Veterinary ophthalmology最新文献

Objective: To describe the clinical and histologic features of a sarcoid arising from the medial caruncle with spread to the third eyelid of a horse.

Animal studied: A 20-year-old Quarter Horse gelding.

Procedures: An incisional biopsy of the medial caruncle mass was initially performed, with histopathology suggesting a sarcoid or other spindle cell neoplasm. The mass grew rapidly following the biopsy, expanding to affect the third eyelid and adjacent superior palpebral conjunctiva. A complete third eyelid and medial caruncle excision with resection of affected palpebral conjunctiva and adjunctive cryotherapy was subsequently performed.

Results: Histopathology revealed the mass to be consistent with an equine sarcoid as evidenced by a densely cellular population of neoplastic spindle cells arranged into interlacing bundles with collagenous stroma and with hyperplastic overlying epithelium extending into the neoplasm as thin rete ridges. Over 90% of neoplastic cells showed strong hybridization signaling for bovine papillomavirus types 1 and 2, supporting an underlying viral cause consistent with the diagnosis of a sarcoid.

Conclusions: This paper describes the first reported case of an equine sarcoid arising from the medial caruncle with spread to the third eyelid, treated with third eyelid and medial caruncle excision and adjunctive cryotherapy. Veterinarians evaluating horses with masses affecting the medial caruncle and third eyelid should consider sarcoids as a differential diagnosis. Rapid growth of cutaneous sarcoids following incisional biopsy is common, and the same may be true for sarcoids that arise from the medial caruncle or third eyelid.

Objectives: To describe the surgical technique and case outcome of a double rhomboid flap for reconstruction of an eyebrow and medial upper eyelid defect after tumor excision in a dog.

Animal studied: A 2-year-old intact male Golden Retriever was evaluated for a large cutaneous tumor affecting the eyebrow and medial upper eyelid of the right eye. Cytology results were consistent with an epithelial tumor of basilar origin, most likely a trichoblastoma.

Procedures: The eyebrow and upper eyelid cutaneous mass was marginally removed under general anesthesia. The area was reconstructed with a double rhomboid flap harvested from the forehead and the glabella region.

Results: Histopathology results confirmed the diagnosis of a benign ribbon-type trichoblastoma excised with clean margins (1.2 mm). Transient lagophthalmos of the medial upper eyelid developed post-operatively, with adequate compensation via globe retraction and third eyelid elevation. On final evaluation 3 months after surgery, tumor recurrence was not observed; there was complete resolution of lagophthalmos, and the redirected fur growth pattern did not result in trichiasis.

Conclusions: The double rhomboid flap is an effective technique for surgical reconstruction of large defects in the eyebrow region of canine patients. Lagophthalmos and trichiasis are potential complications of this procedure.

Objective: To identify the elemental composition of ovine tears using particle-induced X-ray emission (PIXE).

Animals studied: Ten physically healthy female sheep.

Procedures: Tear samples were collected using Schirmer tear test strips. Tear samples were collected once daily over five consecutive days to assess reproducibility. Elemental analysis was performed with PIXE. Data were processed with GUPIX software. Median values of the elements identified were calculated and statistically analyzed with Kruskal-Wallis and post hoc Dunn's tests.

Results: The analysis demonstrated consistent elemental concentrations over the 5-day sampling period. Among the elements detected, chloride (Cl) and sodium (Na) exhibited the highest concentrations.

Conclusions: This study establishes PIXE as a valuable technique for detecting and analyzing the elemental composition of the tear film in sheep. By providing a precise method for elemental analysis in small biological samples, this approach lays the groundwork for future research exploring its reliability and sensitivity in tear analysis and potential as a biomarker for ocular and systemic health. The impact of variables including age, diet, and environmental exposure on tear film constituents should be studied, potentially extending the methodology to other species.

Purpose: To describe the use of prophylactic systemic antibiotics (PSA) in veterinary ophthalmic surgeries.

Methods: A survey of veterinarians who perform ophthalmic surgeries was distributed internationally.

Results: Responses from 296 veterinary clinicians in 30 countries were evaluated. Over 50% use PSA in 10 of 16 procedures, with over 70% using PSA for enucleations, intraocular surgery, and autologous corneal grafts; and over 40% using PSA for eyelid mass removal, prolapsed third eyelid gland repair, blepharoplasties, and superficial keratectomies. PSA use was higher in North America (NA) than in Europe (EU) in 14 out of 16 procedures, with the difference being significant in ectopic cilia removal (11%EU vs. 31%NA, p = 0.001), prolapsed third eyelid gland repair (19%EU vs. 66%NA, p < 0.001), eyelid mass removal (24%EU vs. 56%NA, p < 0.001), entropion/ectropion surgery (43%EU vs. 74%NA, p < 0.001), superficial keratectomy (26%EU vs. 68%NA, p < 0.001), autologous graft non-perforated surgery (56%EU vs. 85%NA, p < 0.001), glaucoma valve placement (81%EU vs. 96%NA, p = 0.014), and enucleation (64%EU vs. 87%NA, p < 0.001). Practitioners in referral practice (RP) had significantly higher PSA use than those in general practice (GP) for eyelid mass removal (12%GP vs. 31%RP, p = 0.026), medial canthoplasties (22%GP vs. 62%RP, p < 0.001), entropion/ectropion surgery (17%GP vs. 48%RP, p = 0.002) and rhytidectomies (46%GP vs. 87%RP, p = 0.005).

