DECISION THEORY
In the days when patients still had to wait three
months for an appointment with their ophthalmologist, it was
fashionable to contemplate a style of practice where one
assistant should take the patient's history, another
assistant measure his acuity and perform the refraction,
and yet a third assistant measure the tension, obtain
the visual fields, perhaps photograph the fundus, and
possibly obtain tonography, leaving to the ophthalmologist
himself the visual examinations, with the slit lamp, the
ophthalmoscope and the gonioscope, but above all reserving
to the ophthalmologist as to a mini-god, the prerogative
and responsibility of making the necessary decisions.
It was unwittingly a quasi Aristotelian division of labor,
with the physician as it were, possessing the knowledge of
the first principles, and being at the same time the prime
mover of the processes by which the patient was to be healed,
and except in the case of surgical operation, leaving the
execution of his instructions to his subordinates.
The making of the decision and the surgical technique,
it appears, are the two essentials, and in glaucoma practice,
where so much of the treatment is non-surgical, the role of the
ophthalmologist as decision-maker looms all the more important.
Given then, the importance ascribed to the decision-making
process, it seemes reasonable, inspired with the Aristotelian
animus, to take a closer look, to ascertain if perhaps one
might not, by investigating the principles of decision making,
come to understand a bit better what one was trying to do.
For many years I puzzled over these problems, aware that
the eagerness to make decisions reflects decision-making as
the badge of power in a rationalized society. This is the case
not only in medicine, but in all the other professions, in
business as well as in government. But while everyone is busy
making decisions, hardly anyone concerns himself with the
decision-making process, a discussion of which would appear to
lead on the one hand into some of the most sterile realms of
mathematics, but in the other direction, into an undisciplined
rummaging about in words which unavoidably have different
shades of meaning for different listeners. Thus, compliant
with the dictates of conventional wisdom, I refrained from
reflecting on decision-making while fulfilling my role of
decision-maker as assiduously as ever. That is how things
stood when, one day, two or three years ago, there came to my
office a patient whose problem inadvertently shed light on the
decision-making process.
It was before the days of laser photocoagulation of the
trabecular meshwork for open angle glaucoma that I was asked
to see in consultation a memorable case. He was the last
patient of the afternoon, a distiguished looking man with
sparse white hair, which was neatly combed backwards, framing
his low, weather-beaten forehead. His eyes, one of which
was apparently already badly scarred from surgery, were
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partially hidden under epicanthal folds which gave them an
aura of knowing and mystery. In reply to my question as to
what I might do for him, he handed me a packet of medical
record sheets, and added softly, "I need to decide for myself."
He spoke these words with a faint foreign accent, and as I
listened, I wondered to myself what it was that he really
meant.
"May I look at these?" I asked.
"Of course," he replied, "that is why I am here," and as I
began to leaf through the sheaf of papers that he had
brought me, he fixed his gaze on some undefined point in
space.
From the record it appeared that his glaucoma, then
already far advanced, had been discovered on a routine eye
examination 7 years previously, when he was sixty-five.
Medication had brought the pressure only to the mid
twenties. A filtering operation to the right eye had been
decided upon and performed. Apparently a functioning
filtering scar had been obtained, but cataract developed,
and three years later, that is four years prior to the
present visit, cataract extraction had been performed from
below. Following this second operation, the filtering bleb
had scarred, and the pressure had risen to the mid thirties.
Six months after the cataract extraction, a trabeculectomy
had been performed, but it too had been only transiently
successful, because soon thereafter, echothiophate was
prescribed, without any noticable effect on the pressure.
A cyclodialysis had proved futile. Cryotherapy, performed
only 9 months previously, had finally succeeded in reducing
the pressure to the mid twenties, but with its performance,
central vision had been lost, and to judge from the
impressionistic field charts in the file, only a peripheral
temporal field of variable dimensions remained. The left, the
fellow eye was recorded as registering pressures between 20
and 25, and the left visual field showed both upper and lower
Bjerrum scotomata that seemed to have been enlarging over the
past several months.
