Evaluation of the effects of age and pituitary pars intermedia dysfunction on corneal sensitivity in horses.

OBJECTIVE: To determine effects of age and pituitary pars intermedia dysfunction (PPID) on corneal sensitivity in horses. ANIMALS: 20 adult horses allocated into 3 groups (PPID group, old [> 15 years old] horses with PPID [n = 5]; old group, old [> 15 years old] horses without PPID [9]; and young group, young [≤ 10 years old] horses without PPID [6]). All horses with PPID had hirsutism and abnormal fat deposition or laminitis; none of the old or young horses had hirsutism, abnormal fat deposition, or laminitis. PROCEDURES: A Cochet-Bonnet aesthesiometer was used to measure the corneal touch threshold (CTT) in both eyes of each horse. The nylon monofilament was applied at a maximum length of 60 mm to the central region of the cornea and length was decreased by 5-mm increments until a consistent blink response was elicited. Tear production was assessed in all eyes via the Shirmer tear test (STT). RESULTS: Mean ± SD CTT was significantly greater for young horses (47.50 ± 4.52 mm) than for horses in the old (28.06 ± 5.72 mm) and PPID (21.5 ± 3.37 mm) groups. Old horses had significantly higher CTT values than did horses with PPID. The STT values were within the reference range for all groups and did not differ significantly among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Corneal sensitivity decreased with both age and PPID. Because decreased corneal sensitivity is associated with impaired wound healing, increasing age and PPID may increase the risk for nonhealing or recurrent corneal ulcers in horses.

Combined excision and intralesional bevacizumab for sebaceous carcinoma of the eyelid in an Amur tiger (Panthera tigris altaica).

An 18-year-old zoo-kept female Amur tiger presented with an approximately 5 mm diameter lateral canthal eyelid mass in the left eye which grossly appeared red and irregular. The mass was completely excised via lateral canthoplasty. Histopathologic evaluation was consistent with a diagnosis of sebaceous cell carcinoma, which is a potentially aggressive cutaneous neoplasm. The sebaceous carcinoma recurred within 3 months and slowly increased in size until a second surgical excision was performed 9 months following the first surgery. The second surgical excision was combined with intralesional injection of 10 mg of the antiangiogenic drug bevacizumab. Histology confirmed the diagnosis. The tiger was euthanized 16 months postoperatively for reasons unrelated to, and without recurrence of, the eyelid neoplasm. At postmortem, no gross periocular or metastatic lesions were noted, and histopathology of the lateral canthus provided no evidence of recurrence. Surgical excision combined with intralesional bevacizumab treatment induced life-long resolution of the sebaceous carcinoma. Bevacizumab treatment may be associated with the regression of periocular angiogenic proliferative conditions, including neoplasia, by inhibiting angiogenesis.