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Intraocular lenses Introduction
Intraocular lenses, also known as IOLS are designed to restore the focusing power of the eye after cataract surgery has taken place. There are different types of IOLS and some models are quite advanced.
These intraocular lenses can have specialized features such as toric, aberrant multifocality, pseudoaccommodation, photochromic operations and blue-light blocking. These designs have been made possible by advancements in surgical methods such as a procedure called wavefront surgery.
Below is a breakdown of the different kinds IOLs that are available on the market right now and the types of vision problems they can correct -
Multifocal intraocular lenses
There are a few things to remember before opting for a multifocal type of IOL. First of all your astigmatism must be under control. The doctor must also select the client carefully to reduce the probability of vision being obstructed by glare and contrast sensitive. The more proficient your ocular surgeon is the better this operation will turn out as well.
The various brands of multifocal lenses available are listed below.
The Array was the pioneer and very first multifocal IOL approved by the Food and Drug Administration (FDA). It consists of three components. It is made of silicone and has focusing (refractive) index of 1.46.
Research has shown that people implanted with the Array lens, as opposed to a monofocal lens) had better distance vision, clearer close up vision, better overall eyesight, and less dependence on wearing glasses.
The weakest thing about Array lenses is that sometimes they fail to report changes in contrast sensitivity and glare.
This multifocal IOL is based on the Array lens. It is a new and improved lens from Advanced Medical Optics, California. This lens is made of hydrophobic acrylic material with a refractive index of 1.47.
The features of this lens are five concentration of focus zones, a rounded anterior edge that decreases glare, sloping edges to deflect reflections them away from the retina and a square vertical posterior rim to help prevent PCO.
The ReSTOR multifocal lens is an apodized, diffractive IOL, adapted from a single-piece of AcrySof lens. This lens restores both close up and far vision when the pupil is narrowed. These are the best lenses for reading. This lense is also supposed to be superior for drivers as it adjusts to a large pupil state at night and ensures suitable distance vision.
This lens features a new process Z-Sharp Optic Technology. It has an anterior aspheric surface that corrects positive corneal aberration by compensating with a minus optic. A Tennis design (model ZM001) with a diffractive posterior surface is the next development when it comes to the Tennis line of lenses.
Toric intraocular lenses
TORIC IOLS are specifically for correcting astigmatism. This lense is fixed with no rotational movement. It is mainly used to mold the cornea with the intention of correcting astigmatism that is caused by cataracts.
The Staar Surgical
This is a single piece toric style intraocular lense made of silicone. It has a posterior chamber and provides a spherical optic with a cylindrical correction.
Alcon’s model SA60TT
This recently launched intraocular lens is another toric style lens that is ad adapted from a single-piece AcrySof IOL. This lens is known for its stability and less likely to degrade into rotation after operations.
Blue Blocking Intraocular Lenses
This unusual lens prevents the aging retina from being damaged any further by blue light. The human eye is more prone to damage with age. This is a crystalline shaded lens that that prevents the retinal pigment cells from degrading by blocking all forms of blue light from entering and potentially damaging the retina. This lens also reduces the risk macular degeneration.
The AcrySof Natural (SN60AT)
This is a special blue blocker lens that is created from a single piece of AcrySof and provides protection from UV rays. They have a slight yellow tint so they can distort the way the wearer sees color. These types of lenses also have a negative effect on color and night vision as the retina needs more blue light to see at night then day.
Smart Yellow IOL
Most yellow intraocular lenses cause night vision and color interpretation problems. This drawback is addressed by the Smart Yellow IOL, which prevents harmful blue rays from entering the eye. This is a three-piece lens created from a proprietary hydrophobic acrylic substance. The lens adjusts in color through a photochromic property which allows the yellow intraocular lens wearer to see better at night. Studies have suggested that its photochromic changes are reversible, can be replicated and can ensures long-term stability.
Accommodative Intraocular Lenses
IOLs are also designed to restore the accommodation ability of the eye. The Eyeonics CrystaLens was created to restore the accommodation ability of the eye. It is created from a silicon material called Biosil that has a refractive index of 1.43. The FDA approved this material in 2003.
The Synchrony IOL is a one-piece silicone lens that is based on the conventional Helmholtz’s theory of accommodation. It is now under clinical examination. Bausch and Lomb is also currently developing another single-piece molded silicone dual-optical accommodating IOL.
Aspheric Intraocular Lenses
Aspheric IOLs correct spherical abnormalities of the human eye. Examples are the lenses made with Z-Sharp Optic Technology such as the CeeOn Edge IOL.
The AcrySof Aspheric
This lense that is adapted from the single-piece AcrySof. It has a minus spherical conformity that is designed to correct cataracts. It is similar to SN60WF lens.
The SofPort Advanced Optics (AO)
This is a Bausch and Lomb lense does not add minus spheric aberration,
Small Incision Intraocular Lenses
There have been many innovations in the world of intraocular lenses but one of the most exciting is the invention to tiny lenses that have now enabled surgeons to remove cataracts through incisions that are as small as 1mm. Examples of these type of tiny lenses is the UltraChoice 1.0. and the SmartIOL.
Light Adjustable Lens
Another protective lense is the Calhoun Vision, which is made of photoosentive silicone and adjusts to light. This three-part silicone lens can correct more complicated or unusual eye defects such aspheric problems and tetrafoil patter. These lenses can also correct hyperopia, myopia and astigmatism.
Implantable Miniature Telescope
The most advanced of prosthetic implants in the ocular implant world are the implantable miniature telescopes. These sophisticated lenses are able to relieve the vision problems that are associated with age related macular degeneration. They can also assist with peudophakia. Their main attribute is that they feel very natural and comfortable.