.
The patient is diagnosed with astigmatism.
Loss of vision occurred after primary lens replacement.
A secondary one has formed.

The above cases do NOT require secondary lens implantation surgery.

If cataract recurrence occurs, they resort to cleaning the surface of the lens using a laser. Such surgical interventions to replace IOLs are performed extremely rarely.

Why does my eye see poorly after lens implantation?

If, after implantation of an optical element, vision is not 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, a visit 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 companies producing IOLs

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

But the TOP 3 are occupied by:

UK – Rumex. This is the first company in the world to begin the production and production of artificial lenses.
USA – Alcon. They produce highly intelligent lenses.
Germany – Carl Zeiss. They produce different lenses, but the most popular are bifractional elements.

Each company has its own line of products, and as a result, the cost of lenses differs.

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 medical institution.

Serious vision pathologies require constructive measures to improve the situation. Modern ophthalmology gives great hope to people suffering from serious eye diseases. One type of problem that requires certain medical interventions is cataracts. Today, patients diagnosed with this disease can count on a highly effective method of vision restoration using IOL implantation. Clinical studies have confirmed that they are able to provide the necessary vision correction in cases of impaired refractive function.

It is worth noting that IOL implantation surgery is not indicated for all patients. There are a number of conditions that are an indication for this intervention. There is also a list of contraindications for surgical treatment cataracts followed by implantation of intraocular lenses.

Complications during surgery

Like any surgical procedure, IOL implantation is associated with certain risks. Specialists may encounter some types of complications already during the operation.

Sometimes damage may occur during the surgical procedure in question. blood vessel. This moment provokes blood to enter the area of the front and rear walls. Such a complication may become an obstacle to continuing the operation. However, there are methods to stop bleeding and isolate blood masses. After this, implantation can continue.
Displacement of the lens. Irrigation of lens components from a specific capsular bag can be significantly complicated. If the masses are distributed over peripheral positions, this cannot cause the manipulation to stop. It is believed that this state of affairs does not pose any particular dangers. There is an opinion that the remnants of the lens masses present in the periphery of the capsule create a special inflammatory process, which, through adhesion, forms favorable soil for the fusion of the intraocular lens and the bag. However, the leakage of masses into the back wall between the lens and the ocular tissues creates an obstacle to the concentration of vision. In this case, the lens masses are removed from the designated space using a special blunt cannula. The cannula is carefully inserted into the space of the posterior wall and, using an isotonic solution and a syringe, all unnecessary remnants of the lens are removed. Removing masses from the space of the front wall is much simpler and does not cause difficulties.
It is extremely rare that a posterior chamber rupture may occur during IOL implantation. This rare complication can occur due to pressure of the vitreous body on a thin capsule or if the anterior chamber is too small.

In the event of such an incident, further IOL implantation may be refused. In each specific case, the decision is made after assessing the situation.

Postoperative complications

After cataract phacoemulsification, some complications may occur in the postoperative period.

Promotion intraocular pressure is a fairly predictable complication that patients sometimes encounter after undergoing this surgical procedure. There may be several reasons for such an incident. For example, insufficient leaching of the special gel from the anterior chamber area. This creates an obstacle to the patency of the eye canals. Also, the basis of this complication may be blockage of the pupil due to displacement in the direction of the iris.
One of the rare complications after this operation may be cystoid macular edema. This variant of the problem is recorded in patients with chronic diseases such as diabetes and uevitis. This complication can be eliminated with conservative treatment. In especially severe forms, vitrectomy may be necessary.
Quite often, after IOL implantation, a postoperative form of astigmatism is recorded. Unfortunately, this type of problem can be the tipping point that completely degrades the outcome. Depending on the degree of visual impairment, corrective therapy using contact lenses or surgical treatment to correct refraction may be prescribed. The development of this complication directly depends on the implantation technique, the length of the incision, the presence of sutures and some associated factors.
Another very common complication after cataract removal is swelling of the cornea. This problem is often caused by chemical or mechanical damage. It is important to note that this type of complication often does not require additional treatment and goes away on its own after 2-3 days.
Extremely rarely, in approximately 0.1% of cases, pseudophakic bullous keratopathy may develop. This problem is treated with special medications or medicated contact lenses. But, the main emphasis of therapy is on eliminating the pathology that influenced the occurrence of this complication.
A rare type of postoperative problem such as intraocular lens displacement occurs. It is believed that the risk of IOL dislocation directly depends on the time elapsed after surgery and some individual characteristics structure of the eye. The more time has passed since surgery, the higher the risk of displacement. However, it is important to emphasize that such risks are estimated in the period from 0.1 to 1.7%. This means that the development of such an event can be called unlikely.
After this type of vision correction, there is a risk of rhegmatogenous retinal detachment. Most often, the problem develops in those patients whose surgery did not go smoothly. Some violations that occurred during the intervention create the ground for the development of this complication.
A fairly rare complication is endophthalmitis. The risk of this dangerous pathological disorder increases in the case of chronic conjunctivitis, canaliculitis, obstruction of the lacrimal ducts and other specific eye diseases. Endophtholmitis can cause partial or complete loss of vision. However, such a complication is extremely rare. There are effective preventive methods to prevent the development of such a situation in cases of increased risk of their development.

