ENDOTHELIAL DEGENERATION - CORNEAL OEDEMA
is fluid retention in the cornea.
of corneal oedema is a blue or cloudy cornea.
1. inflammation of the cornea (keratitis)
2. corneal ulcers
3. age-related corneal endothelial degeneration
4. breed-related corneal endothelial degeneration
more commonly affected include
1. Welsh Springer Spaniel
2. Basset Hound
Some may be
affected in middle age eg 5-6 years of age.
The inner surface
of the cornea is called the endothelium. In young dogs and cats
there are in excess of 3000 cells, however this number reduces with
age. These cells act as pumps whose role is to pump fluid out of
the cornea to keep it in a dehydrated state. This lack of water
results in the cornea being clear and transparent.
In some breeds
and especially in older animals, these pumps may start to fail.
The result is fluid retention in the cornea, or corneal oedema,
and the cornea becomes cloudy.
In severe cases,
the corneal oedema is so severe that vision may be affected. Furthermore,
blisters may form just under the surface of the cornea (epithelium).
If the surface is disrupted, superficial ulcers may result. These
ulcers may be slow to heal.
corneal endothelial degeneration is the use of hypertonic saline
drops. These drops work by drawing fluid out of the cornea, and
they must be administered four times daily. In most cases the oedema
can be reduced, and maintenance therapy is continued at a frequency
of twice daily. The initial treatment of corneal ulceration is topical
hypertonic saline drops four times daily.
treatment, eg Rimadyl tablets, may also be commenced. If the ulceration
fails to heal, surgery may be required to excise the non-healing
ulcer. Following this surgery, the cornea is covered with a third
eyelid flap. In severe cases when this surgery fails, thermal burns
are used to encourage the ulcers to heal. This also works to control
the fluid retention by forming a barrier layer of scar tissue. One
complication following surgery is scarring, which can be unpredictable.
However, in most cases if the ulceration and oedema are severe,
vision has already been affected for some time. In these cases surgery
is performed in order to reduce pain.
in most cases is life long, as this is a problem we can control
rather than cure. If cloudiness reduces, increase the frequency
of the drops back to four times daily. If an eye suddenly becomes
sore, do the same and contact us as soon as convenient, as this
suggests ulceration has occurred.
cases may benefit from surgery. There are (3) types of surgery -
It is vital that these are performed using an OPERATING MICROSCOPE.
Keratectomy: The unhealthy cornea is removed with a corneal
disc knife. The cornea then heals with scar tissue but this is stronger
and is less prone to water bubbles. This scarring can result in
Thermokeratoplasty: The cornea is treated with multiple tiny
pinpoint burns resulting in scarring. Once again this can result
in reduced vision - and is sometimes considered an end stage procedure.
Gunderson Flap: An ultra-thin section of conjunctiva is sutured
directly onto the cornea using an OPERATING MICROSCOPE. The conjunctiva
is permanently left there and the sutures will dissolve out. This
conjunctival graft will then act to "dehydrate" the cornea by providing
another way out for the excess fluid. After 1 month the cornea normally
goes clear. The benefit of surgery is reduced medication and over
time and it may have a sparing effect on the remaining corneal endothelial
of the unhealthy cornea
circle shape where unhealthy cornea was removed
flap place into position
flap sutured into position
Flap images supplied by Bron Williams
2 weeks after surgery
3 months after surgery
Flap images supplied by Dr. Anu O'Reilly
concerns will be discussed with you at the time of the initial consult.
1. Visits following
tablets or paste after surgery
tablets or liquids after surgery
Please let us
know at the time of the initial consult if your pet is currently
taking any medications for any issue- not just their eyes (tablets,
paste or liquid) or has any health issues.