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Well, I did it. In September I
had LASIK eye surgery. In ten minutes I went from
20/400 to 20/20. Amazing! So many of you have asked
about the experience that I thought I would talk
about it in this month's column.
I have watched vision correction
surgery since the late 70's when a friend of mine
had radial keratotomy performed on an experimental
basis. I wasn't an amateur astronomer in those days
but it still made my skin crawl. It sounded like
a huge risk just to avoid wearing glasses or contacts.
All those razor edge cuts into the cornea? No thank
you.
Vision correction surgery has come
a long way since then. But it wasn't until this
year that I felt comfortable with the state of the
art. Until fairly recently laser surgery involved
roughing up the surface of the cornea then "ablating"
away corneal material until the new desired curvature
is obtained. This procedure, coupled with the less
sophisticated laser device itself, meant for slower
healing, sometime permanent haloing at night and,
most importantly, less accurate "cuts"
by the laser than with today's cutting edge technology
(literally).
Today the state of the art is "third
generation LASIK" which involves more accurate
lasers and a simple preparation that almost completely
eliminates any disturbance to the corneal surface.
Rather than "roughing up" the corneal
surface and lasering directly on the surface, the
new procedure involved a very thin slicing of the
corneal surface which is laid back along a hinge
of non-sliced cornea. Think of slicing through a
thin layer of an apple but not all the way. Lift
up the small slice, take a small bite out of the
apple, then lay the cover slice back down in the
original position. The laser ablates corneal matter
BELOW the critical surface area while the flap is
raised. The slice is then repositioned and the tiny
thin line of the cut heals quickly. Most people
can go back to work in a day or so.
The results for astronomy have
been fantastic. Whereas I previously could only
detect six of the Pleides, I was able to see eight
at the last Explore the Stars program. The ten brightest
stars in the Pleiades are under 6th magnitude and
are in theory visible to the naked eye. However
most amateur astronomers can only see six or seven
due to the congestion of stars in the cluster. Next
month I am going to work real hard and see if I
can pick up number nine and ten.
The biggest worry about laser surgery
for the eyes is the phenomenon of haloing around
bright lights at night. Prior to having the surgery
done I had pictured this phenomenon in my mind as
being like a circle of light around a bright object,
sort of like the 22.5 degree circle you sometimes
see around the Moon when there is ice in the upper
atmosphere. After all, that is what a halo should
look like, right? A circle of light like the halo
on an angel. However that's not it. The "haloing"
is more like a circular glow around the bright object,
the glow being of equal brightness from the source
object to the edge of the glow. Picture M97 the
Owl Nebula for a more accurate image of what the
glow looks like.
My biggest question about the haloing
was whether it occurred on astronomical objects
such as bright stars. My suspicion was that it occurred
around bright objects like car lights and traffic
signals, but might not be a problem around the relative
dim light of bright stars. My suspicions were correct.
I can see a hint of haloing around bright stars
such as Vega and Sirius. But it is slight, and it
less apparent than the glare I saw on the same stars
if I wore glasses that were even the slightest bit
smudged or scratched. There is noticeable haloing
around the Moon, but it is not objectionable to
me. The haloing around car and traffic lights is
there, but it does not bother me. I am told that
the haloing effect tends to go away during the healing
process in third generation LASIK (although older
processes could leave some permanent haloing).
The overall effect of viewing the
sky after LASIK is that my eyes have become a magnitude
or so more sensitive. I am seeing stars I have never
seen before. It's wonderful. And getting rid of
the glasses when going back and forth from naked
eye to the telescope or binoculars is fantastic.
On the other hand, there is a downside
to the procedure for many middle aged amateur astronomers.
When you reach your mid-40's your eyes lose their
ability to focus on near objects. Thus the need
for reading glasses as you get older. However people
who are nearsighted get a nifty little perk from
nature. Nearsightedness masks the near focus problem.
So that middle aged nearsighted people can often
go without their glasses all together to read objects
up close. Books, instructions, small print on medicine
bottles, etc. LASIK takes away your nearsightedness
and thus removes the masking effect. So your aging
eyes need the reading glasses that you may have
avoided before. So LASIK is no guarantee that you
will be totally free of the need of reading glasses.
There is a technique called monovision that you
can ask your optometrist about which would eliminate
the need for glasses all together. Basically it
involves setting up one eye for close vision and
the other eye for far vision. This is not for everyone.
In the October issue of Sky &
Telescope Barry Santini (Tele-Vue) wrote a letter
to the editor in which he gives advice concerning
LASIK for amateur astronomers. I have spoken with
Barry several times, both before and after my procedure.
His main point the letter is that you want your
treated area to be as large are your dark adapted
pupil size (7-8 millimeters for most adults). Since
the FDA only approves out to 6mm this can be a problem.
However, you can go larger than that if the procedure
is done on an "experimental" basis. This
is NOT as scary as it sounds. The FDA is a very
conservative organization and has pegged six millimeters
as it current approved range. All procedures beyond
that limit are legally called experimental because
they don't have that FDA stamp of approval. In my
case, my surgeon is one of the few FDA investigators.
He gives his approval to new machines and techniques.
He has performed more than 12,000 LASIK procedures.
My procedure was done based on a seven millimeter
dilation (I sat in a completely darkened room for
twenty five minutes before my pupil size was measured).
Barry's other big concern is that
the person doing the procedure on your eyes have
LOTS of experience at it. He indicated 1200 procedures
as a good guide. When I told him of the experience
of my surgeon (12,000 procedures, FDA investigator,
third generation procedure) he felt very confident
for me. He wrote the S&T letter, in part, because
he wanted people to be sure they got the best care
they can and that they should not assume their surgeon
knows about the special needs of the amateur astronomer.
Do your homework.
One final word of advice: while
I went to 20/20 right after the surgery, one week
after surgery my eyes were slightly farsighted.
I went from a minus 5.0 diopter (moderate nearsighted)
to plus 0.75 diopter (slight farsighted). They told
me before hand that in the healing process the eyes
will tend to come back slightly toward the zero
diopter range. That seems to be happening and I
have another week before my one month checkup. The
goal, of course, would be to be dead on zero diopter.
Santini confirms that there is often a drift back
toward zero, but that there is not enough track
record to state with confidence that this is the
definitive pattern. I'll let you know next month
what happens.
Bottom line: If I had it to do
over again. I would... definitely.
Club News: Our Banquet Speaker,
Laurance Doyle of the SETI Institute is a well thought
of spokesman for the SETI project and will certainly
give us some wonderful insight at our upcoming Annual
Banquet. It is our hope to get as many former presidents
of the club in attendance for special honors. You
won't want to miss it.
The club is moving slowly but surely
forward on research and educational plans for the
future. Hopefully we can tell you more next month.
Don't miss the October meeting.
There will be some fantastic images, videos, and
stories concerning the spectacular prominence studded
total eclipse from last August.
The goodness of the night upon
you
(Othello Act 1 Scene 2)
Russell Sipe |
