Lens-induced uveitis

Characterisation of cataracts and other ophthalmic findings in various species of captive penguins

BACKGROUND

The identification of ophthalmic diseases that affect vision and/or cause discomfort should be a priority in captive penguins to improve their overall health and quality of life.

METHODS

A routine ophthalmological examination was performed on 80 clinically normal penguins (160 eyes), and any lesions observed were recorded.

RESULTS

Ocular lesions were frequent (56% of penguins), with cataracts being the most common (48.8% of penguins). Cortical cataracts (63% of eyes) and posterior subcapsular cataracts (27.4%) were the most commonly occurring. All maturation stages were found; incipient cataracts (52.1% of eyes with cataracts) were predominant, while Morgagnian cataracts (8.2%) were the least frequent. A correlation existed between lenticular changes and increasing age. Uveitis was present in 43.8% of eyes with cataracts, and ectropion uveae was the predominant clinical sign. Other ocular findings included blepharitis (3.8% of all eyes), corneal leukoma (5.6%) and posterior lens subluxation (7.5%).

LIMITATIONS

The small number of birds of some species prevented the comparison of ophthalmic findings between species.

CONCLUSION

This study corroborates the high prevalence of ocular lesions in captive penguins. Cataracts were frequent and age related. Most cataracts were cortical, and the predominant maturation stage was incipient. Lens-induced uveitis was a common finding. Lowered intraocular pressure was related to cataract formation.

Sterile granulomatous panuveitis in dogs in the United Kingdom: A review of 33 cases

PURPOSE

To describe the clinical and histopathological features of a sterile granulomatous panuveitis syndrome in 33 dogs that underwent enucleation and ocular histopathology.

METHODS

Retrospective review of the medical records and ocular histopathology reports of 33 cases. Inclusion criteria were enucleation in conjunction with characteristic clinical and histopathological features.

RESULTS

Thirteen breeds were represented (including crossbreeds). Panuveitis was acute and fulminating, and secondary glaucoma was common (n = 27). Interval from initial presentation to enucleation was 99 days (median 33 days, range 5-605 days). The mean age at enucleation was 6.7 years. Ocular signs were initially unilateral (n = 18) or bilateral (n = 15). The disease became bilateral in 18/25 cases that initially underwent unilateral enucleation, resulting in enucleation or euthanasia in 9/18 (mean interval of 168 days). Seven out of 59 eyes had a good outcome following topical anti-inflammatory and systemic immunosuppressive therapy. None of the dogs had travel history nor relevant systemic signs from presentation to follow-up (mean 619 days, range 16-3012 days). Histopathology revealed histiocytic and lymphoplasmacytic panuveitis with pigment dispersion, and no infectious agents were identified on light microscopy.

CONCLUSION

To the authors' knowledge, this is the first report of a sterile granulomatous panuveitis syndrome in dogs in the UK. The clinical signs are severe, with rapid progression, and can result in bilateral enucleation or euthanasia in affected dogs. There does not appear to be an age or breed predisposition, however further research is necessary in this regard. Early and aggressive intervention, with both topical and systemic immunosuppressive therapy, is recommended to reduce the risk of blindness, enucleation, and euthanasia.

The relationship between corneal calcareous degeneration and various ophthalmic diseases in dogs: A retrospective study

OBJECTIVE

To investigate ocular factors that influence the development of corneal calcareous degeneration (CCD) in dogs.

ANIMALS AND PROCEDURES

The medical records of 96 eyes of dogs with CCD and 288 eyes without CCD were retrospectively reviewed. Dogs with evidence of causative systemic illness associated with CCD were excluded from the study. Logistic regression analysis was used to identify the ocular factors associated with the development of CCD. To identify the effect of phosphate-containing eyedrops on CCD, the application periods of phosphate-containing antiglaucoma eyedrops were compared between the glaucomatous eyes in the CCD and non-CCD groups.

RESULTS

Increased age, brachycephalic breed, keratoconjunctivitis sicca, advanced cataract, history of phacoemulsification, and topical corticosteroid application were significantly associated with CCD development. Glaucoma was significantly overrepresented in the non-CCD group, and the application period of phosphate-containing antiglaucoma eyedrops was significantly longer in eyes with CCD than in those without CCD.

