Irreversible Ocular Lesions in a Dog With Angiostrongylus Vasorum Infection.

This report describes a 10-month-old dog with a sudden loss of vision and severe dyspnoea. The ocular examination revealed bilateral panuveitis, lens subluxation, secondary glaucoma, and retinal detachment. In addition, the ocular ultrasound showed in the vitreous body of the right eye, a small doubled-lined foreign body compatible with an intraocular parasite. Radiographs of the thorax revealed an increased opacity with mixed lung pattern (alveolar and bronchial) and thoracic ultrasonography showed several subpleural nodules. The presence of Angiostrongylus vasorum first stage larvae was confirmed with 324 larvae per gram of feces and an antigen test for the parasite (AngioDetect, IDEXX) also yielded a positive result. The severe and irreversible ocular lesions described in this case enhanced the complexity of the clinical picture of canine angiostrongylosis. Infection with the parasite should be included in the list of differential diagnoses for ocular uveitis to avoid potentially serious complications related to a missed or delayed diagnosis.

Traumatic phacocele in an American Miniature Horse.

An 18-year-old American Miniature Horse mare was presented with a complaint of a scleral swelling affecting the right eye and a history of suspected trauma 6 weeks prior to evaluation. Clinical findings included severe blepharospasm, a bulbous swelling of the dorsotemporal bulbar conjunctiva, and phthisis bulbi. Ocular ultrasound was recommended but declined. Enucleation was elected for the blind, painful eye and was performed standing. Gross and histopathologic examinations of the globe were consistent with extrusion of the lens to the episcleral space, which is classified as a traumatic phacocele when associated with naturally occurring trauma. The location of lens entrapment suggested globe rupture occurred at the limbus, which is described as one of the weakest points of the equine globe. Subconjunctival dislocation of the lens and development of a traumatic phacocele should be considered as a differential diagnosis for horses presenting with subconjunctival masses, apparent aphakia, and historical trauma.

Evaluation of ADAMTS17 in Chinese Shar-Pei with primary open-angle glaucoma, primary lens luxation, or both.

OBJECTIVE To evaluate the coding regions of ADAMTS17 for potential mutations in Chinese Shar-Pei with a diagnosis of primary open-angle glaucoma (POAG), primary lens luxation (PLL), or both. ANIMALS 63 Shar-Pei and 96 dogs of other breeds. PROCEDURES ADAMTS17 exon resequencing was performed on buccal mucosal DNA from 10 Shar-Pei with a diagnosis of POAG, PLL, or both (affected dogs). A candidate causal variant sequence was identified, and additional dogs (53 Shar-Pei [11 affected and 42 unaffected] and 95 dogs of other breeds) were genotyped for the variant sequence by amplified fragment length polymorphism analysis. Total RNA was extracted from ocular tissues of 1 affected Shar-Pei and 1 ophthalmologically normal Golden Retriever; ADAMTS17 cDNA was reverse transcribed and sequenced, and ADAMTS17 expression was evaluated by quantitative reverse-transcription PCR assay. RESULTS All affected Shar-Pei were homozygous for a 6-bp deletion in exon 22 of ADAMTS17 predicted to affect the resultant protein. All unaffected Shar-Pei were heterozygous or homozygous for the wild-type allele. The variant sequence was significantly associated with affected status (diagnosis of POAG, PLL, or both). All dogs of other breeds were homozygous for the wild-type allele. The cDNA sequencing confirmed presence of the expected variant mRNA sequence in ocular tissue from the affected dog only. Gene expression analysis revealed a 4.24-fold decrease in the expression of ADAMTS17 in ocular tissue from the affected dog. CONCLUSIONS AND CLINICAL RELEVANCE Results supported that the phenotype (diagnosis of POAG, PLL, or both) is an autosomal recessive trait in Shar-Pei significantly associated with the identified mutation in ADAMTS17.

Lens-Related Emergencies: Not Always So Clear.

