Prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis, primary glaucoma associated with goniodysgenesis, and secondary glaucoma.

Objectives: The objectives of this study were to (i) evaluate the prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis (ASD), primary glaucoma associated with goniodysgenesis (GD), and secondary glaucoma, and (ii) examine the associations between monocellular and fibrovascular membranes by breed, gender, age and histopathologic ocular changes on light microscopic examination. Methods: Records of dogs who had eyes enucleated due to blindness and uncontrolled glaucoma were reviewed. Glaucoma was categorized clinically and histologically into three groups: congenital/ASD, primary/GD, and secondary glaucoma. The presence or absence and type of pre-iridal membrane (monocellular or fibrovascular) and other intraocular histologic findings were reviewed and compared statistically for each group. Results: In total, 108 canine globes (101 dogs) were included. Pre-iridal monocellular membranes were identified with light microscopy in 10 out of 19 congenital/ASD, 29 out of 40 primary, and 23 out of 49 secondary glaucoma globes. Fibrovascular membranes were observed in 3 out of 19 congenital/ASD, 9 out of 40 in primary, and 24 out of 49 secondary glaucoma globes. There were no associations between the type of membrane and breed, gender, or age. Peripheral anterior synechiae were more common in globes with fibrovascular membranes, and uveal atrophy was more common in globes with monocellular membranes. Conclusion: Pre-iridal monocellular membranes are common in all types of canine glaucoma. They are identified with light microscopy most easily in cases of primary glaucoma, and they are masked by pre-iridal fibrovascular membranes in other forms of glaucoma.

Statistical agreement of gonioscopy performed as a puppy and as an adult in the Samoyed dog.

OBJECTIVE: To assess whether gonioscopy performed on Samoyed puppies (6-14 weeks of age) is a reliable predictor of their gonioscopy results as adults (>11 months of age). PROCEDURE: A retrospective medical record search was performed to identify Samoyed dogs that had undergone gonioscopy as a puppy (6-14 weeks of age). A second prospective gonioscopy examination was performed as an adult (>11 months of age) and the results were compared. Gonioscopy was assessed on two characteristics: percent of iridocorneal angle (ICA) unaffected by pectinate ligament abnormalities (PLA) and ICA width, with PLA results categorized into unaffected ( ≥ $$ \ge $$ 75% open), moderately affected (50%-74% open), and severely affected (<50% open) and the width categorized into wide, moderate, narrow, and closed groups. A multivariate model was created that considered factors such as PLA, angle width, sex, puppy age, neuter status, and time between examinations. RESULTS: The eyes of 77 Samoyed dogs (154 eyes) met inclusion criteria. When assessing PLA, 90% of dogs had the same categorization as a puppy and as an adult. When assessing ICA width, 53.2% of dogs had the same width classification as a puppy and as an adult. There is strong evidence that variation between puppy and adult results increases with time between examination (p = .03). CONCLUSION: Puppies unaffected by PLA and with a wide ICA angle, are likely to retain these features as adults. Selection of puppies with desirable gonioscopic traits may help breeders to choose dogs likely to retain these traits as adults for breeding. This may reduce the incidence of glaucoma in the breed. Puppy examinations should be performed in both eyes. Examination of adults prior to breeding remains prudent.

Congenital glaucoma in a tiger (Panthera tigris).

OBJECTIVE: To describe a case of congenital glaucoma in atiger (Panthera tigris). ANIMAL STUDIED: An 8-month-old intact female tiger wasreferred for suspected glaucoma of the right eye. The right eye was buphthalmicwith moderate episcleral injection, circumferential superficial cornealneovascularization, moderate corneal edema, and a fixed dilated pupil. Tapetalreflection was absent due to a mature cataract. Rebound tonometry under generalanesthesia revealed 70 mmHg and 21 mmHg in the right and left eye, respectively. PROCEDURE: A trans-conjunctival enucleation was performedand the globe was submitted for histopathology. RESULTS: Histopathology revealed a thin sclera, amorphousmaterial contouring an imperforate and hypoplastic iridocorneal angle, ahypoplastic lens with severe anterior-posterior compression, subcapsularepithelial hyperplasia, and Morganian globules, and segmental moderate retinalatrophy. Periodic acid-Schiff stain highlighted segmental dilations of theDescemet's membrane. Masson trichrome stain highlighted a pre-irido collagenmembrane. CONCLUSION: The tiger's age and histopathologic findingsare consistent with congenital goniodysgenesis. This is the first known reportof congenital glaucoma in a tiger.