CONCLUSIONS

Ophthalmic diseases requiring long-term management of ocular inflammation and long-term application of phosphate-containing eyedrops may contribute to the development of CCD. Glaucoma is overrepresented in dogs without CCD, which is thought to be due to the differences in predisposed age and breeds between dogs with glaucoma and CCD.

Lens-related ocular emergencies (LROE) in dogs: treatment and visual outcome after late presentation of 90 eyes

BACKGROUND

Lens-related emergencies need immediate medical intervention to reduce complications, minimize pain, and improve the chances of retaining vision. The present study aimed to demonstrate the common lens-related ocular emergencies in dogs and evaluate the short-term outcomes after the treatment of these cases. Sixty dogs (90 eyes) of different breeds were presented with unilateral (30 eyes, OD = 18, OS = 12) and bilateral (60 eyes) ocular abnormalities related to crystalline lens injury. Clinical, ultrasonographic, and laboratory examinations were achieved. Different treatment protocols were conducted after a complete ophthalmic examination and the associated clinical outcomes were evaluated.

RESULTS

Mean (± SD) age of dogs at initial evaluation was 3.65 (± 2.4) years (range, 1-12 years). Lens luxation and subluxation were diagnosed in 45 eyes (25 with anterior lens luxation, 15 with subluxation, and 5 with posterior lens luxation). Lens-induced anterior uveitis without ocular hypertension (n = 25 eyes), lens-induced uveitis with secondary glaucoma (uveitic glaucoma) (n = 15 eyes), and lens capsule disruption (n = 5 eyes) were also diagnosed. The vision was lost in all 5 eyes with posterior lens luxation and secondary glaucoma (100%), 18/25 eyes with anterior lens luxation (72%), and 5/15 eyes with lens subluxation (33.3%). Vision impairment was also identified in 10/25 eyes (40%) with unresponsive lens-induced anterior uveitis and in 5/5 eyes (100%) with traumatic rupture of the anterior lens capsule.

CONCLUSION

Crystalline lens pathology can cause a wide variety of ocular emergencies that may result in blindness. Early diagnosis and appropriate treatment are crucial for handling lens-related emergencies in dogs.

Evaluation of diabetes mellitus regulation in dogs treated with ophthalmic preparations of prednisolone acetate versus diclofenac sodium

OBJECTIVE

To evaluate and compare regulation of diabetes mellitus (DM) in dogs with cataracts and well-controlled DM that received an ophthalmic preparation of prednisolone acetate versus diclofenac sodium.

ANIMALS

22 client-owned dogs with cataracts and well-controlled DM.

PROCEDURES

A prospective, randomized, double-masked, experimental study was conducted. On days 0 and 32, serum fructosamine concentrations (SFCs), clinical scores, and body weights were determined. Dogs were assigned to receive a topically administered ophthalmic preparation of either prednisolone acetate 1% or diclofenac sodium 0.1% in each eye 4 times daily for 28 days. Data analysis was conducted with generalized linear mixed models.

RESULTS

Findings indicated no meaningful differences in SFCs, clinical scores, or body weights between the treatment groups on days 0 or 32. Clinical score on day 0 was positively associated with SFC, as indicated by the corresponding rate of change such that each 1 -unit increase in clinical score was associated with an approximately 45.6 ± 9.4 μmol/L increase in SFC. In addition, the least squares mean ± SEM SFC was higher in spayed females (539.20 ± 19.23 μmol/L; n = 12) than in castrated males (458.83 ± 23.70 μmol/L; 8) but did not substantially differ between sexually intact males (446.27 ± 49.72 μmol/L; 2) and spayed females or castrated males regardless of the treatment group assigned.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated no evidence for any differential effect on DM regulation (assessed on the basis of SFCs, clinical scores, and body weights) in dogs treated topically with an ophthalmic preparation of prednisolone versus an ophthalmic preparation of diclofenac. Additional research investigating plasma concentrations of topically applied ophthalmic glucocorticoid medications is warranted. (Am J Vet Res 2019;80:1129-1135).

