Download Nonhealing corneal ulcers in cats: 29 cases (19911999)

00_03_0130.QXD
9/30/2005
2:16 PM
Page 733
Noelle C. La Croix, DVM; Alexandra van der Woerdt, DVM, MS, DACVO; Dennis K. Olivero, DVM, DACVO
Objective—To compare mean healing times after
debridement, debridement with grid keratotomy, and
superficial keratectomy in cats with nonhealing
corneal ulcers.
Design—Retrospective study.
Animals—29 cats with 36 nonhealing corneal ulcers.
Procedure—Medical records of cats with nonhealing
corneal ulcers were reviewed. Signalment, duration
of clinical signs, ophthalmic abnormalities, and
response to various treatment protocols were
recorded.
Results—Mean age of affected cats was 7 years, 8
months. Affected breeds included domestic shorthair
(17 cats), Persian (9), Himalayan (2), and Siamese (1).
Clinical signs were evident for approximately 2 weeks
prior to referral. Both eyes were affected in 4 cats.
Mean healing time of ulcers treated with superficial
debridement was 30 days. Mean healing time of
ulcers treated with superficial debridement and grid
keratotomy was 42 days. Superficial keratectomy was
performed on 2 eyes and resulted in a healing time of
2 weeks. Formation of a corneal sequestrum was evident in 2 of 21 eyes treated with superficial debridement. Formation of a corneal sequestrum was evident in 4 of 13 eyes treated with superficial debridement and grid keratotomy.
Conclusions and Clinical Relevance—Brachycephalic cats appear to be predisposed to developing
nonhealing corneal ulcers. The combination of superficial debridement and grid keratotomy did not
decrease mean healing time of nonhealing ulcers,
compared with superficial debridement alone. Grid
keratotomy may predispose cats with corneal ulcers
to develop a corneal sequestrum. (J Am Vet Med
Assoc 2001;218:733–735)
A
nonhealing (indolent) corneal ulcer is a superficial
epithelial defect of the cornea, without stromal
involvement, that is bordered by nonadherent epithelium.1 Indolent ulcers develop in older dogs with a mean
age of 9 years,2 with an apparent predisposition in
Boxers.3 Histologic examination of the epithelium of
dogs with indolent ulcers revealed degeneration of
basal epithelial cells, a thick irregular basement membrane, and a decreased number of hemidesmosomes,
preventing both adherence of epithelial cells to the
stroma and resurfacing of corneal epithelium.4
Healing time for indolent ulcers treated with topical antibiotic solutions or ointments ranges from 14 to
From the Bobst Hospital of the Animal Medical Center, 510 E 62nd
St, New York, NY 10021 (La Croix, van der Woerdt); and the
Veterinary Ophthalmology Specialty Practice, 4053 Highway 7,
Minneapolis, MN 55416 (Olivero).
Address correspondence to Dr. van der Woerdt.
JAVMA, Vol 218, No. 5, March 1, 2001
180 days.2 Various treatments have been suggested to
shorten this healing process in dogs. Additional medications that may be used include topical hyperosmotic solutions or ointments,5 epidermal growth factor,6
polysulfated glycosaminoglycans,7 contact lenses,8 or
collagen shields.5 Surgical procedures include debridement of loose epithelium,3 conjunctival pedicle graft
placement,9 grid or punctate keratotomy,10-12 placement
of a third eyelid flap, or superficial keratectomy.3,6 It is
believed that grid and punctate keratotomy promote
healing of corneal epithelium by exposing stromal
type-1 collagen beneath the basement membrane to
new corneal epithelial cells.1 Contact between the new
cells and collagen may promote an effective attachment
between epithelia and stroma. The advantage of performing grid or punctate keratotomy rather than
superficial keratectomy is that it is an outpatient procedure and does not require general anesthesia.
Nonhealing ulcers have rarely been described in
cats.1,8,12 The purposes of the study reported here were
to determine whether there were any breed, sex, or age
predispositions in the development of corneal ulcers in
cats, as well as to determine the rate of healing of
ulcers treated with corneal debridement alone, corneal
debridement with grid keratotomy, or superficial keratectomy. Complications and sequestrum formation
were also recorded for all techniques.