It is worth remembering that complications as a result of phacoemulsification are recorded in only 2% of cases. In the remaining 98% of cases, the operation gives quite impressive results, allowing us to place high hopes on this type of vision correction.

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Cataracts are an insidious disease; not only does it require surgical removal, but it is also often complicated by additional ailments, in particular astigmatism. In such cases, doctors prescribe the patient improved contact optics - toric intraocular lenses. These lenses allowed a patient with cataracts and astigmatism to increase visual acuity to a fairly high level. A few years ago, after cataract surgery complicated by astigmatism, the patient was prescribed special glasses for vision correction. Implantation of toric intraocular lenses radically solves the problem of cataracts and astigmatism. This is why toric artificial lenses are quite expensive.

What is an intraocular lens?

Lens structure

An intraocular lens is an artificial lens that refracts light rays and forms an image on the retina. A conventional implant consists of two elements - optical and supporting.

The optical element is a lens made of a transparent material that is biologically compatible with ocular tissue. There is a special diffraction zone on its surface, which ensures the clarity of the resulting image. The supporting component allows you to securely attach the artificial lens.

The structure of the eyeball

Varieties

After cataract surgery or refractive lens replacement surgery, an intraocular lens is implanted to replace the natural lens. There are intraocular lenses two types:

hard;
soft.

Read about caring for long-wear contact lenses.

Rigid intraocular lenses have a permanent shape. They lack flexibility, so the operation to implant them has a significant disadvantage: a large surgical incision is made, and then sutures are applied. The patient's rehabilitation period after such an operation lasts quite a long time.

Most modern ophthalmological centers and clinics recommend implanting soft intraocular lenses made of elastic polymer materials. To introduce them, a self-sealing micro-incision (about 1.8 mm) is made, which does not require sutures after surgery. Soft lenses are inserted into the eye when folded, then they unfold independently and are securely fastened.

Based on the principle of impact on the functioning of the visual organ, intraocular lenses are divided into several types. Let's look at each of them in more detail.

Trifocal

If the patient does not want to wear glasses after cataract removal and still wants to have good vision at all distances, a trifocal intraocular lens is implanted. This lens has three focuses, which provides high quality vision at close, medium and long distances.

The optical structure of a trifocal lens is unique. Its design allows for smooth focus shifting. In addition, the trifocal lens is equipped with aspherical properties to correct spherical distortion. This ensures high contrast sensitivity.

Accommodating

Accommodating intraocular lenses in their properties and characteristics are as close as possible to the natural human lens. Their unique design allows the eye muscles to move and flex just like a real lens.

The characteristics of the accommodating lens provide users of any age good vision at any distance. In addition, they relieve the patient from two age-related vision problems at once: cataracts and (age-related farsightedness).

Multifocal

As a rule, with age (usually after 40-45 years), each person begins a natural change in accommodation - the ability of the eye to clearly see objects on different distances. The lens of the eye thickens, becomes less elastic, loses flexibility and the ability to quickly change its shape. All this forces a person to use glasses when working. After some time (at 60–70 years), the ability to accommodate is completely lost and you have to use glasses not only for work, but also for any activity.

Multifocal (pseudo-accommodating) lenses have a special advantage over classic contact lenses. They have not one, but several focuses, thereby making it possible to achieve maximum visual acuity at different distances, as well as reduce a person’s dependence on glasses (or get rid of them altogether).

