The conjunctiva is a mucous membrane that coats the posterior surface
of the eyelids and the anterior surface of the eyeball. It forms a sac,
which is slit open in front in the line of the palpebral fissure.
The conjunctiva consists of three parts (1) the conjunctiva tarsi, the
part on the lids; (2) the conjunctiva bulbi, the part on the eyeball,
and (3) the conjunctiva fornicis, the part connecting the first and
second; it is the retrotarsal fold or the region of transition, often
called the fornix. The first part can be seen by everting the lids. It
is adherent to the tarsus. It is covered with a laminated cylindrical
epithelium. The membrane contains an abundance of lymphocytes similar
to adenoid tissue. This increases with every inflammation of the
conjunctiva. This is why =chronic conjunctivitis= often results in
thickened lids.
The =blood supply= of the conjunctiva of the lids is from the muscular
branches of the ophthalmic artery. The =nerve supply= is from the
ophthalmic division of the 5th cranial and the sympathetic.
The bulbar conjunctiva continues over the cornea. It is covered
with layers of pavement epithelium. Its blood supply comes from the
posterior conjunctival vessels about the retrotarsal fold, and the
anterior ciliary arteries which accompany the tendons of recti muscles;
these two systems anastomose in the conjunctiva. Conjunctival injection
or congestion shows a superficial net work of larger or smaller vessels
that move with the conjunctiva. The color is scarlet or brick red.
Ciliary injection occurs as a rose-red or pale violet zone around the
cornea, spoken of as peri-or circumcorneal injection. It does not move
with the conjunctiva and occurs more with diseases of the cornea, iris
and ciliary body.
In the =etiology of conjunctivitis= a great variety of germs are
considered by different writers. Collins and Mayo give a report of
“germs found in normal conjunctiva.”
Bacillus Xerosis in 94% of normal conjunctivæ; Staphylococcus Albus in
79%; Pneumococcus in 9%; Diplobacillus in 6%; Staphylococcus Aureus in
6%; Streptococcus in 5%.
If this be true, and I do not doubt their statement, we are practically
compelled to say that these germs at least are only secondary in the
etiology of conjunctivitis. Just at this point osteopathy comes with
its flood of light and makes it easily explainable why some conjunctivæ
become inflamed while others do not, when all have germs present. The
lesion disturbing the integrity of blood supply and nerve force to
the eye is the primary cause while the presence of germs may be the
aggravating cause. The lesion prepares the soil in which the germs
thrive sufficiently to become an irritant. There are all gradations
of this soil preparation. The more fertile the field (i. e. the more
profound the effect of the lesion) the more virulent germ life may
become; the resistance is proportionately less.
=Conjunctivitis= is =classified= for convenience in study, diagnosis
and treatment as follows:
(1) Catarrhal, (a) acute, (b) chronic, (c) follicular; (2) gonorrhoeal;
(3) ophthalmia neonatorum; (4) trachoma; (5) diphtheritic; (6)
eczematosa (phlyctenulosa); (7) vernalis; (8) tubercular; (9)
traumatic. This is the clinical classification after Fuch.