Criteria for Selection of Cases
Medical records of all cats evaluated by the ophthalmology service at the Animal Medical Center
(AMC) and the Veterinary Ophthalmology Specialty
Practice (VOSP) between 1991 and 1999 in which a
diagnosis of nonhealing corneal ulcer was made were
reviewed. Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all cats. Cats that had
a superficial corneal epithelial defect surrounded by a
loose lip of epithelium without significant stromal
involvement (as diagnosed via slit lamp biomicroscopy) were also included in the study. Cats with
ulcers of determinable causes (ie, lagophthalmos, keratoconjunctivitis sicca, trichiasis, etc) were excluded
from this study.
Procedures
Data retrieved from medical records included signalment, duration of clinical signs, ophthalmic examination abnormalities, and response to various treatment protocols prior to referral. Cats with nonhealing
corneal ulcers were treated with superficial debridement, superficial debridement and grid keratotomy, or
superficial keratectomy. Superficial debridement was
performed as previously described.10 The cornea was
anesthetized with proparacaine hydrochloride,a and the
Scientific Reports: Retrospective Study
733
SMALL ANIMALS/
EXOTICS
Nonhealing corneal ulcers in cats:
29 cases (1991–1999)
SMALL ANIMALS/
EXOTICS
00_03_0130.QXD
9/30/2005
2:16 PM
Page 734
redundant epithelium was removed with a dry cottontipped swab. Grid keratotomy was performed using a
25-gauge disposable hypodermic needle to make perpendicular crosshatches in the exposed superficial
stroma and the epithelium surrounding the ulcer.
Superficial keratectomy was performed using an operating microscope with the cat under general anesthesia. A microsurgical blade was used to excise the superficial stroma and epithelium under and around the
indolent ulcer. Following these procedures, a collagen
shieldb or bandage lensc was placed in a few cats.
Results
Nonhealing corneal ulcers were diagnosed in 29
cats. Mean age of the cats on initial evaluation at the
AMC or VOSP was 7 years, 8 months (range, 6 months
to 19 years). Twenty-two cats were castrated males, 6
were spayed females, and 1 was a sexually intact
female. Breeds included 17 domestic shorthairs, 9
Persians, 2 Himalayans, and 1 Siamese.
Prior ophthalmic history was available for 15 cats.
Mean time to referral was 2 weeks (range, 2 days to 4
months). Oxytetracycline-polymyxin, chloramphenicol, and atropine ophthalmic ointment were the most
commonly used medications prior to referral. One cat
had been treated with debridement of the ulcer, grid
keratotomy, and soft contact lens placement prior to
referral.
The right eye was affected in 15 cats, the left eye in
10 cats, and both eyes were affected in 4 cats. Two cats
had recurrence of the nonhealing ulcer 14 weeks and 4
years, respectively, after healing of the initial ulcer. One
cat was initially evaluated for a nonhealing ulcer in the
right eye, and the left eye developed a nonhealing ulcer
6 months later. Two cats had histories of ulceration in
the contralateral eye prior to referral; these cats also
had corneal fibrosis. Thirty-six nonhealing ulcers were
diagnosed and treated at the AMC or VOSP.
Thirty-one (86%) of the ulcers were in the central
cornea, 4 (11%) were in the temporal cornea, and 1
(3%) was in the ventral cornea. All cats had evidence
of blepharospasm and conjunctival hyperemia in the
affected eye. Superficial corneal neovascularization was
evident in 11 (38%) cats. Superficial cellular infiltration adjacent to the ulcerated area was evident in 3
(8%) cats.
Abnormalities of the affected eyes included medial canthus entropion (9 eyes), macroblepharon (2
eyes), and 1 each of shallow anterior chamber, prominent lens sutures, incipient anterior cortical cataract,
posterior polar cataract, feline central retinal degeneration, and peripapillary chorioretinal scar. Twenty-one
(72%) cats had histories of upper respiratory tract
infection or recurrent conjunctivitis. One of these cats
was tested for feline herpesvirus-1 infection by use of
polymerase chain reaction, which yielded negative
results.
All 36 ulcers were treated with superficial debridement. A collagen shield was placed in 2 eyes after
debridement. Grid keratotomy was performed in 13
eyes. A soft contact lens was placed in 7 of these eyes
in which a grid keratotomy was performed. Two eyes
were treated with superficial keratectomy at the own734
Scientific Reports: Retrospective Study
ers’ request. A collagen shield was placed in 1 cat after
surgery.
