In 1949, the intraocular lens - a lens that could be implanted inside the eye after the cloudy natural lens had been removed - was introduced to the medical science of cataract surgery. Before then, a patient who needed a cataract removed would be left with no lens at all, and would require extremely thick (and unattractive) glasses following surgery. Therefore, the first such lens developed, a hard, rigid lens made of a material called PMMA, was a significant and welcome advancement for cataract surgery.
Over the years, many continued advances have been made in intraocular lens materials. Now, softer, foldable lenses allow for a much smaller incision during cataract surgery than the hard PMMA lens. The surgeons at Grin Eye Care use the Tecnis Aspheric lens. The Tecnis Aspheric intraocular lens (IOL) provides benefits beyond other intraocular lenses, thanks to the use of wavefront technology, a series of extremely accurate measurements that address spherical aberration in the cornea. While the surface of the eye may look smooth, it actually has many irregularities, which can cause slight differences in the point of focus for light rays as they bend and refract through the eye. A lens that accounts for this spherical aberration will offer a more precise result.
With the traditional IOL, the haziness and blurred vision of cataracts can disappear, and color vision returns to fuller saturation. Contrast sensitivity in normal light conditions is improved by approximately 30 percent compared to older IOLs. Night vision may also increase significantly, as studies have shown that patients enjoy approximately 50-percent improvement in contrast sensitivity in low-light conditions over older IOLs. Many traditional IOL patients report that after their procedure they regain confidence to drive at night.
Although a traditional lens option corrects for single vision only, distance-and-near vision (known as "monovision") can still be achieved by calculating the lens in your dominant eye for distance and the lens in your non-dominant eye for intermediate/near vision--an adjustment also used in contact lens-wearing patients and LASIK patients. However, cataract surgery is not the equivalent to refractive surgery, and it is possible that you may need glasses after cataract removal to achieve your full vision capacity in both eyes.
A multifocal lens is an alternative to a standard intraocular lens, and is notable for a gradual tapering of different refractive levels; this allows the lens to offer distance and near vision. As a result, it will offer the patient significantly more freedom from glasses than other replacement lenses - though, for various medical or physical reasons, it may not be the best option for everyone.
At Grin Eye Care, we use two types of multifocal lenses – the AcrySof IQ ReStor IOL and the Tecnis Multifocal IOL. More options means that we can customize your vision to suit your individual needs.
AcrySof IQ ReSTOR® IOL
AcrySof IQ ReSTOR® offers clear distance vision and offers two choices of near points (reading and intermediate). Reading offers clear vision at about 16 inches, typical for reading a book or menu. Intermediate offers optimal vision for viewing computer screens or browsing shelves at the grocery store and is set for about 21 inches.
Tecnis® Multifocal IOL
Tecnis® Multifocal IOL also offers clear distance and near vision. The Tecnis® offers three different choices of near points, allowing a wider range of vision and the ability to customize vision for each patient's unique needs.
AcrySof Toric® IOL
The human eye consists of many factors in achieving optimal visual acuity. There are three common eye conditions that cause decreased visual acuity. Myopia is an eye condition that ultimately causes decreased visual acuity simply because the eye is too long. When light bends as it enters the eye, the eye length is longer than the light rays are able to travel. If the eye is too long and the light rays are not able to reach the retina, then visual acuity is compromised. The opposite is true for an eye condition called hyperopia. With hyperopia, the eye is too short. When light bends as it enters the eye, the light rays travel beyond the central point on the retina, causing compromised visual acuity. The third eye condition that can compromise visual acuity is called astigmatism. This condition is directly related to the shape of your cornea. Traditionally, people have corneas that are shaped like a basketball. The cornea is perfectly round. If a person's corneas are not perfectly round, they are shaped more like a football and this is called astigmatism. With astigmatism, there are multiple refractive factors that need to be addressed instead of just one. It is very common for people to have a combination of these eye conditions.
The AcrySof Toric intraocular lens was developed specifically for patients with significant astigmatism. Cataract surgery alone has no effect on astigmatism, but choosing the AcrySof Toric lens can help correct it. Nonetheless, cataract surgery - even with this lens - is not the same as refractive surgery and will not guarantee a life without glasses. But for someone with significant astigmatism, the AcrySof Toric lens can make glasses much less necessary than before.