A multifocal intraocular lens is an artificial lens that is implanted in the eye after the natural lens has been removed and is designed to support vision at multiple distances. The procedure is most commonly performed together with cataract surgery. In some people without cataracts, it may be considered as part of refractive lens exchange. The aim of these lenses is to reduce the need for glasses for distance and near vision. Some designs also support intermediate vision. The outcome varies according to the characteristics of the lens and the person's eye health.
What Is a Multifocal Intraocular Lens?
The eye's natural lens is a transparent structure that helps focus light on the retina. When a cataract develops, this lens loses its transparency and is removed during surgery. The intraocular lens implanted in its place takes over the optical function of the natural lens to a certain extent. While monofocal lenses generally focus at one distance, multifocal lenses direct light to more than one focal zone. The aim is therefore to meet the person's distance and near vision needs together. The term smart lens, which is commonly used by the public, does not refer to a single type of lens. It is used to describe certain intraocular lens options that support different viewing distances.
Types and Characteristics of Multifocal Lenses
Bifocal lenses create two focal zones, mainly for distance and near vision. Trifocal intraocular lens options aim to add intermediate vision to these zones. Support for intermediate vision may be important for some people when performing everyday tasks such as using a computer. Diffractive lenses distribute light to different focal points through special optical structures on their surfaces. Refractive lenses use zones with different refractive powers. Some designs may combine these optical approaches. The most suitable lens is determined by considering the person's visual needs and preoperative measurements.
EDOF and Toric Lenses
EDOF lenses are a separate group of intraocular lenses that provide an extended depth of focus. These lenses aim to create a wider range of vision, particularly at distance and intermediate ranges. Their performance at near distances may vary according to the design and structure of the eye. Some people may need glasses to read fine print. Toric multifocal lenses help correct regular corneal astigmatism in addition to providing multifocal vision. The effectiveness of these lenses depends on the accurate measurement of astigmatism and positioning the lens on the correct axis. The suitability of EDOF and toric features is determined through individual assessments that vary from person to person.
How Do Multifocal Lenses Work?
Multifocal lenses have an optical structure that directs light entering the eye to different focal points. This means that multiple images may form on the retina for objects at different distances. The brain attempts to interpret the visual information by prioritising the image needed at that moment. This adaptation process varies from person to person. Distributing light between different focal points may reduce contrast sensitivity under certain conditions. Halos or glare around lights may be seen, particularly in dark environments. Therefore, lens selection takes into account not only the need for glasses but also expectations regarding visual quality.
When Are Multifocal Lenses Used?
Multifocal intraocular lenses are most commonly considered during cataract surgery. An intraocular lens with suitable characteristics is implanted in place of the natural lens removed because of the cataract. Multifocal options may be considered for people who wish to reduce their need for glasses for distance and near vision. Age-related difficulty with near vision, known as presbyopia, may also influence lens selection. Toric lenses may be considered when necessary for people with astigmatism. The decision to perform the procedure is based not only on the refractive error but also on the health of the cornea, retina and optic nerve.
Can an Intraocular Lens Be Used Without Cataracts?
In certain cases, removal of the natural lens and implantation of an intraocular lens may be considered even when no cataract is present. This procedure is called refractive lens exchange. The aim is to address refractive errors and difficulty with near vision together in suitable individuals. However, the procedure requires the irreversible removal of the natural lens. It also carries the risks associated with intraocular surgery. The potential benefits, risks and alternatives to surgery should therefore be assessed individually.
Who Is Suitable for Multifocal Lenses?
Multifocal lenses may be considered for people who wish to reduce their use of glasses and whose eye structure is suitable. Adequate health of the retina, cornea and optic nerve is important during the selection process. The frequency with which near, intermediate and distance vision are used in daily life is assessed in detail. Computer use, reading habits and night-time driving may influence lens selection. It is also important to understand possible effects such as halos and glare in advance. Suitability is not determined solely by age or spectacle prescription.
Who May Not Be Suitable?
Advanced macular diseases, significant diabetic retinal problems and glaucoma with optic nerve damage may limit the suitability of some multifocal lenses. An irregular corneal structure, uncontrolled dry eye and significant corneal diseases may also affect visual quality. Weakness in the structures that support the position of the lens should also be assessed. Other lens designs may be more suitable for people who frequently drive at night or work in jobs requiring high contrast in low-light conditions. Previous eye surgery and accompanying conditions do not necessarily constitute an absolute barrier on their own. The decision is made by assessing the eye examination findings together with the person's visual priorities.
Do Previous Laser Procedures Affect Lens Selection?
The optical structure of the cornea may have changed in people who have undergone laser procedures such as LASIK or PRK. This change may mean that calculating the power of the intraocular lens requires more careful assessment. Irregularities and optical aberrations on the corneal surface may also affect image quality after surgery. Previous laser surgery does not prevent the use of a multifocal lens in every case. However, topography findings, corneal quality and information about the previous procedure should be examined together. Monofocal or extended-depth-of-focus lenses may be considered more suitable for some people.
Which Measurements Are Performed Before Surgery?
A detailed eye examination and biometric measurements are performed to select an appropriate lens. The length of the eye, curvature of the cornea and amount of astigmatism are used to determine the lens power. Corneal topography or tomography may help assess surface irregularities. Examination of the retina and macula is supported by optical coherence tomography when necessary. The tear film and ocular surface are also examined because they affect the reliability of the measurements. If significant dry eye is detected, treatment may be planned before the measurements are taken. Additional appropriate methods are used to calculate the lens power in people who have previously undergone laser surgery.
