942
S.A.
MEDICAL
JOURNAL
NEEDLE-LIKE SUBTARSAL FOREIGN BODIES
P. D.
G.
QUlRKE,
M.B., B.CH.
(RAND),
0.0.
(R.C.P. &S.), Durban
14
September
1963
Needle-like foreign bodies penetrating the tarsal plate,
with aprojecting end causing irritation
of
the
cornea,
are
familiar to most oculists, who
probably
see several cases
every
year
in private
or
hospital practice. Somewhat sur-
prisingly, Ihave
not
seen any reference to this condition
in several
of
the
standard
ophthalmology textbooks. Pro-
bably for this reason, this clinical entity is
not
as well
known as
it
might
be.
The
microscopic appearances
and
properties
of
the
collection
of
foreign bodies illustrated
in this article indicate
and
explain the clinical effects.
The
foreign bodies were
found
driven
into
the
back
surface
of
the
upper
or
lower eyelid
with
asmall projec-
tion scraping
the
cornea.
They
varied between 0·5
and
1·5
mm. in length
and
were
about
as thick as acat's hair. Fig.
1indicates typical positions
and
sites in which they have
been found in different patients.
The
clinical picture is logical
and
is similar to
that
caused by
ordinary
subtarsal foreign bodies.
The
patient
complains
of
watering
of
the
eye, with intense irritation
and
sometimes a
sharp
pricking sensation
on
blinking.
The
cornea is scarified by linear abrasions resulting from
movements
of
the
eye
and
lid.
The
site
of
the foreign
body
mayor
may
not
be
marked
by
an
area
of
congestion
in the palpebral conjunctiva. Alittle oedema
in
the con-
junctiva
may
engulf
and
hide
the
projecting end, with re-
lief
of
symptoms. When the
oedema
subsides, possibly
as the result
of
treatment, re-exposure
of
the
foreign body
may
occur, with
return
of
irritation. Its position is further
indicated
by
the
most
abraded
portion
of
the
cornea.
When
this is
in
the lower
quarter
(Fig. 2)
the
foreign
body is likely to be
in
the
upper
portion
of
the lower
tarsal plate. When
most
scratch
marks
are
in
the
upper
segment
of
the
cornea
(Fig. 3),
the
irritant
is probably
in
the
middle level
of
the
upper
tarsus. Presenting virtually
in cross-section, these foreign bodies
are
usually invisible
without
the
aid
of
aslit-lamp microscope.
They
are
thin
enough to pass between sensory nerve endings and so may
cause
no
pain
or
reactionary congestion
in
the eyelid,
presumably from
lack
of
antidromic impulses
and
minimal
disturbance
of
the
embedding tissue.
It
is the scraping
of
the
cornea
that
causes the symptoms.
In
this it differs
from ophthalmia nodosa, in which local lesions are caused
by caterpillar hairs
in
the
conjunctiva
or
cornea.
The
foreign bodies were too small
to
be
grasped by
forceps
and
were
removed
by stroking with aneedle
under
magnification by
the
corneal microscope. Most were
picked
up
in a
drop
of
tear
fluid
and
mucus
after
being
dislodged from
the
tissues.
In
conveying
the
foreign body
to
the
laboratory
the
mucus usually dried to form atough
encasement from which the specimen was removed by
dissection
under
abinocular microscope, with varying suc-
cess.
The
specimens have been
photographed
under high
power
in
canada
balsam
under
acover slip (plate I).
Many
have been photographed
in
abed
of
mucous detritus from
which isolation was
not
possible.
Many
were lost
in
the
breeze
or
from
an
incautious exhalation.
The
physical properties required
in
theory
to
produce
such clinical effects
are
to
be
found
in
these specimens in
fact.
They
are
light enough
and
small enough to be air-
borne.
One
patient felt
the
irritation first
in
a
boat
sixty
3
Fig. 1. Typical positions and sites. Fig.
2.
Abrasions on cornea.
Fig.
3.
Abrasions on cornea.
