1. OPHTHALMIC DISEASES/DISORDER OF HORSE
VM175
disease/
disorder Other
name
Brief description Epide
miolo
gy
Pathogenesis Clinical signs Lesions Diagnosis Differe
ntial
diagno
sis
Treatment Control/p
revention
Entropion -turning in of the
edges of the eyelid
so that the
eyelashes rub
against the eye
surface
-The turning in of eyelashes
or facial hairs causes
discomfort and irritation of
the conjunctiva and cornea.
Extremely long lashes can
cause scarring, abnormal
coloring, and possibly the
formation of slow-healing
sores or ulcers on the
cornea.
-Blepharo-
spasm
-Lacrimation
-Photophobia
-Scarring
-abnormal
coloring
-Physical
exam
-surgery (Eversion of
affected eyelids
through
placing sutures at the
lid margin to roll out
the offending eyelid
margin
-It is
congenital
,cannot be
prevented
Laceration
of the
eyelid
-rips or tears in the
eyelid. Common in
horses
Eyelid laceration is often
common in horses. If eyelid
defects are not closed or
handled improperly,
complications are as
conjunctivitis , corneal
abrasions, exposure
keratits.
-Laceration of
the eyelids
-Physical
exam
-clean the wound and
use stitches to repair
it so that minimal
scarring occurs.

2. Bacterial
Blepharitis
-Diffuse eyelid
swelling that is
warm and painful
on palpation
Fever
-Inflammation of the
eyelids can
-result from
the spreading of a
generalized inflammation
of the skin, local glandular
infections, or irritants
,Infection with certain fungi
or bacteria.
-sudden onset
edema
-hyperemia of
lids with
pruritus
-thickening
and fibrosis of
the lids loss of
hair
-Edema
-loss of hair
-thickening
and fibrosis of
the lids
-Base on
history
-clinical
sign
-allergen
testing.
-Orbital
celluliti
s
-
Eyelid
trauma
-Meibo
mianitis
.
-Warm compress
-antibiotic
therapy(penicillin,
ceftiofur, ampicillin,
for 4-7 days ) and
analgesic
(phynylbutazone)
Absence of
nasal tear
duct
opening
-congenital absence
of the opening of the
nasal tear duct at
the lower end in the
nose
-This is a most common
developmental anomaly in
the equine nasolacrimal
system causing further
complications if not
corrected.
-watering eyes
and longterm -
conjunctivitis
in foals.
-persistent
epiphora
-Ocular pain
-clinical
sign
-fluoresce
in dye
-surgically opening
the blocked passage
and keeping it open
by inserting a tube
during healing.
No
prevention
Dacryocyst
itis
-inflammation of the
lacrimal sac and
nasolacrimal duct.
-Infections of the
nasolacrimal duct
occasionally occurs in
horses. Foreign bodies
chronic obstruction of the
duct, or infection by
opportunistic
microorganisms causes
dacryocystitis.
ocular
discharge,
reflux
exudation,
hyperemia.
-Dacryocy
storrhino
graphy.
-
conjucti
vitis
-Daily lavage of duct
- topical antibiotic
therapy
-Tubing (polyethylene
or silicon) suture
temporarily
catheterized in the
duct.
Dry eye -
Keratoc
onjunct
ivitis
sicca
-Dry
eye
syndro
me
-an eye
disease caused by
eye dryness, which,
in turn, is caused by
either
decreased tear prod
uction or increased
tear film
evaporation.
-dry eyes can lead to
tiny abrasions on the
surface of the eyes. In
advanced cases,
the epithelium undergoes
pathologic changes,
namely squamous
metaplasia and loss
ofgoblet cells. Etiology can
be congenital drug related
–squinting
- mucoid
discharge
-nonhealing
ulcers
-dry
appearance
-dull cornea
with
vascularization
-Sore and
scarring of the
cornea
-clinical
signs
-Rose
Bengal
stain
- schirmer
tear test
-Antibiotics
(Topical 2%
cyclosporine or 0.o3%
tacrolimus )
-Surgical therapy for
KCS:
–1. Nictitans flap - to
protect cornea when
ulcerated
–2. Conjunctival flap -
Deep corneal ulcers,

