Mark Calderwood, MD
Bitterroot Valley Eye Associates
A Service of Marcus Daly Memorial Hospital
300 North 10th Street
Hamilton, MT 59840
The Aging Eye
It is inevitable. We all get older. Death and taxes and all that... The
days, weeks, months, and years begin slowly but inevitably they catch
up with us. Aging research is one of the fastest growing trends in medicine.
People are living longer and healthier. The eye, like every other structure
of the body, experiences changes that are common and sometimes vision
is threatened. Fortunately, there are things we can do that can minimize
or even eliminate their effects.
The most common condition that occurs with age is the loss of our near
vision called presbyopia. On average most people start feeling the effects
at age 40. People who are near sighted (can see near, but far is blurry)
will notice this later, maybe beyond 50. Those who are far sighted (best
vision is far away) will notice this closer to age 40 or earlier. Though
the cause has still yet to be proven, I believe in the theory of the loss
of elasticity of the lens of the eye. The lens is a disk-shaped structure
found behind the pupil. It changes shape to focus near objects clearly
onto the retina. If it loses its plasticity due to aging (probably oxidation
of the lens proteins) we no longer see things up close and push them away
to focus them. The solutions are bifocals, trifocals, progressive (no
line bifocal), multifocal contact lenses, or new surgical interventions.
To date, we have not found ways to slow its insidious progress or reverse
it. There are current trials underway testing powerful antioxidant eye
drops to see if reversal is possible.
The next most common condition associated with age, which I see in my
clinic, are flashes and or floaters. This is caused by a breakdown in
the jelly of the eye (vitreous humor). The volume of the eye is comprised
of 85% vitreous jelly. It serves many functions, but the important thing
is that as it deteriorates the threads that hold it all together in a
matrix rips away from the retina, bringing with it small pieces of tissue,
which we see as new floaters (gnats, flies, snowflakes). These are annoying
but benign, and do not need to be treated. The pulling of these fibers
can cause a mechanical stimulation of the retina which leads to flashes.
These are also benign and usually go away within a few weeks to months.
The most concerning consequence of this process is a tear in the retina
which can lead to a detachment. This requires urgent treatment, which
is usually surgery. The surgery typically has good results and maintenance
of vision. The risk for this complication increases the more someone is
Cataracts begin around the age of 50. If you live long enough you'll
develop them. A cataract is the yellowing (oxidation) of the lens proteins.
This leads to less light entering the eye, distorting images, and can
lead to total blindness. There are other types but they are all treated
the same. This process occurs slowly in most people, usually taking decades
to become visually significant. The only effective treatment when they
become bad enough is surgery, removing the lens and replacing it with
a permanent crystal clear implant. Though the surgery is generally safe
and outcomes are excellent, it is still a major surgery of the eye. Technology
continues to move forward to the point that in the near future we will
be able to restore vision to its younger state, functioning much like
a camera with auto focus.
The most common cause of permanent central vision loss over the age of
60 is age-related macular degeneration (AMD). Its cause is unknown and
currently affects almost 2 million Americans increasing to 3 million by
2020. There appears to be a family connection. AMD is the slow loss of
retinal cells in the center of our vision, which is our best vision. Reading,
driving, facial recognition, and color are all affected and can eventually
lead to legal blindness (best corrected vision less than 20/200 in the
better eye). We have no way to reverse it but it can be slowed down by
lifestyle modification. Smoking increases the rapidity of the disease
by 300% or more. Cessation is essential. Smoking alone is an independent
risk factor. Nutritional changes are the mainstay of therapy. Eating lots
of green leafy vegetables and dark fruits appear to slow progression.
Supplements may be useful. Cutting out processed foods may be beneficial.
Exercise is very important no matter your age. Ten percent of patients
develop wet macular degeneration which there are good therapies for. Wet
macular degeneration is the sudden loss of vision from abnormal blood
vessel growth or an acute bleed. Treatments for this, ever increasing
condition, are being developed rapidly and a great deal of research is
being conducted to someday relegate it to the dustbins of history.
Dry eye is the single most common problem I deal with on a daily basis.
We live essentially in a high desert climate which contributes to the
ambient humidity often less than 20%. Our eyes prefer humidity ranges
above 70%, and this is quite rare most of the time here. As we get older,
to exacerbate the situation further, our bodies produce fewer and less
effective tears. Hormones play a larger role here, especially testosterone,
and this is why women experience this condition 9X more commonly than
men over the age of 50. The mainstay of treatment is lubrication with
over the counter artificial tears readily found in pharmacies and grocery
stores. Most of these products are very safe and must be used at least
four times a day. Experimentation with different brands, frequency, and
changing symptoms must be tried. Close work such as reading or computer
use exacerbates dry eye symptoms. Restasis is currently the only drug
available to improve dry eye, but new therapies are on the way. Punctal
plugs and cautery are other innovative treatments in select patients.
These few conditions are the most common that affect us as we get older.
However, we can all be more proactive when it comes to our health, potentially
mitigating some or all of them. Eating "real food," exercising
more, and stress reduction activities are some of the clichéd but
real solutions to a long healthy life.
Questions and or comments regarding this week's health column please
contact, Mark Calderwood, MD at Bitterroot Valley Eye Associates, a service
of Marcus Daly Memorial Hospital, 300 North 10th Street, Hamilton, MT
59840. Working together to build a healthier community!