Conclusion: This survey demonstrated that a large proportion of veterinary practitioners use PSA in ophthalmic surgeries with geographical and environmental variations. Further studies to assess the incidence of surgical site infections in correlation with PSA administration are warranted, alongside the imperative for establishing comprehensive guidelines for PSA use in veterinary ophthalmic surgery.

Objective: This study aimed to determine and compare normal variations in tear production, intraocular pressure, B-mode ultrasonographic findings, and the fundus in healthy Sakız and Çine Çaparı sheep.

Methods: Sixty healthy female sheep (30 Sakız and 30 Çine Çaparı), approximately 2 years old, were included. The Schirmer-I tear test (STT-I), rebound tonometry for IOP, B-mode ocular ultrasonography, and fundus photography following mydriasis were performed.

Results: STT-I values were significantly higher in Sakız sheep compared to Çine Çaparı (18.87 ± 0.51 mm/min vs. 15.82 ± 0.61 mm/min; p < 0.001). IOP was also slightly higher in Sakız sheep (16.40 ± 0.42 mmHg vs. 15.75 ± 0.60 mmHg; p < 0.05). Significant differences were observed in some ultrasonographic parameters, such as lens length (M4: 12.8 ± 0.1 mm in Sakız vs. 13.6 ± 0.1 mm in Çine Çaparı; p < 0.01) and vitreous chamber depth (M5: 12.6 ± 0.1 mm vs. 11.8 ± 0.1 mm; p < 0.01) in mean value of both eyes. Fundus evaluation revealed breed-specific variations in tapetal color (more consistent blue-green in Sakız, variable green tones in Çine Çaparı), nontapetal pigmentation (uniformly black in Sakız vs. mixed brown and black in Çine Çaparı), and optic disk shape (predominantly oval in both). Bergmeister's papilla was more prevalent in Sakız sheep (p < 0.05), while arterial and venous distributions in the nontapetal region differed slightly between breeds without statistical significance.

Discussion: It was determined that tear production; IOP; B-mode ultrasonography findings; and normal variations of the fundus in Sakız and Çine Çaparı sheep exhibited similar distributions, albeit with minor differences.

Objective: To describe the diagnosis and treatment of a Mycobacterium avium (M. avium) infection in a cat following subdermal hyaluronic acid (HA) filler injection.

Animal studied: A five-year-old spayed female domestic shorthair cat with chronic inferior lateral entropion and chronic feline atopic skin syndrome (FASS).

Procedures: Left inferior eyelid swelling and ipsilateral mandibular lymphadenomegaly developed approximately 2 weeks following subdermal HA injection OU. Culture of a fine needle aspirate (FNA) from the affected lymph node confirmed a Mycobacterium avium subsp. hominissuis infection resistant to most conventional antibiotics including fluoroquinolones and rifampin. Clinical response to sustained clarithromycin was poor and antitubercular isoniazid was poorly tolerated. As adjunctive therapy, two sequential intralesional injections with amikacin (12.5 mg/kg total dose per treatment) were performed into the affected eyelid and lymph node. Clinical reductions in eyelid swelling and lymphadenomegaly were observed thereafter. Approximately 4 months after diagnosis, mycobacterial PCR from an FNA of the affected lymph node was negative. Antibiotic therapy was completed approximately 6 months following diagnosis. No clinical signs of infection recurrence were present at the time of writing approximately 18 months following completion of antibiotic therapy.

Conclusions: Non-tuberculous mycobacterial (NTM) infections are a known and documented complication of subdermal filler injections in human patients. This is the first described case of NTM infection associated with HA injection in a cat. Treatment success with conventional oral antibiotics may be limited, necessitating extended therapeutic courses and alternative drug delivery routes like intralesional injection.

Objective: To evaluate the occurrence and effect of fibrin formation following phacoemulsification in dogs with pseudophakia and elective aphakia.

Animal studied: A total of 193 eyes (116 dogs) undergoing phacoemulsification with or without intraocular lens implantation.

Procedures: Retrospective evaluation of medical records (2016-2020) from a private referral clinic in the United Kingdom. Signalment, pre-operative ophthalmic findings, surgical parameters, postoperative complications, and duration of follow-up were evaluated. All surgeries were performed by one surgeon using one hydrophobic acrylic lens (LOKI; Cristalens). Cross-tabulations and Fisher's exact tests were used to evaluate associations between lens implantation, fibrin formation, and visual outcome at 6 months postoperatively.