Antagonising Wnt/β-catenin signalling ameliorates lens-capsulotomy-induced retinal degeneration in a mouse model of diabetes

AIMS/HYPOTHESIS

Cataract surgery in diabetic individuals worsens pre-existing retinopathy and triggers the development of diabetic ocular complications, although the underlying cellular and molecular pathophysiology remains elusive. We hypothesise that lens surgery may exaggerate pre-existing retinal inflammation in diabetes, which may accelerate neurovascular degeneration in diabetic eyes.

METHODS

Male heterozygous Ins2^Akita mice (3 months of age) and C57BL/6 J age-matched siblings received either lens capsulotomy (to mimic human cataract surgery) or corneal incision (sham surgery) in the right eye. At different days post surgery, inflammation in anterior/posterior ocular tissues was assessed by immunohistochemistry and proinflammatory gene expression in the retina by quantitative PCR (qPCR). Degenerative changes in the retina were evaluated by electroretinography, in vivo examination of retinal thickness (using spectral domain optical coherence tomography [SD-OCT]) and morphometric analysis of retinal neurons. The therapeutic benefit of neutralising Wnt/β-catenin signalling following lens capsulotomy was evaluated by intravitreal administration of monoclonal antibody against the co-receptor low-density lipoprotein receptor-related protein 6 (LRP6) (Mab2F1; 5 μg/μl in each eye).

RESULTS

Lens capsulotomy triggered the early onset of retinal neurodegeneration in Ins2^Akita mice, evidenced by abnormal scotopic a- and b-wave responses, reduced retinal thickness and degeneration of outer/inner retinal neurons. Diabetic Ins2^Akita mice also had a higher number of infiltrating ionised calcium-binding adapter molecule 1 (IBA1)/CD68⁺ cells in the anterior/posterior ocular tissues and increased retinal expression of inflammatory mediators (chemokine [C-C motif] ligand 2 [CCL2] and IL-1β). The expression of β-catenin was significantly increased in the inner nuclear layer, ganglion cells and infiltrating immune cells in Ins2^Akita mice receiving capsulotomy. Neutralisation of Wnt/β-catenin signalling by Mab2F1 ameliorated ocular inflammation and prevented capsulotomy-induced retinal degeneration in the Ins2^Akita mouse model of diabetes.

CONCLUSIONS/INTERPRETATION

Targeting the canonical Wnt/β-catenin signalling pathway may provide a novel approach for the postoperative management of diabetic individuals needing cataract surgery.

Progression and complications of canine cataracts for different stages of development and aetiologies

OBJECTIVES

To evaluate progression and complications of various cataract aetiologies and stages of development.

MATERIALS AND METHODS

In all, 447 eyes of 250 dogs with cataracts were monitored between 2012 and 2015. Breed, gender, age, vision, types of cataract, stage of cataract development (incipient, immature, mature and hypermature), complications of cataracts, ocular ultrasonography and electroretinography findings were recorded. Re-examinations were performed after a minimum of 1, 6 and 12 months. A relative rate of progression within 1 month was determined and progression was categorised as stationary, slow, moderate or rapid.

RESULTS

Overall, 44∙7% cataracts progressed and 55∙3% remained stationary. Incipient, immature, mature and hypermature cataracts progressed in 34∙1, 72∙7, 66∙7 and 44∙6% of cases, respectively. Hereditary, congenital, diabetic, contusive trauma-related, perforating trauma-related, radiation-related, senile cataracts and cataracts secondary to concurrent ocular diseases progressed in 47∙1, 66∙7, 66∙7, 50, 44∙4, 0, 29∙9 and 48∙9% of cases, respectively. Rapid progression was identified in 13∙3% of diabetic and 4∙3% of hereditary cataracts. Complications were diagnosed in 43∙5% and occurred at any stage but more frequently the further the cataract had developed. Lens-induced uveitis was the most common complication. Diabetic, traumatic, secondary and hereditary cataracts were associated with more complications than senile cataracts.

CLINICAL SIGNIFICANCE

Stage of development and cataract aetiology are associated with different rates of progression and complications.