According to statistics, about 80% of patients who have been implanted do not use glasses at all.

Depending on the principle of impact on the eye, multifocal lenses are divided into two different designs:

with mixed diffractive-refractive nature of optics;
with combined radial sectors.

Toric

In cases where cataracts (partial or complete) are complicated, toric intraocular lenses are used. Astigmatism can be corneal and lens. The first type of astigmatism is more common in patients, since the cornea of the eye has a greater refractive power than the lens.

Some time ago, cataracts combined with astigmatism created great difficulties for the surgeon. Even after cataract removal, the person had to use special cylindrical glasses. The development and active use of toric intraocular lenses has allowed patients with cataracts complicated by astigmatism to gain a new quality of visual life. Such a lens has a significant refractive power, which allows it to reduce and even completely eliminate the patient’s corneal astigmatism and increase distance visual acuity. A toric intraocular implant not only replaces the optical power of the removed cloudy lens, but also corrects the original corneal astigmatism.

Find out how to put on toric lenses in.

Aspherical

These lenses are specially designed to correct spherical aberrations, which are very common in patients after implantation of an artificial lens. The reason for their occurrence is usually a mismatch between the optical system: the human eye and the intraocular lens.

The most common type of distortion is spherical aberration. They arise due to the refraction of light at different angles as it passes through the spherical surface of the intraocular lens and the optical media of the eye. Without the necessary correction, light rays do not focus accurately on the retina and the image may be unclear and blurry. Often, after cataract surgery, patients with good visual function suffer from glare, reflections, and halos, which are most pronounced in the evening or at night.

When using traditional lens models, it is impossible to avoid the occurrence of spherical aberrations. Today, special models of lenses with an aspherical surface have already been developed.

Intraocular aspherical lenses have the same optical power in all their areas, so light rays, refracted through it, are focused at one, and not at several points. These unique characteristics of the implant make it possible to obtain higher quality images, especially in low light conditions with a highly dilated pupil.

With yellow filter

In addition to accommodating characteristics, the natural human lens has special protective properties that protect the retina. With age, the lens of all people turns yellow. This is a natural mechanism to protect the retina from UV and blue rays (to prevent the development of retinal dystrophies). During cataract surgery, the surgeon replaces the cataract-damaged lens with an artificial intraocular lens. The yellow filter is also removed along with the lens. Thus, the protective functions of the eye are reduced and the risk of developing age-related retinal diseases increases.

The new generation lenses have a yellow filter similar to the filter of the natural human lens. Its function is to cut off the rays of the blue spectrum without disturbing the balance of color perception. Thanks to the artificial yellow filter, the intraocular intraocular lens protects the retina in the same way as the natural lens of the eye protects it.

Monoblock

Great progress in cataract surgery was the creation of a unique model of intraocular lenses - Monoblock.

Such a lens contains supporting elements – optics and haptics, which are made from the same bioactive material. Thanks to this, the risk of reaction of eye structures and the development of secondary cataracts is minimized.

The single design of the Monoblock intraocular lens made it possible to reduce the incision for implantation to 1.8 mm, as well as avoid numerous risks and complications during surgery. Any possibility of rejection of such a lens is excluded. During the implantation of a monoblock lens, the tissues of the eye are not injured, while they retain their shape and integrity. The lens itself is inserted through a disposable injector, which reduces the risk of lens infection. The experience of implanting Monoblock artificial lenses is already enormous: more than 15 million operations worldwide.

When a patient is faced with the need to implant an artificial lens, he is faced with a difficult task: What type of intraocular lens should I choose? Of course, you can’t do without expert advice. However, the patient himself should be informed about the pros and cons different types intraocular lenses. And the cost of each of them is not the same. So which lens should you choose?

The first thing you need to pay attention toattention when choosing is the material. The lens must coexist peacefully with the surrounding ocular tissue, and first of all, with the lens capsule. That is why intraocular lenses, that is, natural lens implants, must be made of chemically and biologically inert materials. Synthetic polymers are best suited for this.

Due to the elasticity of synthetic polymers, such lenses can be bent in half before implantation. Therefore, the diameter of intraocular lenses is no more than 3-3.5 mm, and ultra-thin ones - even 2.5 mm. After implantation into the capsule, such a lens takes its original shape.