3. or systemic diseases pigmentation
of cornea
to provide corrective
tissue and blood
vessels.
–3. Parotid duct
transposition
Conjunctiv
itis
Pink
eye
-Inflammation of the
conjunctiva
-Pink eye can be cause by
physical trauma,
bacterial(mycoplasma),
viral(herpes) that causes
inflammation of the
conjunctiva that can lead to
blindness if not treated
early.
–hyperemia
-chemosis
-Serous
discharge
-follicular
hyperplasi
-mild ocular
disconfort
-Conjuctival
scrapings
and culture
- Schir
mer tear
test
-biopsy.
-kerato
conjunc
tivitis
-antibiotic ointment
2-3x a day and anti-
inflammation
-Good
sanitation
practices
and good
manageme
nt
Corneal
ulcers
-A corneal ulcer
occurs when the
corneal epithelium
is disrupted to the
extent that corneal
stroma is exposed. A
shallow ulcer
involves just
disruption of
epithelial cells,
while a deep ulcer
would involve
significant loss of
stroma as
well. Extremely
deep ulcers can
entirely remove
corneal epithelium
and corneal stroma,
exposingDescemet’s
Membrane
-Many equine corneal
ulcers occur as a result of
injury to the eye, with
inflammation of the cornea.
Corneal ulcers may be
complicated by a fungal
invasion; this is termed
equine ulcerative
keratomycosis. The
fungus, which is normally
present in the conjunctiva,
multiplies rapidly after
injury to the cornea and
causes inflammation and
ulcers.
-Blepharo
spasm (a
closed eyelid)
-Photophobia
(avoiding
light)
-Increased
Lacrimation
-Miosis
-corneal ulcers -Ophthal
mic exami
nation
-fluoros
cein dye
-Systemic anti-
inflammatory and
painkiller Flunixin
(Finadyne)
-Topical Antibiotic
-Conjunctival flap
surgery
-Amniotic Membrane
Transplants
-Penetrating
Keratoplasty
-Lamellar
Keratoplasty

4. Corneal
abscesses
- Pus-filled sores in
the connective
tissue of the cornea
-Causative agent organism
are deposited in the stroma
at the time of injury to the
cornea or gain intrance to
the stroma within few days
from the resident
conjuctival flora, the lost
epithelium heal quickly by
migration and mitosis of
cells and seal the bacteria
or fungi within the stroma
allowing abscess formation
-Lacrimation
-Photophobia
-
blepharospas
m
-Abscessed
stroma it is
dense white or
yellow spot
Eye
examina
tion
Corneal
ulcera
tion
-antibiotics natamycin
(5%)
Topical atropine
flunixin meglumine
omeprazole
Doxycycline:
Trimethoprim
Fluconazole -
Voriconazole
Penetrating
Keratoplasty
Corneal
laceration
-Corneal laceration
are usually linear or
triangular corneal
wounds ,
-Corneal ulceration when
not treated immediately
cause lead to abscess. It will
serve as a point entry of
organism
-swelling
- prolapse of
the iris
-swelling of the
ciliary bodies
-blood in the
eye.
-Corneal ulcers -Ophthal
mic exam
-fluores
cein dye
-
Corneal
abscess
- antibiotics
-Topical atropine
-systemic NSAIDS
-Surgical debridement
-suturing large flap of
corneal tissue
-routine
exami
nation
Equine
recurrent
uvietis
-Moon
blindne
ss
-Peri
odic
opthal
mia
iridocy
clitis
-Most common
cause of blindness
in horses. Uveitis
refers to
inflammation of the
uveal tract of the
eye
-
Mostly
affect
adult
horses
-Specific conditions or
agents that may cause this
disorder include certain
bacteria, parasitic worms,
equine influenza (a viral
illness), tooth root
abscesses, and hoof
abscesses. , there are
periods of active
inflammation of the uvea,
followed by varying periods
with no signs at all. During
the so-called inactive
periods, mild inflammation
continues in most horses
-frequent
squinting
-watering eyes,
-cloudiness of
the cornea, and
contraction of
the pupil
-An active
episode may
include
inflamed cells
infiltrating the
retina or
choroid, partial
separation of
the retina,
retinal
bleeding, and a
hazy
appearance to
the vitreous
(the clear
“jelly” that fills
the
-clinical
signs, and
history
lesion
-
conjunctiv
al biopsy
-serology
for
bacterial
and viral
agents.
Aggressive
medication of
systematic and local
corticosteroids, anti-
inflammatory and
antibiotics
To protect
your
horse's
vision, eye
examinatio
ns should
be
included in
its routine
care.
Glaucoma The glaucomas
represent a group of
Most
comm
The glaucomas are a group
of diseases resulting from
-Enlarged eye
-Corneal
-presence of
corneal striae
Tonometry
(Auriculopa
-Reduce IOP.
Dorzolamide and