Emergencies involving the crystalline lens are not common; however, their clinical signs must be recognized quickly to begin treatment or referred immediately to improve the chances of retaining sight. The lens is a unique structure because of its immunologically privileged status and its imperative clarity for vision. Any insult to the lens capsule's integrity, its position within the globe, or to its clarity may result in undesirable sequelae.

Canine Secondary Glaucomas.

Secondary glaucomas are common in dogs, and occur due to obstruction of aqueous humor flow at the pupil, iridocorneal angle, or trabecular meshwork by numerous mechanisms. Secondary glaucoma is suspected based on examination findings, or presence of elevated IOP in an animal with a signalment inconsistent with primary glaucoma. Animals with secondary glaucoma require more diagnostic testing than animals with primary glaucoma. Management is challenging, and treatments used for primary glaucoma may be ineffective or even detrimental. Prognosis for vision and/or globe retention may be better than for primary glaucoma, particularly if underlying causes can be found and addressed promptly.

[Lens luxation in dogs: a retrospective study of 134 dogs (2000-2011)]. / Die Linsenluxation beim Hund: Eine retrospektive Studie von 134 Hunden (2000 - 2011).

This retrospective study evaluated cases of lens luxation in dogs that were documented at the University of Zurich Veterinary Teaching Hospital between 2000 and 2011. A total 134 dogs were included in the study. This population of dogs with lens luxation represents 0.41 % of all dogs presented to the Zurich Veterinary Teaching Hospital (32'523) and 3.02 % of all dogs presented to the ophthalmology service during the same time period. The 134 dogs represented over 40 different breeds, including mixed breeds. 63 of the dogs were male, 71 were female. The 134 dogs were divided in primary lens luxation (86 of the 134 dogs, 64 %) and secondary lens luxation (48 dogs, 36 %). The most frequent causes for secondary lens luxation were glaucoma (58 %), cataract (19 %) and trauma (17 %). This study shows the predisposition for primary lens luxations in terrier breeds, Chinese Crested dogs, Pinscher and Spitz. In contrast, Siberian Huskies, Basset Hounds, Bearded Collies, Cairn Terriers, mixed breed dogs, Bolonka Zwetna, Boston Terriers, Borzoi, Doberman, Eurasian, Leonberg, Luzerner Niederlaufhund and Weimaraner suffered significantly more often from secondary lens luxation. There was no sex predilection for primary or secondary lens luxation. Dogs with primary lens luxation were on average 7.39 ± 3.02 years old, which is significantly younger than the dogs with secondary lens luxation (9.12 ± 3.38 years). Dogs with primary lens luxation showed a significantly higher rate of a bilateral development than those with secondary lens luxation (85.5 % of the dogs with primary lens luxation and only 14.5 % of the dogs with secondary lens luxation showed it in both their eyes).

Cette étude rétrospective reprend tous les chiens présentés entre 2000 et 2011 à l'Hôpital vétérinaire de Zürich pour une luxation du cristallin. Au total 134 chiens souffraient d'une luxation uni- ou bilatéral ce qui représente 0.41 % de la population totale de chiens (32'523) présentés à l'hôpital et 3.02 % des chiens admis en ophtalmologie. Ces 134 chiens appartenaient à 40 races différentes. Les deux sexes étaient représentés de manière égale. Une luxation primaire du cristallin a été diagnostiquée chez 64 % des patients. Les causes les plus fréquentes d'une luxation secondaire étaient le glaucome (58 %), la cataracte (19 %) et les traumatismes (17 %). Les terriers, les chiens chinois à crête, les pinschers et les spitz étaient significativement plus atteints de luxations primaires que de secondaires. Les huskies, les basset-hounds, les bearded collies, les cairn terriers, les croisés, les bolonka zwetna, les boston terriers, les barzoïs, les dobermans, les eurasiens, les leonbergs, les petits courants lucernois et les braques de Weimar souffraient plus souvent, et ceci de façon significative, de luxations secondaires. Le chiens avec une luxation primaire étaient âgés lors de l'apparition de l'affection en moyenne de 7.39 ± 3.02 ans et étaient donc significativement plus jeunes que les chiens avec une luxation secondaire (9.12 ± 3.38 ans). Les luxations primaires étaient significativement plus fréquemment bilatérales que les secondaires (85.5 % des luxations primaires étaient bilatérales contre 14.5 % des secondaires).

