Intraocular Lens Implants: The Inside Story

By Dr Latif Hamed MD

During my 30-year journey in eye surgery, no story has been as dynarnic and exciting as the story of the human natural lens inside the eye, its cloudiness calledcataract, and our relentless attempts to improve the process by which the cataract is removed and replaced with a synthetic lens implant.  The material and the design of this synthetic intraocular lens implant have been the subject of research and refinement for a century.

The cataract story begins here. The human eye has a lens inside of it anchored behind the pupil. This inspired the design of the camera with a lens behind the shutter.

This natural lens is made up of a protein similar to egg white: when it is fresh, it is transparent and when you cook it, it clouds up. With time, the protein that makes up the human natural lens “cooks," a cataract develops, and our vision suffers. The young natural lens is a creative marvel: it focuses at distance and very quickly can zoom to a clear image at near, and is devoid of unwanted optical aberrations. However, as the natural lens ages, it begins to lose some of its remarkable capabilities in a process called the dysfunctional lens syndrome (DLS).  

This syndrome begins with the gradual loss of accommodation (zoom) due to the loss of the natural lens elasticity that is typically first noticed around age 40 (the arms are not long enough) and eventually mandates the use of reading glasses. Some people at this point may elect to have a procedure to exchange this aging dysfunctional lens with a synthetic intraocular lens (IOL) that is designed to help eliminate the need for glasses.  DLS progresses as the lens begins to lose its transparency and some unwanted optical phenomena emerge such as glare and halos.

Eventually, the lens becomes cloudy enough that it affects the person's ability to carry on his or her activities of daily life: this cloudiness is what we call cataract. At this point, the changes in the lens are deemed medically significant and the person may elect to have cataract surgery, Cataract surgery in a nutshell is a procedure by which the old dysfunctional cloudy natural lens is replaced with a man-made intraocular lens or IOL.

This IOL has come a long way since its inception some 70 years ago. The first models of these lens implants were rigid and optically low-tech. Today's IOLs are by far some of the most technologically advanced marvels and are generally divided into two basic groups. The first is an IOL that is monofocal: it corrects the vision at distance but the patient still requires reading glasses. The second is a multifocal IOL that is typically designed to focus images at distance and near and can reduce or eliminate the need to wear glasses for any visual task. This multifocal group has a number of different types: some are most suitable for golfers and active outdoors individuals, others for serious computer users and others for avid small-print readers. It is particularly crucial to match the person with the type of lens implant that most fulfills his or her visual demands.

The field of intraocular lens implants is crowded with numerous offerings. I tell patients that there are many shapes and models of lens implants just as there are many different models of cars on the highway: putting the best implant in the patient's eyes that most fulfill his or her visual demands guarantees a comfortable "ride."

Intraocular lenses differ in rigidity (rigid versus flexible), whether they are one or three pieces, whether they are made of silicon or acrylic or some other material, whether they are spherical or aspherical, and whether they are monofocal, multifocal, or accommodative. These offerings are wonderful in the sense that at the time of surgery we can pick out the lens implant that is the best match for the patient. For instance, patients with potential retinal problems are not suitable for silicon implants because if ever they needed retinal surgery requiring the use of silicon oil, the presence of a silicon implant affects overall visualization. Whereas multifocal implants are a technological wonder, giving most patients the ability to see distance and near without glasses, they are not suitable for everyone. For example, I do not use multifocal implants in patients with macular degeneration or diabetic retinopathy because such patients will not reap the full benefits of such implants and single vision implants may offer such patients better quality vision. I perform cataract surgery one eye at a time, not only as a precaution against infections (extremely rare with modern facilities and techniques), but also because when the first eye is done, we obtain measurements after the surgery that we take into account when performing the surgery on the second eye, to insure that both eyes work optimally in synchrony to give the patient the best vision possible.

Few patients ever ask me what implant I plan to use for them when I perform their cataract procedure in terms of material and design. I do believe that knowledge is power:

I have tried through my writings, lectures, and patient care to increase awareness of implant differences, as I believe that the more informed the patients are, the better choices they will make for their eye health. We ophthalmologists are some of the most detail-oriented professionals as our work is not measured in feet or inches, but in microns.

When that quality is combined with a well-informed, eager-to-learn patient, the results are good choices that make the patient very happy and also pleases the ophthalmologist who is rewarded by seeing the fruit of the long years of education and training making a positive difference in the world.

Discover the Lens That Fits You Best

Your eyes are uniquely yours — your lens implant should be too. At Florida Eye Specialist Institute, Dr. Hamed helps patients choose the ideal intraocular lens for their eyes and lifestyles.

Call (352) 237-0090 or request your consultation today to discover how modern lens implants can transform your sight.