[Painful anisocoria in a five-year-old child: A rare diagnosis which must not be missed]. / Anisocorie douloureuse chez un enfant de cinq ans : un diagnostic rare à ne pas méconnaître.

Congenital ectropion uveae (CEU) is a rare anomaly of the embryonic development of the anterior segment of the eye. We report the case of a 5-year-old child with an undiagnosed CEU who was treated urgently for an acute angle closure attack. CASE DESCRIPTION: A 5-year-old child was referred urgently for evaluation of anisocoria with mydriasis of the right eye and severe headache. Brain imaging with contrast injection was initially performed in the pediatric emergency department and ruled out central nervous system pathology. The initial examination of the right eye revealed an intraocular pressure (IOP) of 37mmHg, corneal edema, congenital ectropion uveae, mydriasis with pupillary block, a closed angle on gonioscopy, and a clear lens. The examination of the left eye was unremarkable, with no visible CEU. The initial management consisted of medical treatment with topical glaucoma drops and miotics and acetazolamide at 10mg/kg/d. Re-evaluation under general anesthesia showed persistent mydriasis and no resolution of the pupillary block. Filtering surgery was performed in the absence of a complete response to medical treatment, allowing control of IOP without drops and complete regression of the corneal edema. DISCUSSION: CEU is a rare malformation, and pressure complications represent an insignificant proportion of pediatric glaucoma cases. The acute presentation of acute angle closure in this potentially blinding short-term setting, however, makes detection and management difficult in very young children in a great deal of pain. Only one similar case has been reported in the pediatric literature. CONCLUSION: Acute angle closure complicating CEU is exceptional and difficult to diagnose in a pediatric context. Parents of children with this predisposing condition should be informed of the need to consult urgently when clinical signs of elevated intraocular pressure appear.

Role of Inflammation in Canine Primary Glaucoma.

Primary glaucoma is a painful, progressive, and blinding disease reported in many canine breeds, characterized by intraocular pressure (IOP) elevation in the absence of antecedent intraocular disease. Clinical observations of dogs with primary glaucoma suggest that many affected eyes develop concurrent intraocular inflammation in addition to elevated IOP. In this work, we summarize the current knowledge that relates inflammation to primary glaucoma in dogs, reviewing studies focused on genetics, physiology, histopathology, bioanalysis of ocular fluids, therapeutics, and clinical outcomes of glaucomatous patients. Through disruption of the blood-aqueous and blood-retinal barriers, pigment dispersion, and biochemical changes to the aqueous humor and tear film, the pathogenesis of canine primary glaucoma appears to involve inflammatory changes to various extents and with various consequences from the front to the back of the eye. Among others, inflammation further impacts IOP by reducing aqueous humor outflow at the level of the iridocorneal angle and accelerates vision loss by promoting neuronal degeneration. As such, the vicious cycle of ocular inflammation and IOP elevation might warrant the use of anti-inflammatory medications as a core component of the treatment regime for dogs with primary glaucoma, either therapeutically (i.e., actively glaucomatous eye) or prophylactically in the yet unaffected contralateral eye.

Endocyclophotocoagulation by pars plana approach in the management of refractory glaucoma with prior phacoemulsification and Ahmed gonioimplantation in a dog.

