Different Types of Intraocular Lenses: Their Comparative Benefits and Costs
Artificial intraocular lenses are used to replace the eye’s natural lens when it has been removed during cataract surgery. When this pioneering surgery received FDA approval in 1981, there was very little choice and generally a monofocal intraocular lens was implanted during surgery. This was intended to give clear distance vision but patients usually needed reading glasses after surgery for reading and close work. Development of these intraocular lenses (IOLS) has continued and there are now several options to consider. Cataract patients are being given more choice in what type of intraocular lens they would prefer, and price plays some part in that decision-making process. Read on to learn about some of the benefits and differences between the intraocular lenses which are currently available.
Monofocal IOLs
These traditional intraocular lenses offer fixed vision at one distance only, which may be far, intermediate or near. These are the cheapest implants available and generally eyeglasses or contact lenses are necessary to read, use a computer or view mid-range objects clearly, especially if you suffered from presbyopia before the cataract surgery.
Monofocal lenses may be used to create monovision if both eyes need cataract surgery. With this technique, one lens is replaced with a monofocal IOL with near vision and the other with an IOL with far vision. This takes some getting used to at first, but the brain can usually cope; however there may be some loss of depth perception as the eyes are no longer working together as before.
Premium IOLs: Multifocal Lenses
The most common Multifocal Intraocular Lenses are made under the brand names of ‘AcrySof IQ ReSTOR’ by Alcon and ‘ReZoom’ and ‘Tecnis’ which are made by Abbott Medical Optics. These multifocal IOLs contain different zones to give sharp vision at multiple distances. They work in a similar way to progressive lenses in eyeglasses. The brain learns how to select the appropriate zone to look through to provide clear vision at near, intermediate or far ranges.
The disadvantages of these lenses are that as the limited space on multifocal IOLs must be divided into zones, some advantages of seeing through just one zone in single vision monofocal lenses are lost, such as contrast sensitivity. This determines how well the eye can see in low light and how well it can distinguish objects from similarly colored backgrounds. Another disadvantage is cost. All types of premium IOLs are more expensive than standard IOLs, and these extra costs are not covered by Medicare or private health insurance, as the benefits are considered optional.
Premium IOLs: Accommodating Lenses
Currently the only accommodating intraocular lens is made under the brand name of ‘Crystalens’. These lenses are termed accommodating lenses as they shift position with the action of the eye muscles to give sharper vision at different ranges. The ciliary muscle of the eye allows the lens to move forward and focus on images that are near. When it relaxes it allows the lens to reshape and focus on intermediate objects. Reading glasses may still be required as a Crystalens does not provide as wide a range of focus as a multifocal lens.
Premium IOLs: Toric IOLs
The most common toric lens is made under the brand name of Staar Surgical Intraocular Lens and comes in a full range of distance vision powers, correcting either up to 2.00 diopters or up to 3.50 diopters of astigmatism. Another brand of toric lens is the AcrySof IQ Toric IOL, which can correct 1.50 to 3.00 diopters. Toric lenses are also available in aspheric versions for crisper vision, and some models can filter UV or blue light (see below).
If the astigmatism is caused by an irregularly shaped cornea, this can be treated with astigmatic keratotomy (specific incisions made in the cornea) during cataract surgery. If the astigmatism is caused by an irregularly shaped natural lens capsule, a toric IOL can be used to correct it.
Aspheric IOLs
Traditional IOLs are spherical whereas aspheric IOLs, such as SofPort Advanced Optics IOL, are slightly flatter at the edges to provide better contrast sensitivity. This allows images in a similar color to their background to be more clearly defined. Younger cataract patients benefit longer from this type of IOL but older patients lose the ganglion cells of the retina so over time contrast sensitivity declines anyway.
Blue Light Filtering IOLs
Some IOLs filter out ultraviolet and high energy blue light waves which are present in natural and artificial light. UV rays are known to be harmful to our vision and are suspected of causing cataracts and other vision problems. Blue light may cause retinal damage and is suspected of playing a role in macular degeneration. These blue light filtering lenses are slightly yellow to filter the blue light, much as the natural lens is.
Varying costs of IOLs
Most cataract patients are fully covered for their surgical procedure and a traditional IOL by Medicare or private health insurance, subject to their deductible. However a premium intraocular lens is not considered essential to restore sight, and the patient may have to pay the additional cost of this lens themselves. This may be an additional $800-$2500 per lens depending upon the surgeon and the type of lens chosen.
Patients with traditional monofocal intraocular lenses usually require reading glasses which also are not covered by Medicare or typical health insurance policies, so the cost of eyeglasses can offset some of the price of the multifocal or accommodating lens. However, keep in mind that it's possible that you'll still need glasses even if you choose a premium IOL.
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