5. diseases
characterized by
increased pressure
within the eye. This
can be primary,
secondary or
congenital type
on in
older
horses
and
appalo
za
breeds
alterations in the formation
and drainage of aqueous
humor (clear eye fluid),
which causes an increase in
intraocular (within the eye)
pressure (IOP) above that
compatible with normal
function of the retina and
optic nerve. The high
pressure eventually
destroys the retina and
optic disk
edema
–Branching
linear stria
–Not painful
–IOP > 30
mmHg
Tonopen
–Mydriasis
–Blindness
(IOP tolerant
eye)
or corneal
endothelial
"band
opacities"
lpebral
nerve
blocks)
- xylazine
(a common
tranquilizer
)
-decreased
intraocular
pressure by
23%. -
Manometry
determined
IOP = (1.38
X Tonopen
IOP) +
2.3mmHg
Timolol BID; Cosopt
-surgical
therapy
–Intravitreal
gentamicin
–(25 mg + 1 mg Dex)
–Cyclocryo
therapy
–Enucleation/
Intraocular prosthesis
Cataracts -Cataracts are a
condition in which
the lens becomes
covered in a cloudy
film that affects
sight, eventually
causing total
blindness
-Foal
and
old
horses
-In foals, cataracts are the
most common congenital
defect of the eye. In adult
horses, most cataracts
occur as a result of the
inflammation of the
anterior uvea associated
with equine recurrent
uveitis
-Lens become
covered in a
cloudy film
-
Ophthalmos
copy
-Surgery -
Congenital
insome
breeds,
affected
horse
should be
excluded
from
breeding.
Lens
displaceme
nt
The displacement
may be due to
trauma, longterm
inflammation of the
uvea (as occurs in
equine recurrent
uveitis), or
glaucoma.
-The normal lens is
suspended behind the iris
and pupil In some ocular
diseases these fibres
become damaged either by
inflammation in adjacent
structures or by being
stretched when the eye
expands under increased
intra-ocular pressure
Leakage of
vitreous
glassy disc
lying directly
behind the
cornea
Ophthalmic
exam
-The only effective
treatment is surgical
removal of the lens.
Affected
animal
should be
excluded
from
breeding
Chorioreti
nitis
Inflammation of the
retina and choroid
-It can be caused by
infectious agents such as
-Swelling
-bloodshot
-“bullet-hole”
lesions
-Ophthal
mic exam
anti-inflammatory
therapy

6. is frequently a result
of a generalized
infection
leptospirosis, equine
herpesvirus-1, Onchocerca
cervicalis, a poorly
controlled immune system,
trauma, or vascular (blood
vessel) disease.
eyes
- nodules or
masses in the
eye itself.
-diffuse lesions
“horizontal
band”
flunixin meglumine
(Banamine) or
phenylbutazone
(Bute)
Retinal
displaceme
nt
-Retinal detachment
is a separation of
the nine layers of
the sensory retina
from the retinal
pigment epithelium
-When the retina become
detached, it is separated
from the back of the eye
and from part of its blood
supply, preventing it from
functioning properly.
-excessive or
prolonged
dilation of the
pupil
-pupils of
different sizes
-vision
impairment,
-bleeding
within the eye.
corneal edema,
a cloudy
vitreous
present
Eye
examinatio
n
-Laser surgery
- anti-inflammatory
Optic
nerve
atrophy
chorior
etinitis
-The optic nerve
shrinks following
various types of
disease. Atrophy of
the optic nerve can
be due to
inflammatory or
non-inflammatory
causes
-Atrophy of the optic nerve
can be due to inflammatory
or non-inflammatory
causes. With time, the optic
disc becomes pale with a
profound reduction in
retinal blood vessels, and
an obvious rough
appearance or granularity
of the optic disc due to loss
of the insulation material
that normally surrounds
each optic nerve fiber
-Blindness and
pupil dilation
-The optic disk
appears
flattened and
smaller than
normal; it is
often pale or
white, with
very noticeable
reduction
in the optic
nerve and
blood vessels
of the retina
ophthalmos
cope
-optic
nerve
hypopla
sia
-retinal
detach
ment,
-
glauco
ma
-
cataract
-there is no therapy
for this condition.
Optic
nerve
hypoplasia
Optic nerve
hypoplasia is a
failure of the optic
nerve to develop
fully. It is a
congenital disorder
in horses. The
condition may occur
in only one eye or
both
-If the optic nerves of both
eyes fail to develop, the foal
will be blind
-Visual
disturbances
history,
signs,
ophthalmos
copy
No available
treatment
Congenital
in horses.
Cannot be
prevented.

