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CVJ / VOL 52 / MARCH 2011 283
Article
Cataracts in 44 dogs (77 eyes): A comparison of outcomes for no
treatment, topical medical management, or phacoemulsification with
intraocular lens implantation
Christine C. Lim, Shannan C. Bakker, Cheryl L. Waldner, Lynne S. Sandmeyer, Bruce H. Grahn
Abstract — Outcomes for 77 cataractous eyes were compared after each eye underwent no treatment, topical
medical treatment only, or phacoemulsification with intraocular lens implantation. Median follow-up time for all
dogs was 2.3 y. Failure occurred in all untreated eyes and the rate of failure was 65 and 255 times higher than in
medically and surgically treated eyes, respectively. The failure rate was 4 times higher in dogs receiving only medical
treatment compared with dogs that received surgery. Across all groups, the success rate for mature and hypermature
cataracts was lower than for immature cataracts. Regardless of cataract stage, the chance of success was higher for
eyes undergoing phacoemulsification than for eyes that received medical management only. Results of this study
support prompt referral for phacoemulsification when cataracts are diagnosed in dogs or, if referral is not possible,
topical anti-inflammatory therapy.
Résumé — Cataractes chez 44 chiens (77 yeux) : Une comparaison des résultats pour l’absence de traitement,
la gestion médicale topique ou la phaco-émulsification avec l’implantation d’une lentille intraoculaire.
Les résultats pour 77 yeux avec cataracte ont été comparés après que chaque œil ait soit subi aucun traitement, un
traitement médical topique seulement ou une phaco-émulsification avec l’implantation d’une lentille intra-oculaire.
Le temps de suivi médian pour tous les chiens était de 2,3 ans. Un échec est survenu dans tous les yeux non traités
et le taux d’échec était de 65 et de 255 fois supérieur que pour les yeux médicalement et chirurgicalement traités,
respectivement. Le taux d’échec était de 4 fois supérieur chez les chiens qui avaient reçu seulement un traitement
médical comparativement aux chiens qui avaient subi la chirurgie. Parmi tous les groupes, le taux de succès pour
les cataractes mûres et hypermûres était inférieur à celui des cataractes immatures. Sans égard au stade de la cataracte,
le taux de succès était supérieur pour les yeux subissant une phaco-émulsification que pour ceux qui recevaient
seulement une gestion médicale. Les résultats de cette étude appuient la recommandation de promptement référé
l’animal pour une phaco-émulsification lorsque des cataractes sont diagnostiquées chez les chiens ou, s’il n’est pas
possible de référer le patient, d’instaurer une thérapie anti-inflammatoire topique.
(Traduit par Isabelle Vallières)
Can Vet J 2011;52:283–288
Introduction
Cataracts occur commonly in dogs and affected dogs are
presented frequently to veterinary ophthalmologists for
evaluation. Underlying causes may include genetic mutations,
diabetes mellitus, uveitis, congenital anomaly, trauma, toxins,
and dietary deficiency (1). Surgical extraction represents the only
method by which cataracts can be effectively treated. Although
surgical success rates have increased over time with refine-
ments of surgical technique, surgical success is not guaranteed.
Surgery is considered to have failed when dogs develop painful
and/or blinding complications such as endophthalmitis, retinal
detachment, or glaucoma (2). Reported success rates, based on
limited follow-up times, exceed 85% to 90% (3,4); however,
these numbers decline over time (2–5).
Although phacoemulsification with intraocular lens implan-
tation is the accepted standard, many dogs do not undergo
surgery due to owner financial status, concurrent ophthalmic
disease such as retinal degeneration, or concurrent systemic
disease which may preclude general anesthesia. In addition,
when presented with the potential complications of phaco-
emulsification, some owners are more comfortable opting for
medical management or no treatment at all. Several studies have
examined the complications arising after phacoemulsification
(2,5–8); however, the authors are not aware of any studies that
Department of Small Animal Clinical Sciences (Lim, Bakker,
Sandmeyer, Grahn) and the Department of Large Animal
Clinical Sciences (Waldner), Western College of Veterinary
Medicine, University of Saskatchewan, 52 Campus Drive,
Saskatoon, Saskatchewan S7N 5B4.
