Treatment of presumed iris melanoma in dogs by diode laser photocoagulation: 23 cases

A semiconductor diode laser was used to cause remission of isolated presumed iris melanoma in 23 dogs. All cases presented as unilateral areas of raised iris hyperpigmentation, ranging in size from 2× 3 mm to 4×12 mm. Cases were treated using a diode laser delivery system through either an operating microscope adapter (OMA) or a laser indirect ophthalmoscope (LIO) with a 20D lens. Laser treatment was delivered 'to effect' using power ranging from 80 to 1000 mW and cumulative durations up to 14 min, 31 s (14:31). Immediate shrinkage of the mass was noted following treatment. Five cases required more than one laser treatment with three eyes receiving two treatments and two eyes receiving three treatments. Follow-up from the last laser treatment ranged from 6 months to 4.5 years during which time the lesions exhibited no enlargement. Minor complications related to laser treatment were seen, including: dyscoria, iris hyperpigmentation, and corneal edema due to collateral hyperthermia. Glaucoma and cataract formation were not observed. Non-invasive diode laser photocoagulation appears to be a safe and effective method of treatment for isolated, pigmented iris masses in dogs.     

Cataracts are not associated with retinal detachment in the Bichon Frise in the UK--a retrospective study of preoperative findings and outcomes in 40 eyes

Objective The aim of this study was to evaluate whether the Bichon Frise population in the UK is at the same risk of developing retinal detachment in association with cataract formation and following phacoemulsification as described in reports from the USA. Procedures The medical records of Bichon Frises which were presented for cataract assessment and of those which were treated with phacoemulsification at Willows Referral Service between 1997 and 2009 were reviewed. Results Forty eyes (26 dogs) with unilateral or bilateral cataracts were included in the study. There was no evidence of retinal detachment associated with the cataracts at initial presentation. Phacoemulsification was performed on 34 eyes (20 dogs). Clinically evident lens‐induced uveitis was treated preoperatively in 17/34 eyes. Artificial lens implantation was carried out in 30/34 eyes; automated anterior vitrectomy was performed in 7/34 eyes. The mean follow‐up time was 16.6 months (range 1.5–73 months). At the last re‐examination, 31/34 eyes (91.2%) were visual. Three eyes (8.8%) were blind – two (in the same dog) because of presumptive bilateral optic nerve disease and one because of uveitis and secondary glaucoma. There was no evidence of retinal detachment following phacoemulsification in any of the 34 eyes. Conclusion This study suggests that the Bichon Frise population in the UK does not appear to have a predisposition for retinal detachment in association with cataract formation or following cataract surgery. Prophylactic random transscleral laser retinopexy or transscleral cryopexy cannot therefore be routinely recommended for Bichon Frises with cataracts in the UK.     

Ocular signs of canine monocytic ehrlichiosis: a retrospective study in dogs from Barcelona, Spain

Canine monocytic ehrlichiosis (CME) is a tick-borne disease caused by the rickettsia Ehrlichia canis. Ocular lesions are a common feature of the disease and can be present in all stages. The purpose of this retrospective study was to determine the prevalence, type and response to treatment of ocular lesions associated with monocytic ehrlichiosis in 46 affected dogs presented to the Autonomous University of Barcelona-Veterinary Teaching Hospital (UAB-VTH) from January 2000 to December 2002. Dogs were included in the study only if they had a positive serologic test for E. canis and information about the clinical outcome was available. Eighteen breeds were represented, with the German Shepherd dog (n = 6) being the most common. There were 25 intact and three castrated males, and 16 intact and two neutered females. Twenty dogs (43.4%) were between 5 and 10 years old. Seventeen dogs (37% of all cases of monocytic ehrlichiosis diagnosed during the study period) had ocular signs, and 11 dogs (64.7% of the ocular cases) had only ocular lesions without apparent systemic signs. Exudative retinal detachment was the most common ocular manifestation; other prevalent findings included anterior exudative uveitis and optic neuritis. Five of the 17 cases with ocular lesions (29.4%) had ocular bleeding disorders (hyphema or retinal hemorrhages). All the dogs with ocular disease presented with bilateral signs. Dogs with posterior segment disease had titers against E. canis that were > or = 1 : 320, while lower titers were noted in dogs with anterior exudative uveitis. Two dogs presented with chronic autoimmune panuveitis after ehrlichiosis treatment. Canine ehrlichiosis should be considered in the differential diagnosis of exudative retinal detachment and anterior uveal inflammatory lesions.     