When choosing an intraocular lens, three more important parameters are taken into account:

diameter of the optical part of the lens;
size of the lens with supporting elements;
thickness.

Video

conclusions

So you've met various types, types of intraocular contact lenses and, if necessary, you will be able to participate in the selection of the most suitable artificial lens. Do not forget that the main recommendation on the selection of lenses remains with the doctor. However, also remember that a literate patient is doubly protected. Moreover, such a lens is implanted by an ophthalmologist and only the doctor knows how to treat and how to choose the right type of lens for cataracts.

The inflammatory reaction determines the postoperative course from the 1st day until the formation of scar tissue by the end of the 3rd month. The cause of the inflammatory reaction is primarily a significant incision of the eye tissue to gain access to the clouded lens. During extracapsular cataract extraction, inflammation can be caused by lens masses that have antigenic properties. No matter how thoroughly the lens masses are washed, it is impossible to remove all the cells, and insignificant amounts of antigen are sufficient for the development of an immune (allergic) reaction. During surgery, injury to the internal structures of the eyeball, such as the iris, is inevitable.

Particularly dangerous is injury to the corneal endothelium, a non-regenerating layer of cells that transport fluid and metabolites into and out of the cornea. Endothelial damage is inevitable. The only question is what part of the endothelial cells will die during the operation. The development of the inflammatory reaction in the corneal tissue largely depends on this. It's possible negative action medicines, used during surgery, for example, dicaine, sodium sulfacyl, mezatone, acetylcholine, etc.

The above factors are important for simple cataract extraction. IOL implantation has additional effects on ocular tissue. The very introduction of an IOL into the eye cavity causes the destruction of a significant part of the endothelial cells of the cornea by mechanical means. This circumstance prompted ophthalmologists to look for ways to reduce trauma. Healon and similar agents have been proposed to fill the anterior chamber. Endothelial injury was reduced but not completely eliminated.

Toxic effects of IOLs are possible due to at least two reasons. Firstly, substances used for sterilization remain on the surface of the IOL. Secondly, the material from which the lens and supporting elements are made is subject to slow destruction in the intraocular fluid. It is possible that chemical agents introduced into the eye enhance the inflammatory response.

The mechanical pressure of the lens and supporting elements on the eye tissue is a special factor that depends on the model of the artificial lens. Pressure on the iris, ciliary body, angle of the anterior chamber, and in case of dislocation, on the inner wall of the cornea, undoubtedly causes an inflammatory reaction.

Thus, there are more than enough reasons for the inflammatory reaction. They are associated with the endogenous properties of eye tissue, material, model, manufacturing quality, and preparation of the IOL for implantation. Surgical technique plays a significant role.

Our observations have shown that during the 1st week after surgery, an inflammatory reaction of three degrees can develop: weak, moderate and strong.

A weak inflammatory response is characterized by the following clinical signs. On the 2nd - 3rd day after surgery, the eye is slightly irritated. The palpebral fissure is slightly narrowed or of normal width. Conjunctival injection is expressed in the wound area. The cornea is rarely completely transparent; more often, delicate cloud-like opacities of the stroma remain. Biomicroscopy reveals delicate grayish stripes in the layer of Descemet's membrane. The moisture of the anterior chamber is transparent. Near the pupil and in the lower part of the anterior chamber there may be individual fibers of the lens masses that have emerged from the posterior chamber. The pupil reacts quickly to the administration of weak mydriatic agents, for example, a 1% solution of mesatone in drops. In the first 2-3 days, visual acuity exceeds 0.1. By 5-7 days, irritation practically disappears. The width of the palpebral fissure becomes normal. The folds of Descemet's membrane are absent or barely visible during biomicroscopy.

An inflammatory reaction of moderate severity is characterized by a pronounced mixed injection. Biomicroscopy clearly identifies the folds of Descemet's membrane. Corneal edema allows you to see the pink reflex, but the details of the fundus cannot be seen. Impaired vascular permeability causes the release of inflammatory products into the eye cavity, which is manifested by opalescence of the anterior chamber moisture, the appearance of delicate fibrin flakes and precipitates on the IOL. Due to impaired media transparency, visual acuity is below 0.1. Posterior synechiae are formed. The pupil dilates slightly after instillation of a 1% mesatone solution and takes on a non-spherical shape. The pupil dilates to its maximum after application or injection under the mucous membrane of a solution of adrenaline hydrochloride. Fusion of the iris with the lens can occupy up to 1/2 of the pupil diameter.