Trans-corneal reduction of anterior lens luxation in dogs with lens instability: a retrospective study of 19 dogs (2010-2013).

OBJECTIVE: To evaluate the success rate and outcome of trans-corneal reduction of anterior lens luxation (TR-ALL) in dogs with lens instability. ANIMALS STUDIED: Nineteen dogs with anterior lens luxation. PROCEDURES: Medical records of dogs with anterior lens luxation (ALL) were reviewed: dogs were included if TR-ALL was performed followed by medical therapy in the form of topical 0.005% latanoprost ophthalmic solution. The duration of ALL, vision status, ophthalmic examination abnormalities, reason for performing TR-ALL and details of TR-ALL were recorded. Success rate for TR-ALL as well as postprocedure complications were also assessed. RESULTS: Twenty eyes from 19 dogs met the inclusion criteria. Median age was 6.5 years (0.3-15 years) and 47% were terriers (9/19). Successful TR-ALL was achieved in 85% of eyes (17/20); failure was attributed to posterior synechia or vitreous expansion. Short-term complications included corneal ulceration (2/20) and anterior uveitis (3/20); recurrence of anterior luxation occurred in only one dog. Median follow-up for visual eyes (11) following successful TR-ALL was 353 days (range of 1 to 1182 days). Vision was retained in 54.5% (6/11) of eyes with a median time to vision loss of 12 months as a result of glaucoma or presumed retinal detachment. CONCLUSIONS: Trans-corneal reduction of ALL provides a non-surgical alternative to intracapsular lens extraction (visual eyes) or enucleation (nonvisual eyes) in dogs. Long-term visual outcome of TR-ALL is comparable to intracapsular lens extraction for ALL.

ADAMTS17 mutation associated with primary lens luxation is widespread among breeds.

Primary lens luxation (PLL) is a well-recognized, painful and potentially blinding inherited ocular condition in dogs. We screened PLL-affected dogs of 30 different breeds, to identify those which carried a previously described c.1473+1 G>A mutation in ADAMTS17 that is associated with PLL in Miniature Bull terriers, Lancashire Heelers, and Jack Russell terriers. This ADAMTS17 mutation was identified in PLL-affected dogs from 14 additional breeds. PLL-affected dogs from some breeds (most notably the Shar pei and the Brittany spaniel) did not carry the G1473+1A ADAMTS17 mutation, indicating they must suffer from a genetically distinct form of the condition. We also estimated the frequency of this ADAMTS17 mutation in some of the breeds. Our findings indicate the mutation segregates in a large number of different breeds of dog, many of which are terriers or breeds with terrier co-ancestry, but some of which have more diverse origins. Our results also indicate that the mutation is present at high frequency within most of the breeds in which it segregates. In the miniature bull terrier breed estimates of mutation frequency ranged from 0.27 to 0.39, corresponding to 7.3-15.2% PLL-affected dogs in this breed. We also identified an increased risk of PLL associated with heterozygosity at ADAMTS17, suggesting that carriers carry a low risk of developing PLL.

Primary lens instability in ten related cats: clinical and genetic considerations.

OBJECTIVES: To describe bilateral lens instability in 10 related domestic shorthair cats over three generations. METHODS: Complete ophthalmic examinations were performed. Lentectomies were carried out. Sections of affected lenses focused on the equatorial area were examined by transmission electron microscopy. The potential involvement of several candidate genes (ADAMTS17, ADAMTSL4, ADAMTS10 and FBN1) known to be associated with lens luxation in other species was investigated. RESULTS: The group of animals included 10 related cats, nine of them being affected by lens instability over three generations. Transmission electron microscopy showed the presence of zonular material at the lens equator. Signs of lens instability were not associated with other ocular disease. Analysis of the pedigree suggests a dominantly inherited condition. A mutation in ADAMTS17 was excluded, but a possible association between the condition and a microsatellite flanking FBN1 indicates this gene should be considered a strong candidate responsible for primary lens luxation in this pedigree. CLINICAL SIGNIFICANCE: These observations suggest an inherent zonular defect unrelated to extraneous factors. The family relationship is compatible with a possible genetic basis, and the pedigree suggests that the condition could be dominant. Data also suggest the mutation in the FBN1 gene could be responsible for primary lens luxation in this pedigree of cats.