Address all correspondence to Dr. Bruce Grahn; e-mail:
bruce.grahn@usask.ca
Reprints will not be available from the authors.
Use of this article is limited to a single copy for personal study.
Anyone interested in obtaining reprints should contact the
CVMA office (hbroughton@cvma-acmv.org) for additional
copies or permission to use this material elsewhere.
284 CVJ / VOL 52 / MARCH 2011
ARTICLE
have assessed the complication rate for dogs with cataracts that
are managed medically, or those that do not receive any therapy.
The authors are also not aware of any studies comparing the
outcomes of surgical versus nonsurgical management strategies.
Such information is useful from a prognostic standpoint and will
improve the ability of ophthalmologists and general practitioners
to guide treatment decisions by owners.
The perception at our practice is that the rate of globe-
threatening complications is much lower in dogs undergoing
phacoemulsification and intraocular lens implantation compared
with dogs receiving topical medical treatment only, or dogs
receiving no treatment. Therefore, the primary objective of
this study was to compare the occurrence of treatment failure
for 3 categories: dogs for which neither medical nor surgical
therapy was instituted, those receiving topical medical therapies
only, and those undergoing phacoemulsification with intraocular
lens implantation. The second objective was to document the
most common complications associated with treatment failure,
defined as globe or vision-threatening complications, in this
practice.
Materials and methods
Medical records of dogs diagnosed with cataracts at the Western
College of Veterinary Medicine between 1995 and 2005 were
reviewed. Criteria for inclusion in the study were the following:
examination by a veterinary ophthalmologist with confirmation
of the diagnosis by complete ophthalmic examination including
tonometry, slit lamp biomicroscopy, and indirect ophthalmos-
copy; and a diagnosis of immature, mature, or hypermature
cataracts. Dogs were excluded from the study if lens luxation and
persistent hyperplastic primary vitreous/tunica vasculosa lentis
were present at the time of initial examination. Dogs were also
excluded from the study if medical records indicated less than
6 months’ follow-up by a veterinary ophthalmologist.
The dogs were divided into 3 groups. Group 1 included dogs
that did not receive any medical or surgical treatment for cata-
racts. Group 2 consisted of dogs that received topical medical
treatment only, in the form of ophthalmic anti-inflammatory
drugs, with or without additional mydriatic therapy. Group 3
included dogs that underwent phacoemulsification with intra-
ocular lens implantation.
Due to caseload bias and the tendency for ophthalmologists
in this practice to prescribe topical anti-inflammatory therapy
for most non-incipient cataracts, dogs that did not receive
either surgical or medical therapy for cataracts were uncom-
mon. However, a small number of such cases were identified,
in which owners either refused treatment recommendations or
were unaware that treatment was available.