7. Proliferati
ve optic
neuropath
y
-It is usually in one
eye with no signs of
pain. There is little
to no effect on
vision in most cases.
-Old
horses
-a slowly enlarging white
mass protruding from the
optic disc into the vitreous
. It is usually in one eye
with no signs of pain. There
is little to no effect on
vision in most cases.
-Presence of
white mass
protruding
from the optic
disc
-
0pthalmosc
ope
No treatment
Prolapse of
the eye
Slipping out of place
of the eye
It is usually cause by
trauma . The chances of a
good outcome depend on
the severity of the injury,
depth of the eye socket, the
condition of the eye and
how long it was displaced,
and other damage near the
eye. Without its blood
supply, the equine eye
quickly becomes damaged.
-Prolapse eye -
Ophthalmic
exam
Surgical
procedure(suturing
the eyelids together )
-Use of antiobiotics
-Avoid
fighting
and fix
facilities
that can
cause
physical
trauma.
Eye worm
disease
Thelazi
asis
Eyeworms
(Thelazia species)
are common
parasites of horses
in many countries
-Eyeworm larvae are
ingested by the fly and
become infective in 2 to 4
weeks. The infective larvae
are then re-deposited in the
horse's eye by the fly
during feeding.
-irritation and
inflammation
of the eye is
likely due to
the rough
outer layer of
the worms
-Inflammation
and swelling
of the cornea -
development
of an opaque
film, slow-
healing sores,
holes, and
permanent
fibrous tissue
-Inspection
of the eye.
-
Microscopic
exam for
the
presence of
egg or
larvae
-Manual removal with
forceps and local
anesthesia
-good fly
control
measures
directed
especially
against the
face fly
Squamous
cell
carcinoma
-a common type of
cancer that usually
develops in the
outer layer of the
skin and sometimes
in mucous
membranes
-Appal
ooza
-draft
breeds
-
olders
horses
(8-11
years)
-the etiology is
multifactorial, heritability,
sunlight, nutrition, eyelid
pigmentation, perhaps viral
involvement. The lesion
usually berin as benign,
smooth, white opaque on
the conjuctival surfaces,
they may progree into
papillomaand then a
-fleshy masses -Pink, with
raised
“cobblestone”
ulcerative
surface , and
often have a
white crust
covering the
pink surface.
-biopsy -
papillo
ma
-sarcoid
-
adenom
a
-
mastoc
y
-surgey
-cryotherapy
-hyperthermia
-radiation therapy
-immunotherapy

8. squamous cell carcinoma.
Lid lesion usually begin as
either an ulcerative or a
hyperkeratotic lesions.
toma
Equine
sarcoids
-a small, lumpy
collection of fibrous
tissue
-
Affects
young
horse
-They appear initially as
subcutaneous masses in the
eyelids or canthi, they
usually enlarged rapidly
and may invade the skin,
appearing as red , fleshy
masses. reoccurrence rate
is high.
-red, fleshy
masses just
below the skin
in the eyelids
or at the
corners of the
eyelid
-Histologically,
sarcoids are
characterized
by epidermal
hyperplasia
and dermal
fibroplasia
with pegs of
hyperkeratotic
epithelium
extending into
the depths of
the dermal
lesions.
-Biopsy for
histologic
evaluation
and
confirmatio
n
-squam
ous cell
carcino
ma
-laser surgery or
cryotherapy (freezing
the tumor) to remove
the sarcoid;
-chemotherapy
-radiation or a
combination of these
therapies.