A strong inflammatory reaction is characterized by pronounced swelling of all layers of the cornea. Bullous protrusions form on the epithelium. Loose fibrin accumulates in the anterior chamber, and there is a tendency to form grayish films. Posterior synechiae are easily formed due to fusion of the iris with the lens or posterior capsule of the lens. Posterior synechiae rupture only with the use of strong mydriatic agents. Sometimes a strip of gray exudate, a sterile hypopyon, is visible in the anterior chamber below. The exudative reaction weakens under the influence of adequate treatment only by the end of the 1st week. Loose fibrin effusion resolves, fibrin films on the lens require further intensive treatment. Clearing of the cornea occurs only at the end of the 2-3rd week, and visual acuity becomes above 0.1.

Establishing the degree of inflammation in each specific case is usually not difficult, but nevertheless, in a number of observations, the difference between the first and second or between the second and third degrees is not clearly defined. The frequency of inflammatory reactions in the patients we observed was as follows: 60% were mild, 35% were moderate, 5% were severe.

Typically, we observed the peak of the inflammatory reaction on the 2nd - 3rd day after surgery, but there were cases (7% of patients) of a late inflammatory reaction. In the first 2 weeks, the eye condition did not cause concern, and patients, as a rule, were discharged home. At the end of the 2nd, 3rd or 4th week, signs of iridocyclitis appeared: ciliary soreness, photophobia, pericorneal injection, precipitates on the lens and cornea, posterior synechiae and, in severe cases, gray deposits of inflammatory products on the lens. If intensive treatment is not applied during this period, the proliferative films will cause a sharp decrease in central vision. Planar fusions of the iris with the posterior capsule of the lens sometimes push the edge of the lens into the anterior chamber. If the pupil is left dilated for 2-3 days, persistent mydriasis forms due to posterior synechiae.

Our limited experience with IOL implantation in children (32 operations) suggests that late inflammatory reactions occur more often in them than in adults.

One of the specific reactions of the eye to surgical trauma is postoperative hypertension, the occurrence of which is explained by the release of prostaglandins and other substances - bradykinins and leucocrines. The vascular tissue barrier is disrupted, causing excessive release of fluid and protein fractions of blood into the eye cavity. Postoperative hypertension can be considered as one of the pathogenetic mechanisms of inflammation. The incidence of postoperative hypertension has not been well studied. There is reason to believe that postoperative hypertension is observed in more than 3/4 of patients (A. Toberville et al., 1983).

Preoperative examination allowed us to exclude glaucoma. Intraocular pressure increased in the first hours after surgery and in some patients remained above the initial level for 8 days (E. I. Sidorenko, 1975). When measuring intraocular pressure according to A. N. Maklakov with a load of 10 g, indicators of 30-40 mm Hg were obtained. Art. (4-5.3 kPa), and sometimes 50 mm Hg. Art. (6.7 kPa). The density of the eyeball was the same as in an acute attack of glaucoma. Pain in the eye on the day of surgery can be explained more by distention of the eye tissues, a sharp jump in intraocular pressure, than by the removal of the effect of novocaine. In the second eye, the pressure remained within normal limits.

The quality of sealing of the surgical wound appears to influence the level of intraocular pressure. There is an assumption that the overlap large quantities sutures on the eye capsule and tighter contact of the wound edges contribute to an increase in intraocular pressure. Rare sutures create conditions for filtering intraocular fluid.

Postoperative hypertension causes partial cutting of sutures, disruption of wound sealing and microfiltration under the conjunctiva.