Canine retinal surgery

Retinal detachment is common in dogs and presents major challenges for the veterinary ophthalmologist. This article reviews recent advances in both technology and technique that have greatly increased the success rate of retinal reattachment surgery. Internal and external techniques for the repair of retinal detachments are discussed, as is the etiopathogenesis of vitreoretinal disease in the dog.     

The use of transscleral cyclophotocoagulation with a diode laser for the treatment of glaucoma occurring post intracapsular extraction of displaced lenses: a retrospective study of 15 dogs (1995-2000)

The objective of this retrospective study was to evaluate transscleral cyclophotocoagulation (TSCP) using a diode laser for treating aphakic glaucoma that developed after intracapsular lens extraction (ICLE) had been performed for displaced lenses. Records of 15 dogs (21 eyes) were reviewed. The intraocular pressure (IOP) and the presence of vision were recorded at the time of ICLE and TSCP and at 1, 3, 6-9, 12 and 24 months post TSCP. The glaucoma was considered controlled if the IOP was less than 25 mmHg. The results indicated that the effectiveness of TSCP using a diode laser for treating aphakic glaucoma was of a short-term duration (1-3 months), with three patients needing repeat TSPC. In addition, adjunctive antiglaucoma medications were often required to maintain an adequately controlled IOP. Over the 24-month period the number of dogs requiring intrascleral prosthesis, intraocular gentamicin or enucleation, or that were lost to follow-up, increased.     

Combined transscleral diode laser cyclophotocoagulation and Ahmed gonioimplantation in dogs with primary glaucoma: 51 cases (1996-2004)

OBJECTIVE: To evaluate the combined diode laser cycloablation procedure and adjunctive Ahmed gonioimplant use in dogs with primary glaucoma. DESIGN: Retrospective study. ANIMALS: 48 dogs, 51 eyes with primary glaucoma. PROCEDURE: Medical records from two large private clinical ophthalmology services were reviewed. Signalment, duration of glaucoma, gonioscopic evaluation, laser power and duration settings, immediate postoperative and final intraocular pressure and visual results, short and long-term visual outcome, and surgical complications were recorded. RESULTS: The age range of affected dogs was 3.0-14.0 years, with a mean age of 7.5 +/- 2.6 years. Eleven pure breeds were represented, with the most common being the American Cocker Spaniel. The sex distribution was 22 neutered males, 1 intact male, 23 spayed females, and 2 intact female dogs. The right eye was affected in 33 cases, and the left eye in 18 cases. The average total joules, which was administered with the diode laser, was 109.6 +/- 23.6 J. Immediate surgical complications included fibrin formation in the anterior chamber (15), corneal ulcers (4), hyphema (7), and focal retinal detachment (1). Long-term complications included cataract formation (8 total, 2 of which were significant, vision-threatening), elevated intraocular pressure (IOP) (6), unstable gonioimplant (1), and glaucoma recurrence (14). Additional surgeries performed on the eyes over the course of study included: intrascleral prosthesis (4), enucleation (1), resection of fibrotic scar tissue (5), and repeat laser cycloablation (8). The dogs were examined for a mean follow-up time of 17.6 months (range: 2-83 months postoperatively). Twenty-nine cases were followed greater than one year. Vision was maintained in 42/51 eyes (82%) in the immediate short-term of this study. In all cases included in the study, good control of IOP was achieved in 39/51 (76%) of eyes, and IOP was poor or uncontrolled in 12/51 (24%) of eyes. Twenty out of 41 eyes (49%) maintained fair to excellent vision six months after surgery. Twelve months postoperative observations demonstrated that 12/29 (41%) of the eyes were still visual. CONCLUSIONS: In primary glaucoma, the combined procedure of laser diode cyclophotocoagulation and Ahmed valve implant was associated with return or maintenance of vision in 42/51 eyes (82%) in the immediate short-term of this study, and a long-term IOP control in 39/51 (76%) of the cases, with 12/29 eyes (41%) visual after 12 months.     