For groups 1 and 2, success was defined as a comfortable,
non-inflamed, non-glaucomatous eye at the time of last follow-
up. For cases in group 3, the eye also had to be visual in order
for the outcome to be defined as successful; therefore, for
Table 1. Cataract stage, concurrent conditions, complications, and outcomes associated with dogs undergoing surgery,
medical management, or no treatment for cataracts (77 eyes from 44 dogs)
No treatment Medical treatment Surgical treatment
Number of eyes (dogs) Number of eyes (dogs) Number of eyes (dogs)
Group 8 (n = 5) 35 (n = 20) 34 (n = 19)
Cataract stage
Immature cataracts 5 (3) 16 (10) 20 (12)
Mature cataracts 3 (2) 15 (8) 6 (4)
Hypermature cataracts 0 (0) 4 (2) 8 (6)
Concurrent condition
Diabetes mellitus 3 (2) 4 (6) 6 (12)
Lens-induced uveitis 1 (1) 12 (8) 17 (10)
Viterous degeneration 0 (0) 4 (3) 0 (0)
Retinal degeneration 0 (0) 13 (7) 0 (0)
Retinal detachmenta 1 (1) 0 (0) 1 (1)b
Corneal disease 2 (1) 3 (2) 0 (0)
Lens instability 2 (2) 0 (0) 0 (0)
Glaucoma 3 (2) 0 (0) 0 (0)
Complications
Preoperative or intraoperative capsule compromisea 0 (0) 0 (0) 2 (2)
Intraoperative hyphema 0 (0) 0 (0) 19 (13)
Corneal disease 0 (0) 9 (6) 27 (19)
Glaucoma 1 (1) 9 (5) 13 (8)
Retinal detachment 0 (0) 1 (1) 6 (4)
Vitreous changes 0 (0) 1 (1) 12 (7)
Lens/IOL instability 0 (0) 7 (5) 1 (1)
Persistent uveitis 0 (0) 12 (8) 4 (3)
Cataract progression 0 (0) 23 (14) 0 (0)
Outcome
Success 0 (0) 15 (9) 27 (16)
Evisceration and prosthesis/enucleation 7 (4) 9 (6) 5 (3)
Blind, no treatment 0 (0) 0 (0) 2 (1)
Euthanasia 1 (1) 11 (6) 0 (0)
n = total number in group.
a Pretreatment retinal detachment was not examined as a risk factor in the analysis because of the infrequent (, 5%) occurrence of this condition.
b Concurrent retinal detachment was present in the fellow eye, which did not undergo surgery.
CVJ / VOL 52 / MARCH 2011 285
ARTICLE
group 3, all eyes that became blind after surgery, regardless of
cause, were considered to be failures. For all groups, a globe was
considered to be a failure if it developed a painful condition,
such as glaucoma or lens luxation, for which enucleation or
evisceration was recommended. In addition to globes that were
enucleated or eviscerated, eyes of dogs that were euthanatized
were also considered to be failures.
Information for each case was summarized in a commercial
spreadsheet program (Microsoft Office Excel 2003; Microsoft,
Redmond, Washington, USA). Because the length of the follow-
up period varied for each dog, the occurrence of treatment
failure was compared across treatment options using the Cox
proportional hazards model (Stata/SE 10.1 for Windows,
StataCorp LP, College Station, Texas, USA). Because the unit of
analysis was the individual eye and the data include more than
1 eye for many of the dogs in this study, the analysis adjusted
for clustering or lack of independence of outcomes within
individual animals. Other risk factors that were considered in
the analysis included signalment (age, sex, and breed type), as
well as pre-existing systemic and ocular conditions, and post-
treatment complications that were identified in at least 5% of
the study population (Table 1).
All risk factors that were unconditionally associated with
the rate of treatment failure (P # 0.25) were considered for
inclusion in the final model examining the association between
treatment group (surgical, medical, or no treatment) and rate
of failure. Backwards elimination was used to establish the final
model that included only the risk factors that were significantly
associated (P , 0.05) with the rate of failure or were important
confounders (removing the variable from the model changed the
effect estimate for treatment by more than 10%). Biologically
sensible first-order interactions were examined where more
than 2 variables were statistically significant (P , 0.05) in the
final model.
The time to failure in each treatment group was also graphed
and compared across treatment groups using a log-rank test
(Stata/SE 10.1 for Windows, StataCorp LP).
Results
A total of 44 dogs (77 eyes) met the inclusion criteria for the
study (Table 1). There were 21 male and 23 female dogs that
were presented at an average age of 8.0 y [standard deviation
(s) = 3.8]. Breeds included purebred and mixed breed cocker
spaniels (n = 8), toy and miniature poodles (n = 6), bichon fri-
sés (n = 6), Boston terriers (n = 3), shih tzus (n = 3), Labrador
retrievers (n = 3), Yorkshire terriers (n = 3), miniature schnau-
zers (n = 3), border collie (n = 1), Chihuahua (n = 1), English
springer spaniel (n = 1), Siberian husky (n = 1), Jack Russell
terrier (n = 1), rottweiler (n = 1), German shepherd (n = 1),
Lhasa apso (n = 1), and silky terrier (n = 1).