When determining the indications for IOL implantation, considerations of labor and social rehabilitation prevailed. Among those operated on there were a significant number of patients with immature cataracts. These were persons under the age of 50 years, in whom the fundus of the eye was visible through the periphery of the dilated pupil during ophthalmoscopy, and clouding of the lens nucleus caused a decrease in visual acuity to OD-0.3. Evacuation of transparent and translucent lens masses is not always easy. Lens masses can be fixed in the duplication of the capsular bag at its equator. After surgery, they either resolve or form a scar conglomerate with the lens capsule, and sometimes, swelling, float into the pupillary area. In 6 patients we observed, on the 2nd - 3rd day after surgery, the lens masses partially filled the anterior chamber and almost completely filled the pupillary area. Lens masses always dissolve without a trace, but this takes time, and patients, having not received the desired vision, show anxiety. The mood of patients is not difficult to understand, especially if the vision in the other eye is poor due to cataracts. In case of abundant release of lens masses, on the 2nd - 3rd day we washed them out using a cannula through corneal paracentesis. The lens masses, as a rule, turned out to be loose, finely dispersed, and their removal was not difficult. The operation takes 2-3 minutes, but it must be carried out with a certain amount of caution to minimize endothelial injury. Lens masses should be removed in small portions by inserting a cannula several times through paracentesis into the anterior chamber. Each time, a certain amount of liquid is first injected into the anterior chamber, and then, bringing the end of the cannula to the cloud of lens masses, they are sucked out without emptying the anterior chamber completely and preventing contact of the endothelium with the iris and IOL.

There have been cases of a thin layer of lens masses getting into the narrow gap between the lens and the posterior capsule. In this case, the pupillary area was partially blocked, and visual acuity decreased slightly. At first, we were afraid for the condition of the lens masses that were trapped in a space with limited fluid circulation. In principle they could be suctioned out with a cannula through one of the microcoloboms made for the upper support elements. Our fears turned out to be exaggerated. The layer of remaining lens masses behind the lens became thinner and disappeared without a trace within 2-3 weeks.

The lens plays the role of a lens in the eye. It is capable of focusing light into the retina. Before the advent of the artificial lens, patients after cataract removal wore glasses with very thick plus lenses or contact lenses.

Today, the choice of artificial lenses is very wide. Not even every surgeon understands the variety of models. The main types of lens will be discussed in this review article.

In what cases is artificial lens implantation required?

An intraocular lens is implanted in the area of the natural lens, provided that it has lost its natural functions. For example, during cataract surgery, when the natural lens loses its transparency, an IOL makes it possible to correct myopia, farsightedness and high-degree astigmatism.

A lens placed inside the eye can act as a natural lens and provide all the necessary vision functions.

The invention of the phakic intraocular lens has become a true solution to the problem for patients with high degrees of myopia, hyperopia and astigmatism. Also, such models are installed in patients who, for various reasons, are contraindicated for vision correction using a laser.

An alternative laser correction vision is a method of refractive artificial IOL model. In this case, the visual apparatus loses the ability of accommodation (seeing objects at different distances). After such surgery, the patient is prescribed to wear glasses for reading and seeing objects at close range. This method is indicated if natural accommodation is lost, which usually applies to patients over 45-50 years of age

The implantation of a phakic intraocular lens has proven itself since the best side in the event that natural accommodation has not yet been lost and it is possible to implant a lens without removing the natural lens. Phakic lenses enable the patient to see objects both near and at a distance.

IOL device

Typically, an intraocular lens includes two elements: optical and support.

The optical component is a lens made of transparent material. It is combined with living tissues of the eye. On the surface of the optical part there is a diffraction zone, which makes it possible to obtain clear vision. The supporting part is responsible for reliable fixation of the lens in the eye capsule.

An implanted artificial intraocular lens does not have an expiration date. It provides a person with full vision for many years.

The main advantages of phakic models

They do not come into contact with the iris and cornea, which prevents the development of dystrophic changes.
Biologically compatible with the human eye.
They have special protection for the retina from the negative effects of ultraviolet radiation.
Provides rapid restoration of vision.
Preserves the structure of the cornea.

Hard and soft modifications

Lenses are divided into two main types: hard and soft. In the practice of ophthalmologists around the world, the golden rule has become the implementation of a stitch-free operation - phacoemulsification.

Phacoemulsification of cataracts by implantation of an intraocular lens involves making a 2.5 mm incision. The lens must be soft. This allows you to roll it into a tube through an injector specially designed for this purpose. Inside the eye it straightens and performs

The outdated technique involved making a 12 mm long incision and suturing for six months. Thus a rigid model was implanted.

Spherical and aspherical type of IOL

The aspherical intraocular lens provides minimal glare from light sources day and night. This means that no matter where the light hits it, it will be subject to refraction everywhere, both in the center and along its edges. This is a very important indicator for the dark time of day, when the pupil of the eye is maximally dilated.