After I had finished looking over the records, I examined
his eyes. I explained that my findings corroborated what his
previous doctors had determined, and I discussed the surgical
options that remained if one wished to try to preserve the
remaining vision in either eye.
"You mean to say," he began slowly and deliberately,
having listened to my exposition, "that you think it might
be worthwhile to perform more surgery on the right eye?"
"Possibly," I said.
"And the left eye?" he asked. "So far as I can infer from
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the records that you bring me," I began cautiously, "it
appears that the visual field in the left eye is gradually
becoming smaller. The pressure in the left eye is not as
low as it should be. If an operation could reduce the
pressure in the left eye to a sufficiently low level, then
it is likely that the vision in the left eye might be
preserved in its present state. But from your experience
with the right eye," I added, "you know that this is not
always the case."
"What do you think I should do?"
"It is a decision for you to make. I wish I could make it
for you, but I can't."
He made no answer. Now, I thought in my vanity, he will
say, I want you to do the operations that are necessary.
That is why I have come. And then, I thought to myself, if
the vision is not preserved, it will become my task to help
him adjust to his blindness. "You must feel free to ask any
questions you like," and I added as an afterthought, "I
cannot promise that I will be able to answer them."
He remained silent, and then I thought I saw that his heavy
lids drew apart, and a faint smile, like a wreath of hope,
began to encircle his lips.
"I apologize to you," he said.
"I see no reason for apology," I encouraged him, "It is a
difficult decision, and sometimes it takes time to make up
ones mind."
"My apology," he began, "concerns not my apparent inability
to make up my mind. I owe you an apology because I have
troubled you for a decision, which I understand now, as I
sit here, and observe your appropriating to your thoughts the
history of my illness, is likely to prove a misunderstanding."
The foreign accent to his words had reappeared. It occurred
to me that he probably spoke many languages and was trying
to express himself in an idiom that I could understand. It
was a strange explanation. No patient had ever told me
anything even remotely comparable.
"I am a ..." he began, and then corrected himself, "My eyes
and I are veterans of decision-making, and the experience
deprives us of some of the confidence we might otherwise
have had. To presume to decide is but another way to say
that you don't know. I play the Numbers Game. I decide
which one to bet on, only because I don't know the winning
number. If I knew the winning number, you can be sure that
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I wouldn't be making any decisions about which number to bet
on. Decisions are the fig leaves of ignorance."
"I've been fishing out of Gloucester for many a year, and I
can't recollect a single time that I 'decided' which course
to take for port, provided I had a chart and a compass and
knew my position. The only time I ever made a decision
under those circumstances is when I was lost and didn't know
where I was, or couldn't find the chart, or the compass was
broke. If I knew what to do for my eyes, I would do it, its
because you don't know, that you tell me that you have to
decide, and you haven't got the guts for that, so you put it
off on me and tell me it's my decision."
I was at a loss for something to say, and it would have
been better had I said nothing. Only later did I realize
that I was, in fact, retreating to the protective circle of
my colleagues, when I suggested, "perhaps you would like to
come to one of our medical conferences, where you will have
the benefit of the opinions of numerous doctors, not just
myself. I would tell them about you, they would all take a
look at your eye, they would discuss your particular case,
and then they would take a vote, and you would know just how
things stood with you."
"I have been there," he said, and I though I heard a faint
echo of triumph in his voice. "I have been there and they
voted, 18 to 2 in favor of surgery, and look where it got
me, although I wouldn't say that the doctors who said they
wouldn't operate were right. They probably just didn't
trust themselves. If I'd taken their advice, I probably
wouldn't be any better off, but no worse either."
I tried to think of some graceful way to end the
consultation, but it was the patient who had the final word.
He got up and reached for the wallet that he carried in his
hip pocket. "Please talk to the secretary," I said, but he
seemed not to hear me. He dug in it for a twenty-five cent
piece which he held up to the light, and scrutinized for a
moment with his good eye. "If it's heads," he declared,
"I'll have the operation, but if it's tails, then, let's put
it this way, then the eyes have suffered enough. And while I
watched in disbelief, he flipped the coin high into the air,
caught it, and laid it on the back of his hand. "Tails," he
said. He got up, and I saw him shudder as if he were cold,
even though the steam had just come up in the radiator and
the room was comfortably warm. "Enough is enough," he
declared. "No more surgery."
