The lens plays the role of a lens in the eye. It is able to focus light in the retina. Before the advent of the artificial lens, patients after cataract removal wore glasses with very massive plus glasses or contact lenses.
Today, the choice of artificial lenses is very wide. Not even any surgeon understands the variety of models. The main types of the lens will be discussed in this overview article.
When is it necessary to implant an artificial lens?
The 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, the IOL makes it possible to correct nearsightedness, farsightedness, and high astigmatism.
The lens placed inside the eye can act as a natural lens and provide all the necessary functions of vision.
The invention of the phakic intraocular lens has become a true solution for patients with a high degree of myopia, hyperopia and astigmatism. Alsosuch models are installed in patients who, for various reasons, are contraindicated in laser vision correction.
An alternative to laser vision correction is the method of refractive replacement of the lens with an artificial IOL model. The visual apparatus at the same time loses the ability to accommodate (seeing objects at different distances). After such an operative intervention, the patient is prescribed to wear glasses for reading and seeing objects up close. This method is indicated if natural accommodation is lost, which usually applies to patients older than 45-50 years
Implantation of a phakic intraocular lens has proven itself from the best side if the natural accommodation is not yet lost and it is possible to implant the lens without removing the natural lens. Phakic lenses allow the patient to see objects both near and at a distance.
IOL device
Usually, an intraocular lens includes two elements: optical and reference.
The optical component is a lens made of a 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 clarity of vision. The supporting part is responsible for the secure fixation of the lens in the capsule of the eye.
Implanted artificial intraocular lens does not have an expiration date. It provides a person with full vision for many years.
Basicbenefits of phakic models
- Do not come into contact with the iris and cornea, which prevents the development of dystrophic changes.
- Combined biologically with the human eye.
- Have a special protection of the retina from the negative effects of ultraviolet radiation.
- Provides a speedy recovery of vision.
- Preserve 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 operation without sutures - phacoemulsification - has become a golden rule.
Phacoemulsification of a cataract by implanting 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 expands and acts as a lens.
The outdated technique involved making a 12 mm incision and suturing for six months. So the rigid model was implanted.
Spherical and aspheric type IOL
Aspheric IOL ensures minimal glare from light sources day and night. This means that no matter where the light hits it, it will be refracted everywhere, both in the center and along its edges. This is a very important indicator for the dark time of the day, when the pupil of the eye is maximally dilated.
For example, there is no blinding fromcar headlights. This property is very important for drivers. Also, the aspherical lens type is characterized by optimal color reproduction and a high level of contrast.
Spherical type involves refraction of different intensity in different areas of the lens. This contributes to the scattering of light, which adversely affects the quality of visual function. This type of lens can cause flare and glare.
Multifocal and monofocal model
A monofocal lens is designed to provide high-quality visual perception of distant objects. Reading after surgery requires plus glasses.
The multifocal type 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, middle, and far vision. 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 the problem of astigmatism. Astigmatism is an irregular shape of the cornea that distorts the image. If such a patient undergoes cataract removal and a standard modification lens is placed, then the pathology will not disappear. This means that after the operation, he will again be shown wearing cylindrical glasses.
When implanting a toric lens model, the patient may experienceprovided compensation for astigmatism and obtaining a contrast vision of objects. The necessary cylinders are already built into the toric lens. By placing such a lens inside the eye using special marks on the lens, the patient can achieve image clarity.
The installation of such models involves clear calculations before surgery. For each patient, they are carried out individually.
Reviews from patients suffering from astigmatism indicate that the implantation of toric models brings the best result. Many patients after surgery say that their vision has become as clear as it was not even in their younger years.
Multifocal toric lens
The IOL series is completed by the multifocal toric model. If the patient suffers from astigmatism and wants to see equally well both near and at a distance, then implantation of this particular type is shown to him. Such a 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 UV filters for IOLs
The natural eye lens has a unique protective ability that blocks the harmful radiation of the sun. This prevents damage to the retina. Modern ophthalmology involves the production of all types of IOLs with an ultraviolet filter.
Special models of lenses are colored with yellow pigments to achieve maximum resemblance to the natural lens. These filters filter out the harmful blue light that is in the invisible part.spectrum.
AcrySof IQ
The AcrySof IQ intelligent lens is used to correct spherical aberrations (glare, ghosting, glare) in bright light. Such a model is able to give excellent vision in any lighting conditions. This is an ultra-thin lens (twice as thin as normal).
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. So the rays of light are not focused at one point. As a result, the image on the retina is not clear.
The AcrySof IQ intraocular lens eliminates this problem. Its rear surface is designed in such a way that it allows all light rays to gather at a single point. The image provided by this model is characterized by a high level of quality, contrast and clarity at any time of the day.