Of these, 8 eyes from 5 dogs were not treated (Group 1).
The average age at diagnosis for these dogs was 7.9 y (s = 1.9).
One of the untreated dogs had unilateral disease while 4 had
bilateral disease. The outcome was failure for all of the untreated
eyes (Table 1).
Thirty-five eyes from 20 dogs were treated medically
(Group 2). The average age at diagnosis was 8.9 y (s = 3.6).
The average time from diagnosis to treatment was 32 d (s = 76).
Five dogs had unilateral disease while 15 dogs had bilateral
disease. A successful outcome was seen in 15 eyes of 9 dogs.
Failure occurred in 20 eyes of 12 dogs (Table 1).
Thirty-four eyes from 19 dogs were surgically treated
(Group 3). The average age at diagnosis was 7.4 y (s = 3.4). The
average time from diagnosis to treatment was 84 d (s = 104).
Four dogs had unilateral disease while 15 dogs had bilateral
disease. A successful outcome was seen in 27 eyes of 16 dogs.
Failure was seen in 7 eyes of 4 dogs (Table 1).
The sex (P = 0.31) of the dog and the location of the affected
eye (P = 0.78) were not associated with the rate of failure for any
group. Other factors not associated with the rate of failure for
any group in this sample (P . 0.25) (Table 1) included preexist-
ing vitreous degeneration (P = 0.77), glaucoma after diagnosis
and treatment (P = 0.31), retinal detachment (P = 0.89), post-
operative vitreous disease (P = 0.41), and postoperative uveitis
(P = 0.94).
Factors that were unconditionally associated (P # 0.25) with
the rate of failure, and therefore considered in the development
of subsequent models, were: treatment type (P = 0.0001), age
at diagnosis in years (P = 0.001), breed (P , 0.0001), breed
size (P = 0.25), cataract stage (P = 0.01), diabetes mellitus
(P = 0.18), pre-existing lens-induced uveitis (P = 0.04), retinal
degeneration (P = 0.08), preexisting corneal disease (P = 0.03),
pre-existing glaucoma (P = 0.001), lens instability (P , 0.001),
intraoperative hyphema (P = 0.18), postoperative corneal disease
(P = 0.18), intraocular lens instability (P = 0.001), and cataract
progression (P = 0.02).
After accounting for other important risk factors listed
below, the rate of failure for dogs that received no treatment
was 64.5 times [95% confidence interval (CI) 9.7 to 403;
P , 0.0001] higher than in dogs receiving medical treatment
and 255 times (95% CI, 28 to 2369; P = 0.0001) higher than
in dogs receiving surgical treatment. The rate of failure for dogs
receiving medical treatment alone was 4.0 times higher (95%
CI, 1.0 to 15; P = 0.047) than for dogs undergoing surgery.
In the final model examining differences among treat-
ment groups, only cataract stage (P = 0.004), age at diagnosis
(P = 0.003), breed size (P = 0.03), and an interaction between
age and breed size (P = 0.0001) were associated with the failure
rate.
Across all groups, failure rates were higher in eyes with mature
(HR, 12, 95% CI, 2.8 to 52; P = 0.001) and hypermature (HR,
4.0, 95% CI, 1.1 to 15; P = 0.04) cataracts than in eyes with
immature cataracts. There was no difference in the failure rate
between eyes with mature and hypermature cataracts (P = 0.11).
