Ocular Manifestations of Systemic Diseases

Subconjunctival liposomal sirolimus vs. cyclosporine or tacrolimus as treatment of keratoconjunctivitis sicca in dogs: A double-blind, randomized study

PURPOSE

To compare the safety and efficacy of a 100 microgram subconjunctival injection of liposome-encapsulated sirolimus (SCJS) to cyclosporine (CsA) or tacrolimus (CsA/T) for the treatment of keratoconjunctivitis sicca (KCS) in dogs.

METHODS

Dogs with signs and symptoms of KCS were block-randomized to one of two treatment groups: Biweekly SCJS or conventional treatment (CsA/T). Schirmer tear test 1 (STT-1) scores, conjunctival hyperemia (CH) scores, corneal opacity (CO) scores, and clinical evaluation of potential side effects were recorded every 2 weeks for 14 weeks for both groups. Differences between groups were analyzed using the mixed results ANOVA and U-Mann Whitney tests (p < .05 was considered significant).

RESULTS

A total of 30 eyes were included in the study, of which 20 eyes completed follow-up. There was no statistically significant interaction between the treatment group and time on STT-1 score (p = .165), and median CH and CO scores showed no statistically significant differences between groups (p = .353 and p = .393, respectively). There were no clinically significant side effects present in any subject at any time.

CONCLUSION

In this trial, a 1 mg/mL (100 micrograms) SCJS every 2 weeks showed similar safety and efficacy profiles as daily CsA/T in dogs with KS after 14 weeks of treatment. Larger studies should be performed to further assess SCJS as an alternative treatment for KCS.

Using a smartphone-based digital fundus camera for screening of retinal and optic nerve diseases in veterinary medicine: A preliminary investigation

BACKGROUND

Ophthalmoscopy is a valuable tool in clinical practice. We report the use of a novel smartphone-based handheld device for visualisation and photo-documentation of the ocular fundus in veterinary medicine.

METHODS

Selected veterinary patients of a referral ophthalmology service were included if one or both eyes had clear ocular media, allowing for examination of the fundus. Following pharmacological mydriasis, fundic images were obtained with a handheld fundus camera (Volk VistaView). For comparison, the fundus of a subset of animals was also imaged with a veterinary-specific fundus camera (Optomed Smartscope VET2).

RESULTS

The large field of view achieved by the Volk VistaView allowed for rapid and thorough observation of the ocular fundus in animals, providing a tool to visualise and record common pathologies of the posterior segment. Captured fundic images were sometimes overexposed, with the tapetal fundus artificially appearing hyperreflective when using the Volk VistaView camera, a finding that was less frequent when activating a 'veterinary mode' that reduced the sensitivity of the camera's sensor. The Volk VistaView compared well with the Optomed Smartscope VET2.

LIMITATION

The main study limitation was the small sample size.

CONCLUSIONS

The Volk VistaView camera was easy to use and provided good-quality fundic images in veterinary patients with healthy or diseased eyes, offering a wide field of view that was ideal for screening purposes.

OPHTHALMOLOGIC INVOLVEMENT IN PATIENTS WITH HEREDITARY TRANSTHYRETIN AMYLOIDOSIS

PURPOSE

The aim of this study was to determine the ophthalmologic involvement in patients with hereditary transthyretin amyloidosis and its correlation with the mutations described in the literature.

METHODS

Cross-sectional, noninterventional study. Fifty-two eyes of 26 consecutive patients diagnosed with hereditary transthyretin amyloidosis who visited the Puerta de Hierro-Majadahonda University Hospital from September 2019 to March 2022. All patients underwent complete ophthalmologic examination and multimodal imaging. Cardiologic, neurologic, digestive, and renal examinations were also recorded.

RESULTS

Eighteen eyes of the total (34.61%) showed amyloid-related ocular involvement, vitreous amyloid deposits being the most common ocular manifestation (18/52). Statistically significant differences were found for the presence of vitreous amyloid deposits ( P < 0.01), crystalline amyloid deposits ( P < 0.05), parenchymal amyloid deposits ( P < 0.01), and vascular alterations ( P < 0.01) when comparing affected and unaffected eyes. Moreover, affected eyes showed worse best-corrected visual acuity ( P < 0.01).

CONCLUSION

Ocular manifestations are present in a substantial number of patients with ATTR that could potentially lead to devastating consequences to patients' best-corrected visual acuity and quality of life. Therefore, it is important to emphasize the importance of multidisciplinary management and ophthalmologic assessment, follow-up and surgical treatment when necessary. To the best of our knowledge, this represents the largest series in Spain of amyloidosis' ophthalmologic involvement.

A review of investigated risk factors for developing equine recurrent uveitis

Equine recurrent uveitis (ERU) is an ocular inflammatory disease that can be difficult to manage clinically. As such, it is the leading cause of bilateral blindness for horses. ERU is suspected to have a complex autoimmune etiology with both environmental and genetic risk factors contributing to onset and disease progression in some or all cases. Work in recent years has aimed at unraveling the primary triggers, such as infectious agents and inherited breed-specific risk factors, for disease onset, persistence, and progression. This review has aimed at encompassing those factors that have been associated, implicated, or substantiated as contributors to ERU, as well as identifying areas for which additional knowledge is needed to better understand risk for disease onset and progression. A greater understanding of the risk factors for ERU will enable earlier detection and better prognosis through prevention and new therapeutics.

