Types of lenses
After removal of the opacified lens, a new artificial lens called an intraocular lens (IOL) will be placed whether in the natural site of the lens or just behind the cornea (in front of the iris). The concept of the Intraocular lens is to provide the ideal refraction power to collect light rays at one point on the retina. IOLs are manufactured with different focusing powers to fit every eye perfectly.
Most IOLs are made of acrylic, silicone, plastic, or other polymers as synthetic implants. These materials are inert, meaning they do not react with your eye nor cause inflammatory responses. IOLs are covered with a layer of special material that shields your eyes from potentially harmful ultraviolet (UV) rays. unlike natural eye lenses, IOLs usually cannot accommodate their focusing power according to how far is the seen object. There are four main types of IOLs in the market, and each of them will be discussed separately.
1. Monofocal lenses are the standard and most common type of IOL implants used for cataract removal patients. They can provide significant visual assistance, but it is designed to focus light beams on a single focal point that typically covers a specific distance. It may be customized to concentrate on close work, medium-range, or distance vision, depending on your visual requirements. most patients choose to have it adjusted for clear distance vision; this is ideal for driving, biking, and viewing people from a distance. Reading or handcrafting usually requires the use of glasses.
2. Toric lenses are aimed to fix myopia (nearsightedness) with astigmatism as well as hypermetropia (farsightedness) with astigmatism. Toric lenses are typically used to correct astigmatism in eyeglasses, contact lenses, and intraocular lenses. Such a lens functions as a hybrid of a spherical and a cylindrical lens. Although choosing a toric lens may help fix astigmatism, patients who have this kind of IOL implant will still need to wear reading glasses for any close activities such as handcrafting, reading, writing, and typing.
3. A multifocal IOL is a better tool to enhance the outcome of cataract surgery. multifocal IOL helps correct vision for close, intermediate, and distant vision. You may use reading glasses for very tiny text and in low-light settings, but you should be able to do most of your regular tasks without them. If you are extremely nearsighted or have significant astigmatism, the multifocal IOL may not be suitable for you. Furthermore, multifocal IOLs should also be avoided if you have or are at risk of developing another eye illness such as glaucoma, papilledema, macular degeneration, or diabetic retinopathy. Multifocal IOLs are found to be associated with some optical side effects such as seeing halos and glare, so you may not enjoy it if you seek a perfect flawless vision.
4. Extended depth of focus IOL is a premium IOL created and developed by Abbott medical optics inc. (Now Johnson-Johnson Vision). This lOL was called TECNIS symphony and was approved by the FDA in 2016. Many ophthalmologists favor this type over monofocal and multifocal IOL because it has a better side effects profile than both of them. These lenses act by focusing light over a spectrum of vision rather than just in one spot. They do not divide light like multifocal lens implants which reduce the chromatic aberrations as halos. By elongating or “extending out” the focal point of the lens, the extended depth of focus lens provides a range of vision. doubtlessly, extended depth of focus IOL is the future of intraocular lenses. as it provides wide-ranged and excellent quality of vision with minimal cons.
