Causes: as in iritis: traumatic and infective. Exudative. Suppurative.
Symptoms: as in iritis: less change in iris and of flocculi in the
aqueous humor; opacity of lens and vitreous. Lack lustre choroid under
ophthalmoscope, uneven, detached. Suppurative form: early profuse
weeping, bleeding, later suppuration, pus oozing from orifice;
panophthalmitis. Treatment: as in iritis; atropia; cocaine;
astringents; purgatives; diuretics.
_Causes._ These are largely the same as those of iritis and cyclitis.
Blows, traumas, foreign bodies, sand, cinders, dust, lime, fierce light,
reflection from snow, water, etc., chills, draughts, storms, irritant
gases, and a number of specific diseases like influenza, contagious
pneumonia, canine distemper, rheumatism, omphalitis, pyæmia, etc., may
be named. It is a common lesion of recurrent ophthalmia in horses, and
is not unknown in tuberculous cattle. It is usually more or less
involved in iritis, as the iris is in choroiditis. The name given to the
disease which involves both, will depend mainly on whether the
inflammation predominates in the iris or choroid. Mayer divides it into
exudative and suppurative, the latter being a common result of trauma,
and likely to issue in panophthalmitis.
_Symptoms._ These are largely those of iritis. The congestion and
redness of the sclerotic around the margin of the cornea, the fact that
the enlarged vessels are firm in the sclera and not easily moved as in
conjunctival congestion, and a certain partial blindness, without much
change in the brilliancy of the iris, or opacity or flocculi of the
aqueous humor, would suggest choroiditis. Later some opacity of the
lens, or its capsule or of the vitreous humor would be equally
significant.
The only certain manifestations would be such as are found on
ophthalmoscopic examination. Swelling and unevenness of the inner
surface of the choroid, and a loss of luster, a change of its dark
surface to light colored spots and patches, (dull-red, yellowish red,
grayish green) and of the tapetum lucidum to a dirty grayish green in
solipeds. Areas of minute blood clot may also be seen. But these are
rarely recognized or indeed skillfully sought during life, and it is
mainly to necropsies that we owe most of our diagnosis of choroiditis in
the lower animals.
In the _suppurative form_ there is early profuse lachrymation more or
less tinged with blood, and later oozing of pus from between the lids.
The redness and swelling of the conjunctiva and lids are very prominent
features, and if the lids can be separated the corneal or scleral
orifice may be seen oozing pus. If visible at all the anterior chamber
shows yellowish opaque contents, and the symptoms of panophthalmitis
supervene.
_Treatment_ of the exudative form is essentially the same as for iritis.
Atropia lotions with or without cocaine, also astringents, which may be
used warm, and generally purgatives, diuretics, local bleeding, cupping,
and counter-irritants are in order. In obstinate cases ointment of the
yellow iodide of mercury, and in cases of extra tension puncture of the
cornea may be the means of relief. Iridectomy may be advantageous under
careful antiseptic precautions. In case of extensive or general
suppuration (_panophthalmitis_) enucleation of the eye may be the only
resort, and may contribute to save the other eyeball. (See
Panophthalmitis).