Eleven cats were treated with gentamicin sulfate
ophthalmic solution, 9 with neomycin-polymyxin-B
sulfate and bacitracin-zinc antibiotic ophthalmic ointment, 7 with oxytetracycline-polymyxin ophthalmic
ointment, and 2 with chloramphenicol ophthalmic
ointment. Trifluorothymidine was used in 5 cats, and
atropine was used (topically) in 6 cats.
Of the 36 eyes, 14 were lost to follow-up before
healing of the ulcer. Of the 22 eyes in which follow-up
examinations were performed (until the ulcer healed),
mean healing time was 5 weeks (with 2 reevaluations
at the AMC or VOSP). Thirteen eyes were treated with
superficial debridement alone. Four of these eyes were
debrided again during a subsequent reevaluation
because of lack of reduction in ulcer size. Mean time
for healing of ulcers that were treated by debridement
alone was 30 days (range, 7 to 240 days).
Seven cats that had grid keratotomy performed in
addition to debridement returned for reevaluation.
One of these cats had grid keratotomy performed 2
months after initial debridement; the ulcer healed 3
weeks later. Superficial debridement was performed in
3 cats during a subsequent reevaluation. Mean healing
time of ulcers treated with 1 or more superficial
debridements and grid keratectomy was 6 weeks
(range, 3 to 9 weeks).
The remaining 2 cats were treated by superficial
keratectomy. In 1 cat, surgery was performed immediately after diagnosis of nonhealing corneal ulcer. The
other had a history of multiple debridements and formation of a sequestrum. The corneal ulcers in both cats
healed within 2 weeks after surgery.
Two cats had a corneal sequestrum prior to
debridement or grid keratotomy. One was a Himalayan
with a 6-week history of a nonhealing ulcer and was
lost to follow-up. The other was a Persian with a 7month history of recurrent eye problems. This Persian’s
sequestrum was allowed to slough naturally. Two years
later, another nonhealing ulcer developed in the same
eye. The eye developed a sequestrum 5 weeks after
debridement.
Of the 21 eyes treated with superficial debridement, 2 (10%) developed a sequestrum in the area of
the nonhealing ulcer. In 1 cat (domestic shorthair), a
sequestrum developed 10 weeks after debridement.
Another cat (Persian) had a previous history of
sequestrum formation in the same eye. Of the 13 eyes
treated with debridement and grid keratotomy, 4 (31%)
developed a sequestrum in the area of the nonhealing
ulcer. The sequestrum was evident in 2 cats (a Persian
and a Himalayan) at the time of first reevaluation. One
domestic shorthair that was treated for a nonhealing
ulcer in both eyes developed a sequestrum 5 and 12
months, respectively, after grid keratotomy was performed.
Discussion
Mean age of cats with a nonhealing corneal ulcer
in our study was 7 years, 8 months. This is similar to
the mean age of 6.5 years recorded for Boxers.4
However, the age range (6 months to 19 years) in the
JAVMA, Vol 218, No. 5, March 1, 2001
00_03_0130.QXD
9/30/2005
2:16 PM
Page 735
JAVMA, Vol 218, No. 5, March 1, 2001
an etiologic factor in any nonhealing corneal ulcer in a
cat. Feline herpesvirus-1 has also been associated with
sequestrum formation.15 Diagnostic testing (eg, polymerase chain reaction) and antiviral treatment may be
indicated in such instances.
a
Ophthetic, Allergan, Hormigueros, Puerto Rico.
Oasis, Glendora, Calif.
c
Canis 2 soft contact lens, The Cutting Edge Division NNQ Inc,
Diamond Springs, Calif.
b
References
1. Morgan R, Abrams K. A comparison of six different therapies for persistent corneal erosions in dogs and cats. Vet Compend
Ophthalmol 1994;4:38–43.
2. Kirschner S, Niyo Y, Betts D. Idiopathic persistent corneal
erosions: clinical and pathological findings in 18 dogs. J Am Anim
Hosp Assoc 1989;25:84–90.