Surgical lens replacement for cataracts
Today, implantation of an intraocular lens by ultrasonic phacoemulsification is a manipulation with a low risk for patients. It has a high level of efficiency. Almost 95% of cataracts in Europe, USA and our country are removed in this way.
The World He alth Organization recognized the operation as the only one among all surgical interventions, which is distinguished by complete rehabilitation.
What is the pointsurgery?
The basis of cataract surgery is the removal 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:
- The patient must report to the clinic one hour before the start of the operation.
- In order to dilate the pupil, drops containing an anesthetic are instilled in him.
- The patient is placed on the operating table. The anesthetist performs 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.
- One hour after the operation, the patient is sent home.
- The next day, the patient must be seen by a doctor.
How is the operation going
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 that is removed from the eye. An intraocular flexible lens is inserted into the capsule by means of an injector. It enters the eye in the form of a tube, where it unfolds itself and is securely fixed.
The microscopic incision is further sealed without outside interference. Therefore, suture is not necessary in this case. The patient's vision returnsusually already 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 a strain 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, the doctor prescribes special eye drops to the patient and determines the frequency of their use. Dates of additional examinations with a preventive purpose are also assigned. The patient is allowed to lead his usual way of life: read, write, work at the 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 the calculation and choice of the lens model, as well as the professional work of an ophthalmologist. That is why the most important condition before the operation is a full diagnosis. Only a detailed examination, carried out using a whole range of modern equipment, makes it possible to obtain an objective state of the patient's vision.
Benefits
Ultrasonic cataract phacoemulsification is distinguished by the perfection of the technology worked out over the years. The operation is carried out in compressedterms. The patient feels comfortable and safe. However, behind such an idea of manipulation is the high skill of the operator and the utmost clarity of the organization of the process.
The main advantages of such a surgical intervention include:
- absolute elimination of cataracts;
- achieving high visual performance;
- fast patient recovery;
- no restrictions on physical and visual stress due to the seamless method;
- lack of pain, as the lens has no nerve endings;
- passing through a quick rehabilitation, in a week you can go to work;
- compliance with restrictions throughout the month;
- excellent lens color and contrast reproduction.
Indications for surgery
Indications for surgery may be a cataract at any stage. The best option is to perform surgery for an immature form of cataract, which allows for a risk-free operation.
For the patient, this is also a big plus: you do not have to wait for the moment of complete blindness of the eye, as it was before. Removal of opacification at the initial stages of the disease development minimizes complications both during and after surgery.
Possible complications after surgery
In the vast majority of phacoemulsification by intraocular lens implantation, which are performed by professional surgeons, have a favorable outcome. If the surgeon is a novice specialist, then inComplications occur in 10-15% of cases.
They can be summoned:
- weakness of the lens ligaments;
- combination of cataracts with diabetes mellitus, glaucoma or myopia;
- presence of common eye diseases.
Complications after surgery include:
- cornea damage by 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 have arisen after surgery can lead to serious problems. Treatment in this case will be long-term, and the result may not be very positive.
Remove lens
Sometimes an inflammatory process or pathological processes in the retina require removal of the intraocular lens. In such cases, a total IOL vitrectomy is performed. The lens is captured by the tweezers and moved forward. The sclerostomy for the introduction of the endo-illuminator is closed with a plug. The surgeon makes an incision in the cornea with diamond-tipped scissors. The IOL can be intercepted by a doctor from a 25G forceps to another, such as a 20G diamond forceps.
After removing the lens, the incision is sutured with a solid or X-shaped suture with nylon thread No. 10-0. The use of thin suture material causes less astigmatism but requires extreme caution as there is a high risk of leakage through the suture during manipulation.
Sometimesthe intraocular lens is removed in the presence of a fibrovascular membrane, which is a consequence of fibrovascular proliferation at the anterior base of the vitreous due to trauma or uveitis. Such a process can also be caused by diabetes.
In this case, the haptic components are crossed with scissors, and in order to maintain the depth of the anterior chamber, a viscoelastic is used.
Haptic elements may 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 applied to the wounds. Monofilament thread 9-0 or 10-0 is used.
Which IOL manufacturers are preferred?
How to choose intraocular lenses? Manufacturers present a wide range of models with different characteristics. To date, modifications of ICL phakic lenses (STAAR, CIBA Vision) with a rear camera have become widespread.
These models are implantable 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.
Reviews
Intraocular lenses, reviews of which are the most positive, have become for many people the only and surest way to regain lost vision.
According to patients' feedback, ultrasonic cataract phacoemulsification with IOL implantation is highly effective,a reliable and painless method that can get rid of cataracts forever and provide excellent vision. The intraocular lens has become a real breakthrough in the field of cataract treatment.