Semiconductor diode laser transscleral cyclophotocoagulation for the treatment of glaucoma in horses: a retrospective study of 42 eyes

Objective To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses. Procedure Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow‐up data were collected, and telephone follow‐up was performed. Results Forty‐two eyes of 36 horses were included. Twenty‐four hours prior to surgery mean intraocular pressure (IOP) was 37.17 ± 13.48 mmHg (42 eyes). Forty‐one of 42 eyes (98%) were sighted and 39 of 39 (100%) of eyes were receiving topical glaucoma medication. At 3–5 weeks postoperatively the average IOP was 19.36 ± 12.04 mmHg (22 eyes). IOP remained significantly lower than pretreatment values at all periods of clinical follow‐up (P < 0.05). There was no significant difference in vision outcome, or the requirement for topical glaucoma medication relative to pretreatment values at any follow‐up period. Hyphema in 5 of 42 eyes was the only complication noted. Of the 27 eyes seen for clinical follow‐up, 2 were enucleated because of refractory elevation of IOP. Mean telephone follow‐up was 49 months. Twenty‐one of 22 owners contacted (95%) reported that the treatment had been of value, 14 of 22 eyes (64%) were receiving topical glaucoma medication, and 13 of 22 eyes (59%) were considered sighted. Conclusions Diode laser TSCP aided in the control of IOP and maintenance of vision but did not eliminate the need for topical glaucoma medication during the period of clinical follow‐up.     

Clinical, cytologic and histopathologic manifestations of protothecosis in two dogs

Two cases of sudden onset of blindness associated with ocular protothecosis in dogs are reported. Both were adult, spayed female, mixed-breed dogs that lacked the usual clinical signs of systemic infection with Prototheca species. Physical abnormalities at the time of presentation were limited to the affected eyes which had serous discharge, hyperemic conjunctiva, and aqueous flare. The pupillary light reflexes were slow, and the menace reflexes were absent. Both dogs had glaucoma. Results of complete blood counts and serologic titres for antibodies to Blastomyces dermatitidis and Histoplasma capsulatum were within reference intervals. Protothecosis was diagnosed by cytologic analysis of vitreous humor and was confirmed at necropsy. These two cases were unusual because of their presenting signs and prolonged course of disease progression.     

Retinopathy of Coton de Tulear dogs: clinical manifestations, electroretinographic, ultrasonographic, fluorescein and indocyanine green angiographic, and optical coherence tomographic findings

Objectives  To document the clinical manifestations, development, progression, and mode of inheritance of the retinopathy of Coton de Tulear dogs.
Materials and methods  Multiple Coton de Tulear dogs were examined with biomicroscopy, indirect ophthalmoscopy, photopic and scotopic electroretinography, fluorescein and indocyanine green angiography, optical coherence tomography, ultrasonography, and fundic photography for 3 years.
Results  The retinopathy of Coton de Tulear dogs is inherited as an autosomal recessive condition and manifests as multifocal serous retinal detachments in homozygous puppies, between 3 and 4 months of age. Optic coherence tomography and ultrasonography confirm multiple focal serous retinal detachments. Serial fundic photographs confirmed minimal progression of lesions beyond 1 year of age. Electroretinography identified diminished scotopic and photopic amplitudes; however, the only significant differences between affected and age-matched control Coton de Tulear dogs were noted during photopic flicker electroretinograms. Leakage of fluorescein or indocyanine green through the blood ocular barriers was not detected during repeated angiograms prior to, during, and after development of the retinopathy. There was no focal pooling of fluorescein in any of the dogs examined. Focal retinal thinning was detected with optical coherence tomography over each detachment and the serous content of some of the bullae diminish after several years leaving focal areas of hyper-reflectivity.
Conclusions  Multifocal retinopathy of Coton de Tulear dogs is inherited as an autosomal recessive condition. The retinopathy manifests early in life as nonprogressive multifocal bullous retinal detachments. The blood ocular barrier remains intact. Photopic and scotopic electroretinography are minimally diminished compared to age-matched dogs.     

