Lifting the Clouds of Cataracts 
by Ellen Hale 

You're approaching retirement, feeling healthy and looking forward to many
more active and productive years.  But then your vision begins to grow
cloudy.  Everything you look at has a yellowish tint.  Simple tasks like
reading or driving a car become difficult.  Street signs and faces aren't as
sharp as they once were.  Bright sun and auto headlights hurt your eyes. New
eyeglass prescriptions improve vision for a while--but eventually they no 
longer help.

The culprit is cataracts, a condition that will beset most people if they 
live long enough.  This disorder affects 60 percent of people older than 60 
and occurs when the normally clear, aspirin-sized lens of the eye starts to 
become cloudy, impairing vision.

Experts estimate that 1.2 million Americans will be diagnosed in 1989 with
cataracts that require treatment, compared with 123,000 in 1978.  Most of 
the increase is due to the growing numbers of elderly in the United States, 
many of whom want to continue driving cars, reading and 
traveling--activities for which clear sight is vital. 

Until recently, anyone who developed cataracts and needed surgery faced a 
procedure that involved pain and often less than satisfactory results.
Until the late 1970s, doctors removed the cloudy lens in a surgical 
procedure that required a hospital stay of five to seven days.  Afterward,
the patient had to wear thick "Coke bottle" glasses or contact
lenses--neither of which could completely restore vision to its previous
level.

Today, there's little need for such complicated treatment.  Advances in 
medicine have made cataracts much less worrisome.  Now, the clouded lens is 
surgically removed and replaced with a plastic intraocular lens (IOL) in an 
hour-long operation that often requires no hospitalization. 

"The intraocular lens has revolutionized the treatment of cataracts," says
Carl Kupfer, M.D., director of the National Eye Institute in Bethesda, Md.
"Implantation of the lens is one of the most successful operations in 
medicine."

How a Cataract Forms

A cataract forms in the eye's lens, the transparent structure behind the
iris (the colored membrane surrounding the pupil).  The lens focuses light
on the retina, the light-sensitive membrane at the back of the eye which
converts light impulses into nerve signals to produce clear visual images.
Clouding of the lens--much like smearing grease over the lens of a
camera--can develop at any age but most often appears in people older than
42. 

Most cataracts are caused by a change in the chemical composition of the
lens.  In a small percentage of cases, the chemical changes are caused by a 
hereditary enzyme defect, trauma to the eye, diabetes, or use of certain
drugs, such as the steroid prednisone.

Precisely why cataracts occur with age is unknown, but ultraviolet
radiation, particularly from the sun, is thought to play a major role in
creating the chemical change in the lens responsible for most cataracts.
Experimental evidence suggests that UV radiation can cloud the lens by
forming highly reactive chemical fragments called "free radicals."  These,
in turn, disrupt the delicate structure of the lens.  The type of 
ultraviolet radiation from the sun called UVB--the kind that causes 
blistering sunburn and skin cancer--is thought to be a major factor because 
the lens absorbs these rays.

Indeed, in a recent study of 838 Chesapeake Bay professional fishermen, Hugh
Taylor, M.D., of Johns Hopkins Hospital in Baltimore, Md., found a strong 
association between ultraviolet radiation and cataract formation.  Fishermen
with the highest levels of ultraviolet radiation exposure had three times 
the risk of contracting cataracts compared with those with the least
exposure.  Those with cataracts had 20 percent more exposure to sunlight in 
every year of life.  Taylor's studies suggest that cataracts can be 
prevented by avoiding sun exposure between 10 a.m. and 4 p.m., when sunlight
is strongest, and by wearing a wide-brimmed hat and sunglasses.  (See 
accompanying article, "Shielding Your Eyes from the Sun.")

A cataract can develop so slowly that a person may not even know it's 
there.  If the cataract is on the outer edge of the lens, no change in
vision may be noticeable.  Cloudiness near the center of the lens, however, 
usually interferes with clear sight.

Symptoms

Symptoms of developing cataracts include double or blurred vision,
sensitivity to light and glare (which may make driving difficult), less 
vivid perception of color, and frequent changes in eyeglass prescriptions.
As the cataract grows worse, stronger glasses no longer improve sight,
although holding objects nearer to the eye may help reading and close-up
work.  The pupil, which normally appears black, may undergo noticeable color
changes and appear to be yellowish or white, says Peter Hersh, M.D., an 
assistant surgeon at Boston's Massachusetts Eye and Ear Infirmary.