PURPOSE: To describe successful intraocular pressure control of refractory glaucoma and vision preservation with an endocyclophotocoagulation (ECP) procedure by pars plana approach. ANIMAL STUDIED: An 8-year-old, female-spayed, mixed-breed goniodysgenic dog with glaucoma following phacoemulsification with intraocular lens placement (IOL) refractory to maximized medical therapy and Ahmed gonioimplantation in both eyes (OU). PROCEDURES: For the first glaucoma interventional surgery, bilateral goniovalve implantation was performed following cataract surgery. A goniovalve was implanted in the left eye (OS) 2-days post-phacoemulsification, and 14-days post-phacoemulsification in the right eye (OD). Short-term intraocular pressure (IOP) control was achieved. However, glaucoma recurred 41-days post-phacoemulsification OU, and an endocyclophotocoagulation by pars plana approach was performed OU to treat 300° of the ciliary body with a 23-gauge argon laser endoscope. RESULTS: Th ECP pars plana approach was successful in obtaining IOP-control and vision preservation during a 15-month follow-up period. No intraoperative complications were encountered. Short-term postoperative complications included intraocular inflammation with fibrin and postoperative ocular hypertension. Intraocular pressure-control and vision preservation were maintained at the last follow-up examination, 15 months postoperative pars plana ECP. CONCLUSION: Endocyclophotocoagulation by pars plana approach achieved long-term (>1 year) IOP-control, preserved vision, and reduced the number of anti-glaucoma medications following failure of previous Ahmed gonioimplantation for uncontrolled glaucoma. This is the first case report of an endocyclophotocoagulation procedure by a pars plana approach for uncontrolled glaucoma following Ahmed gonioplantation. With the appropriate skill set, this novel surgical approach can be considered as a surgical intervention for glaucoma in canine patients.

Histologic, immunohistochemical, and scanning electron microscopic comparison of pre-iridal monocellular and fibrovascular membranes in normal and glaucomatous canine globes.

OBJECTIVES: (i) To evaluate immunohistochemical labeling of pre-iridal monocellular and fibrovascular membranes and (ii) describe the light and scanning electron microscopic (SEM) characteristics of these membranes in glaucomatous and normal/control canine globes. MATERIALS AND METHODS: All globes were evaluated with light microscopy. Immunohistochemical labeling for CD18, Smooth muscle actin (SMA), and CD117 was completed on 40 canine globes with congenital/anterior segment dysgenesis-associated glaucoma (n = 10), primary/goniodysgenesis-associated glaucoma (n = 10), secondary glaucoma (n = 10), and normal/control globes (n = 10). SEM was completed on 10 globes: 5 with monocellular membranes, 3 with fibrovascular membranes, and 2 without a histologically detectable membrane. RESULTS: Monocellular membranes were detected in all normal/control globes with light microscopy and appeared to be morphologically very similar to those in diseased globes. CD18 labeling was detected in 9/10 monocellular membranes in normal/control globes, 15/23 monocellular, and 7/8 fibrovascular membranes in globes with glaucoma. SMA and CD117 labeling was not detected in monocellular membranes of normal/control globes. SMA was expressed in 10/23 monocellular and 7/8 fibrovascular membranes of glaucomatous globes. CD117 was expressed in 7/23 monocellular and 5/8 fibrovascular membranes of glaucomatous globes. SEM of monocellular membranes revealed a continuous sheet of mostly spindle cells and few individual round cells that extended over the anterior iris face in normal/control and all glaucomatous globes. CONCLUSION: Pre-iridal monocellular membranes are a normal component of the anterior iris surface, and CD18 immunoreactivity suggests some cells within these are of leukocytic origin. SMA and CD117 labeling of monocellular membranes in glaucomatous, but not normal/control globes, suggest metaplastic cellular change secondary to intraocular pathology related to glaucoma.

Autosomal dominant foveal hypoplasia without visible macular abnormalities and PAX6 mutations.