An ADAMTS17 splice donor site mutation in dogs with primary lens luxation.

PURPOSE: To identify the genetic cause of isolated canine ectopia lentis, a well-characterized veterinary disease commonly referred to as primary lens luxation (PLL) and to compare the canine disease with a newly described human Weill-Marchesani syndrome (WMS)-like disease of similar genetic etiology. METHODS: Genomewide association analysis and fine mapping by homozygosity were used to identify the chromosomal segment harboring the PLL locus. The resequencing of a regional candidate gene was used to discover a mutation in a splice donor site predicted to cause exon skipping. Exon skipping was confirmed by reverse transcription-polymerase chain reaction amplification of RNA isolated from PLL-affected eyes and from skin fibroblast cultures from PLL-affected dogs. An allelic discrimination assay was used to genotype individual dogs at the splice donor site mutation. RESULTS: The PLL locus was mapped to a 664-kb region of canine chromosome 3 containing regional candidate gene ADAMTS17. Resequencing ADAMTS17 revealed a GT-->AT splice-donor-site mutation at the 5' end of intron 10. The predicted exon 10 skipping and resultant frame shift were confirmed with RNA derived from PLL-affected dogs. The ADAMTS17 mutation was significantly associated with clinical PLL in three different dog breeds. CONCLUSIONS: A truncating mutation in canine ADAMTS17 causes PLL, a well-characterized veterinary disease, which can now be compared to a recently described rare WMS-like disease caused by truncating mutations of the human ADAMTS17 ortholog.

Intracapsular lensectomy and sulcus intraocular lens fixation in dogs with primary lens luxation or subluxation.

OBJECTIVE: To evaluate the postoperative results of lensectomy and sulcus intraocular lens fixation (SIOLF) via an ab interno approach in dogs with progressive lens subluxation or early luxation. STUDY DESIGN: Retrospective study. ANIMALS STUDIED: Twenty eyes from 19 dogs presented to the Animal Eye Clinic for lens luxation or subluxation between 1999 and 2006. METHODS: Medical records were reviewed to evaluate preoperative lens position, vision status, intraocular pressure (IOP), and whether surgery was performed on an emergent or elective nature. Lensectomy and SIOLF were performed and postoperative status including vision, glaucoma, and retinal detachment was assessed. RESULTS: Average age was 8.6 years (range 4-14 years) and 55% (11/20) were terriers. Patients were followed a mean of 29.2 months (range 1-92 months) after surgery. Retinal detachment or secondary glaucoma was observed in 1 of 20 (5%) and 5 of 20 (20%) eyes, respectively, with 1 of 20 (5%) exhibiting both. Mean preoperative IOP was 16 mmHg and preoperative lens position was equally divided between luxated and subluxated lenses. Surgery was performed more frequently as an elective procedure (18/20; 90%) due to normalized IOP vs. an emergency procedure (2/20; 10%). Vision was retained in 70% (14/20) of eyes with a mean time to vision loss of 41 months in the remaining eyes due to glaucoma, retinal detachment, or retinal degeneration. CONCLUSIONS: Complications of glaucoma and retinal detachment after SIOLF in this study were less when compared with previously reported incidence rates in the literature for lensectomy alone which may reflect improved patient selection.

Outcomes of nonsurgical management and efficacy of demecarium bromide treatment for primary lens instability in dogs: 34 cases (1990-2004).