For example, there is no glare from car headlights. This property is very important for drivers. Also, the aspherical type of lens is characterized by optimal color reproduction and a high level of contrast.

The spherical type involves refraction of different intensities in different areas of the lens. This contributes to light scattering, which negatively affects the quality of visual function. This type of lens can cause glare and flare.

Multifocal and monofocal model

A monofocal lens is designed to provide high-quality visual perception of objects located at a distance. Plus glasses are required for reading after surgery.

The multifocal intraocular lens (IOL) device is the most advanced. This determines its high cost. It allows the patient to see objects at all distances. This function is provided by the complex configuration of its optics. Three different zones are responsible for near, mid, and far vision. In this case, the patient does not need to wear glasses. That is why the cost of such devices is extremely high.

Toric models

Toric models are designed to solve a problem called the irregular shape of the cornea, which distorts the image. If such a patient undergoes cataract removal and is fitted with a standard lens modification, the pathology will not disappear. This means that after the operation he will again be advised to wear cylindrical glasses.

When implanting a toric lens model, the patient can be provided with compensation for astigmatism and obtain contrast vision of objects. The required cylinders are already built into the toric lens. By installing such a lens inside the eye using special marks on the lens, the patient can achieve clear images.

Installation of such models requires clear calculations before surgery. They are carried out individually for each patient.

Reviews from patients suffering from astigmatism indicate that implantation of toric models brings better results. After surgery, many patients note that their vision has become as clear as it was not even in their younger years.

Multifocal toric lens

The IOL range is completed by a multifocal toric model. If a patient suffers from astigmatism and wants to see equally well both near and at a distance, then he is indicated for implantation of this particular type. This lens allows you to restore vision. In this case, the patient will never need glasses. This is the most expensive type of lens.

Yellow and blue IOL UV filters

The natural lens of the eye has a unique protective ability that blocks harmful radiation from the sun. This prevents damage to the retina. Modern ophthalmology involves the production of all types of IOLs with an ultraviolet filter.

Special lens models are painted with yellow pigments to achieve maximum resemblance to the natural lens. These filters filter out harmful blue light, which is in the invisible part of the spectrum.

AcrySof IQ

The AcrySof IQ smart lens is used to correct spherical aberrations (the presence of glare, halos, highlights) in bright light. This model is capable of providing excellent vision in any lighting conditions. This is an ultra-thin lens (twice as thin as a regular one).

In the central part, the normal lens is thinner than on the sides. It is thanks to this that the light rays that pass through its peripheral region are focused to the retina, and the central rays are focused on it. This is how light rays are focused at more than one point. As a result, the image on the retina is not clear.

The AcrySof IQ intraocular lens eliminates this problem. Its back surface is created in such a way that it allows all light rays to converge at a single point. The image provided by this model is distinguished by a high level of quality, contrast and clarity at any time of the day.

Surgical lens replacement for cataracts

Today, intraocular lens implantation using ultrasound phacoemulsification is a procedure with little risk for patients. It has a high level of efficiency. In almost 95% of cataract cases in Europe, the USA and our country, they are removed using this method.

The World Health Organization has recognized the operation as the only one among all surgical interventions that is characterized by complete rehabilitation.

What is the essence of surgery?

The basis is the elimination of the clouded lens, which prevents the full flow of light to the retina. An artificial intraocular lens replaces a damaged natural lens.

Main stages of implantation

The vast majority of phacoemulsification operations are performed in private clinics on an outpatient basis. The stages of preparation for surgery are almost the same everywhere:

An hour before the start of the operation, the patient must come to the clinic.
In order to dilate the pupil, drops containing an anesthetic are instilled into it.
The patient is placed on the operating table. The anesthesiologist administers anesthesia.
The surgeon removes the cataract and implants the lens.
The operation does not require stitches.
After the operation, the patient is redirected to the ward.
An hour after the operation, the patient is sent home.
The next day the patient must come for examination to the doctor.

How is the operation performed?

To gain access to the cornea, a microscopic incision 1.8 mm long is made. The clouded lens is softened by ultrasound and transformed into an emulsion, which is removed from the eye. An intraocular flexible lens is inserted into the capsule using an injector. It enters the eye in the form of a tube, where it unfolds itself and is securely fixed.