PURPOSE: Autosomal dominant foveal hypoplasia (FVH1) is a rare disorder associated with mutations in the PAX6 gene. As an isolated disease entity, FVH1 does not include ocular disorders such as aniridia, microphthalmia, albinism, and achromatopsia. However, it only includes isolated foveal hypoplasia and foveal hypoplasia with presenile cataract. The purpose of this report is to present our findings in four patients from two families with FVH1 without visible ophthalmic macular abnormalities. STUDY DESIGN: A review of the medical records of two families with FVH1 and genetic confirmation of mutations in the PAX6 gene. METHODS: Fundus photographs, optical coherence tomographic (OCT) and OCT angiographic (OCTA) images, and slit-lamp anterior segment findings were determined. The type of mutation of the PAX6 gene was determined. RESULTS: A 3-year-old girl (Patient 1) had signs and symptoms of an impairment in the development of vision without other retinal abnormalities OU. OCT images showed a shallow foveal pit, and OCTA showed the absence of the foveal avascular zone. The second patient (Patient 2) was a 6-year-old girl with unilateral mild cataract and shallow foveal pits OU. Similar shallow foveal pits were found in her asymptomatic mother (Patient 3) and maternal grandfather (Patient 4). Although the iris and posterior fundus were normal, all patients with FVH1 had goniodysgenesis. Genetic testing of the PAX6 gene revealed that Patient 1 had a novel heterozygous mutation (p.Asn365Lys) as a de novo mutation, and Patients 2, 3 and 4 had a novel heterozygous mutation (p.Pro20Ser). CONCLUSIONS: Heterozygous mutations in the PAX6 gene can cause FVH1 with nearly normal appearing macula. FVH1 is difficult to diagnose, but detailed observations of the foveal structure and vasculature, and detecting the presence of goniodysgenesis can be helpful in identifying patients with FVH1.

A variant in OLFML3 is associated with pectinate ligament abnormality and primary closed-angle glaucoma in Border Collies from the United Kingdom.

PURPOSE: Canine primary closed-angle glaucoma (PCAG) is a complex disease caused by multiple genetic factors. A c.590G>A variant in OLFML3 was recently reported to be a candidate for pectinate ligament abnormality (PLA) and PCAG in the Border Collie. We investigated the association of this variant with PLA and PCAG in Border Collies from the United Kingdom. METHODS: The OLFML3 variant was genotyped in 106 Border Collies comprising 90 with normal eyes (controls) and 16 with PLA (n = 11) and/or PCAG (n = 5) (cases). Genotyping was performed in an additional 103 Border Collies to estimate variant frequency within the population. To investigate the association of the variant with disease in other breeds, genotyping was performed in 337 non-Border Collies with PLA and/or PCAG. RESULTS: Of the 90 controls, 71 were homozygous for the wild-type allele, two were homozygous for the variant, and 17 were heterozygous. Of the 16 cases, three were homozygous for the wild-type allele, 11 were homozygous for the variant, and two were heterozygous. The association of the variant allele with disease was significant (P = 1.1 x 10-9 ). We estimated the frequency of this variant to be 4.4% within the United Kingdom Border Collie population, and it was not identified in clinically affected dogs of any other breed. CONCLUSIONS: This study confirms the association of the OLFML3 variant with PLA and PCAG in Border Collies from the United Kingdom. DNA testing for the variant and selective breeding can reasonably be expected to result in a reduction of PLA and PCAG prevalence in the breed.

Short-term incidence and management of glaucoma after successful surgery for stage 4 retinopathy of prematurity.

Purpose: The purpose of this study is to describe the short-term incidence, clinical features, and management of glaucoma in children after successful surgery for stage 4 retinopathy of prematurity (ROP). Methods: The retrospective study included all eyes undergoing successful surgery for stage 4 ROP with good outcomes at a tertiary eye care center between June 2014 and June 2016. Cases developing postoperative glaucoma underwent examination under anesthesia for measurement of intraocular pressures (IOP), corneal diameters, Retcam-assisted fundus imaging, and gonioscopy. Outcomes of glaucoma management were evaluated. Results: Hundred eyes of 70 babies underwent successful surgery for stage 4 ROP (with postoperative attached retina, and minimal sequelae) with minimum follow-up of 15 months. Six eyes (6%) developed postoperative glaucoma. Of these, four eyes had undergone lens-sparing vitrectomy and two were managed with lensectomy and vitrectomy (LV). Median time duration for development of glaucoma after primary vitreous surgery was 17.5 weeks. Two cases could be managed with topical IOP-lowering agents alone, whereas four required filtering surgeries (trabeculotomy with trabeculectomy and 0.04% mitomycin C [MMC] application). Average IOP decreased from 25 ± 2.36 to 12.2 ± 2.05 mmHg at 12 months from glaucoma diagnosis. Conclusion: Glaucoma is a potential adverse event following successful vitreous surgery for stage 4 ROP. A combined trabeculotomy-trabeculectomy along with MMC gives favorable outcome.