OBJECTIVE: To determine outcome of initial conservative management for primary lens luxation and evaluate topically administered demecarium bromide miotic treatment for prevention of anterior lens luxation, glaucoma, and vision loss in dogs. DESIGN: Retrospective case series. ANIMALS: 34 dogs with primary lens luxation. PROCEDURES: Medical records of affected dogs were reviewed for times to anterior luxation, luxation of the lens in the opposite eye, development of glaucoma, and vision loss. RESULTS: At 4 to 6 weeks and at 3 months after diagnosis of lens instability (subluxation or posterior luxation), 100% (34/34 and 29/29, respectively) of conservatively managed eyes retained vision. At 1 year after diagnosis of lens instability, 80% (16/20) of conservatively managed eyes retained vision, and at 2 years after diagnosis of lens instability, 11 of 19 conservatively treated eyes retained vision. The only significant effect of miotic treatment was to delay anterior lens luxation in eyes with lens instability. Miotic treatment did not significantly affect the time from anterior lens luxation in 1 eye to anterior luxation in the other eye, time to onset of glaucoma, or time to loss of vision in eyes with an unstable lens. CONCLUSIONS AND CLINICAL RELEVANCE: Prophylactic topically administered miotic treatment may be effective at delaying anterior luxation of an unstable lens in eyes affected by primary lens instability. Conservative medical management of dogs with primary lens instability is a reasonable alternative to surgical removal of a subluxated or posteriorly luxated lens via intracapsular lens extraction.

Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004).

OBJECTIVE: To determine the immediately antecedent cause of secondary glaucoma and the prevalence of secondary glaucoma with anterior uveitis or lens dislocation in dogs. DESIGN: Retrospective case series. ANIMALS: 156 dogs with secondary glaucoma. PROCEDURES: Cause of glaucoma was determined from records. Breed, age, sex, and neuter status of all dogs with secondary glaucoma were compared with the general hospital population. The prevalence of secondary glaucoma in dogs with a primary diagnosis of lens dislocation or anterior uveitis during the same period was determined. RESULTS: Secondary glaucoma was diagnosed in 156 of 2,257 (6.9%) dogs examined because of ophthalmic disease and was bilateral in 33 (21.2%) of those dogs. In 31 (94%) bilaterally affected dogs, the antecedent cause was the same in both eyes. Common causes of secondary glaucoma were non-surgical anterior uveitis (44.9%), anterior uveitis associated with prior phacoemulsification (15.8%), and lens dislocation (15.2%). Parson Russell Terriers, Poodles, Boston Terriers, Cocker Spaniels, Rhodesian Ridgebacks, and Australian Cattle Dogs had diagnoses of secondary glaucoma more often than expected, compared with the reference population. Age, sex, neuter status, and laterality were not associated with secondary glaucoma. The prevalence of secondary glaucoma in dogs with lens dislocation or uveitis was 15% or 17%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Glaucoma develops secondary to many intraocular diseases, particularly uveitis and lens dislocation. Diagnosis of these diseases should prompt frequent monitoring of intraocular pressure, regardless of signalment.

Light-microscopy evaluation of zonular fiber morphology in dogs with glaucoma: secondary to lens displacement.

