A cataract is an opacity or cloudiness in the natural lens of the eye. It is still the leading
cause of blindness worldwide and represents an important cause of visual impairment in the
United States. The development of cataracts in the adult is related to aging, sunlight
exposure, smoking, poor nutrition, eye trauma, systemic diseases, and certain medications
such as steroids. A single study has suggested that use of oral vitamin C may help delay
the progression of cataracts. Just as a smudged or dirty camera lens may spoil a
photograph, opacity in the natural lens of the eye can result in a blurred image. Patients
with cataracts usually complain of blurred vision either at distance, near, or both. This may
interfere with tasks such as driving or reading. Other common complaints include glare,
halos, and dimness of color vision.
A diagnosis of cataract can only be made by a thorough eye examination including slit
lamp(microscopic) evaluation. Other devices are sometimes used to determine if glare
interferes with vision. If cataract surgery is being considered, an ophthalmologist will also
examine the posterior aspect of the eye, which will include evaluation of
the retina and optic nerve.
The progression of cataracts is highly variable, however, they will invariably worsen in
severity. Changing glasses may sometimes be useful in improving vision as the cataract
progresses, since cataracts may induce relative nearsightedness. This is the answer as to
why some patients with hyperopia (farsightedness) will actually have better vision without
glasses in the early stages of cataract development. For most patients, however, changing
glasses has minimal impact on overall visual quality. Besides changing glasses, the only
other option for treatment of cataracts is cataract surgery.
2. Decision for Cataract Surgery
The decision for cataract surgery is reached only between the EyeMD and the patient. In
general, this decision is based on the degree to which the patient’s vision is impaired, and
the impact that impairment has on his or her quality of life. When a patient is significantly
bothered by symptoms of cataract, cataract surgery is usually offered. Many patients will
ask if a cataract must be “ripe” before surgery. The answer with today’s technology is “no.”
Before the development of small incision cataract surgery and intraocular lens implants,
outcomes with cataract surgery were far inferior to outcomes today. Therefore,
ophthalmologists would typically wait until a cataract was very advanced before offering
surgery. Today, with advanced surgical techniques and equipment, cataract surgery can be
offered at a much earlier stage. In fact, most ophthalmologists will agree that it is safer to
proceed with cataract surgery at an earlier stage of development rather than waiting until
the cataract is advanced and very dense.
Selecting the right intraocular lens
When a cataract is removed, it is replaced with an artificial intraocular lens (IOL). There
are a variety of IOLs that can be used in cataract surgery, and they each have their own
set of advantages and disadvantages. No single IOL works best for everyone, and only your
ophthalmologist can determine the most appropriate IOL for your needs. The FDA approval
process for IOLs is among the most rigorous in the world. You can rest assured than any
IOLs used in the U.S. have undergone very extensive testing for safety and efficacy. These
same IOLs are also used for a refractive surgery procedure known as refractive lens
exchange. In refractive lens exchange, the IOL is used solely in an attempt to reduce or
eliminate the need for glasses or contact lenses. This article outlines some of the choices of
IOLs that are available for use in cataract surgery and refractive lens exchange.
Fixed Focus Monofocal IOLs are used in the majority of cataract procedures. These
lenses have the advantage of excellent quality distance vision under a variety of lighting
conditions. Since these lenses have a fixed focal point which is generally set for distance
vision, reading glasses are typically required for good near vision(1). For patients willing to
use reading glasses for near tasks, these IOLs are an excellent choice. Several million
lenses of this variety have been used for decades with an excellent safety record. Recent
refinements in the optical quality of these lenses have allowed an even higher quality of
vision than previously achievable.
Multifocal IOLs use a different strategy to achieve good distance and near vision without
glasses. These lenses have highly specialized optical properties that can divide light to
bring it into focus at more than one point at the same time. This allows the eye to see both
3. near and far, usually without glasses. Excellent results for distance and near vision have
been achieved by both of the FDA approved lenses of this type. The ReZoom™ multifocal
IOL has several zones of optical power that are designed to provide good vision at varying
distances, under varying lighting conditions. In a clinical study, 92 percent of ReZoom™ IOL
patients reported never or only occasionally having to wear glasses. Another multifocal IOL
is the ReSTOR™. This IOL uses a patented diffractive optical design to divide light into two
focal zones so that near and distance objects can both be seen without glasses. An
impressive 80% of patients from the ReSTOR FDA trial reported that they never wore
glasses after the procedure(3). Multifocal IOLs have a slightly greater tendency to cause
night vision complaints than other IOLs, so those who drive a great deal at night may wish
to consider a different IOL. The vast majority of patients with these IOLs are not bothered by
night vision complaints, however.
Cataract surgery today is typically performed using a micro incisional procedure. To the
patient, this means minimal discomfort during or after surgery, a more speedy recovery of
vision, and reduced risk of induced astigmatism. This means less dependence on glasses
Below, we’ve detailed the major steps of cataract surgery using a micro incision procedure,
phacoemulsification (ultrasonic cataract removal), and a foldable lens implant. This type of
procedure is considered state-of-the-art for cataract surgery today. The procedure
demonstrates basic principles only, however, and eye surgeons use many variations of the
general theme, even from one case to another, depending on the type of cataract being
The most commonly used cataract incision is about 3 millimeters in size – just about one-
eighth of an inch! Because of the careful construction of this incision, and its small size, the
incision is generally self-sealing. This translates to a “no-stitch” type operation.