Primary angle-closure glaucoma with goniodysgenesis in a Beagle dog.

BACKGROUND: Open angle glaucoma is the only type of primary glaucoma reported in Beagles. This case report describes a primary angle-closure glaucoma in a Beagle and its diagnostic and prognostic relevance. CASE PRESENTATION: A 12-year-old, neutered male Beagle presented to the Michigan State University (MSU) Comparative Ophthalmology Service for evaluation of suspected visual impairment. Complete ophthalmic examination of the left eye (OS) revealed: blepharospasm, absent menace response, moderate episcleral congestion, mild diffuse corneal edema, mydriasis, asteroid hyalosis, decreased myelination and cupping of the optic nerve head, and mild retinal vascular attenuation. Examinations of the right eye (OD) were within normal limits. Intraocular Pressure (IOP) were 24 mmHg OD and 49 mmHg OS. Gonioscopy OD revealed a narrow iridocorneal angle with moderate pectinate ligament dysplasia characterized by broad-based pectinate ligament strands (fibrae latae) and solid sheets (laminae) throughout all 4 quadrants. DNA testing revealed that the dog did not carry the Gly661Arg ADAMTS10 mutation responsible for primary open angle glaucoma (POAG) in Beagles. The OS was medically managed with latanoprost 0.005% and dorzolamide HCl 2% /timolol malate 0.5% ophthalmic solutions for 7 months and then enucleated due to uncontrolled IOP. Histopathologic evaluation was consistent with goniodysgenesis with a broad, non-perforate, sheet-like band of uveal stroma bridging from the base of the iris to the terminal arborization of Descemet's membrane. Approximately 14 months from the initial diagnosis of glaucoma OS, OD also developed glaucoma and was enucleated. Histopathologic findings were consistent with goniodysgenesis OD. CONCLUSIONS: To our knowledge, this is the first reported case of PACG with goniodysgenesis in a Beagle supported by clinical, genetic, and histopathologic data. It highlights the importance of gonioscopy in Beagles with glaucoma. Further studies with a larger number of dogs are warranted to characterize clinical manifestations and inheritance of PACG in this breed.

Arginine to Glutamine Variant in Olfactomedin Like 3 (OLFML3) Is a Candidate for Severe Goniodysgenesis and Glaucoma in the Border Collie Dog Breed.

Goniodysgenesis is a developmental abnormality of the anterior chamber of the eye. It is generally considered to be congenital in dogs (Canis lupus familiaris), and has been associated with glaucoma and blindness. Goniodysgenesis and early-onset glaucoma initially emerged in Border Collies in Australia in the late 1990s and have subsequently been found in this breed in Europe and the USA. The objective of the present study was to determine the genetic basis of goniodysgenesis in Border Collies. Clinical diagnosis was based on results of examinations by veterinary ophthalmologists of affected and unaffected dogs from eleven different countries. Genotyping using the Illumina high density canine single nucleotide variant genotyping chip was used to identify a candidate genetic region. There was a highly significant peak of association over chromosome 17, with a p-value of 2 × 10-13 Expression profiles and evolutionary conservation of candidate genes were assessed using public databases. Whole genome sequences of three dogs with glaucoma, three severely affected by goniodysgenesis and three unaffected dogs identified a missense variant in the olfactomedin like 3 (OLFML3) gene in all six affected animals. This was homozygous for the risk allele in all nine cases with glaucoma and 12 of 14 other severely affected animals. Of 67 reportedly unaffected animals, only one was homozygous for this variant (offspring of parents both with goniodysgenesis who were also homozygous for the variant). Analysis of pedigree information was consistent with an autosomal recessive mode of inheritance for severe goniodysgenesis (potentially leading to glaucoma) in this breed. The identification of a candidate genetic region and putative causative variant will aid breeders to reduce the frequency of goniodysgenesis and the risk of glaucoma in the Border Collie population.