Due to low numbers of individuals per breed, there was insuf-
ficient power to examine breed-specific differences. Instead, dogs
were categorized into groups based on breed size. Small breed
dogs included Boston terrier, bichon frisé, Jack Russell terrier,
Yorkshire terrier, miniature schnauzer, silky terrier, shih tzu,
Lhasa apso, and Chihuahua. The cocker spaniel and the English
springer spaniel were considered to be medium-sized dogs, and
the border collie, Siberian husky, rottweiler, German shepherd,
and Laborador retrievers were considered to be large breed
dogs. Small–sized breeds . 8 y old had a higher failure rate
286 CVJ / VOL 52 / MARCH 2011
ARTICLE
(P = 0.003) than younger small breed dogs. There was no sig-
nificant age difference in the failure rate for medium (P = 0.83)
or large dogs (P = 0.09). For dogs , 8 y old, the failure rate was
higher for large breed dogs (P = 0.02) and for medium breed
dogs (P = 0.014) than for small breed dogs. There was no sig-
nificant difference between medium and large breed groups for
young dogs (P = 0.99). For dogs . 8 y old, the failure rate was
higher for both small (P = 0.03) and medium breeds (P = 0.001)
than for large breed dogs. There was no significant difference
in the failure rate between small and medium breeds for older
dogs (P = 0.67).
The median time from diagnosis of the cataract to failure was
significantly different among dogs receiving no treatment and
dogs receiving either medical or surgical treatment (P = 0.0001)
(Figure 1). Overall, the most common complications seen in this
study were cataract progression, postoperative corneal disease
(consisting mainly of deep corneal ulceration and keratocon-
junctivitis sicca), and intraoperative hyphema. The median time
to failure in dogs receiving no treatment was 0.9 y. The most
common complications in this group were persistent uveitis
and glaucoma. The most common complications associated
with medical treatment were cataract progression, persistent
uveitis, corneal disease, and glaucoma, with the median time
to failure being 1.5 y. The most common complications in the
surgery group were postoperative corneal disease, intraoperative
hyphema, and postoperative glaucoma (defined as an elevation
in intraocular pressure above 30 mmHg after the immediate
72 h following surgery, requiring medical intervention in order
to decrease the intraocular pressure). Median time to failure for
dogs undergoing phacoemulsification was 2.9 y.
Discussion
This study brings new information to the literature and rein-
forces previously published information. A higher rate of success
occurred in dogs undergoing cataract surgery compared with
medical management or no treatment at all in the current study.
Although the success rate for hypermature and mature cataracts
was less than for immature cataracts, the chances of success were
still higher for all eyes undergoing phacoemulsification and
intraocular lens implantation, regardless of stage, than for eyes
that did not receive surgery.
The overall proportion of surgical success (79%) in this study
is slightly lower than success rates from other studies in which
average follow-up times ranged from 6 to 23 wk after surgery
(3,5,9). Follow-up times likely influenced our success rate. In
this study, mean follow-up time was 2.3 y, which is higher than
the average follow-up time in other studies (3,5,9). Differences
may be attributable to variations in surgical technique, postop-
erative treatment regimens, and study methodology. The rate of
surgical success is known to decline over time (2–5). The most
common complications for dogs undergoing phacoemulsifica-
tion in this study were corneal disease (79.4%), intraoperative
hyphema (55.9%), and glaucoma (38.2%). This is in agreement
with previous findings that eyes experiencing intraoperative
hemorrhage are at higher risk of surgical failure (6) and that
glaucoma is a common postoperative complication (2,6,8,10).
In contrast, Davidson et al (5) found retinal detachment to be
the most common post-surgical complication, occurring in
4.7% of dogs. In a more recent study, 16.8% of dogs undergoing
phacoemulsification developed glaucoma, while 0% to 1.25%
developed retinal detachments (2).
The incidence of post-operative glaucoma (38.2%) in this
study is higher than in others (2,5,8,10). The differences in
follow-up times are likely to have contributed to the differences
between this and other studies; however, criteria for diagnosis
of glaucoma may also have played a role in the disparities. In
other studies, glaucoma was generally defined as an increase
in intraocular pressure accompanied by intraocular changes
arising during the immediate postoperative period, up to 72 h
following surgery (2,8). In this study, all eyes in which intra-
ocular pressures rose above 30 mmHg during this time period
were given the diagnosis of glaucoma. While all eyes with post-
operative glaucoma required medications to lower intraocular
pressure, a number of these cases were successfully weaned off
anti-glaucoma medications after several weeks of treatment, did
not have clinically detectable sequelae, and did not lose vision.