How Is Multifocal Lens Surgery Performed?
Multifocal lens surgery involves removing the eye's natural lens and implanting the selected artificial lens in its place. The procedure is generally planned under local or topical anaesthesia. During cataract surgery, the natural lens is usually broken up and removed using phacoemulsification. The intraocular lens is then implanted in the lens capsule when appropriate. When a toric lens is used, it is positioned according to the axis of astigmatism. If surgery is to be performed on both eyes, the timing is determined separately according to the patient's condition. The speed at which vision becomes clear after surgery depends on the individual's healing process.
Possible Side Effects of Multifocal Lenses
Multifocal lenses may cause certain visual symptoms because light is distributed between different focal points. These include rings around lights, glare and starbursts. The symptoms may be more noticeable in the evening or when driving at night. Reduced contrast sensitivity in dim environments may also affect image quality in some people. Although the symptoms may decrease over time, it cannot be said that they will disappear completely. Their severity varies according to the lens design, the optical characteristics of the eye and the individual's adaptation process.
Which Risks May Occur After Surgery?
Intraocular lens implantation carries medical risks similar to those associated with cataract surgery. Infection, inflammation inside the eye, corneal oedema and changes in intraocular pressure may occur. More serious conditions such as retinal oedema, retinal tears or retinal detachment are also among the possible risks. Loss of integrity of the posterior capsule during surgery or movement of the lens from its planned position may also need to be assessed. Some patients may have a different spectacle prescription or residual astigmatism after surgery than expected. Prompt assessment is required if severe pain, increasing redness, a sudden reduction in vision, flashes of light or the sensation of a curtain across the field of vision occurs.
Neuroadaptation and Visual Adjustment
After a multifocal lens has been implanted, the brain may gradually adapt to interpreting visual information arriving from different focal points. This is called neuroadaptation. The duration and extent of adaptation are not the same for everyone. While some people quickly become accustomed to their everyday activities, others may experience halos or glare for longer. Factors such as dry eye, uncorrected astigmatism and the position of the lens may make this process more difficult. If symptoms persist, their cause is investigated and an appropriate approach is determined. Neuroadaptation does not mean that all visual symptoms will disappear in every patient.
Does the Need for Glasses End Completely?
The aim of multifocal lens implantation is to reduce the need for glasses in daily life. However, it cannot be guaranteed that glasses will never be required after surgery. Additional glasses may be needed when reading small print, using a computer for long periods or driving at night. This is related to the lens design, any residual refractive error and the person's visual expectations. With EDOF lenses, glasses may still be required, particularly for reading at close distances. Clearly assessing expectations before surgery helps ensure an appropriate lens selection.
What Causes Blurred Vision After Surgery?
Blurred vision after surgery does not always mean that the lens is unsuitable. In the early period, corneal oedema, dryness of the ocular surface or the healing process may affect image quality. A residual spectacle prescription and astigmatism may also reduce clarity at different distances. Decentration of the lens or a change in the axis of a toric lens are other possible causes. Posterior capsule opacification or retinal problems may be assessed at a later stage. Depending on the cause of the blurred vision, treatment may include glasses, ocular surface treatment, laser treatment or additional surgery when necessary.
How Is Posterior Capsule Opacification Treated?
After an intraocular lens has been implanted, the posterior capsule that surrounds the natural lens may become cloudy over time. This does not mean that the cataract has returned. However, symptoms such as reduced vision, light scatter or loss of contrast may occur. When posterior capsule opacification is detected, YAG laser capsulotomy may be considered for suitable patients. This procedure aims to clear the opacity along the optical axis. Whether the procedure is necessary is determined according to the visual symptoms and examination findings.
What Should Be Considered After Surgery?
The prescribed eye drops should be used as directed after surgery. Avoiding rubbing the eye and preventing contact with contaminated water are important for healing. The timing of returning to swimming, strenuous exercise and similar activities is determined through individual assessment. Light sensitivity, fluctuating vision or a mild stinging sensation may occur during the first few days. Intraocular pressure, lens position, and corneal and retinal findings are assessed during follow-up appointments. If unexpected pain, significant redness or loss of vision develops, the scheduled follow-up date should not be awaited.
Multifocal Intraocular Lenses in Izmir
Assessment for multifocal intraocular lenses in Izmir is planned by considering the person's visual needs and eye structure. The severity of the cataract, corneal characteristics, retinal health and astigmatism are assessed together when selecting a lens. The person's expectations in daily life may also be considered during an assessment performed by Assoc. Prof. Dr. Berkay Akmaz in the Konak district. It is not medically appropriate to recommend the same lens to every patient. Trifocal or toric lenses may be considered for some people, while monofocal or EDOF lenses may be suitable for others. Surgical planning should be personalised according to the examination and measurement results.
Multifocal Intraocular Lens Prices
Multifocal intraocular lens prices may vary according to the optical design of the selected lens and the treatment plan. Trifocal features, a toric design that corrects astigmatism and the lens model used may affect the assessment. Whether surgery is planned for one or both eyes is also taken into account. Accompanying eye conditions and any necessary additional examinations are important in individual planning. It is therefore not appropriate to state a single fee that applies to everyone without an examination. You can contact us through the website for information about multifocal intraocular lens options and the assessment process.