A case of unusual persistent pupillary membrane with total anterior capsular pigmentation

A 5-year-old castrated male poodle presented with blindness. Ophthalmic examinations including slit-lamp biomicroscopy, tonometry, ultrasonography, and electroretinography were performed. The anterior lens capsule of the right eye (OD) was totally pigmented, with persistent pupillary membranes (PPMs). Ultrasonography of the same eye showed severe lens atrophy and retinal detachment. Electroretinography revealed flat a- and b-waves in OD, but normal amplitudes in the left eye (OS). No ocular defects were detected in OS except mature cataract. In this case, it was determined that hypermature cataract with PPMs caused both lens-induced-uveitis and total anterior lens capsule pigmentation. This condition needs to be differentiated from absent pupil. Notably, PPMs with total anterior lens capsular pigmentation are extremely rare in dogs.

Caracterização clínica e histopatológica de bulbos oculares de cães e gatos (2005-2015)

RESUMO: Objetivou-se realizar a caracterização clínica e histopatológica de bulbos oculares de cães e gatos, removidos cirurgicamente por indicação clínica, no período entre 2005-2015. Foram realizados 101 procedimentos de remoção do bulbo ocular, 93 enucleações (92%) e 8 exenterações (8%). Os procedimentos foram realizados em 80 cães, (79% dos casos) e em 21 gatos (21% dos casos). Os cães submetidos à intervenção cirúrgica apresentavam perfurações oculares (n=31, 39%), glaucoma (n=19, 24%), protrusão ocular (n=13, 16%), diagnósticos sugestivos de neoplasia (n=10, 12,5%) e outros (n=3, 2,97%). Dentre os gatos os diagnósticos clínicos compreenderam perfuração ocular (n=9, 49%), glaucoma (n=3, 14,2%), microftalmia (n=3, 14,2%), sugestivo de neoplasia (n=2, 9,5%), protrusão ocular (n=2, 9,5%) e outros (n=2, 9,5%). Vinte e sete amostras de bulbos oculares foram submetidas para avaliação histopatológica, sendo 23 provenientes de cães e quatro de gatos. Dentre as amostras de origem canina, sete exibiram achados histopatológicos compatíveis com glaucoma, sete perfurações oculares, seis neoplasias intraoculares, duas panoftalmites e um quadro de Phthisis bulbi. Nos bulbos oculares de gatos foram diagnosticadas duas neoplasias intraoculares, uma microftalmia e uma perfuração ocular. Constatou-se que o glaucoma secundário, as neoplasias e as perfurações oculares estão entre as principais causas de enucleação em cães, e associadas a alterações primárias como a ceratoconjuntivite seca e as uveítes. Estas afecções, diferentemente das neoplasias, podem ter êxito terapêutico mediante diagnóstico e tratamento precoces, prevenindo a cegueira e a remoção do bulbo ocular.

Genetic dissection of anterior segment dysgenesis caused by a Col4a1 mutation in mouse

Ocular anterior segment dysgenesis (ASD) describes a spectrum of clinically and genetically heterogeneous congenital disorders affecting anterior structures that often lead to impaired vision. More importantly, 50-75% of patients with ASD develop early onset and aggressive glaucoma. Although several genes have been implicated in the etiology of ASD, the underlying mechanisms remain elusive. Type IV collagen alpha 1 (COL4A1) is an extracellular matrix protein and a critical component of nearly all basement membranes. COL4A1 mutations cause multi-system disorders in patients, including ASD (congenital cataracts, Axenfeld-Rieger's anomaly, Peter's anomaly and microphthalmia) and congenital or juvenile glaucoma. Here, we use a conditional Col4a1 mutation in mice to determine the location and timing of pathogenic events underlying COL4A1-related ocular dysgenesis. Our results suggest that selective expression of the Col4a1 mutation in neural crest cells and their derivatives is not sufficient to cause ocular dysgenesis and that selective expression of the Col4a1 mutation in vascular endothelial cells can lead to mild ASD and optic nerve hypoplasia but only on a sensitized background. In contrast, lens-specific expression of the conditional Col4a1 mutant allele led to cataracts, mild ASD and optic nerve hypoplasia, and age-related intraocular pressure dysregulation and optic nerve damage. Finally, ubiquitous expression of the conditional Col4a1 mutation at distinct developmental stages suggests that pathogenesis takes place before E12.5. Our results show that the lens and possibly vasculature play important roles in Col4a1-related ASD and that the pathogenic events occur at mid-embryogenesis in mice, during early stages of ocular development.