It is not known if cases such as these were included within the
glaucoma groups of other studies.
In this study, deep corneal ulcers and keratoconjunctivitis
sicca (KCS) represented the majority of corneal diseases and
were seen in both the surgically treated and medically treated
groups. The development of KCS in many dogs is not surpris-
ing given that diabetic dogs, comprising a high proportion of
the dogs in this study, tend to have decreased tear production
compared with normal dogs (11), and that diabetic dogs with
cataracts have lower tear production than non-diabetic dogs
without cataracts (12). The presence of KCS may have pre-
disposed these dogs to corneal ulceration. Another potential
explanation for the high incidence of corneal ulcers may relate
to the medications applied to the eyes. Chronic use of ophthal-
mic steroids, as is routine following cataract surgery, impairs
corneal wound healing and may predispose to the development
of bacterial keratitis (13,14). Additionally, medications in this
study were dispensed in multidose vials, necessitating the use of
Figure 1. Comparison of ocular survival times between dogs
receiving surgical treatment (34 eyes from 19 dogs), medical
treatment (35 eyes from 20 dogs), or no treatment (8 eyes from
5 dogs). Note that the y-axis represents the probability of eye
survival at the time indicated on the x-axis.
Kaplan-Meier survival estimates
Time to failure (years)
No treatment Medical Surgical
CVJ / VOL 52 / MARCH 2011 287
ARTICLE
ophthalmic preservatives, known to be the toxic to the corneal
epithelium (15). Chronic exposure to ophthalmic preserva-
tives may have compromised corneal health in the long-term,
especially in combination with topical application of steroids
and reduced aqueous tear production. This supports the higher
incidence of corneal disease in the surgically treated group
compared with the medically treated group (19 of 34 compared
to 9 of 35), as eyes undergoing phacoemulsification typically
receive many more medications, and therefore more exposure to
preservatives, than eyes receiving medical management only. It is
not known why the incidence of post-operative corneal disease
in this study is higher than in previous studies (2,7); however,
postoperative treatment protocols likely play a significant role
in these differences.
Previous work has shown lens-induced uveitis to be present
at all stages of cataract, regardless of clinical evidence of uveitis
(16–18). The finding that clinically detectable pre-operative
lens-induced uveitis did not influence outcome was therefore
expected. In this study, the rates of failure for mature and
hypermature cataracts were not significantly different, but were
higher than the failure rate for immature cataracts. The finding
of lowest success rates for mature and hypermature cataracts
in this study is in agreement with others (2,5,8) and suggests
the rate of surgical success declines with increasing chronicity
of lens-induced uveitis. One explanation for this may be the
obstruction of aqueous outflow by preiridal fibrovascular mem-
branes, which are known to occur in the presence of persistent
intraocular inflammation (19).
The lower success rate in dogs receiving medical therapy was
expected. Secondary glaucoma occurs more frequently in eyes
with cataract than in eyes that have undergone phacoemul-
sification (10,20). It is thought that approximately 20% of
cataractous eyes will develop glaucoma (10). Medical treatment
is aimed at reducing phacolytic uveitis, present at all stages of
cataract, but cannot eliminate it because the underlying cause
remains (10,16,18). Further, medical treatment does not inhibit
secondary changes such as preiridal fibrovascular membrane
formation (21). Intraocular pathology related to chronic uveitis
would therefore be expected to increase with cataract progression
and over time. Although not specifically examined in this study,
owner compliance with recheck examinations may also have
played a role in the decreased success rate of medical manage-
ment. Owners of dogs undergoing surgery are typically highly
motivated and are extensively counseled on the importance of
intensive postoperative monitoring for maintaining vision. By
contrast, owners of blind dogs may not see the value of admin-
istering medications long-term and re-examination of these dogs
may be less often than for dogs that have undergone surgery.
