Equine ocular parasites: A review

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

Section: Discussionmentioning

confidence: 99%

Traumatic phacocele in an American Miniature Horse

Knickelbein

Stock

Carrasco

et al. 2018

“…16,39 Infectious causes may be bacterial, 16 viral (FHV-1), 45 fungal, 46 or parasitic. 8,47,48 Neoplasia arising from tissues of the lacrimal apparatus or adjacent tissues can also cause intraluminal, intramural or extramural obstruction. 34,49 A comprehensive evaluation of the lacrimal outflow system involves testing for patency (Jones test, irrigating and catheterizing), 2,15 cytology and culture, 15 and imaging studies.…”

Section: Discussionmentioning

confidence: 99%

Bilateral nasolacrimal duct atresia in a cria

Mangan

Gionfriddo

Powell

2008

A 2-month-old, male alpaca had a 1-month history of mucoid ocular discharge from the left eye. Signalment, history and clinical findings were suggestive of a congenital nasolacrimal outflow obstruction. A dacryocystorhinogram confirmed bilateral nasolacrimal duct atresia, which involved the distal half of both nasolacrimal ducts. In order to establish alternative outflow, a conjunctivomaxillosinusotomy and conjunctivorhinostomy were performed on the right and left eye, respectively. The surgical openings remain patent after 11 months, and there have been no clinical signs of nasolacrimal disease.

“…7,12 Other rare nonpigmented ocular neoplasms reported to affect the ocular surfaces in horses are MCT. [16][17][18][19] Onchocerciasis may cause conjunctival granulomas affecting mostly the lateral limbus, 20,21 and eosinophilic keratitis has been frequently reported as a cause of granulation tissue affecting the cornea and conjunctiva. 15 Solitary exuberant granulation tissue may be induced by habronemiasis at the skin of the medial canthus, but it may also involve the conjunctiva and the third eyelid.…”

Section: Differential Diagnosismentioning

confidence: 99%

Mast cell tumor invading the cornea in a horse

Halse

Pizzirani

Parry

et al. 2013

A 3-year-old Marwari mare was presented for evaluation of an irregular, reddish mass protruding from behind the right third eyelid. The mass appeared to arise at the ventral limbal area, involved the perilimbal bulbar conjunctiva and widely extended into corneal tissue. No other ocular or systemic abnormalities were detected at the time of presentation. The mass was surgically removed by lamellar keratectomy, with defocused CO(2) laser used as adjunctive therapy to treat the surgical exposed area and its surroundings. Histopathologic evaluation showed sheets of densely packed, well-differentiated neoplastic mast cells separated by fibrovascular connective tissue. Nuclear staining for Ki-67 was performed, and an average of 370 cells were positive per 1000 counted cells. Two months postoperatively, the surgical site was filled with flat fibrovascular and pigmented tissue, while the surrounding cornea was transparent with no superficial vascularization around the fibrotic scar. Thirty-two months after treatment, no recurrence of the neoplasia was reported.