Summary: Key pathogenic events in anterior segment dysgenesis, a congenital ocular disease with complex etiology, are recapitulated in a mouse model of Col4a1-related ASD.

Causes of Feline Uveitis: A Retrospective Study of 96 Cases at the Faculty of Veterinary Medicine Bucharest, 2012-2015

Uveitis is a common cause of blindness in feline patients as incorrectly treated or its chronicization can lead to formation of pre-iridal fibrovascular membranes, pupillary block and secondary glaucoma. The objective of this study was to investigate the causes of uveitis in cats diagnosed at the Faculty of Veterinary Medicine, Bucharest between 2012 and 2015. Medical records were reviewed and cats were considered if complete diagnostic work-up, clinical examination and imaging studies were performed. All the feline cases were serologically tested for at least two of the common infectious causes: feline leukemia virus, feline immunodeficiency virus, feline coronavirus, Toxoplasma gondii, and Bartonella spp. Ninety-six cats with a mean age of 5.42 years, ranging from 1 month to 17 years old, with a male to female ratio of 1.33/1 were diagnosed with uveitis. The European domestic cat was overrepresented at 76% followed by Birman cat (6.3%), Persian cat (4.2%), Russian blue (4.2%), Norwegian cat (2%), British Short Hair (1%), Sphynx (1%) and Cornish Rex (1%). Infectious diseases were the cause of uveitis in 31 cases (32.3%), neoplasia was diagnosed in 22 cases (22.9%), uveitis secondary to septic keratitis in 8 cases (8.3%) and uveitis secondary to direct ocular trauma in 6 cases (6.3%). Twenty-nine cats (30.2%) with a mean age of 4.33 years old were diagnosed with idiopathic or immune-mediated uveitis, less than previously reported. Aqueous flare occurred in 91 cats and keratic precipitates were noted in 39 cats. The most common infectious cause of uveitis in this study was Toxoplasma gondii (n=18). Infectious diseases remain the most common cause of feline uveitis, therefore systemic evaluation and serological investigations should be performed in all cats with uveitis, cataract and glaucoma.

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.

Anterior ocular abnormalities of captive Asian elephants (Elephas maximus indicus) in Thailand

OBJECTIVE

To survey and classify anterior ocular abnormalities in 1478 captive Asian elephants (Elephas maximus indicus) in six regions of Thailand.

METHODS

Anterior ocular examination was performed in both eyes (n = 2956) of 1478 elephants selected from the annual health check program involving 2958 animals within six regions of Thailand from January to November 2013. Lesions were described and compared between age and gender.

RESULTS

A total of 17.83% (527/2956) of examined eyes from 24.97% (369/1478) of examined elephants had anterior ocular abnormalities. The most common lesions in these examined eyes were frothy ocular discharge (5.85%), corneal edema (5.31%), and conjunctivitis (5.18%). In addition, epiphora, phthisis bulbi, other corneal abnormalities, anterior uveitis, and lens abnormalities were noted. Almost all lesions increased in frequency with age (P < 0.01).

CONCLUSIONS

Regular ophthalmic examination in elephants should be included in their annual health check program. Early detection and treatment of any ocular abnormality may avoid the development of subsequent irreversible ocular pathology.

[Cataracts in dogs--overview and guideline for decision making in treatment]

Cataract is the leading cause of impaired vision and vision loss in dogs. Because of the considerable progress in cataract surgery in recent decades, lens opacities can now be operated on with very good short-term success (90-95%), taking into account that proper patient selection is essential to maximize the probability of a successful surgical outcome. Following a description of anatomical and physiological lens characteristics, the etiology and complications of untreated cataracts are discussed. Furthermore, specific criteria for patient selection are addressed while delineating essential steps of the examination. This article aims to aid decision making in cataract therapy on the basis of diagnostic guidance and to facilitate the selection of an appropriate point of time for surgery.

Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses

In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.