Lens displacement resulting in secondary glaucoma is common in terrier breeds. This study was carried out to evaluate whether light microscopy was useful in detecting abnormal patterns in zonular fiber protein. Eyes from 63 dogs with glaucoma secondary to lens displacement were evaluated for the presence of abnormal zonular fiber morphology using the following stains: hematoxylin and eosin, periodic acid Schiff (PAS), Masson's trichrome and Verhoeff's elastin stains. Two distinct forms of abnormal zonular fiber morphology were recognized and designated as zonular fiber dysplasia (ZFD) and zonular fiber collagenization (ZFC). ZFD protein morphology was characterized by being tightly adherent to the nonpigmented ciliary body epithelium, exhibiting a distinct lamellar and cross-hatched pattern and staining strongly positive with PAS and trichrome stains, and staining negative with elastin stains. ZFD was predominant in terrier breeds (18 of 29) and Shar-Pei dogs (4 of 29). ZFC abnormality was characterized by excessive zonular fiber that was not tightly adherent to the ciliary body epithelium and staining positive with PAS, trichrome (blue for collagen) and elastin stains. Only 7 of 19 dogs with ZFC changes were terrier breeds, and there was no pattern in the breeds affected. Fifteen of the 63 dogs used in the study had normal appearing zonular fibers. The staining pattern in these dogs matched normal controls by staining positive with PAS and Verhoeff's elastin stains and had only minimal positive staining with Masson's trichrome stain. Results suggest that light microscopy is useful in detecting breed-related changes in zonular fiber morphology in cases of glaucoma secondary to lens displacement. These changes may correlate with the presence of abnormal zonular fiber proteins and might be important in the pathogenesis of primary lens displacement in terrier and Shar-Pei dogs.

Secondary glaucomas in the dog in North America.

OBJECTIVE: To determine the prevalence of secondary glaucomas in dogs associated with cataract formation, lens luxation or displacement, cataract surgery, uveitis, hyphema and intraocular neoplasia. METHODS: Information was obtained from the Veterinary Medical Data Base (VMDB) from all veterinary medical teaching hospitals in North America from March 1964 to March 2003. Secondary glaucomas were diagnosed at the same examination or after the primary diagnosis was made, and included those associated with cataract formation, lens luxation, cataract surgery, uveitis of unknown cause, hyphema of unknown cause, and intraocular neoplasia. The data were evaluated by decade, breed, gender and age of presentation. RESULTS: A total of 1 592 831 dogs were presented, and 9695 canine secondary glaucomas. Secondary glaucoma associated with cataract formation represented 81% of all the canine secondary glaucomas. Breeds (n = 7890 dogs) predisposed to secondary glaucoma and cataracts had an overall prevalence of 0.5%, but nearly 20% of all the cataractous dogs developed secondary glaucoma in at least one eye. For the years 1994-2003, these breeds included the American Cocker Spaniel; Boston Terrier; Toy, Miniature and Standard Poodle; English Springer Spaniel; Bichon Frise; and Labrador Retriever. The other forms of secondary glaucoma occurred less frequently, and included those glaucomas with lens luxation or displacement (779 dogs; 12.0%), postcataract surgery (528 dogs; 5.1%), with uveitis from unknown cause (399 dogs; 7.1%), with hyphema from unknown cause (117 dogs; 7.3%), and with intraocular neoplasia (19 dogs; 3.5%). The risk of the secondary glaucomas from 1984 to 2002 was highest after the intracapsular lens extraction (ICLE), less in the extracapsular technique (ECLE), and lowest for the phacoemulsification/phacofragmentation method. CONCLUSION: Prevalence of the canine secondary glaucomas ranges from 0.25% (1964-1973), 0.46% (1974-1983), 0.79% (1984-1993), to 0.80% (1994-2003) and are as frequent as the primary or breed-related glaucomas during these same time periods.

Intracapsular lens removal in a Przewalski's wild horse (Equus caballus przewalskii).

A 11.5-yr-old female Przewalski's wild horse (Equus caballus przewalskii) presented for unilateral blepharitis and drainage from the left eye. The left cornea was not ulcerated, and intraocular evaluation was hampered by severe corneal edema. The left eye appeared to respond positively to treatment with anti-inflammatories and a topical mydriatic agent. During the ensuing 2 yr, there were minor episodes of epiphora from the left eye. The discharge then increased, and a luxated lens was noted during an examination by a veterinary ophthalmologist as part of the preshipment examination. Initially, the lens was located in the anterior compartment but was in the vitreal compartment at the time of surgery, complicating the intracapsular extraction. After successful removal of the lens, the horse was transferred to a new institution without incident, where it appears to have adapted well to its probable loss of vision in the left eye. No further episodes of uveitis, corneal edema, or epiphora have been reported, and the horse has successfully foaled at the new institution.

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.