Goniodysgenesis-associated glaucoma in a Jindo dog / 대한수의학회지

A 10-year-old intact female Jindo dog was presented with a 1-week history of conjunctival redness and ocular discharge in the left eye. There was an absence of menace response, dazzle reflex, and direct pupillary light reflex. Slit-lamp biomicroscopy revealed corneal edema, ciliary flush, and aqueous flare. Intraocular pressure was 68 mmHg. Based on the information available, a diagnosis of glaucoma and uveitis was made. Subsequent histopathologic examination showed the glaucoma was produced by the effects of goniodysgenesis, posterior synechia, and pigment dispersion in the trabecular meshwork. This is the first report of primary glaucoma caused by goniodysgenesis in Jindo dogs.

Pectinate ligament dysplasia in the Border Collie, Hungarian Vizsla and Golden Retriever.

Pectinate ligament dysplasia (PLD) is significantly associated with primary closed angle glaucoma (PCAG) in several dog breeds. Gonioscopy screening for PLD is advised in breeds in which PLD and PCAG are particularly prevalent in order that affected dogs may be eliminated from the breeding population. The Border Collie (BC), Hungarian Vizsla (HV) and Golden Retriever (GR) breeds are currently under investigation for PLD by the British Veterinary Association/Kennel Club/International Sheep Dog Society (BVA/KC/ISDS) Eye Scheme. The authors aimed to determine the prevalence of PLD in UK populations of BC, HV and GR and to investigate possible associations between the degree of PLD and age and sex. Gonioscopy was performed in 102 BCs, 112 HVs and 230 GRs and the percentage of iridocorneal angle affected by PLD was estimated and classified as unaffected (0 per cent), mildly affected (<20 per cent), moderately affected (20-90 per cent) or severely affected (>90 per cent). Eleven of 102 (13.8 per cent) BCs, 16/112 (14.3 per cent) HVs and 60/230 (26.1 per cent) GRs were moderately or severely affected by PLD. The prevalence of PLD was significantly higher in GR than both BC and HV. There was a significant positive correlation between PLD and age in the HV and GR but not in the BC. There was no association between PLD and sex in any breed.

Chronic Glaucoma in Dogs: Relationships Between Histologic Lesions and the Gonioscopic Diagnosis of Pectinate Ligament Dysplasia.

Pectinate ligament dysplasia (PLD) is a common cause of canine glaucoma and the definitive clinical diagnosis is based on gonioscopy. Although the histologic lesions of PLD have been described, it has not been determined whether these changes are specific for PLD or if similar histologic changes can develop as a consequence of secondary glaucoma. The filtration angles of 61 enucleated canine globes with chronic glaucoma were evaluated with light microscopy by 3 examiners who were masked to the clinical history, signalment, and gonioscopic results. A histologic diagnosis of PLD versus non-PLD was determined by each examiner based on previously reported morphologic criteria and compared with the clinical gonioscopic diagnosis. Of the 61 enucleated glaucomatous eyes, 40 were clinically diagnosed with PLD. For all 3 examiners, a histologic diagnosis of PLD corresponded poorly with the clinical diagnosis of PLD (range of kappa score: 0.149-0.269; range of AUC: 0.592-0.621). There was no difference between examiners in their ability to correctly diagnose PLD histologically (P = .978). A fair degree of agreement was noted among examiners in obtaining their suspected histologic diagnosis of PLD (kappa score 0.256). No individual or sets of histologic ICA features were consistent with clinical PLD. The results indicate the histologic ICA changes proposed to be characteristic of PLD are also noted in canine globes affected with chronic secondary glaucoma. Therefore, using routine histologic evaluation, a histologic diagnosis of PLD is not possible in the face of chronic canine glaucoma.

Prevalence of pectinate ligament dysplasia and associations with age, sex and intraocular pressure in the Basset hound, Flatcoated retriever and Dandie Dinmont terrier.