He offered me the quarter, and when I made no motion to take
it, he put it on my desk. "It's for you doc," he said,
"that's how to make a decision." He picked up the bundle of
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his medical records, and walked out.
To attempt to give a comprehensive account of the
logical, mathematical and psychological processes decision-
making is to brave a quicksand of argumentation, which, if
it were to have any expectation of success, would require a
dissertation of such length as to exhaust the patience and
interest of the reader. Nonetheless, the lessons that my
patient taught me are well worth repeating, even though they
must, unavoidably, remain incomplete.
Decisions are difficult, and the first rule is not to
make them unless you have to. Many decisions that one makes,
of course, have so little practical import as hardly to
deserve that name. One should not minimize the difficulty
or hazard of making decisions that vitally affect the health
and happiness of ones patient. To be eager to make decisions
is as surely the mark of an immature clinician as it is the
mark of an immature surgeon to want badly to operate. Making
decisions in the treatment of glaucoma, as, I suppose, in any
other area of significance, is an art, in some ways not
unlike the art of surgery, which requires to be learned by
diligent and careful and humble practice. There is no
question but that the quality of the decision will vary from
one ophthalmologist to the other, just as some of us are more
skillful surgeons than others. But the quality of decision-
making, like the quality of surgery, is not so much a matter
of talent as of effort. It is ones ability to subordinate
all other competing interests to satisfactory solution of
that one, unavoidably unique particular problem, which
leads in one case as in the other to the most constructive
and fruitful application of ones efforts.
It is obvious, as my patient had pointed out, that we
become aware that we are making a decision, only when we
are confronted with uncertainty, and, to simplify the
discussion, it seems reasonable to discard the notion of
possibly "unconscious" decisions, and to reserve the term
"decision" for those crossroads of thought that we recognize
when we arrive at them and which give us the occasion to
articulate a considered choice between two or more alternatives.
If the goal for which we aim is fixed, and let us assume,
arguendo, that in the care of glaucoma patients, this goal
is the preservation of the patient's sight, then the only
uncertainties between which we have to decide are the means
by which that goal might best be accomplished. Decision-
making is all too often a poor substitute for knowledge, and
better than forcing a difficult decision is to obtain more
facts. It is, in my experience, very common that a proposed
decision concerning, for example, the institution of medical
treatment or the recommendation of surgical therapy, appears
necessary solely for lack of some readily obtainable facet
of knowledge. The question, for example, whether the
patient requires medication because the pressure is too
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high, can often be avoided by obtaining a few more
measurements of the pressure, which might make it apparent
that the pressure was indeed so high as to require treatment
without any doubt, or that most of the time it was so low as
to make treatment clearly superfluous. Or that a patient
requires filtering surgery because he is losing field, when
sufficiently frequent examinations of the field would show
that the apparent increase in field loss was only illusory.
The first rule, therefore, in decision-making in the
treatment of glaucoma is to make sure that a decision is in
fact required, to be certain that the marginal value of
additional information about the patient's problem is
sufficiently slight so as to make superfluous further
efforts at obtaining historical or clinical data.