Cataracts are typically detected through a medical eye examination.  The
usual test for visual acuity, the letter eye chart, may not, however, 
reflect the true nature of visual loss, says the American Academy of
Ophthalmology.  Other tests--which measure glare sensitivity, contrast
sensitivity, night vision, color vision, and side or central vision--help 
nail down the diagnosis.

Because most cataracts associated with aging develop slowly, many patients
may not notice their visual loss until it has become severe.  Some cataracts
remain small and never need treatment; others grow more quickly and 
progressively larger.  Only when a cataract seriously interferes with normal
activities is it time to consider surgery, doctors say.  People who depend
on their eyes for work, play and other activities may want their cataracts
removed earlier than those whose needs are less demanding.

Some experts estimate that about 88 of every 100 persons receiving IOLs will
achieve 20/40 vision or better.  (An individual with 20/40 vision can read
letters on an eye chart from 20 feet away, while a person with normal 20/20 
vision can read the chart from 40 feet away; 20/40 vision is good enough to 
get a driver's license in most states.)  Among those who do not have other
eye diseases, about 94 of 100 will achieve 20/40 vision.

Treatment Options 

During the diagnostic examination, an ophthalmologist will carefully measure
the shape, size and general health of the eye to determine whether a lens 
implant will be effective.  In the relatively small number of cases where it
won't be, eyeglasses or contact lenses will improve vision after traditional
cataract surgery.  Glasses, while used for years, have drawbacks.  Their
extreme thickness makes them unattractive and heavy.  Magnification and 
distortion of the visual image causes objects to appear closer and 25 
percent larger than they are.  Peripheral vision may be reduced.  Contact 
lenses provide fairly good vision, but many elderly people have trouble 
inserting, removing and cleaning them.

An implanted IOL is usually the best replacement.  Because the implant is 
placed in or near the original position of the removed natural lens, vision 
is restored with good peripheral vision and depth perception yet with 
minimal magnification and distortion. 

Getting an IOL

IOLs remain permanently in place, require no maintenance or handling, and 
are neither felt by the patient nor noticed by others.  Eyeglasses with thin
lenses for near or distant viewing may still be required, but thick glasses 
are not necessary.  A doctor can determine the appropriate implant
prescription with an ultrasound device that measures eye length and corneal 
curvature.  These measurements are combined by computer to calculate the
lens power required.

The standard surgical procedure, which ranges in cost from $3,000 to $5,000,
is performed in a hospital or doctor's office.  Peering through an operating
microscope, the surgeon makes a minute, curved incision in the cornea--the
surface of the eye.  Then the clouded lens is cut loose with a thin needle
and suctioned out, leaving intact the rear wall of the transparent capsule
that encloses the lens. 

The surgeon enlarges the original incision, and the new lens--a clear hard
plastic disc--is then slipped in behind the iris and up against the back
wall of the capsule.  Two tiny "c" shaped arms attached to the lens 
eventually become scarred into the side of the eye and hold the lens firmly 
in place.  The incision is closed with 7 to 10 nearly invisible stitches of 
fine nylon or silk. 

In a newer method, an ultrasonic probe enters the cut in the cornea and 
high-speed vibrations break the lens into microscopic flecks that are then
removed by suction.  A folded flexible plastic lens one-quarter of an inch
in diameter can be inserted through the cut with a scissors-like device 
called an injector and positioned behind the pupil against the capsule
wall.  Once in place, the injector is removed and the lens opens. 

The flexible lens is one of two advances already on the market in half a
dozen European countries.  This softer lens, designed to allow a smaller
incision and thus less tissue damage than implantation of the standard hard 
lens, is now undergoing clinical trials in the United States and is expected
to be available here in late 1990.

Some manufacturers are also developing bifocal IOLs, which may eliminate the
need in some patients for prescription  glasses after surgery.  The bifocal 
IOLs could be on the market in the United States in 1991. 

The procedure to remove the natural lens and replace it with a synthetic one
is done under a general or local anesthesia with injections made in muscles 
around the eye.  Recovery takes several hours in the hospital; in a few 
cases, it may require an overnight stay.  The patient wears a metal shield
over the eye at night; wrap-around sunglasses are recommended during the day. 