Septic implantation syndrome in dogs and cats: a distinct pattern of endophthalmitis with lenticular abscess

OBJECTIVE

To summarize the clinical and pathologic findings in a group of dogs and cats with progressive clinical ocular disease, which were diagnosed with suppurative endophthalmitis and lens capsule rupture.

ANIMALS STUDIED

Twenty cats and forty-six dogs that underwent unilateral enucleation or evisceration for intractable uveitis and/or glaucoma.

PROCEDURE

Biopsy submission requests and microscopic case material were evaluated for clinical and histological features, including history of ocular trauma, duration of ocular disease, pattern of inflammation, and the presence of intralenticular microorganisms.

RESULTS

The median duration for cats and dogs was 6 and 5 weeks, respectively. A history of trauma was reported for four (20%) cats and 18 (39%) dogs. All confirmed cases of trauma-three in cats and 14 in dogs-were caused by a cat scratch. Microscopically, all cases had suppurative endophthalmitis centered on the lens, lens capsule rupture, cataract, and lenticular abscess. Infectious organisms were identified by Gram stain within the lens of 14 (70%) cats and 30 (65%) dogs. Gram-positive cocci were seen most commonly. Male cats were overrepresented as compared to females. There were no apparent gender, age or breed predilections in dogs.

CONCLUSIONS

A unique pattern of slowly progressive or delayed-onset endophthalmitis with lens capsule rupture, lenticular abscess, and frequently intralenticular microorganisms is associated with traumatic penetration of the globe and lens capsule. The term Septic Implantation Syndrome (SIS) is favored in lieu of 'phacoclastic uveitis' to avoid confusion with phacolytic uveitis and to clearly implicate the role of intralenticular microorganisms in the pathogenesis.

The lens capsule

The lens capsule is a modified basement membrane that completely surrounds the ocular lens. It is known that this extracellular matrix is important for both the structure and biomechanics of the lens in addition to providing informational cues to maintain lens cell phenotype. This review covers the development and structure of the lens capsule, lens diseases associated with mutations in extracellular matrix genes and the role of the capsule in lens function including those proposed for visual accommodation, selective permeability to infectious agents, and cell signaling.

Cataracts: when to refer

Unique stages of cataract development have been characterized in both human and animal lenses. These lens opacities impair visual acuity and are associated with inflammation. Total lens removal is typically followed by implantation of an artificial intraocular lens to restore vision. The success of this procedure is mainly dependent on the developmental stage of the cataract to be removed. This article reviews cataract development and provides the clinician with cataract referral criteria.

Canine and feline uveitis

The clinical signs of uveitis occur as a result of inflammation within the vascular coat of the eye, which causes breakdown of the blood-aqueous barrier and blood-retinal barrier. Many infectious and noninfectious causes can incite episodes of uveitis. Although a complete diagnostic evaluation is highly recommended to identify any underlying etiologic agent, many cases remain idiopathic in nature. The goals of therapy are preserving vision, minimizing pain, and halting inflammation.

Immunohistochemical identification of Encephalitozoon cuniculi in phacoclastic uveitis in four rabbits

PURPOSE

Encephalitozoon cuniculi is a microsporidium with a wide range of mammalian hosts. In rabbits it can be responsible for cataract and lens-induced uveitis (LIU). The aim of this study was to provide specific immunohistochemical demonstration and localization of E. cuniculi within the eye, in rabbits with LIU.

MATERIAL AND METHODS

Four rabbits were presented with a white mass in the eye and iris discoloration. Complete ophthalmic examinations were performed and a presumptive diagnosis of LIU was made in all cases. Initial therapy with a topical steroid, atropine and systemic enrofloxacin was instituted while serologic (IFA or ICA tests) and cytologic lab results were pending. The final outcome in all cases was enucleation. Routine histology and immunohistochemistry (ABC method) with an antiserum anti-Encephalitozoon cuniculi were performed.

RESULTS

Indirect immunofluorescence performed on one rabbit serum expressed a titer of 1 : 32; carbon immunoassay on the serum of the other three rabbits expressed a titer of 1 : 5120 in one, and a titer of 1 : 2560 in the other two cases. Histologically, an intraocular, locally extensive pyogranulomatous infiltration that partially filled the posterior chamber, encasing a wide anterior lens capsule break, was detected in all cases. Immunohistochemically, spores reacting with anti-Encephalitozoon cuniculi antiserum were present in all specimens, occasionally within macrophages and lens epithelial cells.