This hypothesis may be supported by the follow-up times in
this study, which were highest for group 3 (2.5 y), followed by
group 2 (1.9 y), and group 1 (0.92 y).
The finding that older small dogs were more likely to expe-
rience failure was not surprising, although this contrasts with
another study in which age was not a factor in surgical outcome
(4). The reasons for the findings herein likely include the fact
that older dogs probably have less robust healing responses
compared with younger animals. An additional factor, though
not specifically examined in this study, may be a higher preva-
lence of more advanced cataracts and the associated secondary
pathologies in older dogs.
The reason for breed-related differences in failure rates is not
clear. There were insufficient numbers in this study to analyze
failure rates for each breed individually; however, we were able
to divide the breeds by size — small, medium, and large. For
dogs , 8 y old, large and medium breeds were more likely to
experience failure than small breeds, while for dogs . 8 y old,
medium and small breeds were more likely to experience failure
than large breeds. The variation of outcomes by breed is consis-
tent with the literature, which reports a wide variety of breeds
as being more susceptible to various postoperative complica-
tions. For example, a disproportionately high rate of glaucoma
has been documented for the Boston terrier (6) while a high
incidence of retinal detachment is seen in the bichon frisé fol-
lowing cataract surgery (22). Other studies examining secondary
glaucoma, including that developing after phacoemulsification,
have found a variety of breeds to be overrepresented (10,20).
Labrador retrievers were over-represented in a study examining
spontaneous lens rupture in diabetic dogs (23).
Due to the small number of untreated dogs (group 1), the
ability to analyze these data was limited. However, due to
the presence of lens-induced uveitis for all stages of cataract,
untreated inflammation could have led to the development
of complications requiring enucleation or evisceration and
intrascleral prosthesis. This hypothesis is supported by previ-
ous work that documents phacolytic uveitis as one of the most
common causes of secondary glaucoma, which was one of the
more common complications in the untreated eyes (10,20).
Given the poor outcomes for all affected eyes, it is apparent that
anti-inflammatory treatment is the minimum accepted standard
for dogs diagnosed with cataracts.
Blindness and decreased quality of life was given as the pri-
mary reason by owners of 4 of the 7 dogs who chose euthanasia
following medical or no treatment. This is similar to findings
of a previous study, in which approximately 10% of blind dogs
were euthanized due to problems associated with blindness (24).
This suggests that phacoemulsification is important not only for
maximizing the chances of retaining a comfortable eye, but also
for overall welfare of the dog. Restoration of vision, when pos-
sible, is clearly superior to blindness. Although blindness is still
a potential outcome following phacoemulsification, a median
time of 2.9 y before failure represents a significant portion of
a dog’s lifespan.
There were several limitations in this study. We included
only dogs with more than 6 months of follow-up. This may
have negatively biased the success rate, as dogs with persistent
complications are more likely to be returned for follow-up care
compared with dogs for which no problems are detected. In
addition, the dogs presenting to a referral institution are only
a small subset of the population as a whole, and these results
do not account for the individuals that are never presented to a
veterinary ophthalmologist. Finally, the retrospective nature of
this study limits the ability to obtain detailed clinical informa-
tion from all records as well as the ability to control for multiple
variables. However, differences in clinical management were
288 CVJ / VOL 52 / MARCH 2011
ARTICLE
minimized, as only 2 ophthalmologists managed the patients
in this study and a standard postoperative treatment protocol
is used at this institution.
The results of this study show a superior success rate for
surgery when compared with other modes of cataract manage-
ment, especially when performed early in the disease process.
This should encourage general practitioners to recommend
phacoemulsification more often and to refer more promptly
after initial presentation. This study also underscores the grave
prognosis for cataractous eyes when no treatment is instituted.
This information should therefore reinforce to practitioners
that when phacoemulsification is not possible, doing nothing is
unacceptable and, at minimum, anti-inflammatory therapy and
continued monitoring are essential for maintenance of ocular
health. CVJ
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