BACKGROUND: The aims of this study were to: determine the prevalence of pectinate ligament dysplasia (PLD) in populations of Basset hounds (BH), Flatcoated retrievers (FCR) and Dandie Dinmont terriers (DDT) resident in the UK; investigate possible associations between the degree of PLD and age, sex and intraocular pressure (IOP) and; investigate possible associations between IOP and age and sex. Gonioscopy was performed in both eyes of 198 BH, 170 FCR and 95 DDT and the percentage of iridocorneal angle affected by PLD was estimated and classified as unaffected (0 %), mildly affected (<20 %), moderately affected (20-90 %) or severely affected (>90 %). Rebound tonometry was performed bilaterally in the majority of enrolled dogs. RESULTS: Seventy-six of 198 (38.4 %) BH, 36/170 (21.2 %) FCR and 21/95 (22.1 %) DDT were moderately or severely affected by PLD. The prevalence of PLD was significantly higher in BH than both FCR and DDT. In all breeds there was a significant positive correlation between PLD and age. In the BH only there was a significant association between PLD and sex. In the DDT only there was a weak negative correlation between PLD and IOP and a moderately strong negative correlation between IOP and age. CONCLUSIONS: PLD is prevalent and significantly associated with age in all three breeds we investigated. The linear relationship between PLD and age can be explained by the progression of PLD over time which would contribute to the high prevalence of PLD despite widespread screening.

Survey of the incidence of pectinate ligament dysplasia and glaucoma in the UK Leonberger population.

OBJECTIVE: To determine the prevalence of pectinate ligament dysplasia (PLD) in UK Leonbergers and identify cases affected by glaucoma. Also, to define the spectrum of pectinate ligament (PL) appearance in this breed and determine whether gonioscopic monitoring should be recommended. ANIMALS STUDIED: Data were compiled from 78 prospective gonioscopy examinations performed by one author (GF) and retrospective analysis of 233 UK eye scheme certificates (2009-2014). Clinical cases of glaucoma in Leonbergers diagnosed by UK veterinary ophthalmologists, where gonioscopy of the fellow eyes or histology of affected eyes had been performed, were also reviewed. PROCEDURE: In the prospective study, intraocular pressure was recorded prior to gonioscopy using a rebound tonometer. Gonioscopy was performed using a slit-lamp biomicroscope with a Koeppe goniolens. PLD was categorized according to the percentage of the iridocorneal drainage angle affected (grade 0 = <25% affected; grade 1 = 25-50% affected; grade 2 = 51-75% affected; and grade 3 = >75% affected), and the degree of narrowing of the angle was noted. RESULTS: Of 78 dogs examined prospectively, 64/78 (82%) were grade 0, 7/78 (9%) were grade 1, 3/78 (4%) were grade 2, and 4/78 (5%) were grade 3. A large phenotypic variation was observed. Spearman's rank correlation showed a positive correlation between age and severity of PLD (P < 0.0055). 52 (22%) of Leonbergers examined under the UK eye scheme 2009-2014 were affected by PLD. Five clinical cases of glaucoma were reviewed where gonioscopy had been performed and one where histology was performed. All individuals had grade 3 PLD with gonioscopy of the contralateral eye or severe goniodysgenesis with histological sections of the affected eye. CONCLUSION: This survey suggests the prevalence of PLD is sufficient to justify ongoing screening of Leonbergers.

Definition, Classification, and Pathophysiology of Canine Glaucoma.

Glaucoma is a common ocular condition in humans and dogs leading to optic nerve degeneration and irreversible blindness. Primary glaucoma is a group of spontaneous heterogeneous diseases. Multiple factors are involved in its pathogenesis and these factors vary across human ethnic groups and canine breeds, so the clinical phenotypes are numerous and their classification can be challenging and remain superficial. Aging and oxidative stress are major triggers for the manifestation of disease. Multiple, intertwined inflammatory and biochemical cascades eventually alter cellular and extracellular physiology in the optic nerve and trabecular meshwork and lead to vision loss.

Microscopic Lesions in Canine Eyes with Primary Glaucoma.

Although the clinical classification of primary glaucoma in dogs is quite simple, the phenotypes of glaucoma in most of the species are indeed multiple. Ophthalmologists can often evaluate the dynamic changes of clinical signs at different times in the course of the disease, whereas pathologists are often presented with globes that have undergone abundant therapies and are at the end stage. Therefore, an open collaboration between clinicians and pathologists can produce the most accurate interpretation in the pathology report and improve patient outcomes. This article focuses on the histomorphologic elements that characterize, and are important to, canine primary glaucomas.