Effects of sevoflurane, isoflurane and halotane anaesthesia on fluorescein angiographic phases of dogs: a comparative study

A fluorescein angiography method was developed to compare the onset and the total duration of the fluorangiographic phases between three anaesthetic protocols in six healthy mixed-breed dogs. The animals were anaesthetized three times. Each dog received, as pre-anaesthetic protocol, atropine (10 micrograms/kg intramuscularly), and as a sedative, romifidine (80 micrograms/kg intravenously). Fifteen minutes later, induction of anaesthesia was delivered with propofol (1 mg/kg intravenously) and maintained either with sevoflurane (SEVO group), isoflurane (ISO group) or halothane (HAL group) for 30 min in all cases. Some angiographic, cardiovascular and respiratory variables were registered during the procedure. Recovery times were also registered. Angiographic variables recorded were: onset of the arterial phase (TA), onset of the arteriovenous phase (TAV), onset of the venous phase (TV), complete arterial phase duration (I1), complete arteriovenous phase duration (I2) and I1 plus I2 (I3). Mean heart rate, mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate, tidal volume, arterial oxygen saturation and end-tidal CO2 during SEVO and ISO anaesthesia, were similar in dogs. Minute ventilation and rectal temperature were higher in dogs with SEVO than ISO. HAL produced higher arterial pressures and a lower arterial oxygen saturation than ISO and SEVO. Mean respiratory rate, rectal temperature and minute ventilation were higher in HAL. Pulse rate, end-tidal CO2 and tidal volume were similar in the dogs of the three groups. No differences in recovery times were found. The fluorescein angiographic times were within the normal range. There were no significant differences between protocols in I1, I2 or I3. HAL produced a significant increase of all temporal variables (TA, TAV and TV) when compared with ISO; TA was higher in HAL than SEVO-treated dogs. All protocols appear to be safe and effective for inducing and maintaining general anaesthesia in healthy dogs for performing fluorescein angiography.     

Leptospirosis and panuveitis in a dog

A case of panuveitis as a result of leptospiral infection in an 8-year-old Jack Russell Terrier is reported. Mild hyphema, aqueous flare, and partial serous retinal detachments were noted in both eyes on initial ophthalmic examination. The serum microscopic agglutination testing for Leptospira serovarieties revealed titers of 1 : 12 800 for Leptospira canicola and 1 : 200 for Leptospira icterohemorrhagiae. With medical therapy, the panuveitis resolved and functional vision was regained. Four weeks after the initial presentation, convalescent titers were 1 : 200 for L. canicola and 1 : 100 for L. icterohemorrhagiae. The incidence of leptospirosis, along with difficulties diagnosing, and current medical therapies for this disease are also discussed.     

Inherited retinal dysplasia and persistent hyperplastic primary vitreous in Miniature Schnauzer dogs

The objectives of this study were to define the clinical syndrome of retinal dysplasia and persistent primary vitreous in Miniature Schnauzer dogs and determine the etiology. We examined 106 Miniature Schnauzers using a biomicroscope and indirect ophthalmoscope. The anterior and posterior segments of affected dogs were photographed. Four enucleated eyes were examined using routine light microscopy and scanning electron microscopy. A pedigree was constructed and related dogs were test-bred to define the mode of inheritance of this syndrome. Congenital retinal dysplasia was confirmed in 24 of 106 related Miniature Schnauzer dogs. Physical and postmortem examinations revealed that congenital abnormalities were limited to the eyes. Biomicroscopic, indirect ophthalmoscopic, and neuro-ophthalmic examinations confirmed that some of these dogs were blind secondary to bilateral retinal dysplasia and detachment (nonattachment) (n = 13), and the remainder had generalized retinal dysplasia (n = 11). Fifteen of these dogs were also diagnosed with unilateral (n = 9) or bilateral (n = 6) persistent hyperplastic primary vitreous. Nutritional, infectious, or toxic etiologies were not evident on physical, postmortem, light microscopic, or transmitting and scanning electron microscopic examination of four affected Miniature Schnauzers. We examined the pedigree and determined that an autosomal recessive mode of inheritance was most likely. Three test-bred litters including those from affected parents, carrier and affected parents, and carrier parents confirmed this mode of inheritance. This study confirms that retinal dysplasia and persistent hyperplastic primary vitreous is a congenital abnormality that is inherited as an autosomal recessive condition in Miniature Schnauzers.