The surgeon then creates an opening in the capsule, which is a micro-thin membrane
surrounding the cataract. This procedure, called capsulorhexus, requires extraordinary
precision since the capsule is only about four-thousandths of a millimeter thick! This
membrane is actually thinner than a red blood cell and the surgeon must delicately remove
the capsule while manipulating instruments within the anterior chamber – a space only 3
4. Phacoemulsification is the aspect of the procedure in which ultrasonic vibrations are used to
break the cataract into smaller fragments. These fragments are then aspirated from the eye
using the same instrumentation.
Once the denser central nucleus of the cataract has been removed, the softer peripheral
cortex of the cataract is removed using an irrigation/aspiration hand piece. The
The posterior, or back side, of the lens capsule is left intact to help support
the intraocular lens (IOL) implant.
The intraocular lens is often folded and passed through the tiny incision where it is opened
(implanted) inside the “capsular bag”. In this illustration, the lens is being inserted via an
“injector”. This is an instrument designed to help keep the incision size small while allowing
implantation of a 6 millimeter lens through a 3 millimeter (or even smaller) incision!
The IOL is shown here implanted within the “capsular bag” where it is neatly centered. The
springy “arms” of the IOL, known as haptics, hold the lens implant within the capsular bag.
The IOL does not generally require sutures to remain in good position.
5. This lateral view of the IOL implant shows the lens within the “capsular bag,” which is the
desired location. This position is the same as that of the natural lens (cataract) of the eye
and, therefore, is generally tolerated best and provides the most optimal visual results. At
this stage, the cataract operation with IOL implantation is complete.
What to Expect During Surgery
Modern cataract surgery is performed almost exclusively on an outpatient basis. Most
patients will be asked to arrive at the surgery center about an hour prior to surgery. Prior to
surgery, a number of eye drop medications will be applied to the eye to prevent pain, to
reduce inflammation and the risk of infection, and to fully dilate the pupil. The surgery is
typically performed under local or topical anesthesia. With local anesthesia, the entire eye
and eye muscles are numbed to prevent discomfort. With topical anesthesia, just the front
of the eye is numbed. Either type of anesthesia allows the procedure to be performed
painlessly. The type of anesthesia chosen depends on surgeon preference and many
During surgery, most patients remain fully awake, however, mild sedation may be used
depending on physician and patient wishes. The patient is asked to lie still during surgery
and, if the procedure is performed with topical anesthesia, the patient will usually be asked
to look toward the light of the operating microscope. Surgery is usually completed in just 20
to 30 minutes. Patients are asked to remain still during the procedure and to inform the
surgeon if needing to cough or otherwise move for any reason. Once the surgery is
complete, the patient will be briefly monitored, post-op instructions given, and in most
cases, the patient may be discharged to home within an hour.
What to Expect After Surgery
After discharge from the surgery center, patients will usually be asked to return for a follow-
up visit later that day or the next day, however, this will be based on individual
circumstances. Also depending on the type of incision and surgeon preference, some
patients will be asked to wear a shield over the eye, particularly while sleeping. The eye
6. should not be rubbed, or pressure placed directly on the eye through the eyelid, during the
first few weeks following surgery. Eye drop medications will be required, usually consisting
of antibiotic and anti-inflammatory medicines. These will often be tapered off during the first
month after surgery.
The best vision may not be obtained until several weeks following surgery, but individual
results vary considerably, depending on many variables. The great majority of patients may
resume normal activities on the day of or day after surgery. Activities such as reading,
watching television, and light work will not hurt the operated eye. Most surgeons arbitrarily
recommend waiting 4 to 6 weeks before new glasses are obtained. This allows the eye to
achieve considerable stability from a refractive standpoint and, therefore, the glasses
prescription should be accurate and relatively stable.
Many patients are surprised at how clear their vision is after cataract surgery. Some
patients may have better vision than they ever did before cataract surgery. Furthermore,
depending on the degree of refractive error (need for glasses) prior to surgery, many
patients will be much less dependent on glasses for far vision than they were before
surgery. Patients will often notice that colors are brighter and more brilliant. The results are
Potential Complications with Cataract surgery
Though cataract surgery is one of the most successful procedures in all of medicine,
complications may still occur. Potential complications range from devastating visual loss to
minor inflammation in the eye following surgery. In general, the risk of severe visual loss is
very rare, but may occur as a result of infection or bleeding inside the eye, or even retinal
detachment, which may occur months or years after a perfectly successful cataract
procedure. Most complications are minor, such as swelling of the cornea or retina,
increased pressure in the eye, and droopy eyelid. These complications usually resolve with
medications and continued healing time.
Over 98% of cataract surgeries are successfully completed without surgical complications,
and more than 95% of patients have improved vision. Those patients whose vision fails to
improve often have underlying ocular disorders, such as age related macular
degeneration (ARMD), diabetic retinopathy, and other conditions. In some cases, these
patients may benefit from other procedures or from low vision aids.
Envision Your Future
Cataract surgery today is truly a miracle of modern medicine. With the collaborative efforts
of physicists, bioengineers, and EyeMDs, modern cataract surgery has reached a new
pinnacle of success. If your vision has faded as a result of cataracts, your likelihood of
recovering more youthful vision with cataract surgery is exceedingly high. If you choose to
have cataract surgery, you will likely enjoy a rapid recovery of enhanced vision with little
disruption to your lifestyle.