3. Peiffer R, Gelatt K, Gwin R. Superficial keratectomy in the
management of indolent ulcers of the Boxer cornea. Can Pract
1976;3:31–33.
4. Gelatt K, Samuelson D. Recurrent erosions and epithelial
dystrophy in the Boxer dog. J Am Anim Hosp Assoc 1982;18:
453–460.
5. Kirschner S. Persistent corneal ulcers, what to do when
ulcers won’t heal. Vet Clin North Am Small Anim Pract 1990;20:
627–642.
6. Kirschner S, Brazzell R, Stern M, et al. The use of topical
epidermal growth factor for treatment of non-healing corneal erosions in dogs. J Am Anim Hosp Assoc 1991;27:449–452.
7. Miller W. Effective new option for persistent corneal erosion or Boxer ulcer. Vet Med 1996;91:916–922.
8. Morgan R, Bachrach A, Ogilvie G. An evaluation of soft
contact usage in the dog and cat. J Am Anim Hosp Assoc 1984;
20:885–888.
9. Kuhns E. Complicated ulcerative keratitis in a Boxer. Mod
Vet Prac 1976;57:36–38.
10. Chavkin M, Riis R, Scherlie P. Management of a persistent
corneal erosion in a Boxer dog. Cornell Vet 1990;80:347–356.
11. Champagne E, Munger R. Multiple punctate keratotomy for
the treatment of recurrent epithelial erosions in dogs. J Am Anim
Hosp Assoc 1992;28:213–216.
12. Pickett P. Treating persistent corneal erosions with a crosshatch keratotomy technique. Vet Med 1995;90:561–572.
13. Startup F. Corneal ulceration. In: Wilkinson G, ed. Disease
of the canine eye. New York: Pergamon Press, 1969;177.
14. Nasisse M, Guy J, Davidson M, et al. Experimental ocular
herpes virus infection in the cat. Invest Ophthalmol Vis Sci 1989;30:
1758–1768.
15. Whitley R, Moore C. Advances in feline ophthalmology. Vet
Clin North Am Small Anim Pract 1984;14:1271–1288.
Scientific Reports: Retrospective Study
735
SMALL ANIMALS/
EXOTICS
cats of our study was wider than that reported for
Boxers (2 to 10 years).4
Bilateral development or recurrence of nonhealing
corneal ulcers was common in the cats of our study.
Four cats had bilateral nonhealing corneal ulcers, and
3 cats had recurrence in the same or contralateral eye.
This recurrence in affected and unaffected eyes was
similar to that found in dogs.4
Mean healing time of nonhealing corneal ulcers
(22 eyes) was 5 weeks from initial evaluation by an
ophthalmologist. Grid keratotomy resulted in healing
of the corneal ulcers within approximately 6 weeks. In
dogs, it has been reported that grid keratotomy may
shorten healing time of indolent ulcers to approximately 25 days.1 Grid keratotomy did not appear to
decrease the healing time of nonhealing corneal ulcers
in the cats of our study.
As in dogs,2,3 superficial keratectomy of nonhealing corneal ulcers in cats results in rapid resolution of
the ulcer. However, the disadvantage of performing
keratectomy is the need for general anesthesia and specialized equipment such as an operating microscope.
Sequestrum formation was observed in all treatment groups in this study except in the 2 cats treated
with superficial keratectomy alone. We found an
apparent predisposition for corneal sequestrum formation in Persians and Himalayans, which is consistent
with previous reports.13 Of 21 eyes treated with
debridement, 2 (10%) developed a corneal sequestrum; 1 of those was in a Persian. Of 13 eyes treated by
grid keratotomy, 4 (31%) developed a corneal
sequestrum. The 2 cats that developed a sequestrum by
the time of first reevaluation were a Persian and a
Himalayan. It has been proposed that sequestrum formation may develop as a nonspecific sequela to substantial stromal damage.14
Nonhealing corneal ulcer formation in cats may or
may not be related to a defective corneal epithelial
basement membrane, as seen in dogs. Feline herpesvirus-1 can cause punctate and dendritic epithelial
lesions in cats14; these dendritic erosions may coalesce
to form large corneal ulcerations. Because a large number (21/29) of cats in this study had a history of upper
respiratory infection with or without recurrent conjunctivitis, feline herpesvirus-1 should be suspected as