?except as a side-effect of neuroleptic drugs. It consists of an
uncomfortable forced upward or up-
and-lateral tonic deviation of the eyes42.

No Nystagmus or Dementia -- Nystagmus is not seen in idiopathic PD in
contrast to
postencephalitic PD, where it was common. Dementia is not found in
young-onset PD patients. In
elderly patients with PD, dementia is present far more often than in
controls.

Signs -- Meyerson's sign is the failure of the blink reflex to habituate
to repeated glabellar tap.
Wilson's sign is the need to blink in order to change saccadic
direction.

3. MANAGEMENT
Patients with PD typically complain of difficulty reading because of
blurred vision, diplopia,
photophobia, asthenopia, decreased vergences, ocular surface
abnormalties33.

In defining the complaint, take a careful history.  Ask the patient
about his activities at home and
at work, how much time the patient spends reading, and the typical
reading distance. Ask about
computer time, since patients with PD often have difficulty with
handwriting and may spend a lot
of time at the computer.  Ask the patient and caregiver about response
to antiParkinson's
medications.  The effects of medications are often erratic and
unpredictable.  Parkinson's patients
describe feeling like Alice in Wonderland, taking the  “Eat me”- Sinemet
but never knowing when
they will be small enough to fit through a keyhole or big enough to fill
the room. Ask how much
time during a day is spent in the OFF-state, ON, and ON with
dyskinesias. Ask whether the
patient experiences more visual difficulty when OFF or when dyskinetic.
Ask the patient where in
the cycle of medication he considers his current state to fall.
Eyeglasses should be made to
correct in all eventualities.

Take a careful medication history. Particularly note antidepressants and
anticholinergics, which
may contribute to hallucinations, dry eyes, etc. Make sure patient is
adequately medicated with
dopamine. Too much L-dopa leads to dyskinesias, making the patient
appear less socially
acceptable. But the patient may be more comfortable having dyskinesias
than when rigid, akinetic,
dependent, and in pain.  PD patients should be managing their
medications with the guidance of
an enlightened movement disorder specialist, not the local internist.

Do a careful refraction, providing the patient with a headrest to
support the head during
refraction.  If the patient has difficulty sitting still at the
phoropter, refract using a trial frame. In a
patient experiencing dyskinesias and dystonias, bizarre head postures
will interfere with astigmatic
correction at near.  Distance glasses are likely to fall off, get
dropped and become bent and
misaligned. Therefore, consider dispensing the spherical equivalent
rather than a significant
astigmatic correction for most patients.   Dispense separate glasses for
near, intermediate, and
distance, not bifocals, even though this may necessitate 2 or 3 separate
pairs of glasses.  Patients
with Parkinson’s have balance problems and those with a tendency to fall
should not attempt to
walk in bifocals.  If the patient insists on bifocals resist Varilux
since the patient's head control is
too limited to find the right locus on the glasses most of the time.
Provide a generous reading add in young PD patients. Under-correct
myopia in young patients
with PD so they can avoid the need for readers.
Look for convergence and divergence insufficiency. Prescribe base-out
prisms for distance and
base-in prisms for near. If fusional amplitudes are too limited to
permit single vision even with
prismatic correction, comfortable single vision can be provided by
translucent occlusion of one
spectacle lens.

Examine the eye movements. In the presence of severe supranuclear
ophthalmoplegia, selective
downgaze paresis, frequent squarewave jerks, axial rigidity, forward
neck flexion, cerebellar signs,
or prominent dysarthria, consider alternate diagnoses to idiopathic
PD39.

 Blepharospasm is rare in idiopathic PD, and more common in PSP.
Nevertheless, when it occurs
it can be treated with BOTOX.   Perhaps surprisingly, apraxia of eyelid
opening also can improve
with BOTOX.

Before injecting BOTOX, aggressively treat external disease. Blepharitis
has been traditionally
treated with daily baby-shampoo lid scrubs in the shower; but for a
slow-moving patient who
needs help with balance in the shower, commercially available lid-scrub
pads are easier to
manage independently and yield better results. Non-preserved artificial
tears should be
recommended for frequent use throughout the day, but the patient may
need help applying them if
he has tremor. If Schirmer test shows low tear secretion, punctal
occlusion can be considered.
Many patients with low blink rates may enjoy resolution of visual
blurring after a few good blinks.
Avoid treating blepharitis with steroid preparations since they can
precipitate glaucoma, which is
difficult to diagnose and to follow in patients in whom performing
visual fields and obtaining
accurate intraocular pressure are problematic. Try to check the
intraocular pressure by
applanation tonometry, but use a tonopen if the patient has
blepharospasm.

Difficulties with reading can result from the patient losing his place
through inability to hold his
head still when he has dyskinesias. This can be ameliorated by using a
finger as a placeholder.
Slow reading due to paucity of eye movements also can be improved by
using the finger to draw
the eye across the page. Even with perfect refraction and clear vision,
it is hard to read when the
hand that is holding the book has a four cycle per second tremor of
large amplitude. The patient
should be encouraged to obtain a music stand or cookbook-holder so that
the hand tremor will
not interfere with his reading. One of the reasons patients with
Parkinson's spend so much time on
the Internet is that the computer screen sits still on the desk.

Empathetic rehabilitation of the visual capacity of patients with PD may
have an enormous
positive impact on quality of life, not only for the patient but also
for the family. These patients
are usually intellectually alert but have lost control of motor
functions that enable physical
exploration, expression of personhood, and communication of ideas. Sight
is therefore an
especially critical “lifeline” for these patients.


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