Results: Records of 193 eyes from 116 dogs were reviewed. Postoperative fibrin formation was recorded in 31/72 (43%) pseudophakic eyes and 18/121 (15%) aphakic eyes. Pseudophakic eyes were three times more likely to experience fibrin formation compared to aphakic eyes (p < 0.001). Signalment, diabetic status, presence of concurrent ocular or systemic disease, cataract stage, or development of postoperative ocular hypertension were not associated with fibrin formation (p > 0.1). At 6 months postoperatively fibrin formation was significantly associated with vision loss in pseudophakic eyes (p = 0.003), but there was no association between fibrin formation and vision loss in aphakic eyes (p = 0.6). There was no direct association between the presence of an intraocular lens and vision loss (p > 0.4).

Conclusion: In this study, pseudophakia was associated with increased occurrence of postoperative fibrin formation. Although pseudophakia was not directly associated with vision loss, fibrin formation in pseudophakic eyes was associated with a poorer visual outcome.

Objective: To validate the accuracy of the iFalcon V100 rebound tonometer in measuring intraocular pressure (IOP) in enucleated normal canine eyes.

Animals studied: Four freshly enucleated normal canine eyes tested within 12 h postmortem.

Procedures: A 1.5 mL water syringe was inserted into the vitreous chamber, and an implantable pressure sensor was inserted into the anterior chamber. IOP measurements were initiated at 5 mmHg and gradually increased to 50 mmHg by incrementally advancing the syringe plunger. Measurements were taken with the iFalcon V100 from the central cornea using the canine mode, and results were compared to those obtained from the implantable pressure sensor using linear regression analysis and Bland-Altman plots.

Results: The iFalcon V100 readings showed a strong linear correlation with the implantable sensor (r² = 0.96). Bland-Altman analysis revealed a mean bias of +0.34 mmHg, with 95% limits of agreement ranging from -4.29 to +4.98 mmHg; the overestimation was slightly in the lower pressure range. Notably, multiple attempts were required to obtain the measurements at 5-10 mmHg with the iFalcon V100.

Conclusions: The iFalcon V100 tonometer provides accurate central corneal IOP measurements in normal canine eyes within the physiological range of 5-50 mmHg, showing good agreement with direct implantable pressure sensor readings. Although the validated 5-50 mmHg range is wider than normal physiological pressures and encompasses commonly encountered pathological levels, we did not evaluate performance at 70-80 mmHg levels occurring in acute glaucoma, which is a study limitation.

Objective: To investigate the potential contribution of herpesvirus infection in the development of ocular surface disease in Asiatic black bears (Ursus thibetanus).

Animals studied: Eight captive Asiatic black bears housed at a wildlife sanctuary were examined during routine health assessments.

Methods: Fourteen cytobrush conjunctival samples were collected from eight subjects. A first bear was sampled in January 2024 with a pooled sample acquired from both eyes. Seven more animals underwent a full ophthalmic exam and conjunctival cytobrush sampling in February 2024. From those animals, one cytobrush sample per eye was acquired. DNA was extracted from the samples and tested for the presence of herpesviruses by polymerase chain reaction (PCR).

Results: All but one animal showed evidence of active or past ocular surface disease. Nested PCR on a highly conserved region in herpesvirus genomes showed the presence of herpesvirus DNA in six samples obtained from 5 individuals. Three animals tested negative. PCR products from positive cases were subjected to Sanger sequencing, and results were aligned against the NCBI nucleotide collection. Sequences returned with over 95% similarity to Ursid gammaherpesvirus 2 (UrHV-2). Five of the positively tested eyes (5/6, 83%) and two of the negatively tested eyes (2/9, 22%) showed active ocular surface disease.

Conclusions: This study represents the first report of ursid gammaherpesvirus identification in bears with keratoconjunctivitis. The findings indicate a potential association between UrHV-2 and active ocular surface disease in Asiatic black bears. Further research is warranted to clarify its role in the pathogenesis of ocular surface disease in this species.

Objective: To describe the case details of an equine corneal squamous cell carcinoma (SCC) arising from the central scar of a previous conjunctival pedicle graft.

Animal studied: An 18-year-old Thoroughbred gelding, showing a progressive increase in diameter, depth, opacity, and pigmentation of a conjunctival pedicle graft scar of the left eye, 34 months after surgery.

Procedure(s): Complete ophthalmic examination, standard histologic and immunohistochemical evaluation of an incisional biopsy to formulate a definitive diagnosis. Carbon dioxide (CO₂) laser photoablation combined with topical mitomycin C treatment.

Results: Initial examination with slit-lamp biomicroscopic examination revealed a raised, pale pink and peripherally pigmented, ovoid corneal mass (25 × 20 mm, raised 5 mm) with a smooth to cobblestone contour, paraxial ventral at 6 o'clock of the left eye. Corneal neovascularization extended from the ventral limbus to the graft scar. The remaining ophthalmic examination was unremarkable. Histologic and immunohistochemical evaluation of an incisional biopsy were supportive of a diagnosis of corneal SCC. Two rounds of CO₂ laser photoablation, 10 weeks apart, combined with topical mitomycin C chemotherapy, without surgical debulking, was successful in resolving the neoplastic lesion. The horse was euthanized 4 years later for unrelated reasons, with no evidence of SCC recurrence grossly or histologically.

Conclusion: To the authors' knowledge, this is the first report in a horse of a SCC developing at the site of corneal scarring after a conjunctival pedicle graft.