Within a few days of the operation, most people are back at work.  In 
several office visits during the first six to eight weeks after surgery, the
doctor will check for infections or other complications and fit the patient 
for reading glasses.  Vision is significantly improved in 95 to 98 percent
of cases. 

However, results of the operation aren't always worry free.  After the IOL
implantation, a clouding of the lens capsule, known as a "secondary 
cataract," occurs in roughly 40 percent of cases.  To restore vision, a 
pulsed yttrium, aluminum, garnet (YAG) laser is used to produce a hole
non-thermally, by "optical breakdown," in the capsule to allow the normal 
passage of light rays back to the retina.  This painless procedure takes a
few minutes; improvement usually is immediate.  Other problems that may 
occur in a small percentage of patients include swelling of the cornea, 
glaucoma, and swelling of the retina, which distorts vision.

Overall, though, IOLs "have turned out to be much better than anyone ever 
expected," says FDA's Brogdon.

At a time when more older Americans than ever before are looking forward to 
years of active life ahead of them, IOLs offer hope and a better life.

Ellen Hale is a free-lance writer in Washington, D.C. 

FDA Consumer
Dec89-Jan90 
Cataracts sidebar 

Shielding Your Eyes from the Sun

Headed for the ski slopes or beach?  These pleasures can pose dangers to
your eyes unless you take precautions against the sun's harmful rays. 

Ultraviolet radiation is invisible and cannot be felt, yet long-term
exposure to it may be associated with development of cataracts.  Short-term 
exposure to very intense ultraviolet light--such as you get on a ski
slope--can produce photokeratitis, also called actinic keratopathy or snow
blindness.  There is even some evidence ultraviolet radiation may damage the
eye's retina. 

By spring of 1990, a new voluntary labeling program developed by the
Sunglass Association of America in cooperation with the Food and Drug 
Administration is expected to be in place to tell consumers how much UV 
protection they can expect from nonprescription sunglasses.  (Prescription
sunglasses already meet standards of protection against UV radiation and are
not included in this labeling program.) 

The voluntary labeling program calls for manufacturers to attach a tag to 
sunglasses that specifies the level of protection from the two types of 
ultraviolet rays: the longer wavelength ultraviolet A (UVA) radiation and 
the shorter wavelength ultraviolet B (UVB) rays.  The standards were
developed in 1986 by the American National Standards Institute in New York
City through consultation with eye-care professionals and educators,
research scientists, industry, and military and other government agencies.
The labeling standards are the only recognized statement on the properties
and performance of sunglasses.

The different categories describe minimum levels of protection and are
designed to help consumers pick the best glasses for the types of activities
they plan:

*  Cosmetic:  For non-harsh sunlight and around-town uses such as shopping. 
These will block at least 70 percent of UVB, 20 percent of UVA, and less
than 60 percent of visible light. 
*  General Purpose:  For most outdoor activities such as boating, flying, 
hiking, picnicking, and beach outings.  They also can be used for snow
settings.  They will block at least 95 percent of UVB, at least 60 percent
of UVA, and from 60 to 92 percent of visible light. 
*  Special Purpose:  For very bright environments such as tropical beaches
and ski slopes and for activities like mountain climbing.  They will block
at least 99 percent of UVB and 60 percent of UVA, in addition to from 20 to 
97 percent of visible light.

The amount of visible light--glare--blocked by sunglasses depends on the
darkness of the lenses.  The darker shades of special-purpose sunglasses are
intended for a high level of brightness, while the lighter shades can be
used for less bright situations like skiing on a cloudy day.

In addition, within the categories, look for the actual percentage of the 
sun's UV radiation that each particular model of glasses claims to block. 
The greater the blockage, the lower the risk of UV damage to the eye. 

Thomas Loomis, technical director of the Sunglass Association of America, 
offers this advice when buying nonprescription sunglasses:

First, decide on the purpose, color and fashion you want.  Once you've made 
a selection, hold the sunglasses up at arm's length and look through them at
an object with a straight border, such as window or door frame.  Move the 
glasses slowly across the line.  If it seems to wiggle, sway or curve, the
lenses contain an optical defect and should be replaced with another pair.

Since 8 percent of males and 3 percent of females have a vision color 
defect, be sure the glasses don't distort the colors of a traffic signal. 
Pay for the glasses, says Loomis, walk outside the store and conduct your 
own test.  If they distort the colors, exchange them for another pair.

--E.H.