CONCLUSION

Detection of E. cuniculi in rabbits with phacoclastic uveitis has been investigated in the past with different methods. Based on our results, we suggest that immunohistochemistry should be regarded as a useful tool both for specific demonstration of E. cuniculi and for its localization within tissues.

Ophthalmic emergencies

Ophthalmic emergencies are common presenting complaints in an emergency room. Most ophthalmic emergencies can be treated and stabilized until an ophthalmologist can be consulted. Most ocular emergencies involve loss of vision, compromised globe integrity, or severe ocular pain. Delay in treating true emergencies may result ina blind eye or loss of an eye. This article discusses the clinical signs,diagnosis, and treatment as well as the prognosis of some of the more common ophthalmic emergencies.

EGF suppresses hydrogen peroxide induced Ca2+ influx by inhibiting L-type channel activity in cultured human corneal endothelial cells

Endogenous generated hydrogen peroxide during eye bank storage limits viability. We determined in cultured human corneal endothelial cells (HCEC) whether: (1) this oxidant induces elevations in intracellular calcium concentration [Ca2+]i; (2) epidermal growth factor (EGF) medium supplementation has a protective effect against peroxide mediated rises in [Ca2+]i. Whereas pathophysiological concentrations of H2O2 (10 mM) induced irreversible large increases in [Ca2+]i, lower concentrations (up to 1 mM) had smaller effects, which were further reduced by exposure to either 5 microM nifedipine or EGF (10 ng ml(-1)). EGF had a larger protective effect against H2O2-induced rises in [Ca2+]i than nifedipine. In addition, icilin, the agonist for the temperature sensitive transient receptor potential protein, TRPM8, had complex dose-dependent effects (i.e. 10 and 50 microM) on [Ca2+]i. At 10 microM, it reversibly elevated [Ca2+]i whereas at 50 microM an opposite effect occurred suggesting complex effects of temperature on endothelial viability. Taken together, H2O2 induces rises in [Ca2+]i that occur through increases in Ca2+ permeation along plasma membrane pathways that include L-type Ca2+ channels as well as other EGF-sensitive pathways. As EGF overcomes H2O2-induced rises in [Ca2+]i, its presence during eye bank storage could improve the outcome of corneal transplant surgery.

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.

Detection of anti-lens crystallin antibody in dogs with and without cataracts

OBJECTIVE

To determine if antilens crystallin (ALC) serum and aqueous humor antibodies were present in normal dogs and dogs with cataracts, whether antibody incidence varied with stage of cataract, and whether antibody titer had a relationship to the presence of lens-induced uveitis.

METHODS

Serum and aqueous humor samples were obtained from normal dogs and dogs with cataracts. Lens crystallin was separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and antilens crystallin antibodies were detected by Western immunoblot analysis. An indirect ELISA using crystallin protein as antigen was also used to detect antilens crystallin antibodies in serum and aqueous humor. Test groups included normal, incipient, immature, mature, hypermature and diabetic cataract.

RESULTS

SDS-PAGE identified bands with molecular weights of lens crystallin subunits. Western immunoblotting demonstrated reaction between canine serum and these protein bands. The five canine serum samples that reacted with crystallin subunits on Western blots had corresponding reactivity on the ELISA. All aqueous humor samples (30) were negative. Serum ALC antibodies were detected in 59.3% (16/27) of controls, 66.7% (16/24) of incipients, 50.0% (10/20) of immatures, 37.9% (11/29) of matures, 28.6% (6/21) of hypermatures, and 26.7% (4/15) of diabetics. Serum ALC antibodies were detected in 43.1% (47/109) of all cataract samples. There was a statistically significant negative association between the presence (P = 0.004) and maturity (P = 0.004) of cataract and presence of ALC serum antibodies. In the immature and hypermature cataract groups, there was a statistically significant negative association between ALC serum antibody titer and severity of uveitis (95% confidence interval).

CONCLUSIONS

There is a negative association between the presence (P = 0.004) and maturity (P = 0.004) of cataract and presence of ALC serum antibodies.