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Why
have them?
Eye
diseases are important. They can be obvious to owners, or they can
result in blindness which can be distressing, or they can result
in pain. Unfortunately some eye diseases are common in certain breeds.
Checking dogs for eye disease is commonly practice all round the
world.
Equipment
Used
1. Focal light
This gives a bright, concentrated light source. It is used to check
the pupil response, the cornea and the iris.
2.Slit
Lamp
This
provides magnification, with a variable slit beam of light. It is
extremely useful to examine the eyelids, cornea, aqueous (fluid
of the eye), iris, lens, and the anterior portion of the vitreous
( jelly of the eye). Using this machine may enable the detection
of early cataracts or small lesions.
3.
Voroscope
This
is ideal for checking the eyelids and the openings of the tear ducts.
It enables a magnified view with both hands free to move the eyelids.
4.
Indirect Ophthalmoscope
A
light source and a hand lens allows examination of the fundus (retina
and optic nerve). A large area is seen at any one time.
5.
Direct Ophthalmoscope
This hand held item is used for a magnified look at the fundus.
It can also be used to fully examine the edges of the retina. Using
the two types of ophthalmoscope maximises the view I get of the
retina and optic nerve. Some diseases are more obvious when viewed
with one type versus the other type.
Examining
the Eye
The
front of the eye (eyelids, cornea, anterior chamber) is examined
with the focal light. The pupil responses are checked, a normal
pupil should become smaller when a bright light is shone into the
eye. The other pupil also becomes smaller.
Drops
to dilate the pupil are then put in. These are short acting (3 to
5 hours), and unlike in man, they do not significantly affect the
dog's vision. They take at least 10 to 15 minutes to dilate the
pupil.
The
eyelids, cornea, anterior chamber, iris and the conjunctiva with
a slit lamp are then checked. This gives us a magnified (10 to 25
times) image of these structures. WeI may see extra eyelashes, entropion,
ectopic hairs, corneal lesions, persistent pupillary membranes,
iris or anterior chamber or conjunctival problems.
The
voroscope is used to recheck the eyelids, looking for extra eyelashes
and also to check the openings of the tear ducts that are on the
inside corner of the eyelids.
After
the pupils have been dilated, the lens is checked for cataracts
with the slit lamp. Using this magnification, very early cataracts
may be detected.
The
retina and the optic nerve are then checked with two types of ophthalmoscopes.
A indirect ophthalmoscope gives us a look at a large area of these
tissues, then the direct ophthalmoscope is used to examine the retina
and optic nerve in greater detail.
Certificates
Internationally acceptable certificates are given. All problems
are noted on this certificate. It is up to the individual breeder
and the breed club to decide whether to use this animal at stud.
Dogs
should be examined before breeding then each year until 7 to 8 years
of age. Some diseases are not apparent until later in life, e.g.
PRA. Therefore a final clear certificate can only be given at this
late stage.
Reporting
All
the information gathered is treated as confidential. A report can
be made to the club, but only information on the numbers and the
types of conditions seen are reported. No dog or breeder can be
identified.
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