Ocular Tuberculosis: More than 'Of Mice and Men'

Tuberculosis (TB), caused by infection with members of the Mycobacterium tuberculosis-complex, is one of the oldest known infectious disease entities, resulting in the death of millions of humans each year. It also results in a substantial degree of morbidity and mortality in animal species. Extrapulmonary TB is well recognized in humans, and the eye is one site that can be affected. Studies seeking to understand ocular TB have often relied on animal models; however, these have their limitations and may not truly reflect what happens in humans. We wish to raise awareness among ophthalmologists and vision scientists of naturally occurring cases of ocular TB in animals, namely cattle and domestic cats, and the possibilities of gaining further understanding of this presentation of TB by adopting a collaborative approach. This will hopefully improve outcomes for both human and animal patients.

Ocular tuberculosis in a calf

Background

Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation mainly in retropharyngeal, tracheobronchial, mediastinal lymph nodes and lungs of bovines. The presence of these lesions in other tissues such as the eyeball is very rare and difficult to diagnose. This study describes macroscopic and microscopic pathological findings in a calf with ocular and meningeal tuberculosis.

Case presentation

March 2019, an eight-month-old Holstein Friesian calf was identified in a dairy farm located in central Mexico with a clinical cough, anorexia, incoordination, corneal opacity and vision loss. At necropsy, pneumonia, lymphadenitis, meningitis, and granulomatous iridocyclitis were observed. The histopathological examination revealed granulomatous lesions in lung tissue, lymph nodes, meninges and eyes with the presence of acid-fast bacilli associated with Mycobacterium spp.

Conclusion

To the best of our knowledge, this is the first report that describes macroscopic and microscopic pathological findings of ocular tuberculosis in cattle. This report highlights the importance of considering bovine tuberculosis in the differential diagnosis of corneal opacity and loss of vision in cattle.

Facial nerve paralysis in 64 equids: Clinical variables, diagnosis, and outcome

BACKGROUND

Facial nerve paralysis (FNP) in equids is not well described in the veterinary literature.

OBJECTIVE

To investigate the causes of FNP and associations among clinical variables, diagnosis, and outcome.

ANIMALS

Sixty-four equids presenting with FNP between July 2000 and April 2019. Cases of postanesthetic FNP were excluded.

METHODS

Medical records were retrospectively reviewed. Variables were evaluated for associations with outcomes (diagnosis and case outcome) using logistic regression.

RESULTS

The most common cause of FNP was trauma (n = 20). Additional diagnoses included central nervous system (CNS) disease (n = 16), idiopathic (n = 12, 4 of which had adequate diagnostic investigation and were considered "true" idiopathic, and 8 of which were considered "not investigated" idiopathic), temporohyoid osteoarthropathy (n = 10), otitis media-interna (n = 3), lymphoma (n = 1), iatrogenic as a consequence of infiltration of local anesthetic (n = 1), and clostridial myositis (n = 1). Follow-up was available for 55 (86%) cases. Twenty-nine (53%) equids had full resolution of FNP, 14 (25%) were euthanized, 6 (11%) partially improved, and 6 (11%) were unchanged or worse.

CONCLUSIONS AND CLINICAL IMPORTANCE

If FNP is the consequence of CNS disease, successful treatment of the primary disease likely leads to resolution of FNP. Most cases of FNP in equids are traumatic in origin. True idiopathic cases are uncommon.

Keratitis due to microfilariae in dogs: a newly recognized disease

Parasitic agents have been associated with keratitis, but a diagnosis of parasitic keratitis has not been commonly made in domestic animals. The purpose of this study was to describe the clinical and histopathological findings in seven dogs with chronic keratitis caused by microfilariae diagnosed in Brazil. All dogs presented with superficial corneal opacities of varying degrees affecting the perilimbal and central regions of the cornea, with other opaque areas appearing as crystalline deposits and corneal vascularization. The lesions were bilateral and were associated with mild-to-moderate conjunctival hyperemia. There was no history of blepharospasm or pruritus, and no subjects presented with epithelial erosions. Corneal biopsy revealed free microfilariae in the corneal stroma, with varying degrees of inflammation and collagen fiber destruction. The microfilariae were also found in skin lesions by skin snip technique. No adult worms were found in these dogs, and no dogs were on heartworm preventative before diagnosis. Monthly doses of oral ivermectin improved ocular and dermal lesions. One dog showed complete remission with the treatment. The species of the microfilariae was not identified.

Canine keratomycosis in 11 dogs: a case series (2000-2011)

Keratomycosis is rarely reported in dogs. The purpose of this study was to review the signalment, clinical characteristics, predisposing factors, and outcome of 11 cases of canine keratomycosis. Medical records of included dogs were reviewed and follow-up information was obtained by re-examination of patients following their initial diagnosis. All 11 patients possessed predisposing factors for fungal keratitis, including an underlying endocrinopathy, pre-existing corneal disease, intraocular surgery, and/or prolonged use of either topical antibiotics or corticosteroids at the time of initial examination. Diagnostic techniques included corneal cytology demonstrating yeast or hyphae in 6 of 11 eyes, and fungal cultures with positive results in 7 of 11 eyes. Fungal organisms isolated included Cladosporium spp. (n = 1), Chrysosporium spp. (n = 1), Curvularia spp. (n = 2), Aspergillus spp. (n = 1), Penicillium spp. (n = 1), and Phialemonium spp. (n = 1). Of the 11 patients, 6 responded to medical management alone. Two resolved after a superficial keratectomy, and three were enucleated due to either endophthalmitis or progression of corneal disease. This study identified potential risk factors for developing fungal keratitis.