The microscopic incision is subsequently sealed without external intervention. Therefore, suture is not necessary in this case. The patient’s vision usually returns in the operating room.

The duration of the operation is 10-15 minutes. In this case, drip anesthesia is used, which is easily tolerated by the body and does not put stress on the heart and blood vessels. After surgery, the patient quickly returns to the normal rhythm of life. The restrictions are minimal. They mainly concern hygiene.

Rehabilitation period

After the operation is completed, the doctor prescribes special eye drops to the patient and determines the frequency of their use. Dates for additional examinations for preventive purposes are also set. The patient is allowed to lead his usual lifestyle: read, write, work on a computer, watch television, take baths, sit and lie in a comfortable position. There are also no dietary restrictions.

What is the complexity of the operation?

Implantation of an intraocular lens has a certain complexity, which lies in the high requirements for the accuracy of calculation and selection of the lens model, as well as the professional work of the ophthalmologist. That is why the most important condition before performing an operation is a complete diagnosis. Only a detailed examination, carried out using a whole complex of modern equipment, makes it possible to obtain an objective state of the patient’s vision.

Advantages

Ultrasonic phacoemulsification of cataracts is characterized by the perfection of technology developed over many years. The operation is carried out in a short time. The patient feels comfortable and safe. However, behind this idea of manipulation is the high skill of the operator and the utmost clarity in the organization of the process.

The main advantages of such a surgical intervention include:

absolute relief from cataracts;
achieving high visual characteristics;
rapid patient recovery;
no restrictions on physical and visual activity thanks to the seamless method;
absence of pain, since the lens does not have nerve endings;
undergoing rapid rehabilitation, after a week you can go to work;
compliance with restrictions throughout the month;
excellent transmission of color and contrast through lenses.

Indications for surgery

Cataracts at any stage may be indications for surgical intervention. The best option is to perform surgery for an immature form of cataract, which allows the operation to be performed without risk.

This is also a big plus for the patient: there is no need to wait for the moment of complete blindness of the eye, as was the case before. Removing cloudiness from initial stages development of the disease minimizes complications both during and after surgery.

Possible complications after surgery

The vast majority of phacoemulsifications with intraocular lens implantation, which are performed by professional surgeons, have a successful outcome. If the surgeon is a novice specialist, complications occur in 10-15% of cases.

They can be caused by:

weakness of the lens ligaments;
combination of cataracts with diabetes mellitus, glaucoma or myopia;
the presence of common eye diseases.

Complications after surgery include:

damage to the cornea through ultrasound;
violation of the integrity of the lens ligaments;
rupture of the lens capsule, causing vitreous prolapse;
displacement of the artificial lens, etc.

It should be noted that all complications that arise after surgery can lead to serious problems. Treatment in this case will be lengthy, and the result may not be very positive.

Removing the Lens

Sometimes when inflammatory process or pathological processes in the retina require removal of the intraocular lens. In such cases, total IOL vitrectomy is performed. The lens is grabbed with tweezers and moved forward. The sclerostomy for insertion of the endo-illuminator is closed with a plug. The surgeon makes an incision in the cornea using diamond-coated scissors. The IOL can be grasped by a physician from 25G tweezers with another, for example, 20G diamond tweezers.

After the lens is removed, the incision is closed with a continuous or X-shaped suture using 10-0 nylon suture. Using thin suture material causes less astigmatism, but requires extreme caution as there is a high risk of leakage through the suture during manipulation.

Sometimes the intraocular lens is removed in the presence of fibrovascular membrane, which is a consequence of fibrovascular proliferation at the anterior base of the vitreous due to trauma or uveitis. This process can also be caused by diabetes.

In this case, the haptic components are divided with scissors, and viscoelastic is used to maintain the depth of the anterior chamber.

Haptic elements can be left in the ocular cavity if they are surrounded by a fibrous capsule and cannot be removed with tweezers. To increase the level of tightness, several X-shaped sutures are placed on the wounds. Use monofilament thread No. 9-0 or 10-0.

Which IOL manufacturers are preferred?

How to choose intraocular lenses? Manufacturers present a wide range of models with different characteristics. Today, modifications of phakic ICL lenses (STAAR, CIBA Vision) with a rear camera have become widespread.

These models are to be implanted behind the iris in front of the lens and provide high optical performance. If desired, such lenses can be removed from the eye without disturbing its anatomy.