If one considers clinical decision-making in the
treatment of glaucoma at all closely, one cannot help but be
impressed by the degree to which the decision proves to be a
reflection of society's expectations. Before he obtains
permission to exercise his judgment in this regard, the
ophthalmologist is required to spend years in training. The
litany upon the length of medical education is too familiar
to bear repetition. In the course of all those years, he
learns not only the "facts" about anatomy, physiology and
pathology which will utltimately guide his judgment. He is
also trained to observe in a special way, and not least
important, his powers of judgment are constrained by the
prevailing dogma. In consideration of all the forces that
would tend to bring his decisions into conformity with those
of his colleagues, one must wonder that there is, about
decision-making, any originality at all. Indeed, the
circumstance that this is so speaks most eloquently for the
independence of the human spirit. Nonetheless,
indoctrination and training do leave their marks, and when
we evaluate the decisions that are made, by ourselves or by
others, we would do well to consider from time to time, to
what extent our minds are merely mirrors that reflect rules
of thought that others have enunciated, that are socially
acceptable, and that have been drilled into us during the
course of our professional training. This adherence to
patterns of thought that are essentially social, is
reinforced by the patient's expectation of a uniformity of
opinion and judgment among physicians. It is common enough
to hear the statement that if one consults several doctors,
one obtains a different opinion from each one, and this is
anything other than a compliment to the doctor on his
originality. Also, of course, we must be aware that our
colleagues are looking over our shoulders, prepared to
endorse the rightness of our actions even when these issue
in catastrophe, and prepared to criticize our actions as
unconventional, even when what we do is overtly successful
in attaining the desired end. And if all these social
constraints were insufficient, there are the lawyers,
soaring like vultures upon the thermals of legal fantasy,
ready to pounce and profit from the misfortune of doctor and
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patient alike. In this context it might well be said
explicitly that, closely examined, the standards of
professional conduct that lawyers conjure up as it suits
their purposes, are ex post facto contraptions that they
fashion for the issue at hand.
In consideration of the diverse social constraints upon
our decision-making, it is not surprising that one should,
from time to time, encounter their institutionalization. It
is, for example, not unheard of, to invite patients to
appear before a group of physicians, who are presented with
the medical history, and are given the opportunity, usually
perfunctory, to perform some fragment of the eye examination,
who then, like jurors sitting upon a legal action, discuss
the patient's problem that has been presented to them and
take a vote as to the proper decision. Interestingly, when
the societal forces upon decision-making are carried to such
an extreme, it becomes apparent to what large extent,
notwithstanding all social constraints under which it takes
place, the making of decisions is an individual enterprise;
and while group decisions such as I have described may
protect the patient from some absurd eccentricity of an
aberrant practitioner, they almost never provide the optimal
solution. It is important to understand why this must be
the case.
Except in the trivial case of unthinking conformity,
the individual who conforms his judgment to that of his
social group does so through the mediation of ideas and
concepts. The bond that holds together the members of a
society is communication in mathematical symbols, or, more
commonly, in words and sentences. What distinguishes the
verbal from the mathematical symbol is that individual
experience controls the meaning of the verbal symbol while
individual experience is controlled by the symbolism of
mathematics. What distinguishes the verbal from the
mathematical symbol is that the meaning of the verbal symbol
is controlled by individual experience. The meaning of the
mathematical symbol, however, is rigorously defined, and men
spend years in disciplining their mental processes to
accord to the imperatives of the mathematical scheme.
In mathematics it is not the experience which defines the
symbol but the symbol which defines the experience.
Considering now the members of this clinical jury, one
sees that each of them attaches to the words and phrases
that are exchanged between them a meaning slightly
different, corresponding to his own unique experiences. It
is not only that one person may be a more acute oberver than
the next, but the logical fabric in which the patient's
problem is defined may have to him also a different, call
it more realistic, call it a more truthful meaning. And
though one may argue ones way to a common definition of
words, the judgmental processes by which propositions and
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merits are weighed one against the other and inaccessible to
control, so that, confronted with the same set of
propositions, two clinicians may well, and often do, arrive
at differing conclusions, and an individual who is sensitive
and thoughtful and, in the technical sense, passionate about
his judgment will very possibly arrive at different and
superior decisions from those that evolve from an electoral
decision-making process.
On the scientific horizon there looms the theoretical
possibility of clinical decision-making entirely independent
of individual judgment. The mathematical algorithms for
computerized decision-making have long since been invented,
and the computers are ready to run. What stands in the way
is the circumstance that much of the clinical data that
enters into the decision, the appreance of the optic disc
is a prime example, is itself the product of judgment,
circumstance borne out by the fact that it is infrequently
solely an issue of data interpretation, whether the disc is
excavated or whether field loss is progressing, upon which
the clinical decision hinges. If and when all the
significant historical and clinical data that enter into the
glaucoma decision can be reproduceably encoded into symbols,
a new era of automatic decision-making may dawn.
* * * * *
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Copyright 2006, Ernst Jochen Meyer